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Question 1
Correct
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A 40-year-old man visits his doctor for a routine check-up and is informed that his cholesterol levels are elevated. He has a significant family history of high cholesterol and genetic testing reveals that he is heterozygous for the affected allele. If he has a child with a woman who does not carry the affected allele, what is the probability that their child will inherit the condition?
Your Answer: 50%
Explanation:Familial Hypercholesterolaemia: Causes, Diagnosis, and Management
Familial hypercholesterolaemia (FH) is a genetic condition that affects approximately 1 in 500 people. It is an autosomal dominant disorder that results in high levels of LDL-cholesterol, which can lead to early cardiovascular disease if left untreated. FH is caused by mutations in the gene that encodes the LDL-receptor protein.
To diagnose FH, NICE recommends suspecting it as a possible diagnosis in adults with a total cholesterol level greater than 7.5 mmol/l and/or a personal or family history of premature coronary heart disease. For children of affected parents, testing should be arranged by age 10 if one parent is affected and by age 5 if both parents are affected.
The Simon Broome criteria are used for clinical diagnosis, which includes a total cholesterol level greater than 7.5 mmol/l and LDL-C greater than 4.9 mmol/l in adults or a total cholesterol level greater than 6.7 mmol/l and LDL-C greater than 4.0 mmol/l in children. Definite FH is diagnosed if there is tendon xanthoma in patients or first or second-degree relatives or DNA-based evidence of FH. Possible FH is diagnosed if there is a family history of myocardial infarction below age 50 years in second-degree relatives, below age 60 in first-degree relatives, or a family history of raised cholesterol levels.
Management of FH involves referral to a specialist lipid clinic and the use of high-dose statins as first-line treatment. CVD risk estimation using standard tables is not appropriate in FH as they do not accurately reflect the risk of CVD. First-degree relatives have a 50% chance of having the disorder and should be offered screening, including children who should be screened by the age of 10 years if there is one affected parent. Statins should be discontinued in women 3 months before conception due to the risk of congenital defects.
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This question is part of the following fields:
- Renal System
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Question 2
Incorrect
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A 26-year-old man has been in a car accident and his right leg has been trapped for 5 hours during transportation. During examination, his foot is found to be insensate and there is only a weakly felt dorsalis pedis pulse. Which of the following biochemical abnormalities is most likely to be present?
Your Answer: Hypocalcaemia
Correct Answer: Hyperkalaemia
Explanation:The patient is expected to suffer from compartment syndrome, which may lead to delayed diagnosis and muscle necrosis. Muscle necrosis can cause the release of potassium, and there is a high probability of renal dysfunction, which can result in elevated serum potassium levels.
Hyperkalaemia is a condition where there is an excess of potassium in the blood. The levels of potassium in the plasma are regulated by various factors such as aldosterone, insulin levels, and acid-base balance. When there is metabolic acidosis, hyperkalaemia can occur as hydrogen and potassium ions compete with each other for exchange with sodium ions across cell membranes and in the distal tubule. The ECG changes that can be seen in hyperkalaemia include tall-tented T waves, small P waves, widened QRS leading to a sinusoidal pattern, and asystole.
There are several causes of hyperkalaemia, including acute kidney injury, drugs such as potassium sparing diuretics, ACE inhibitors, angiotensin 2 receptor blockers, spironolactone, ciclosporin, and heparin, metabolic acidosis, Addison’s disease, rhabdomyolysis, and massive blood transfusion. Foods that are high in potassium include salt substitutes, bananas, oranges, kiwi fruit, avocado, spinach, and tomatoes.
It is important to note that beta-blockers can interfere with potassium transport into cells and potentially cause hyperkalaemia in renal failure patients. In contrast, beta-agonists such as Salbutamol are sometimes used as emergency treatment. Additionally, both unfractionated and low-molecular weight heparin can cause hyperkalaemia by inhibiting aldosterone secretion.
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This question is part of the following fields:
- Renal System
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Question 3
Incorrect
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A 28-year-old woman with autosomal dominant polycystic kidney disease type 1 is seeking guidance from her general practitioner regarding family planning. She recently lost her father to a subarachnoid haemorrhage, which prompted her to undergo genetic testing to confirm her diagnosis. Despite her desire to start a family with her husband, she is worried about the possibility of passing on the renal disease to her children. On which chromosome is the genetic defect for this condition most commonly found?
Your Answer: X chromosome
Correct Answer: Chromosome 16
Explanation:The patient’s autosomal dominant polycystic kidney disease type 1 is not caused by a gene on chromosomes 13, 18, or 21. It is important to note that nondisjunction of these chromosomes can lead to other genetic disorders such as Patau syndrome, Edward’s syndrome, and Down’s syndrome. The chance of the patient passing on the autosomal dominant polycystic kidney disease type 1 to her children would depend on the inheritance pattern of the specific gene mutation causing the disease.
Autosomal dominant polycystic kidney disease (ADPKD) is a commonly inherited kidney disease that affects 1 in 1,000 Caucasians. The disease is caused by mutations in two genes, PKD1 and PKD2, which produce polycystin-1 and polycystin-2 respectively. ADPKD type 1 accounts for 85% of cases, while ADPKD type 2 accounts for 15% of cases. ADPKD type 1 is caused by a mutation in the PKD1 gene on chromosome 16, while ADPKD type 2 is caused by a mutation in the PKD2 gene on chromosome 4. ADPKD type 1 tends to present with renal failure earlier than ADPKD type 2.
To screen for ADPKD in relatives of affected individuals, an abdominal ultrasound is recommended. The diagnostic criteria for ultrasound include the presence of two cysts, either unilateral or bilateral, if the individual is under 30 years old. If the individual is between 30-59 years old, two cysts in both kidneys are required for diagnosis. If the individual is over 60 years old, four cysts in both kidneys are necessary for diagnosis.
For some patients with ADPKD, tolvaptan, a vasopressin receptor 2 antagonist, may be an option to slow the progression of cyst development and renal insufficiency. However, NICE recommends tolvaptan only for adults with ADPKD who have chronic kidney disease stage 2 or 3 at the start of treatment, evidence of rapidly progressing disease, and if the company provides it with the agreed discount in the patient access scheme.
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This question is part of the following fields:
- Renal System
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Question 4
Correct
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A 42-year-old woman is undergoing left kidney donation surgery for her sister. During the procedure, which structure will be located most anteriorly at the hilum of the left kidney?
Your Answer: Left renal vein
Explanation:The anterior position is occupied by the renal veins, while the artery and ureter are located posteriorly.
Anatomy of the Renal Arteries
The renal arteries are blood vessels that supply the kidneys with oxygenated blood. They are direct branches off the aorta and enter the kidney at the hilum. The right renal artery is longer than the left renal artery. The renal vein, artery, and pelvis also enter the kidney at the hilum.
The right renal artery is related to the inferior vena cava, right renal vein, head of the pancreas, and descending part of the duodenum. On the other hand, the left renal artery is related to the left renal vein and tail of the pancreas.
In some cases, there may be accessory arteries, mainly on the left side. These arteries usually pierce the upper or lower part of the kidney instead of entering at the hilum.
Before reaching the hilum, each renal artery divides into four or five segmental branches that supply each pyramid and cortex. These segmental branches then divide within the sinus into lobar arteries. Each vessel also gives off small inferior suprarenal branches to the suprarenal gland, ureter, and surrounding tissue and muscles.
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This question is part of the following fields:
- Renal System
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Question 5
Correct
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A 39-year-old male visits his GP for a routine check-up of his high blood pressure. Despite being on a maximum dose of ramipril, amlodipine, and spironolactone, his blood pressure remains consistently at or above 160/100 mmHg. During the consultation, the patient reveals that he has been experiencing episodes of intense anxiety, sweating, palpitations, and fear about twice a week for the past six months.
What is the source of the hormone responsible for the symptoms experienced by this man?Your Answer: Adrenal medulla
Explanation:The patient’s symptoms suggest a phaeochromocytoma, which is caused by a tumor in the adrenal medulla that leads to the release of excess epinephrine. This results in refractory hypertension and severe episodes of sweating, palpitations, and anxiety.
While the pituitary gland produces hormones like thyroid-stimulating hormone and adrenocorticotropic hormone, these hormones do not directly cause the symptoms seen in this patient. Additionally, excess ACTH production is associated with Cushing’s syndrome, which does not fit the clinical picture.
The adrenal cortex has three distinct zones, each responsible for producing different hormones. The zona fasciculata produces glucocorticoids like cortisol, which can lead to Cushing’s syndrome. The zona glomerulosa produces mineralocorticoids like aldosterone, which can cause uncontrolled hypertension and electrolyte imbalances. The zona reticularis produces androgens like testosterone. However, none of these conditions match the symptoms seen in this patient.
The renin-angiotensin-aldosterone system is a complex system that regulates blood pressure and fluid balance in the body. The adrenal cortex is divided into three zones, each producing different hormones. The zona glomerulosa produces mineralocorticoids, mainly aldosterone, which helps regulate sodium and potassium levels in the body. Renin is an enzyme released by the renal juxtaglomerular cells in response to reduced renal perfusion, hyponatremia, and sympathetic nerve stimulation. It hydrolyses angiotensinogen to form angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme in the lungs. Angiotensin II has various actions, including causing vasoconstriction, stimulating thirst, and increasing proximal tubule Na+/H+ activity. It also stimulates aldosterone and ADH release, which causes retention of Na+ in exchange for K+/H+ in the distal tubule.
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This question is part of the following fields:
- Renal System
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Question 6
Incorrect
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Jill, who is in her mid-30s, has just completed a half marathon and is now dehydrated. The decreased perfusion pressure in her kidneys is detected by baroreceptors, leading to the activation of the renin-angiotensin-aldosterone system (RAAS). As a result, renin cleaves angiotensinogen to angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme (ACE). What effect does angiotensin II have on the arteriole that branches off from the renal artery and carries blood away from the glomerulus? And how does this impact Jill's glomerular filtration rate (GFR)?
Your Answer: Vasoconstriction - decreases GFR
Correct Answer: Vasoconstriction - increases GFR
Explanation:Angiotensin II causes vasoconstriction of the efferent arteriole, which increases the pressure difference between the afferent and efferent arterioles. This increase in pressure leads to an increase in filtration pressure and thus an increase in GFR. Therefore, efferent arteriole constriction increases GFR.
Reabsorption and Secretion in Renal Function
In renal function, reabsorption and secretion play important roles in maintaining homeostasis. The filtered load is the amount of a substance that is filtered by the glomerulus and is determined by the glomerular filtration rate (GFR) and the plasma concentration of the substance. The excretion rate is the amount of the substance that is eliminated in the urine and is determined by the urine flow rate and the urine concentration of the substance. Reabsorption occurs when the filtered load is greater than the excretion rate, and secretion occurs when the excretion rate is greater than the filtered load.
The reabsorption rate is the difference between the filtered load and the excretion rate, and the secretion rate is the difference between the excretion rate and the filtered load. Reabsorption and secretion can occur in different parts of the nephron, including the proximal tubule, loop of Henle, distal tubule, and collecting duct. These processes are regulated by various hormones and signaling pathways, such as aldosterone, antidiuretic hormone (ADH), and atrial natriuretic peptide (ANP).
Overall, reabsorption and secretion are important mechanisms for regulating the composition of the urine and maintaining fluid and electrolyte balance in the body. Dysfunction of these processes can lead to various renal disorders, such as diabetes insipidus, renal tubular acidosis, and Fanconi syndrome.
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This question is part of the following fields:
- Renal System
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Question 7
Incorrect
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A 35-year-old woman, gravida 3 para 1, is scheduled for a caesarian-section. During the procedure, it is crucial to avoid damaging certain structures, such as the bladder and its vascular supply, to prevent complications. What is the female bladder's venous drainage structure?
Your Answer:
Correct Answer: Vesicouterine venous plexus
Explanation:The vesicouterine venous plexus is responsible for draining the bladder in females, while the vesicoprostatic venous plexus serves the same function in males by connecting the prostatic venous plexus and vesical plexuses. The pampiniform plexus is responsible for draining the ovaries in females. It is important to note that the terms vesicorectal and vesicovaginal plexuses are not accurate anatomical structures, but rather refer to fistulas that may form between the bladder and nearby structures.
Bladder Anatomy and Innervation
The bladder is a three-sided pyramid-shaped organ located in the pelvic cavity. Its apex points towards the symphysis pubis, while the base lies anterior to the rectum or vagina. The bladder’s inferior aspect is retroperitoneal, while the superior aspect is covered by peritoneum. The trigone, the least mobile part of the bladder, contains the ureteric orifices and internal urethral orifice. The bladder’s blood supply comes from the superior and inferior vesical arteries, while venous drainage occurs through the vesicoprostatic or vesicouterine venous plexus. Lymphatic drainage occurs mainly to the external iliac and internal iliac nodes, with the obturator nodes also playing a role. The bladder is innervated by parasympathetic nerve fibers from the pelvic splanchnic nerves and sympathetic nerve fibers from L1 and L2 via the hypogastric nerve plexuses. The parasympathetic fibers cause detrusor muscle contraction, while the sympathetic fibers innervate the trigone muscle. The external urethral sphincter is under conscious control, and voiding occurs when the rate of neuronal firing to the detrusor muscle increases.
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This question is part of the following fields:
- Renal System
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Question 8
Incorrect
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A 73-year-old man comes to the clinic with complaints of increasing nocturia, a feeble urinary stream, and some weight loss in the past few months. Upon examination, an enlarged prostate with nodules is observed, and he is promptly referred for further testing, which reveals prostate cancer cells.
During the local urology cancer multidisciplinary team meeting, his case is discussed, and the team recommends a course of bicalutamide. What is the mechanism of action of this medication?Your Answer:
Correct Answer: Androgen receptor blocker
Explanation:Bicalutamide, a non-steroidal drug, is utilized in the treatment of prostate cancer as an androgen receptor blocker. It is often used in combination with other approaches such as hormonal treatment, radiotherapy, chemotherapy, and prostatectomy. Abiraterone, on the other hand, is an androgen synthesis blocker that inhibits enzymes required for production. It is typically used for hormone-relapsed metastatic prostate cancer in patients who have no or mild symptoms after anti-androgen therapy has failed. Goserelin is a gonadotrophin-releasing hormone (GnRH) agonist that ultimately downregulates sex hormones. It is initially co-prescribed with an anti-androgen due to its potential to cause an initial flare in testosterone levels. More recently, GnRH antagonists like abarelix have been used to quickly suppress testosterone without the initial flare seen with agonists. Cyproterone acetate, which exhibits progestogenic activity and steroidal and antiandrogenic effects, is another drug used in prostate cancer management but is less commonly used due to the widespread use of non-steroidal drugs like bicalutamide.
Prostate cancer management varies depending on the stage of the disease and the patient’s life expectancy and preferences. For localized prostate cancer (T1/T2), treatment options include active monitoring, watchful waiting, radical prostatectomy, and radiotherapy (external beam and brachytherapy). For localized advanced prostate cancer (T3/T4), options include hormonal therapy, radical prostatectomy, and radiotherapy. Patients may develop proctitis and are at increased risk of bladder, colon, and rectal cancer following radiotherapy for prostate cancer.
In cases of metastatic prostate cancer, reducing androgen levels is a key aim of treatment. A combination of approaches is often used, including anti-androgen therapy, synthetic GnRH agonist or antagonists, bicalutamide, cyproterone acetate, abiraterone, and bilateral orchidectomy. GnRH agonists, such as Goserelin (Zoladex), initially cause a rise in testosterone levels before falling to castration levels. To prevent a rise in testosterone, anti-androgens are often used to cover the initial therapy. GnRH antagonists, such as degarelix, are being evaluated to suppress testosterone while avoiding the flare phenomenon. Chemotherapy with docetaxel is also an option for the treatment of hormone-relapsed metastatic prostate cancer in patients who have no or mild symptoms after androgen deprivation therapy has failed, and before chemotherapy is indicated.
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This question is part of the following fields:
- Renal System
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Question 9
Incorrect
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A 26-year-old man is involved in a car crash and develops oliguria with worsening renal function. How can acute tubular necrosis be differentiated from pre-renal azotemia in this case?
Your Answer:
Correct Answer: No response to intravenous fluids
Explanation:Inability to respond to intravenous fluids is observed in acute tubular necrosis due to the damage originating from the renal system itself, rather than being caused by a reduction in volume.
Understanding the Difference between Acute Tubular Necrosis and Prerenal Uraemia
Acute kidney injury can be caused by various factors, including prerenal uraemia and acute tubular necrosis. It is important to differentiate between the two to determine the appropriate treatment. Prerenal uraemia occurs when the kidneys hold on to sodium to preserve volume, leading to decreased blood flow to the kidneys. On the other hand, acute tubular necrosis is caused by damage to the kidney tubules, which can be due to various factors such as toxins, infections, or ischemia.
To differentiate between the two, several factors can be considered. In prerenal uraemia, the urine sodium level is typically less than 20 mmol/L, while in acute tubular necrosis, it is usually greater than 40 mmol/L. The urine osmolality is also higher in prerenal uraemia, typically above 500 mOsm/kg, while in acute tubular necrosis, it is usually below 350 mOsm/kg. The fractional sodium excretion is less than 1% in prerenal uraemia, while it is greater than 1% in acute tubular necrosis. Additionally, the response to fluid challenge is typically good in prerenal uraemia, while it is poor in acute tubular necrosis.
Other factors that can help differentiate between the two include the serum urea:creatinine ratio, fractional urea excretion, urine:plasma osmolality, urine:plasma urea, specific gravity, and urine sediment. By considering these factors, healthcare professionals can accurately diagnose and treat acute kidney injury.
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This question is part of the following fields:
- Renal System
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Question 10
Incorrect
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A 75-year-old man has been admitted to the renal ward with acute kidney injury. His blood test reveals low sodium levels and high potassium levels, likely due to his current renal function. You review his medications to ensure they are not exacerbating the situation. Which medication would you contemplate discontinuing due to its link with hyperkalemia?
Your Answer:
Correct Answer: Spironolactone
Explanation:Spironolactone is a diuretic that helps to retain potassium in the body, which can lead to hyperkalaemia. It is important to discontinue its use in patients with hyperkalaemia. Furthermore, it should not be used in cases of acute renal insufficiency.
Salbutamol, on the other hand, does not cause hyperkalaemia. In fact, it can be used to reduce high levels of potassium in severe cases.
Paracetamol, when used as directed, does not have any impact on potassium levels.
Verapamil is a medication that blocks calcium channels and does not affect potassium levels.
Drugs and their Effects on Potassium Levels
Many commonly prescribed drugs have the potential to alter the levels of potassium in the bloodstream. Some drugs can decrease the amount of potassium in the blood, while others can increase it.
Drugs that can decrease serum potassium levels include thiazide and loop diuretics, as well as acetazolamide. On the other hand, drugs that can increase serum potassium levels include ACE inhibitors, angiotensin-2 receptor blockers, spironolactone, and potassium-sparing diuretics like amiloride and triamterene. Additionally, taking potassium supplements like Sando-K or Slow-K can also increase potassium levels in the blood.
It’s important to note that the above list does not include drugs used to temporarily decrease serum potassium levels for patients with hyperkalaemia, such as salbutamol or calcium resonium.
Overall, it’s crucial for healthcare providers to be aware of the potential effects of medications on potassium levels and to monitor patients accordingly.
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This question is part of the following fields:
- Renal System
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Question 11
Incorrect
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A 20-year-old male with sickle cell disease arrives at the hospital exhibiting symptoms of dehydration, infection, and acute kidney injury. What is the direct activator of the renin-angiotensin system in this case?
Your Answer:
Correct Answer: Low blood pressure
Explanation:The RAS is a hormone system that regulates plasma sodium concentration and arterial blood pressure. When plasma sodium concentration is low or renal blood flow is reduced due to low blood pressure, juxtaglomerular cells in the kidneys convert prorenin to renin, which is secreted into circulation. Renin acts on angiotensinogen to form angiotensin I, which is then converted to angiotensin II by ACE found in the lungs and epithelial cells of the kidneys. Angiotensin II is a potent vasoactive peptide that constricts arterioles, increasing arterial blood pressure and stimulating aldosterone secretion from the adrenal cortex. Aldosterone causes the kidneys to reabsorb sodium ions from tubular fluid back into the blood while excreting potassium ions in urine.
The renin-angiotensin-aldosterone system is a complex system that regulates blood pressure and fluid balance in the body. The adrenal cortex is divided into three zones, each producing different hormones. The zona glomerulosa produces mineralocorticoids, mainly aldosterone, which helps regulate sodium and potassium levels in the body. Renin is an enzyme released by the renal juxtaglomerular cells in response to reduced renal perfusion, hyponatremia, and sympathetic nerve stimulation. It hydrolyses angiotensinogen to form angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme in the lungs. Angiotensin II has various actions, including causing vasoconstriction, stimulating thirst, and increasing proximal tubule Na+/H+ activity. It also stimulates aldosterone and ADH release, which causes retention of Na+ in exchange for K+/H+ in the distal tubule.
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This question is part of the following fields:
- Renal System
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Question 12
Incorrect
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A 67-year-old man is undergoing a radical cystectomy due to T2 non-invasive bladder cancer. As a medical student shadowing the urological surgeons during the procedure, I was asked to identify the origin of the inferior and superior vesical arteries that needed to be ligated.
Your Answer:
Correct Answer: Internal iliac artery
Explanation:The internal iliac artery is the correct answer as it supplies the pelvis, including the bladder, and gives rise to the superior and inferior vesical arteries.
The direct branch of the aorta is an incorrect answer as it refers to the origin of major vessels, not specifically related to the bladder.
The external iliac artery is also an incorrect answer as it continues into the leg and does not supply the bladder.
Similarly, the inferior mesenteric artery is an incorrect answer as it supplies the hind-gut of the digestive tract and is not directly related to the bladder.
Bladder Anatomy and Innervation
The bladder is a three-sided pyramid-shaped organ located in the pelvic cavity. Its apex points towards the symphysis pubis, while the base lies anterior to the rectum or vagina. The bladder’s inferior aspect is retroperitoneal, while the superior aspect is covered by peritoneum. The trigone, the least mobile part of the bladder, contains the ureteric orifices and internal urethral orifice. The bladder’s blood supply comes from the superior and inferior vesical arteries, while venous drainage occurs through the vesicoprostatic or vesicouterine venous plexus. Lymphatic drainage occurs mainly to the external iliac and internal iliac nodes, with the obturator nodes also playing a role. The bladder is innervated by parasympathetic nerve fibers from the pelvic splanchnic nerves and sympathetic nerve fibers from L1 and L2 via the hypogastric nerve plexuses. The parasympathetic fibers cause detrusor muscle contraction, while the sympathetic fibers innervate the trigone muscle. The external urethral sphincter is under conscious control, and voiding occurs when the rate of neuronal firing to the detrusor muscle increases.
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This question is part of the following fields:
- Renal System
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Question 13
Incorrect
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A 13-year-old boy presents to his pediatrician with complaints of red-colored urine and foamy urine for a while. His parents also noticed puffiness in his face and high blood pressure for his age and sex. The boy has been complaining of hearing difficulties in class and requested to be seated in front. The doctor suspects a genetically inherited disease that is passed down from affected mothers to fifty percent of their daughters and from fathers to all their sons. What is the underlying pathology of this patient's condition?
Your Answer:
Correct Answer: Abnormal type IV collagen causing glomerular basement membrane splitting
Explanation:The patient’s symptoms suggest a combination of nephritic and nephrotic syndrome, along with hearing problems, indicating a likely diagnosis of Alport syndrome. This X-linked dominant condition is caused by a defect in type IV collagen, which forms the basement membrane. The glomerular basement membrane in Alport syndrome is characterized by thinning and thickening with areas of splitting, resulting in a basketweave appearance on electron microscopy. The condition is inherited from affected mothers to 50% of their daughters and from fathers to all their sons.
IgA nephropathy, also known as Berger disease, is characterized by IgA-based mesangial deposits on immunofluorescence and mesangial proliferation on light microscopy. Type 1 membranoproliferative glomerulonephritis presents with symptoms of both nephritic and nephrotic syndrome and is characterized by a tram-track appearance on periodic acid-Schiff stain due to mesangium proliferating into the glomerular basement membrane. Subendothelial immunocomplex deposits are seen on immunofluorescence. Poststreptococcal glomerulonephritis is a type of nephritic syndrome that occurs after a group A streptococcal infection and is characterized by enlarged and hypercellular glomeruli on light microscopy and subepithelial immunocomplexes on electron microscopy. Diffuse proliferative glomerulonephritis, often seen in SLE patients, presents with symptoms of both nephritic and nephrotic syndrome and is characterized by wire looping of capillaries on light microscopy and subendothelial immunocomplex deposits on electron microscopy. A granular appearance is found on immunofluorescence.
Alport’s syndrome is a genetic disorder that is typically inherited in an X-linked dominant pattern. It is caused by a defect in the gene responsible for producing type IV collagen, which leads to an abnormal glomerular-basement membrane (GBM). The disease is more severe in males, with females rarely developing renal failure. Symptoms usually present in childhood and may include microscopic haematuria, progressive renal failure, bilateral sensorineural deafness, lenticonus, retinitis pigmentosa, and splitting of the lamina densa seen on electron microscopy. In some cases, an Alport’s patient with a failing renal transplant may have anti-GBM antibodies, leading to a Goodpasture’s syndrome-like picture. Diagnosis can be made through molecular genetic testing, renal biopsy, or electron microscopy. In around 85% of cases, the syndrome is inherited in an X-linked dominant pattern, while 10-15% of cases are inherited in an autosomal recessive fashion, with rare autosomal dominant variants existing.
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This question is part of the following fields:
- Renal System
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Question 14
Incorrect
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A 70-year-old male was admitted to the hospital due to delirium observed in the nursing home. Upon diagnosis, he was found to have a lower respiratory tract infection which progressed to sepsis. During his stay in the ICU, he was discovered to have severe hyponatremia. The medical team has prescribed tolvaptan along with other medications.
What is the mechanism of action of tolvaptan?Your Answer:
Correct Answer: Vasopressin V2 receptor antagonist
Explanation:Tolvaptan is a drug that blocks the action of vasopressin at the V2 receptor, which reduces water absorption and increases aquaresis without sodium loss. Vasopressin is a hormone that regulates water balance in the body.
Autosomal dominant polycystic kidney disease (ADPKD) is a commonly inherited kidney disease that affects 1 in 1,000 Caucasians. The disease is caused by mutations in two genes, PKD1 and PKD2, which produce polycystin-1 and polycystin-2 respectively. ADPKD type 1 accounts for 85% of cases, while ADPKD type 2 accounts for 15% of cases. ADPKD type 1 is caused by a mutation in the PKD1 gene on chromosome 16, while ADPKD type 2 is caused by a mutation in the PKD2 gene on chromosome 4. ADPKD type 1 tends to present with renal failure earlier than ADPKD type 2.
To screen for ADPKD in relatives of affected individuals, an abdominal ultrasound is recommended. The diagnostic criteria for ultrasound include the presence of two cysts, either unilateral or bilateral, if the individual is under 30 years old. If the individual is between 30-59 years old, two cysts in both kidneys are required for diagnosis. If the individual is over 60 years old, four cysts in both kidneys are necessary for diagnosis.
For some patients with ADPKD, tolvaptan, a vasopressin receptor 2 antagonist, may be an option to slow the progression of cyst development and renal insufficiency. However, NICE recommends tolvaptan only for adults with ADPKD who have chronic kidney disease stage 2 or 3 at the start of treatment, evidence of rapidly progressing disease, and if the company provides it with the agreed discount in the patient access scheme.
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This question is part of the following fields:
- Renal System
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Question 15
Incorrect
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A 65-year-old male is recovering from a community acquired pneumonia in hospital. He has undergone some blood tests that morning which indicate that he is experiencing AKI stage 2. The results are as follows:
- Na+ 133 mmol/L (135 - 145)
- K+ 3.6 mmol/L (3.5 - 5.0)
- Bicarbonate 23 mmol/L (22 - 29)
- Urea 6.0 mmol/L (2.0 - 7.0)
- Creatinine 150 µmol/L (55 - 120)
Over the past 12 hours, he has only produced 360ml of urine. In light of this, what is the most crucial medication to discontinue from his drug chart?Your Answer:
Correct Answer: Diclofenac
Explanation:In cases of acute kidney injury (AKI), it is crucial to discontinue the use of nonsteroidal anti-inflammatory drugs (NSAIDs) as they can potentially worsen renal function. Ibuprofen, being an NSAID, falls under this category.
NSAIDs work by reducing the production of prostaglandins, which are responsible for vasodilation. Inhibiting their production can lead to vasoconstriction of the afferent arteriole, resulting in decreased renal perfusion and a decline in estimated glomerular filtration rate (eGFR).
To prevent further damage to the kidneys, all nephrotoxic medications, including NSAIDs, ACE inhibitors, gentamicin, vancomycin, and metformin (which should be discussed with the diabetic team), should be discontinued in cases of AKI.
Acute kidney injury (AKI) is a condition where there is a reduction in renal function following an insult to the kidneys. It was previously known as acute renal failure and can result in long-term impaired kidney function or even death. AKI can be caused by prerenal, intrinsic, or postrenal factors. Patients with chronic kidney disease, other organ failure/chronic disease, a history of AKI, or who have used drugs with nephrotoxic potential are at an increased risk of developing AKI. To prevent AKI, patients at risk may be given IV fluids or have certain medications temporarily stopped.
The kidneys are responsible for maintaining fluid balance and homeostasis, so a reduced urine output or fluid overload may indicate AKI. Symptoms may not be present in early stages, but as renal failure progresses, patients may experience arrhythmias, pulmonary and peripheral edema, or features of uraemia. Blood tests such as urea and electrolytes can be used to detect AKI, and urinalysis and imaging may also be necessary.
Management of AKI is largely supportive, with careful fluid balance and medication review. Loop diuretics and low-dose dopamine are not recommended, but hyperkalaemia needs prompt treatment to avoid life-threatening arrhythmias. Renal replacement therapy may be necessary in severe cases. Patients with suspected AKI secondary to urinary obstruction require prompt review by a urologist, and specialist input from a nephrologist is required for cases where the cause is unknown or the AKI is severe.
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This question is part of the following fields:
- Renal System
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Question 16
Incorrect
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John, 72-years-old, visits his GP with concerns of frequent urination accompanied by a burning sensation and interrupted flow of urine that have persisted for approximately 5 months. During a digital rectal examination, an enlarged, nodular prostate is detected and his PSA levels are significantly elevated. Following a biopsy, he is diagnosed with prostate cancer. Which zone of the prostate is commonly affected by prostate cancer and experiences enlargement?
Your Answer:
Correct Answer: Peripheral zone
Explanation:Prostate cancer is a common condition with up to 30,000 men diagnosed and 9,000 deaths per year in the UK. Diagnosis involves PSA measurement, digital rectal examination, and imaging for staging. Pathology shows 95% adenocarcinoma, often multifocal and graded using the Gleason system. Treatment options include watchful waiting, radiotherapy, surgery, and hormonal therapy. Active surveillance is recommended for low-risk men, with treatment decisions made based on disease progression and individual factors.
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This question is part of the following fields:
- Renal System
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Question 17
Incorrect
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A 47-year-old man is found to have a tumor in his right adrenal gland. The surgical plan is to remove it through an open anterior approach. What tool or technique will be most beneficial during the procedure?
Your Answer:
Correct Answer: Mobilisation of the colonic hepatic flexure
Explanation:In open adrenal surgery from an anterior approach, it is customary to perform mobilization of the hepatic flexure and right colon. However, mobilization of the liver is typically not necessary.
Adrenal Gland Anatomy
The adrenal glands are located superomedially to the upper pole of each kidney. The right adrenal gland is posteriorly related to the diaphragm, inferiorly related to the kidney, medially related to the vena cava, and anteriorly related to the hepatorenal pouch and bare area of the liver. On the other hand, the left adrenal gland is postero-medially related to the crus of the diaphragm, inferiorly related to the pancreas and splenic vessels, and anteriorly related to the lesser sac and stomach.
The arterial supply of the adrenal glands is through the superior adrenal arteries from the inferior phrenic artery, middle adrenal arteries from the aorta, and inferior adrenal arteries from the renal arteries. The right adrenal gland drains via one central vein directly into the inferior vena cava, while the left adrenal gland drains via one central vein into the left renal vein.
In summary, the adrenal glands are small but important endocrine glands located above the kidneys. They have a unique blood supply and drainage system, and their location and relationships with other organs in the body are crucial for their proper functioning.
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This question is part of the following fields:
- Renal System
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Question 18
Incorrect
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An 71-year-old man arrives at the emergency department complaining of severe back pain that started 2 hours ago. The pain is radiating from his flank to his groin and comes and goes in waves. He had a kidney stone 2 months ago. A CT scan reveals a hyperdense calculus in his left ureter. His serum calcium level is 2.1 mmol/L (normal range: 2.2-2.6) and his urine calcium level is 9.2 mmol/24hours (normal range: 2.5-7.5). What medication is the most appropriate to reduce the risk of further renal stones?
Your Answer:
Correct Answer: Bendroflumethiazide
Explanation:Thiazide diuretics, specifically bendroflumethiazide, can be used to decrease calcium excretion and stone formation in patients with hypercalciuria and renal stones. The patient’s urinary calcium levels indicate hypercalciuria, which can be managed with thiazide diuretics. Bumetanide and furosemide, both loop diuretics, are not effective in managing hypercalciuria and renal stones. Denosumab, an antibody used for hypercalcaemia associated with malignancy, is not used in the management of renal stones.
Management and Prevention of Renal Stones
Renal stones, also known as kidney stones, can cause severe pain and discomfort. The British Association of Urological Surgeons (BAUS) has published guidelines on the management of acute ureteric/renal colic. Initial management includes the use of NSAIDs as the analgesia of choice for renal colic, with caution taken when prescribing certain NSAIDs due to increased risk of cardiovascular events. Alpha-adrenergic blockers are no longer routinely recommended, but may be beneficial for patients amenable to conservative management. Initial investigations include urine dipstick and culture, serum creatinine and electrolytes, FBC/CRP, and calcium/urate levels. Non-contrast CT KUB is now recommended as the first-line imaging for all patients, with ultrasound having a limited role.
Most renal stones measuring less than 5 mm in maximum diameter will pass spontaneously within 4 weeks. However, more intensive and urgent treatment is indicated in the presence of ureteric obstruction, renal developmental abnormality, and previous renal transplant. Treatment options include lithotripsy, nephrolithotomy, ureteroscopy, and open surgery. Shockwave lithotripsy involves generating a shock wave externally to the patient, while ureteroscopy involves passing a ureteroscope retrograde through the ureter and into the renal pelvis. Percutaneous nephrolithotomy involves gaining access to the renal collecting system and performing intra corporeal lithotripsy or stone fragmentation. The preferred treatment option depends on the size and complexity of the stone.
Prevention of renal stones involves lifestyle modifications such as high fluid intake, low animal protein and salt diet, and thiazide diuretics to increase distal tubular calcium resorption. Calcium stones may also be due to hypercalciuria, which can be managed with thiazide diuretics. Oxalate stones can be managed with cholestyramine and pyridoxine, while uric acid stones can be managed with allopurinol and urinary alkalinization with oral bicarbonate.
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This question is part of the following fields:
- Renal System
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Question 19
Incorrect
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A 32-year-old construction worker becomes dehydrated after spending the day working under the sun.
What can be inferred about this person?Your Answer:
Correct Answer: Most of the ultrafiltrated water in the nephron to be reabsorbed in the proximal tubule
Explanation:The majority of filtered water is absorbed in the proximal tubule, while the highest amount of sodium reabsorption occurs in this area due to the Na+/K+ ATPase mechanism. This results in the movement of fluid from the proximal tubules to peritubular capillaries.
After a strenuous run, the individual is likely to be slightly dehydrated, leading to an increased activation of the renin-angiotensin-aldosterone system. This would cause an increase in aldosterone release from the zona glomerulosa. Additionally, vasopressin (also known as ADH) would be elevated to enhance water reabsorption in the collecting duct.
Renal cortical blood flow is higher than medullary blood flow, as tubular cells are more susceptible to ischaemia.
The Loop of Henle and its Role in Renal Physiology
The Loop of Henle is a crucial component of the renal system, located in the juxtamedullary nephrons and running deep into the medulla. Approximately 60 litres of water containing 9000 mmol sodium enters the descending limb of the loop of Henle in 24 hours. The osmolarity of fluid changes and is greatest at the tip of the papilla. The thin ascending limb is impermeable to water, but highly permeable to sodium and chloride ions. This loss means that at the beginning of the thick ascending limb the fluid is hypo osmotic compared with adjacent interstitial fluid. In the thick ascending limb, the reabsorption of sodium and chloride ions occurs by both facilitated and passive diffusion pathways. The loops of Henle are co-located with vasa recta, which have similar solute compositions to the surrounding extracellular fluid, preventing the diffusion and subsequent removal of this hypertonic fluid. The energy-dependent reabsorption of sodium and chloride in the thick ascending limb helps to maintain this osmotic gradient. Overall, the Loop of Henle plays a crucial role in regulating the concentration of solutes in the renal system.
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This question is part of the following fields:
- Renal System
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Question 20
Incorrect
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A 56-year-old man with a history of alcohol excess and type 2 diabetes presents to the emergency department in an intoxicated state. He takes metformin and his recent HbA1c was 44 mmol/mol. On arrival, his blood sugar is 5.1 mmol/L and he frequently needs to urinate. The examination is unremarkable except for his intoxicated state. His blood test shows a creatinine level of 66 µmol/L (55 - 120). What is causing the patient's polyuria?
Your Answer:
Correct Answer: ADH suppression in the posterior pituitary gland
Explanation:Alcohol bingeing can result in the suppression of ADH in the posterior pituitary gland, leading to polyuria.
Polyuria, or excessive urination, can be caused by a variety of factors. A recent review in the BMJ categorizes these causes by their frequency of occurrence. The most common causes of polyuria include the use of diuretics, caffeine, and alcohol, as well as diabetes mellitus, lithium, and heart failure. Less common causes include hypercalcaemia and hyperthyroidism, while rare causes include chronic renal failure, primary polydipsia, and hypokalaemia. The least common cause of polyuria is diabetes insipidus, which occurs in less than 1 in 10,000 cases. It is important to note that while these frequencies may not align with exam questions, understanding the potential causes of polyuria can aid in diagnosis and treatment.
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This question is part of the following fields:
- Renal System
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Question 21
Incorrect
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A 70-year-old man visits the endocrinology clinic complaining of muscle cramps, headaches, and lethargy. During the clinic visit, his vital signs are heart rate 80/min, respiratory rate 18/min, blood pressure 150/100 mmHg, temperature 36.5ºC, and saturations 99% on air. Recent blood tests reveal:
- Na+ 147 mmol/L (135 - 145)
- K+ 3.2 mmol/L (3.5 - 5.0)
- Bicarbonate 28 mmol/L (22 - 29)
- Urea 6.0 mmol/L (2.0 - 7.0)
- Creatinine 95 µmol/L (55 - 120)
An adrenal mass is detected on his abdominal CT scan. Can you identify where the hormone responsible for his symptoms is produced?Your Answer:
Correct Answer: Zona glomerulosa
Explanation:The correct answer is the zona glomerulosa. This patient is experiencing symptoms of hyperaldosteronism, which is likely caused by an adenoma in the zona glomerulosa, as indicated by the mass seen on CT scan (also known as Conn’s syndrome). The adenoma stimulates the production of aldosterone, leading to hypertension and hypokalemia.
The adrenal medulla produces catecholamines, such as adrenaline and noradrenaline.
The juxtaglomerular apparatus is located in the kidney and produces renin in response to decreased renal perfusion.
The zona fasciculata is the middle layer of the adrenal cortex and is responsible for producing glucocorticoids, such as cortisol.
The zona reticularis is the innermost layer of the adrenal cortex and produces androgens, such as dehydroepiandrosterone (DHEA).
The renin-angiotensin-aldosterone system is a complex system that regulates blood pressure and fluid balance in the body. The adrenal cortex is divided into three zones, each producing different hormones. The zona glomerulosa produces mineralocorticoids, mainly aldosterone, which helps regulate sodium and potassium levels in the body. Renin is an enzyme released by the renal juxtaglomerular cells in response to reduced renal perfusion, hyponatremia, and sympathetic nerve stimulation. It hydrolyses angiotensinogen to form angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme in the lungs. Angiotensin II has various actions, including causing vasoconstriction, stimulating thirst, and increasing proximal tubule Na+/H+ activity. It also stimulates aldosterone and ADH release, which causes retention of Na+ in exchange for K+/H+ in the distal tubule.
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This question is part of the following fields:
- Renal System
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Question 22
Incorrect
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A 70-year-old woman with bilateral pitting edema that extends above the knee is prescribed furosemide. What is the mechanism of action of this medication?
Your Answer:
Correct Answer: Inhibits the sodium-potassium-chloride cotransporter
Explanation:Furosemide is a type of loop diuretic that works by inhibiting the cotransporter in the thick ascending loop of Henle, which prevents the reabsorption of sodium, chloride, and potassium. This results in significant diuresis.
Mannitol is an osmotic diuretic that is commonly used to reduce intracranial pressure after a head injury. Spironolactone is an aldosterone antagonist, while bendroflumethiazide acts on the sodium-chloride transporter in the distal convoluted tubule. Acetazolamide is a carbonic anhydrase inhibitor that is often prescribed for the treatment of acute angle closure glaucoma.
Diuretic drugs are classified into three major categories based on the location where they inhibit sodium reabsorption. Loop diuretics act on the thick ascending loop of Henle, thiazide diuretics on the distal tubule and connecting segment, and potassium sparing diuretics on the aldosterone-sensitive principal cells in the cortical collecting tubule. Sodium is reabsorbed in the kidney through Na+/K+ ATPase pumps located on the basolateral membrane, which return reabsorbed sodium to the circulation and maintain low intracellular sodium levels. This ensures a constant concentration gradient.
The physiological effects of commonly used diuretics vary based on their site of action. furosemide, a loop diuretic, inhibits the Na+/K+/2Cl- carrier in the ascending limb of the loop of Henle and can result in up to 25% of filtered sodium being excreted. Thiazide diuretics, which act on the distal tubule and connecting segment, inhibit the Na+Cl- carrier and typically result in between 3 and 5% of filtered sodium being excreted. Finally, spironolactone, a potassium sparing diuretic, inhibits the Na+/K+ ATPase pump in the cortical collecting tubule and typically results in between 1 and 2% of filtered sodium being excreted.
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This question is part of the following fields:
- Renal System
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Question 23
Incorrect
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During an on-call shift, you are reviewing the blood results of a 72-year-old man. He was admitted with abdominal pain and has a working diagnosis of acute cholecystitis. He is currently on intravenous cefuroxime and metronidazole, awaiting further surgical review. His blood results are as follows:
Hb 115 g/L : (115 - 160)
Platelets 320* 109/L (150 - 400)
WBC 18.2* 109/L (4.0 - 11.0)
Na+ 136 mmol/L (135 - 145)
K+ 6.9 mmol/L (3.5 - 5.0)
Urea 14.8 mmol/L (2.0 - 7.0)
Creatinine 225 µmol/L (55 - 120)
CRP 118 mg/L (< 5)
Bilirubin 15 µmol/L (3 - 17)
ALP 410 u/L (30 - 100)
ALT 32 u/L (3 - 40)
Albumin 39 g/L (35 - 50)
You initiate treatment with intravenous calcium gluconate, salbutamol nebulisers, and furosemide. On discussion with the renal team, they recommend additional treatment with calcium resonium.
What is the mechanism of action of calcium resonium?Your Answer:
Correct Answer: It increases potassium excretion by preventing enteral absorption
Explanation:The correct answer is that calcium resonium increases potassium excretion by preventing enteral absorption. This is achieved through cation ion exchange, where the resin exchanges potassium for Ca++ in the body. The onset of action is usually 2-12 hours when taken orally and longer when administered rectally. It is important to note that calcium resonium does not act on the Na+/K+-ATPase pump, which is the mechanism of action for drugs like digoxin. Additionally, it does not shift potassium from the extracellular to the intracellular compartment, which is the mechanism of action for salbutamol nebulisers. Lastly, calcium resonium does not stabilise the cardiac membrane, which is the action of calcium gluconate.
Managing Hyperkalaemia: A Step-by-Step Guide
Hyperkalaemia is a serious condition that can lead to life-threatening arrhythmias if left untreated. To manage hyperkalaemia, it is important to address any underlying factors that may be contributing to the condition, such as acute kidney injury, and to stop any aggravating drugs, such as ACE inhibitors. Treatment can be categorised based on the severity of the hyperkalaemia, which is classified as mild, moderate, or severe based on the patient’s potassium levels.
ECG changes are also important in determining the appropriate management for hyperkalaemia. Peaked or ‘tall-tented’ T waves, loss of P waves, broad QRS complexes, and a sinusoidal wave pattern are all associated with hyperkalaemia and should be evaluated in all patients with new hyperkalaemia.
The principles of treatment modalities for hyperkalaemia include stabilising the cardiac membrane, shifting potassium from extracellular to intracellular fluid compartments, and removing potassium from the body. IV calcium gluconate is used to stabilise the myocardium, while insulin/dextrose infusion and nebulised salbutamol can be used to shift potassium from the extracellular to intracellular fluid compartments. Calcium resonium, loop diuretics, and dialysis can be used to remove potassium from the body.
In practical terms, all patients with severe hyperkalaemia or ECG changes should receive emergency treatment, including IV calcium gluconate to stabilise the myocardium and insulin/dextrose infusion to shift potassium from the extracellular to intracellular fluid compartments. Other treatments, such as nebulised salbutamol, may also be used to temporarily lower serum potassium levels. Further management may involve stopping exacerbating drugs, treating any underlying causes, and lowering total body potassium through the use of calcium resonium, loop diuretics, or dialysis.
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This question is part of the following fields:
- Renal System
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Question 24
Incorrect
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A 47-year-old man is under the care of an ophthalmologist for open angle glaucoma. He visits his GP to express his worries about the medication prescribed after reading online information. What is the medication that the ophthalmologist has prescribed, which can function as a diuretic by acting on the proximal convoluted tubule of the kidney?
Your Answer:
Correct Answer: Acetazolamide (carbonic anhydrase inhibitor)
Explanation:Diuretic drugs are classified into three major categories based on the location where they inhibit sodium reabsorption. Loop diuretics act on the thick ascending loop of Henle, thiazide diuretics on the distal tubule and connecting segment, and potassium sparing diuretics on the aldosterone-sensitive principal cells in the cortical collecting tubule. Sodium is reabsorbed in the kidney through Na+/K+ ATPase pumps located on the basolateral membrane, which return reabsorbed sodium to the circulation and maintain low intracellular sodium levels. This ensures a constant concentration gradient.
The physiological effects of commonly used diuretics vary based on their site of action. furosemide, a loop diuretic, inhibits the Na+/K+/2Cl- carrier in the ascending limb of the loop of Henle and can result in up to 25% of filtered sodium being excreted. Thiazide diuretics, which act on the distal tubule and connecting segment, inhibit the Na+Cl- carrier and typically result in between 3 and 5% of filtered sodium being excreted. Finally, spironolactone, a potassium sparing diuretic, inhibits the Na+/K+ ATPase pump in the cortical collecting tubule and typically results in between 1 and 2% of filtered sodium being excreted.
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This question is part of the following fields:
- Renal System
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Question 25
Incorrect
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A patient in his 60s is recovering on the ward following a kidney transplant. Six days after the operation he still requires dialysis, however he is not in any pain and the graft was a very good HLA match from a deceased donor. His renal function test results are shown below.
Hb 93 g/L
Plts. 232 x 109
Na+ 151 mmol/l
K+ 5.7 mmol/l
Urea 7.9 mmol/l
eGFR 27 mL/min/1.73m2
What could be the probable reason for his abnormal renal function tests?Your Answer:
Correct Answer: Delayed graft function
Explanation:Delayed graft function (DGF) is a common form of acute renal failure that can occur following a kidney transplant. In this case, delayed graft function is the most likely explanation for the patient’s symptoms. It is not uncommon for patients to require continued dialysis after a transplant, especially if the donor was deceased. However, if the need for dialysis persists beyond 7 days, further investigations may be necessary. Other potential causes, such as Addison’s disease or hyper-acute graft rejection, are less likely based on the patient’s history and the characteristics of the transplant.
Complications Following Renal Transplant
Renal transplantation is a common procedure, but it is not without its complications. The most common technical complications are related to the ureteric anastomosis, and the warm ischaemic time is also important as graft survival is directly related to this. Long warm ischaemic times increase the risk of acute tubular necrosis, which can occur in all types of renal transplantation. Organ rejection is also a possibility at any phase following the transplantation process.
There are three types of organ rejection: hyperacute, acute, and chronic. Hyperacute rejection occurs immediately due to the presence of preformed antibodies, such as ABO incompatibility. Acute rejection occurs during the first six months and is usually T cell mediated, with tissue infiltrates and vascular lesions. Chronic rejection occurs after the first six months and is characterized by vascular changes, with myointimal proliferation leading to organ ischemia.
In addition to immunological complications, there are also technical complications that can arise following renal transplant. These include renal artery thrombosis, renal artery stenosis, renal vein thrombosis, urine leaks, and lymphocele. Each of these complications presents with specific symptoms and requires different treatments, ranging from immediate surgery to angioplasty or drainage techniques.
Overall, while renal transplantation can be a life-saving procedure, it is important to be aware of the potential complications and to monitor patients closely for any signs of rejection or technical issues.
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This question is part of the following fields:
- Renal System
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Question 26
Incorrect
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A 25-year-old patient arrives at the emergency department with a head injury after a night of heavy drinking. All his vital signs are normal, and his pupils react to light equally. A CT scan of his head shows no abnormalities. He reports feeling thirsty and experiencing excessive urination.
What is causing his polyuria?Your Answer:
Correct Answer: Inhibition of posterior pituitary gland
Explanation:Excessive alcohol consumption can result in the suppression of ADH in the posterior pituitary gland, which can lead to polyuria.
Normally, dehydration causes an increase in plasma osmolality, which triggers the release of vasopressin (antidiuretic hormone) from the posterior pituitary gland. This hormone increases the insertion of aquaporin 2 channels in the distal convoluted tubules and collecting duct in the kidney, which in turn increases water reabsorption. This leads to a decrease in plasma osmolality and a reduction in the volume of urine produced, i.e., antidiuretic.
However, alcohol inhibits this mechanism, resulting in polyuria and dehydration. Polyuria can then cause thirst, i.e., polydipsia.
It is important to note that the sugars in alcohol do not typically cause osmotic diuresis unless there is an underlying condition such as diabetes and hyperglycemia.
Polyuria, or excessive urination, can be caused by a variety of factors. A recent review in the BMJ categorizes these causes by their frequency of occurrence. The most common causes of polyuria include the use of diuretics, caffeine, and alcohol, as well as diabetes mellitus, lithium, and heart failure. Less common causes include hypercalcaemia and hyperthyroidism, while rare causes include chronic renal failure, primary polydipsia, and hypokalaemia. The least common cause of polyuria is diabetes insipidus, which occurs in less than 1 in 10,000 cases. It is important to note that while these frequencies may not align with exam questions, understanding the potential causes of polyuria can aid in diagnosis and treatment.
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This question is part of the following fields:
- Renal System
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Question 27
Incorrect
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A 28-year-old man presents to his GP complaining of abdominal pain and diarrhea. The GP suspects gastritis but decides to perform a urine test to rule out a UTI. The results of the urine dipstick test are as follows:
Blood: Negative mmol/l
Protein: Negative mmol/l
Leukocytes: ++ mmol/l
Nitrites: Negative mmol/l
What could be the reason for the abnormal urine dipstick result?Your Answer:
Correct Answer: Chlamydia
Explanation:Sterile pyuria can be caused by urethritis as a result of a sexually transmitted disease such as chlamydia.
Understanding Sterile Pyuria and Its Causes
Sterile pyuria is a medical condition characterized by the presence of white blood cells in the urine without any bacterial growth. It is a common finding in patients with urinary tract infections (UTIs) but can also be caused by other underlying conditions.
Some of the common causes of sterile pyuria include partially treated UTIs, urethritis (such as Chlamydia), renal tuberculosis, renal stones, appendicitis, bladder or renal cell cancer, adult polycystic kidney disease, and analgesic nephropathy.
It is important to identify the underlying cause of sterile pyuria to ensure proper treatment and prevent complications. Patients with this condition should seek medical attention and undergo further evaluation to determine the root cause of their symptoms. Early detection and treatment can help prevent further damage to the urinary tract and improve overall health outcomes.
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This question is part of the following fields:
- Renal System
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Question 28
Incorrect
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A 65-year-old woman is admitted to the ICU with a multidrug-resistant urinary tract infection. She has a medical history of type 2 diabetes, hypertension, and a previous cerebrovascular accident. After three days, she experiences an altered sensorium and her urine output has been 100 ml over the past 12 hours. Her creatinine level has increased from 1 mg/dl to almost 5 mg/dl, and her blood pressure is currently 180/100 mmHg. The patient is currently taking amikacin, insulin, atorvastatin, atenolol, ramipril, and clopidogrel.
Which medication, other than ramipril, should be discontinued for this patient?Your Answer:
Correct Answer: Amikacin
Explanation:The patient’s symptoms suggest that they may be experiencing acute kidney injury (AKI) as a result of a severe urinary tract infection and potential sepsis. It is important to note that ACE inhibitors such as ramipril should not be used in cases of AKI, and aminoglycosides like amikacin should also be discontinued. Beta-blockers like atenolol, on the other hand, are generally safe to use in AKI patients and may be preferred over ACE inhibitors and ARBs as antihypertensives. While statins like atorvastatin are generally safe in AKI, they can rarely cause rhabdomyolysis, which can worsen renal function and lead to renal failure. Therefore, patients who experience muscle pain should be evaluated further to rule out the possibility of rhabdomyolysis.
Acute kidney injury (AKI) is a condition where there is a reduction in renal function following an insult to the kidneys. It was previously known as acute renal failure and can result in long-term impaired kidney function or even death. AKI can be caused by prerenal, intrinsic, or postrenal factors. Patients with chronic kidney disease, other organ failure/chronic disease, a history of AKI, or who have used drugs with nephrotoxic potential are at an increased risk of developing AKI. To prevent AKI, patients at risk may be given IV fluids or have certain medications temporarily stopped.
The kidneys are responsible for maintaining fluid balance and homeostasis, so a reduced urine output or fluid overload may indicate AKI. Symptoms may not be present in early stages, but as renal failure progresses, patients may experience arrhythmias, pulmonary and peripheral edema, or features of uraemia. Blood tests such as urea and electrolytes can be used to detect AKI, and urinalysis and imaging may also be necessary.
Management of AKI is largely supportive, with careful fluid balance and medication review. Loop diuretics and low-dose dopamine are not recommended, but hyperkalaemia needs prompt treatment to avoid life-threatening arrhythmias. Renal replacement therapy may be necessary in severe cases. Patients with suspected AKI secondary to urinary obstruction require prompt review by a urologist, and specialist input from a nephrologist is required for cases where the cause is unknown or the AKI is severe.
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This question is part of the following fields:
- Renal System
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Question 29
Incorrect
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A 65-year-old man is undergoing assessment for polycythemia and has no history of smoking. What type of solid-organ cancer could be a possible cause?
Your Answer:
Correct Answer: Renal cell carcinoma
Explanation:Renal cell carcinoma has the potential to secrete various hormones such as erythropoietin, PTHrP, renin, or ACTH. This can lead to secondary polycythemia, hypercalcemia, or other related conditions. On the other hand, small cell lung cancer can cause ectopic secretion of ACTH or ADH, but not erythropoietin. Pituitary tumors, on the other hand, may secrete prolactin.
Renal cell cancer, also known as hypernephroma, is a primary renal neoplasm that accounts for 85% of cases. It originates from the proximal renal tubular epithelium and is commonly associated with smoking and conditions such as von Hippel-Lindau syndrome and tuberous sclerosis. The clear cell subtype is the most prevalent, comprising 75-85% of tumors.
Renal cell cancer is more common in middle-aged men and may present with classical symptoms such as haematuria, loin pain, and an abdominal mass. Other features include endocrine effects, such as the secretion of erythropoietin, parathyroid hormone-related protein, renin, and ACTH. Metastases are present in 25% of cases at presentation, and paraneoplastic syndromes such as Stauffer syndrome may also occur.
The T category criteria for renal cell cancer are based on tumor size and extent of invasion. Management options include partial or total nephrectomy, depending on the tumor size and extent of disease. Patients with a T1 tumor are typically offered a partial nephrectomy, while alpha-interferon and interleukin-2 may be used to reduce tumor size and treat metastases. Receptor tyrosine kinase inhibitors such as sorafenib and sunitinib have shown superior efficacy compared to interferon-alpha.
In summary, renal cell cancer is a common primary renal neoplasm that is associated with various risk factors and may present with classical symptoms and endocrine effects. Management options depend on the extent of disease and may include surgery and targeted therapies.
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This question is part of the following fields:
- Renal System
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Question 30
Incorrect
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A 69-year-old man is admitted to the medical assessment unit with reduced urine output and nausea. He has a complex medical history, including heart failure, hypercholesterolemia, hypertension, type 1 diabetes mellitus, and hypothyroidism. Among his regular medications are bisoprolol, furosemide, simvastatin, insulin, and levothyroxine. The medical team suspects that he is currently experiencing an acute kidney injury.
Which of his usual medications should be discontinued?Your Answer:
Correct Answer: Furosemide
Explanation:In cases of AKI, it is advisable to discontinue the use of diuretics as they may aggravate renal function. Loop diuretics like Furosemide should be stopped. Additionally, drugs that have the potential to harm the kidneys, such as aminoglycoside antibiotics (e.g. gentamicin), non-steroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors (e.g. ramipril), angiotensin II receptor antagonists (e.g. losartan), and diuretics, should also be discontinued.
Fortunately, the remaining drugs are generally safe to continue as they are not typically considered nephrotoxic. Insulin, a peptide hormone drug used in treating type 1 and type 2 diabetes mellitus, is cleared from the body through enzymatic breakdown in the liver and kidneys and is not usually harmful to the kidneys.
Acute kidney injury (AKI) is a condition where there is a reduction in renal function following an insult to the kidneys. It was previously known as acute renal failure and can result in long-term impaired kidney function or even death. AKI can be caused by prerenal, intrinsic, or postrenal factors. Patients with chronic kidney disease, other organ failure/chronic disease, a history of AKI, or who have used drugs with nephrotoxic potential are at an increased risk of developing AKI. To prevent AKI, patients at risk may be given IV fluids or have certain medications temporarily stopped.
The kidneys are responsible for maintaining fluid balance and homeostasis, so a reduced urine output or fluid overload may indicate AKI. Symptoms may not be present in early stages, but as renal failure progresses, patients may experience arrhythmias, pulmonary and peripheral edema, or features of uraemia. Blood tests such as urea and electrolytes can be used to detect AKI, and urinalysis and imaging may also be necessary.
Management of AKI is largely supportive, with careful fluid balance and medication review. Loop diuretics and low-dose dopamine are not recommended, but hyperkalaemia needs prompt treatment to avoid life-threatening arrhythmias. Renal replacement therapy may be necessary in severe cases. Patients with suspected AKI secondary to urinary obstruction require prompt review by a urologist, and specialist input from a nephrologist is required for cases where the cause is unknown or the AKI is severe.
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This question is part of the following fields:
- Renal System
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