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Question 1
Correct
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A female infant is being assessed for recurrent urinary tract infections. An abdominal ultrasound scan displays bilateral hydronephrosis, a thickened bladder wall with thickened smooth muscle trabeculations. Voiding cystourethrogram (VCUG) reveals reflux.
What is the most probable diagnosis, which is commonly seen in this scenario?Your Answer: Posterior urethral valves
Explanation:Posterior urethral valves are a common cause of bladder outlet obstruction in male infants, which can be detected before birth through the presence of hydronephrosis. On the other hand, epispadias and hypospadias are conditions where the urethra opens on the dorsal and ventral surface of the penis, respectively, but they are not typically associated with bladder outlet obstruction. Urethral atresia, a rare condition where the urethra is absent, can also cause bladder outlet obstruction.
Posterior urethral valves are a frequent cause of blockage in the lower urinary tract in males. They can be detected during prenatal ultrasound screenings. Due to the high pressure required for bladder emptying during fetal development, the child may experience damage to the renal parenchyma, resulting in renal impairment in 70% of boys upon diagnosis. Treatment involves the use of a bladder catheter, and endoscopic valvotomy is the preferred definitive treatment. Cystoscopic and renal follow-up is necessary.
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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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Sarah, who is in her 50s, has recently undergone a kidney transplant. A few hours after the surgery, she begins to feel extremely sick, experiencing a fever of 39°C and overall discomfort. She also reports pain at the site of the transplant, and the medical staff have noted a significant decrease in her urine output. The consultant suggests that this could be due to pre-existing antibodies, given the timing of the symptoms.
What is the most probable diagnosis in Sarah's case?Your Answer: Post-transplant lymphocele
Correct Answer: Hyperacute transplant rejection
Explanation:Based on the symptoms and timeframe, it is likely that the patient is experiencing hyperacute transplant rejection. This type of rejection is classified as a type II hypersensitivity reaction, which occurs when pre-existing IgG or IgM antibodies attack HLA or ABO antigens. This autoimmune response causes thrombosis in the vascular supply to the transplanted organ, leading to ischemia and necrosis. Unfortunately, the only treatment option is to remove the graft.
Acute graft failure, on the other hand, typically occurs over several months and is often caused by HLA mismatch. This condition can be treated with immunosuppressants and steroids.
Chronic graft failure is characterized by antibody- and cell-mediated mechanisms that lead to fibrosis of the transplanted organ over time. This process usually takes more than six months to develop.
Post-transplant acute tubular necrosis is another possible complication that can cause reduced urine output and muddy brown casts on urinalysis. However, it does not typically present with the hyperacute symptoms described above.
Lymphocele is a common post-transplant complication that is usually asymptomatic but can cause a mass and compress the ureter if it becomes large enough. It can be drained through percutaneous or intraperitoneal methods.
The HLA system, also known as the major histocompatibility complex (MHC), is located on chromosome 6 and is responsible for human leucocyte antigens. Class 1 antigens include A, B, and C, while class 2 antigens include DP, DQ, and DR. When matching for a renal transplant, the importance of HLA antigens is ranked as DR > B > A.
Graft survival rates for renal transplants are high, with a 90% survival rate at one year and a 60% survival rate at ten years for cadaveric transplants. Living-donor transplants have even higher survival rates, with a 95% survival rate at one year and a 70% survival rate at ten years. However, postoperative problems can occur, such as acute tubular necrosis of the graft, vascular thrombosis, urine leakage, and urinary tract infections.
Hyperacute rejection can occur within minutes to hours after a transplant and is caused by pre-existing antibodies against ABO or HLA antigens. This type of rejection is an example of a type II hypersensitivity reaction and leads to widespread thrombosis of graft vessels, resulting in ischemia and necrosis of the transplanted organ. Unfortunately, there is no treatment available for hyperacute rejection, and the graft must be removed.
Acute graft failure, which occurs within six months of a transplant, is usually due to mismatched HLA and is caused by cell-mediated cytotoxic T cells. This type of failure is usually asymptomatic and is detected by a rising creatinine, pyuria, and proteinuria. Other causes of acute graft failure include cytomegalovirus infection, but it may be reversible with steroids and immunosuppressants.
Chronic graft failure, which occurs after six months of a transplant, is caused by both antibody and cell-mediated mechanisms that lead to fibrosis of the transplanted kidney, known as chronic allograft nephropathy. The recurrence of the original renal disease, such as MCGN, IgA, or FSGS, can also cause chronic graft failure.
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This question is part of the following fields:
- Renal System
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Question 3
Correct
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A 22-year-old man is referred to a cardiologist by his family physician due to consistently high cholesterol levels in his blood tests. During the assessment, the cardiologist observes yellowish skin nodules around the patient's Achilles tendon and white outer regions of the iris. The cardiologist informs the patient that he has inherited the condition from his biological parents and that there is a 50% chance of passing it on to his offspring, regardless of his partner's status. The patient reports a paternal uncle who died at 31 due to a heart-related condition. The cardiologist recommends treatment to manage cholesterol levels and prevent future cardiovascular events. What is the most likely underlying pathology in this patient's condition?
Your Answer: Defective low-density lipoprotein receptors
Explanation:The patient’s symptoms and signs suggest that they may have one of the familial dyslipidemias, likely familial hypercholesterolemia. This is supported by the presence of Achilles tendon xanthomas and corneal arcus in a relatively young patient, as well as the cardiologist’s statement that there is a 50% chance of inheritance if the mother is normal, indicating an autosomal dominant inheritance pattern. Familial hypercholesterolemia is caused by defective or absent LDL receptors.
Other familial dyslipidemias include dysbetalipoproteinemia, which is caused by defective apolipoprotein E and has an autosomal recessive inheritance pattern, hypertriglyceridemia, which is caused by overproduction of VLDL and has an autosomal dominant inheritance pattern, and hyperchylomicronemia, which is caused by deficiency of lipoprotein lipase or apolipoprotein C-II and has an autosomal recessive inheritance pattern. Hyperchylomicronemia is not associated with a higher risk of atherosclerosis, unlike the other forms of familial dyslipidemia.
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 4
Correct
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An 82-year-old man is admitted to the neurology ward and complains to the nurse that he is experiencing difficulty urinating. He expresses significant distress and reports feeling pain due to urinary retention. To alleviate his discomfort, the nurse places him in a warm bath, which finally allows him to relax his sphincter and urinate.
What nervous structure was responsible for maintaining detrusor capacity and causing the patient's difficulty in urinating?Your Answer: Hypogastric plexuses
Explanation:The superior and inferior hypogastric plexuses are responsible for providing sympathetic innervation to the bladder, which helps maintain detrusor capacity by preventing parasympathetic contraction of 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 5
Correct
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A 63-year-old man is seen in the oncology clinic. He is being monitored for known breast cancer. His recent mammogram and biopsy suggest an increased disease burden. It is decided to initiate Tamoxifen therapy while awaiting a mastectomy.
What is the mechanism of action of this new medication?Your Answer: Androgen receptor blocker
Explanation:Bicalutamide is a medication that blocks the androgen receptor and is commonly used to treat prostate cancer. Abiraterone, on the other hand, is an androgen synthesis inhibitor that is prescribed to patients with metastatic prostate cancer who have not responded to androgen deprivation therapy. GnRH agonists like goserelin can also be used to treat prostate cancer by reducing the release of gonadotrophins and inhibiting androgen production. While cyproterone acetate is a steroidal anti-androgen, it is not as commonly used as non-steroidal anti-androgens 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 6
Incorrect
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A 6-year-old boy is referred to the child assessment unit for recurrent urinary tract infections. He is started on antibiotics and sent home with advice on supportive care.
Upon his return a week later, his renal function tests have worsened and an ultrasound scan reveals hydronephrosis in his kidneys, ureters, and bladder. The diagnosis is acute pyelonephritis and further investigations are ordered to determine the underlying cause. A voiding cystourethrogram (VCUG) confirms the diagnosis of posterior urethral valves (PUV).
The child and parents are informed of the diagnosis and inquire about treatment options. What is the definitive treatment for PUV?Your Answer: Permanent catheter
Correct Answer: Endoscopic valvotomy
Explanation:The preferred and most effective treatment for a child with posterior urethral valves (PUV) is endoscopic valvotomy. While bilateral cutaneous ureterostomies can be used for urinary drainage, they are not considered the definitive treatment for PUV. Bladder augmentation may be necessary if the bladder cannot hold enough urine or if bladder pressures remain high despite medication and catheterization. However, permanent antibiotic prophylaxis and catheterization are not recommended.
Posterior urethral valves are a frequent cause of blockage in the lower urinary tract in males. They can be detected during prenatal ultrasound screenings. Due to the high pressure required for bladder emptying during fetal development, the child may experience damage to the renal parenchyma, resulting in renal impairment in 70% of boys upon diagnosis. Treatment involves the use of a bladder catheter, and endoscopic valvotomy is the preferred definitive treatment. Cystoscopic and renal follow-up is necessary.
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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 65-year-old woman with a past medical history of heart failure presents to the emergency department complaining of palpitations. During the history-taking process, it is revealed that she takes ramipril and paracetamol regularly, but her cardiologist prescribed a new medication a week ago. She is unsure of the name of the medication but describes it as a 'water pill'. An electrocardiogram is performed, which shows abnormal tall T waves. What is the name of the 'water pill' that was recently prescribed?
Your Answer: Furosemide (loop diuretic)
Correct Answer: Spironolactone (potassium-sparing diuretic)
Explanation:Spironolactone is a medication that works as an aldosterone antagonist in the cortical collecting duct. It is used to treat various conditions such as ascites, hypertension, heart failure, nephrotic syndrome, and Conn’s syndrome. In patients with cirrhosis, spironolactone is often prescribed in relatively large doses of 100 or 200 mg to counteract secondary hyperaldosteronism. It is also used as a NICE ‘step 4’ treatment for hypertension. In addition, spironolactone has been shown to reduce all-cause mortality in patients with NYHA III + IV heart failure who are already taking an ACE inhibitor, according to the RALES study.
However, spironolactone can cause adverse effects such as hyperkalaemia and gynaecomastia, although the latter is less common with eplerenone. It is important to monitor potassium levels in patients taking spironolactone to prevent hyperkalaemia, which can lead to serious complications such as cardiac arrhythmias. Overall, spironolactone is a useful medication for treating various conditions, but its potential adverse effects should be carefully considered and monitored.
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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 27-year-old man is involved in a car crash resulting in a fracture of his right tibia. He undergoes fasciotomies and an external fixator is applied. Within 48 hours, his serum creatinine levels increase and his urine is analyzed, revealing the presence of muddy brown casts. What is the probable underlying diagnosis?
Your Answer: Thin basement membrane disease
Correct Answer: Acute tubular necrosis
Explanation:It is probable that the patient suffered from compartment syndrome due to a tibial fracture and subsequent fasciotomies, which can result in myoglobinuria. The combination of deteriorating kidney function and the presence of muddy brown casts in the urine strongly indicate acute tubular necrosis. Acute interstitial nephritis is typically caused by drug toxicity and does not typically lead to the presence of muddy brown casts in the urine.
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 9
Correct
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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: 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 10
Incorrect
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A 72-year-old male patient with heart failure experiences significant physical activity limitations. He is prescribed a medication that targets the collecting duct of the kidney, but is cautioned about potential breast tissue enlargement. What electrolyte imbalance could result from this medication?
Your Answer: No electrolyte abnormalities
Correct Answer: Hyperkalaemia
Explanation:Hyperkalaemia may be caused by Spironolactone
Spironolactone is recognized for its potential to cause breast tissue growth as a side effect. As an aldosterone receptor antagonist, it hinders the elimination of potassium, making it a potassium-sparing diuretic.
Spironolactone is a medication that works as an aldosterone antagonist in the cortical collecting duct. It is used to treat various conditions such as ascites, hypertension, heart failure, nephrotic syndrome, and Conn’s syndrome. In patients with cirrhosis, spironolactone is often prescribed in relatively large doses of 100 or 200 mg to counteract secondary hyperaldosteronism. It is also used as a NICE ‘step 4’ treatment for hypertension. In addition, spironolactone has been shown to reduce all-cause mortality in patients with NYHA III + IV heart failure who are already taking an ACE inhibitor, according to the RALES study.
However, spironolactone can cause adverse effects such as hyperkalaemia and gynaecomastia, although the latter is less common with eplerenone. It is important to monitor potassium levels in patients taking spironolactone to prevent hyperkalaemia, which can lead to serious complications such as cardiac arrhythmias. Overall, spironolactone is a useful medication for treating various conditions, but its potential adverse effects should be carefully considered and monitored.
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This question is part of the following fields:
- Renal System
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