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Question 1
Incorrect
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Which one of the following statements are not typically true in hypokalaemia?
Your Answer: It may be associated with aciduria
Correct Answer: It often accompanies acidosis
Explanation:Potassium depletion can occur through the gastrointestinal tract or the kidneys. Chronic vomiting is less likely to cause potassium loss than diarrhea because gastric secretions contain less potassium than lower GI secretions. However, if vomiting leads to metabolic alkalosis, renal potassium wasting may occur as the body excretes potassium instead of hydrogen ions. Conversely, potassium depletion can result in acidic urine.
Hypokalemia is often associated with metabolic alkalosis due to two factors. Firstly, common causes of metabolic alkalosis, such as vomiting and diuretics, directly cause loss of H+ and K+ (via aldosterone), leading to hypokalemia. Secondly, hypokalemia can cause metabolic alkalosis through three mechanisms. Firstly, it causes a transcellular shift where K+ leaves and H+ enters cells, raising extracellular pH. Secondly, it causes an intracellular acidosis in the proximal tubules, promoting ammonium production and excretion. Thirdly, in the presence of hypokalemia, hydrogen secretion in the proximal and distal tubules increases, leading to further reabsorption of HCO3-. Overall, this results in an increase in net acid excretion.
Understanding Hypokalaemia and its Causes
Hypokalaemia is a condition characterized by low levels of potassium in the blood. Potassium and hydrogen ions are competitors, and as potassium levels decrease, more hydrogen ions enter the cells. Hypokalaemia can occur with either alkalosis or acidosis. In cases of alkalosis, hypokalaemia may be caused by vomiting, thiazide and loop diuretics, Cushing’s syndrome, or Conn’s syndrome. On the other hand, hypokalaemia with acidosis may be caused by diarrhoea, renal tubular acidosis, acetazolamide, or partially treated diabetic ketoacidosis.
It is important to note that magnesium deficiency may also cause hypokalaemia. In such cases, normalizing potassium levels may be difficult until the magnesium deficiency has been corrected. Understanding the causes of hypokalaemia can help in its diagnosis and treatment.
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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 woman presents with symptoms of agalactorrhoea, amenorrhoea, intolerance to cold, constipation, and weight loss six months after giving birth. She experienced postpartum bleeding during delivery and has now been diagnosed with hypopituitarism. What could be the possible reason for this condition?
Your Answer:
Correct Answer: Sheehan's syndrome
Explanation:Sheehan’s syndrome is a condition that arises from pituitary ischaemia, which is caused by blood loss during or after childbirth. The syndrome is characterized by symptoms that indicate global hypopituitarism, including agalactorrhoea (lack of prolactin), amenorrhoea (lack of FSH and LH), cold intolerance and constipation (lack of thyroid hormones), and weight loss (lack of steroid hormones).
Malignancy is an uncommon cause of hypopituitarism.
While pituitary adenoma is a frequent cause of hypopituitarism, it is unlikely to be the cause of this patient’s symptoms, given that they occurred after childbirth. Pituitary adenoma may also present with symptoms related to mass effect, such as headache and bilateral hemianopia.
Understanding Hypopituitarism: Causes, Symptoms, and Management
Hypopituitarism is a medical condition that occurs when the pituitary gland fails to produce enough hormones. This can be caused by various factors such as compression of the gland by non-secretory pituitary macroadenoma, pituitary apoplexy, Sheehan’s syndrome, hypothalamic tumors, trauma, iatrogenic irradiation, and infiltrative diseases like hemochromatosis and sarcoidosis. The symptoms of hypopituitarism depend on which hormones are deficient. For instance, low ACTH can cause tiredness and postural hypotension, while low FSH/LH can lead to amenorrhea, infertility, and loss of libido. Low TSH can cause constipation and feeling cold, while low GH can result in short stature if it occurs during childhood. Low prolactin can cause problems with lactation.
To diagnose hypopituitarism, hormone profile testing and imaging are usually conducted. Treatment involves addressing the underlying cause, such as surgical removal of pituitary macroadenoma, and replacement of deficient hormones. It is important to manage hypopituitarism promptly to prevent complications and improve the patient’s quality of life.
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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 16-year-old girl arrives at the emergency department with a sudden worsening of her asthma symptoms. The medical team administers nebulizers containing salbutamol and ipratropium bromide, along with IV steroids. Salbutamol is known to be a β2 receptor agonist. What metabolic impact should be monitored in response to this medication?
Your Answer:
Correct Answer: Hypokalaemia
Explanation:Salbutamol reduces serum potassium levels by acting as a β2 agonist when administered through nebulisation or intravenous routes.
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 4
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 5
Incorrect
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A 55-year-old man has recently been prescribed atorvastatin due to a high QRISK score and elevated cholesterol levels. He has a medical history of hypertension and takes amlodipine for it. However, he has returned to the GP after three weeks of taking atorvastatin, complaining of intolerable leg cramps. The GP is worried about the potential cardiac complications if the patient's cholesterol levels are not controlled. What alternative treatment options can be considered as second-line therapy?
Your Answer:
Correct Answer: Ezetimibe
Explanation:Ezetimibe is the recommended second line treatment for patients who cannot tolerate the side effects of statins, according to NICE guidelines. Atorvastatin is the preferred statin due to its lower incidence of side effects compared to simvastatin. Switching to simvastatin may not be beneficial and its dose would be limited to 20mg due to the concurrent use of amlodipine, which weakly inhibits the CYP enzyme responsible for simvastatin metabolism, effectively doubling the dose. Other options are not recommended by NICE as alternatives to statin therapy.
The Use of Ezetimibe in Treating Hypercholesterolaemia
Ezetimibe is a medication that helps lower cholesterol levels by inhibiting cholesterol receptors in the small intestine, reducing cholesterol absorption. In 2016, the National Institute for Health and Care Excellence (NICE) released guidelines on the use of ezetimibe in treating primary heterozygous-familial and non-familial hypercholesterolaemia.
For individuals who cannot tolerate or are unable to take statin therapy, ezetimibe monotherapy is recommended as an option for treating primary hypercholesterolaemia in adults. Additionally, for those who have already started statin therapy but are not seeing appropriate control of serum total or LDL cholesterol levels, ezetimibe can be coadministered with initial statin therapy. This is also recommended when a change from initial statin therapy to an alternative statin is being considered.
Overall, ezetimibe can be a useful medication in managing hypercholesterolaemia, particularly for those who cannot tolerate or do not see adequate results from statin therapy.
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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 55-year-old man with a medical history of ischaemic heart disease, gout, and diabetes presents with sudden and severe pain in his left renal angle that radiates to his groin. Upon undergoing an urgent CT KUB, it is confirmed that he has nephrolithiasis with hydronephrosis. As a result, he is admitted under the urology team for immediate intervention due to acute kidney injury.
What is the most common material that makes up these calculi in the general population?Your Answer:
Correct Answer: Calcium oxalate
Explanation:Renal stones can be classified into different types based on their composition. Calcium oxalate stones are the most common, accounting for 85% of all calculi. These stones are formed due to hypercalciuria, hyperoxaluria, and hypocitraturia. They are radio-opaque and may also bind with uric acid stones. Cystine stones are rare and occur due to an inherited recessive disorder of transmembrane cystine transport. Uric acid stones are formed due to purine metabolism and may precipitate when urinary pH is low. Calcium phosphate stones are associated with renal tubular acidosis and high urinary pH. Struvite stones are formed from magnesium, ammonium, and phosphate and are associated with chronic infections. The pH of urine can help determine the type of stone present, with calcium phosphate stones forming in normal to alkaline urine, uric acid stones forming in acidic urine, and struvate stones forming in alkaline urine. Cystine stones form in normal urine pH.
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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 25-year-old man presents to his GP with a complaint of blood in his urine. He reports that it began a day ago and is bright red in color. He denies any pain and has not observed any clots in his urine. The patient is generally healthy, but had a recent upper respiratory tract infection 2 days ago.
Upon urine dipstick examination, +++ blood and + protein are detected. What histological finding would be expected on biopsy, given the likely diagnosis?Your Answer:
Correct Answer: Mesangial hypercellularity with positive immunofluorescence for IgA & C3
Explanation:The histological examination of IgA nephropathy reveals an increase in mesangial cells, accompanied by positive immunofluorescence for IgA and C3.
Understanding IgA Nephropathy
IgA nephropathy, also known as Berger’s disease, is the most common cause of glomerulonephritis worldwide. It typically presents as macroscopic haematuria in young people following an upper respiratory tract infection. The condition is thought to be caused by mesangial deposition of IgA immune complexes, and there is considerable pathological overlap with Henoch-Schonlein purpura (HSP). Histology shows mesangial hypercellularity and positive immunofluorescence for IgA and C3.
Differentiating between IgA nephropathy and post-streptococcal glomerulonephritis is important. Post-streptococcal glomerulonephritis is associated with low complement levels and the main symptom is proteinuria, although haematuria can occur. There is typically an interval between URTI and the onset of renal problems in post-streptococcal glomerulonephritis.
Management of IgA nephropathy depends on the severity of the condition. If there is isolated hematuria, no or minimal proteinuria, and a normal glomerular filtration rate (GFR), no treatment is needed other than follow-up to check renal function. If there is persistent proteinuria and a normal or only slightly reduced GFR, initial treatment is with ACE inhibitors. If there is active disease or failure to respond to ACE inhibitors, immunosuppression with corticosteroids may be necessary.
The prognosis for IgA nephropathy varies. 25% of patients develop ESRF. Markers of good prognosis include frank haematuria, while markers of poor prognosis include male gender, proteinuria (especially > 2 g/day), hypertension, smoking, hyperlipidaemia, and ACE genotype DD.
Overall, understanding IgA nephropathy is important for proper diagnosis and management of the condition. Proper management can help improve outcomes and prevent progression to ESRF.
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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 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 9
Incorrect
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A 6-year-old girl is undergoing a renal biopsy due to recent haematuria and proteinuria. Upon histological analysis, immune complex deposition is found within the glomeruli. Further investigation reveals the presence of IgG, IgM, and C3 within the complexes.
What is the probable diagnosis?Your Answer:
Correct Answer: Post-streptococcal glomerulonephritis
Explanation:The correct diagnosis is post-streptococcal glomerulonephritis, which is a condition that commonly affects young children following an upper respiratory tract infection. Symptoms include haematuria, proteinuria, and general malaise. Biopsy samples typically show immune complex deposition of IgG, IgM, and C3, endothelial proliferation with neutrophils, and a subepithelial ‘hump’ appearance on electron microscopy. Immunofluorescence may show a granular or ‘starry sky’ appearance.
Minimal change disease is an incorrect diagnosis as it typically presents with nephrotic syndrome and does not include haematuria as a symptom. Additionally, minimal changes in glomerular structure should be seen on histology.
IgA nephropathy is also an incorrect diagnosis as it has IgA complex deposition on histology, which is different from the immune complex deposition seen in post-streptococcal glomerulonephritis.
Amyloidosis is another incorrect diagnosis as it is a cause of nephrotic syndrome and is characterised by amyloid deposition.
Post-streptococcal glomerulonephritis is a condition that typically occurs 7-14 days after an infection caused by group A beta-haemolytic Streptococcus, usually Streptococcus pyogenes. It is more common in young children and is caused by the deposition of immune complexes (IgG, IgM, and C3) in the glomeruli. Symptoms include headache, malaise, visible haematuria, proteinuria, oedema, hypertension, and oliguria. Blood tests may show a raised anti-streptolysin O titre and low C3, which confirms a recent streptococcal infection.
It is important to note that IgA nephropathy and post-streptococcal glomerulonephritis are often confused as they both can cause renal disease following an upper respiratory tract infection. Renal biopsy features of post-streptococcal glomerulonephritis include acute, diffuse proliferative glomerulonephritis with endothelial proliferation and neutrophils. Electron microscopy may show subepithelial ‘humps’ caused by lumpy immune complex deposits, while immunofluorescence may show a granular or ‘starry sky’ appearance.
Despite its severity, post-streptococcal glomerulonephritis carries a good prognosis.
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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 50-year-old woman comes to the GP clinic with her husband after attempting a dehydration detox. She appears confused and drowsy, and reports having vomited three times in the past 12 hours without passing urine. The patient has a medical history of allergic rhinitis, anxiety, hypothyroidism, type 2 diabetes mellitus, and chronic lower back pain.
During the examination, you observe dry mucous membranes, a pulse rate of 112/min, a respiratory rate of 24/min, a blood pressure of 97/65 mmHg, a temperature of 37.1ºC, and O2 saturation of 98%.
Given the patient's condition, you suspect that she requires immediate hospital care and refer her to the emergency department.
What medication should be stopped immediately for this patient?Your Answer:
Correct Answer: Losartan
Explanation:In cases of AKI, it is recommended to discontinue the use of angiotensin II receptor antagonists such as Losartan as they can worsen renal function by reducing renal perfusion. This is because angiotensin II plays a role in constricting systemic blood vessels and the efferent arteriole of the glomerulus, which increases GFR. Blocking angiotensin II can lead to a drop in systemic blood pressure and dilation of the efferent glomerular arteriole, which can exacerbate kidney impairment.
Cetirizine is not the most important medication to discontinue in AKI, as it is a non-sedating antihistamine and is unlikely to be a major cause of drowsiness. Diazepam may be contributing to drowsiness and is excreted in the urine, but sudden discontinuation can result in withdrawal symptoms. Levothyroxine does not need to be stopped in AKI as thyroid hormones are primarily metabolized in the liver and are not considered high risk in renal impairment.
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 11
Incorrect
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A 49-year-old man with a history of chronic alcohol abuse presents with abdominal distension and is diagnosed with decompensated alcoholic liver disease with ascites. The consultant initiates treatment with spironolactone to aid in the management of his ascites.
What is the mode of action of spironolactone?Your Answer:
Correct Answer: Inhibition of the mineralocorticoid receptor in the cortical collecting ducts
Explanation:Aldosterone antagonists function as diuretics by targeting the cortical collecting ducts.
By inhibiting the mineralocorticoid receptor in the cortical collecting ducts, spironolactone acts as an aldosterone antagonist.
Loop diuretics like furosemide work by blocking the sodium/potassium/chloride transporter in the loop of Henle.
Thiazide diuretics, such as bendroflumethiazide, block the sodium/chloride transporter in the distal convoluted tubules.
Carbonic anhydrase inhibitors, like dorzolamide, act on the proximal tubules.
Amiloride inhibits the epithelial sodium transporter in the distal convoluted tubules.
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 12
Incorrect
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A 65-year-old man with type 2 diabetes mellitus is undergoing his annual diabetic examination. He reports feeling more fatigued than usual and has missed his previous three annual check-ups. His blood glucose control has been inadequate, and he has not been adhering to his medications. His blood pressure measures 170/90 mmHg, and a urinalysis reveals microalbuminuria. A blood test shows that his glomerular filtration rate (GFR) is 27mL/min per 1.73m².
Assuming a renal biopsy is conducted on this patient, what are the anticipated findings?Your Answer:
Correct Answer: Nodular glomerulosclerosis and hyaline arteriosclerosis
Explanation:The patient in question is suffering from T2DM that is poorly controlled, resulting in diabetic nephropathy. The histological examination reveals the presence of Kimmelstiel-Wilson lesions (nodular glomerulosclerosis) and hyaline arteriosclerosis, which are caused by nonenzymatic glycosylation.
Amyloidosis is characterized by apple-green birefringence under polarised light.
Acute post-streptococcal glomerulonephritis is identified by enlarged and hypercellular glomeruli.
Rapidly progressive (crescentic) glomerulonephritis is characterized by crescent moon-shaped glomeruli.
Diffuse proliferative glomerulonephritis (often due to SLE) is identified by wire looping of capillaries in the glomeruli.
Understanding Diabetic Nephropathy: The Common Cause of End-Stage Renal Disease
Diabetic nephropathy is the leading cause of end-stage renal disease in the western world. It affects approximately 33% of patients with type 1 diabetes mellitus by the age of 40 years, and around 5-10% of patients with type 1 diabetes mellitus develop end-stage renal disease. The pathophysiology of diabetic nephropathy is not fully understood, but changes to the haemodynamics of the glomerulus, such as increased glomerular capillary pressure, and non-enzymatic glycosylation of the basement membrane are thought to play a key role. Histological changes include basement membrane thickening, capillary obliteration, mesangial widening, and the development of nodular hyaline areas in the glomeruli, known as Kimmelstiel-Wilson nodules.
There are both modifiable and non-modifiable risk factors for developing diabetic nephropathy. Modifiable risk factors include hypertension, hyperlipidaemia, smoking, poor glycaemic control, and raised dietary protein. On the other hand, non-modifiable risk factors include male sex, duration of diabetes, and genetic predisposition, such as ACE gene polymorphisms. Understanding these risk factors and the pathophysiology of diabetic nephropathy is crucial in the prevention and management of this condition.
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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 65-year-old man visits the haemofiltration unit thrice a week for treatment. What is responsible for detecting alterations in salt concentrations, such as sodium chloride, in normally functioning kidneys and adjusting the glomerular filtration rate accordingly?
Your Answer:
Correct Answer: Macula densa
Explanation:The macula densa is a specialized area of columnar tubule cells located in the final part of the ascending loop of Henle. These cells are in contact with the afferent arteriole and play a crucial role in detecting the concentration of sodium chloride in the convoluted tubules and ascending loop of Henle. This detection is affected by the glomerular filtration rate (GFR), which is increased by an increase in blood pressure. When the macula densa detects high sodium chloride levels, it releases ATP and adenosine, which constrict the afferent arteriole and lower GFR. Conversely, when low sodium chloride levels are detected, the macula densa releases nitric oxide, which acts as a vasodilator. The macula densa can also increase renin production from the juxtaglomerular cells.
Juxtaglomerular cells are smooth muscle cells located mainly in the walls of the afferent arteriole. They act as baroreceptors to detect changes in blood pressure and can secrete renin.
Mesangial cells are located at the junction of the afferent and efferent arterioles and, together with the juxtaglomerular cells and the macula densa, form the juxtaglomerular apparatus.
Podocytes, which are modified simple squamous epithelial cells with foot-like projections, make up the innermost layer of the Bowman’s capsule surrounding the glomerular capillaries. They assist in glomerular filtration.
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 14
Incorrect
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A 6-year-old girl is referred to the child assessment unit (CAU) for recurrent urinary tract infections. The paediatric consultant on CAU orders a group of investigations to find out the underlying cause.
What are the risk factors for UTIs in children, as the paediatrics trainee has asked the medical student?Your Answer:
Correct Answer: Posterior urethral valves
Explanation:The risk of urinary tract infection is higher in individuals with posterior urethral valves.
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 15
Incorrect
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Which is least likely to cause hyperuricaemia?
Your Answer:
Correct Answer: Amiodarone
Explanation:The drugs that cause hyperuricaemia due to reduced urate excretion can be remembered using the mnemonic Can’t leap, which stands for Ciclosporin, Alcohol, Nicotinic acid, Thiazides, Loop diuretics, Ethambutol, Aspirin, and Pyrazinamide. Additionally, decreased tubular secretion of urate can occur in patients with acidosis, such as those with diabetic ketoacidosis, ethanol or salicylate intoxication, or starvation ketosis, as the organic acids that accumulate in these conditions compete with urate for tubular secretion.
Understanding Hyperuricaemia
Hyperuricaemia is a condition characterized by elevated levels of uric acid in the blood. This can be caused by an increase in cell turnover or a decrease in the excretion of uric acid by the kidneys. While some individuals with hyperuricaemia may not experience any symptoms, it can be associated with other health conditions such as hyperlipidaemia, hypertension, and the metabolic syndrome.
There are several factors that can contribute to the development of hyperuricaemia. Increased synthesis of uric acid can occur in conditions such as Lesch-Nyhan disease, myeloproliferative disorders, and with a diet rich in purines. On the other hand, decreased excretion of uric acid can be caused by drugs like low-dose aspirin, diuretics, and pyrazinamide, as well as pre-eclampsia, alcohol consumption, renal failure, and lead exposure.
It is important to understand the underlying causes of hyperuricaemia in order to properly manage and treat the condition. Regular monitoring of uric acid levels and addressing any contributing factors can help prevent complications such as gout and kidney stones.
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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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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 17
Incorrect
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Which one of the following is not a characteristic of the distal convoluted tubule in the kidney?
Your Answer:
Correct Answer: Its secretory function is most effective at low systolic blood pressures (typically less than 100 mmHg)
Explanation:Compartment syndrome can lead to necrosis of the proximal convoluted tubule, which plays a crucial role in reabsorbing up to two thirds of filtered water. Acute tubular necrosis is more likely to occur when systolic blood pressure falls below the renal autoregulatory range, particularly if it is low. However, within this range, the absolute value of systolic BP has minimal impact.
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 18
Incorrect
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A 65-year-old man comes to the clinic for a medication review. He reports no negative effects and wishes to continue his current treatment. After conducting a blood test, you notice that his serum potassium level is slightly elevated. Which of the following frequently prescribed drugs is linked to an increase in serum potassium?
Your Answer:
Correct Answer: Ramipril
Explanation:Ramipril is the correct answer. Before starting ACE inhibitor therapy, a baseline potassium level is measured because these drugs can cause an increase in serum potassium.
Loop diuretics like furosemide can cause hypokalaemia and hyponatraemia.
Salbutamol does not lead to hyperkalaemia and can actually be used to lower serum potassium levels in emergency situations.
Taking paracetamol within recommended doses 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 19
Incorrect
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A 45-year-old obese female patient presents with persistent abdominal pain in her right upper quadrant that extends to her right shoulder, along with nausea and vomiting. During the physical examination, a palpable mass is detected in her right upper quadrant and she exhibits a positive Murphy's sign.
What abnormalities are expected to be observed in her liver function test (LFT) results?Your Answer:
Correct Answer: ALT 113 u/L, AST 129 u/L, ALP 549 u/L
Explanation:Elevated levels of alkaline phosphatase enzymes and slightly elevated liver transaminase enzymes indicate the possibility of biliary disease. Based on the patient’s medical history, it is likely that she has cholecystitis, which can lead to biliary obstruction and post-hepatic jaundice. In cholestatic diseases, the ALP level is typically much higher than liver transaminases. If the liver transaminases are elevated to the same or greater extent than ALP, it suggests a hepatocellular cause of disease, such as alcoholic liver disease or viral hepatitis. Normal or decreased liver function test results are unlikely in cases of cholestatic diseases.
Understanding Alkaline Phosphatase and its Causes
Alkaline phosphatase (ALP) is an enzyme found in various tissues throughout the body, including the liver, bones, and intestines. When the levels of ALP in the blood are elevated, it can indicate a potential health issue. The causes of raised ALP can be divided into two categories based on the calcium level in the blood.
If both ALP and calcium levels are high, it may indicate bone metastases, hyperparathyroidism, osteomalacia, or renal failure. On the other hand, if ALP is high but calcium is low, it may be due to cholestasis, hepatitis, fatty liver, neoplasia, Paget’s disease, or physiological factors such as pregnancy, growing children, or healing fractures.
It is important to note that elevated ALP levels do not necessarily indicate a serious health problem, and further testing may be needed to determine the underlying cause. Regular monitoring of ALP levels can help detect potential health issues early on and allow for prompt treatment.
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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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What substance is most effective in obtaining the most precise measurement of the glomerular filtration rate?
Your Answer:
Correct Answer: Inulin
Explanation:The decrease in renal function and muscle mass as one ages leads to a decline in creatinine levels. The kidney reabsorbs glucose, protein (amino acids), and PAH.
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 21
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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Question 22
Incorrect
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A 60-year-old patient visits the renal clinic after being diagnosed with stage 4 chronic kidney disease due to hypertension and diabetes. She inquires about the recommended diet for her condition.
What dietary advice should be provided to the patient?Your Answer:
Correct Answer: Low protein, phosphate, potassium and sodium
Explanation:For individuals with chronic kidney disease, it is recommended to follow a diet that is low in protein, phosphate, potassium, and sodium. This is because protein can produce ammonia, which is not effectively excreted by the kidneys in CKD. Phosphate can combine with calcium to form kidney stones, while sodium can raise blood pressure and further damage the kidneys. Potassium is also not efficiently eliminated by failing kidneys and can lead to irregular heartbeats.
Dietary Recommendations for Chronic Kidney Disease Patients
Chronic kidney disease patients are recommended to follow a specific diet that is low in protein, phosphate, sodium, and potassium. This dietary advice is given to reduce the strain on the kidneys, as these substances are typically excreted by the kidneys. By limiting the intake of these nutrients, patients can help slow the progression of their kidney disease and manage their symptoms more effectively. It is important for patients to work closely with their healthcare provider or a registered dietitian to ensure they are meeting their nutritional needs while following these dietary restrictions. With proper guidance and adherence to this diet, patients with chronic kidney disease can improve their overall health and quality of life.
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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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An 80-year-old woman arrives at the emergency department with complaints of palpitations. She denies any history of cardiac issues or chest pain. Upon conducting an ECG, you observe small P waves and tall tented T waves. You suspect hyperkalaemia and urgently order a blood test to measure her potassium levels. What could be a potential cause of hyperkalaemia?
Your Answer:
Correct Answer: Renal failure
Explanation:Renal failure is the correct answer. The kidneys play a crucial role in maintaining potassium balance in the body by regulating potassium intake and excretion. When renal failure occurs, the excretion of potassium is disrupted, leading to hyperkalaemia.
On the other hand, vomiting and diarrhoea can cause hypokalaemia.
Alkalosis is characterized by a high serum pH. In this condition, the reduced number of hydrogen ions entering the cell results in less potassium leaving the cell, which can lead to hypokalaemia.
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 24
Incorrect
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A 58-year-old man has had a radical nephrectomy. Upon bisecting the kidney, the pathologist observes a pink fleshy tumor in the renal pelvis. What is the probable illness?
Your Answer:
Correct Answer: Transitional cell carcinoma
Explanation:Renal tumours typically have a yellow or brown hue, but TCCs stand out as they have a pink appearance. If a TCC is detected in the renal pelvis, a nephroureterectomy is necessary.
Renal Lesions: Types, Features, and Treatments
Renal lesions refer to abnormal growths or masses that develop in the kidneys. There are different types of renal lesions, each with its own disease-specific features and treatment options. Renal cell carcinoma is the most common renal tumor, accounting for 85% of cases. It often presents with haematuria and may cause hypertension and polycythaemia as paraneoplastic features. Treatment usually involves radical or partial nephrectomy.
Nephroblastoma, also known as Wilms tumor, is a rare childhood tumor that accounts for 80% of all genitourinary malignancies in those under the age of 15 years. It often presents with a mass and hypertension. Diagnostic workup includes ultrasound and CT scanning, and treatment involves surgical resection combined with chemotherapy. Neuroblastoma is the most common extracranial tumor of childhood, with up to 80% occurring in those under 4 years of age. It is a tumor of neural crest origin and may be diagnosed using MIBG scanning. Treatment involves surgical resection, radiotherapy, and chemotherapy.
Transitional cell carcinoma accounts for 90% of lower urinary tract tumors but only 10% of renal tumors. It often presents with painless haematuria and may be caused by occupational exposure to industrial dyes and rubber chemicals. Diagnosis and staging are done with CT IVU, and treatment involves radical nephroureterectomy. Angiomyolipoma is a hamartoma type lesion that occurs sporadically in 80% of cases and in those with tuberous sclerosis in the remaining cases. It is composed of blood vessels, smooth muscle, and fat and may cause massive bleeding in 10% of cases. Surgical resection is required for lesions larger than 4 cm and causing symptoms.
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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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You have been requested to evaluate a 45-year-old Caucasian individual who has recently been diagnosed with hypertension. Despite making dietary modifications and engaging in physical activity, their blood pressure remains above 160/100 mmHg, prompting you to recommend medication.
During the consultation, the patient inquires about the drug's mechanism of action. You clarify that the medication obstructs an enzyme responsible for converting a peptide hormone into its active state.
Based on the medication you have prescribed, which of the following alterations is expected to happen?Your Answer:
Correct Answer: Reduced ADH release
Explanation:The drug in question is most likely an ACE inhibitor, which is commonly prescribed as first-line therapy for hypertension in older patients of certain races. ACE inhibitors work by inhibiting the enzyme responsible for converting angiotensin I to angiotensin II, which is a key component of the renin-angiotensin-aldosterone system that regulates blood pressure. Angiotensin II has several actions that help to counteract drops in blood pressure, including vasoconstriction, increased aldosterone secretion, and increased ADH release. ACE inhibitors have the opposite effect, leading to reduced levels of ADH. However, ACE inhibitors can also cause a buildup of bradykinin, which may result in a persistent dry cough as a side effect.
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 26
Incorrect
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A 67-year-old man is attending the urology clinic and receiving goserelin for his metastatic prostate cancer. Can you explain the drug's mechanism of action?
Your Answer:
Correct Answer: Overstimulation of GnRH receptors
Explanation:GnRH agonists used in the treatment of prostate cancer can paradoxically lead to lower LH levels in the long term. This is because chronic use of these agonists can result in overstimulation of GnRH receptors, which in turn disrupts endogenous hormonal feedback systems. While initially stimulating the production of LH/FSH and subsequent androgen production, chronic use of GnRH agonists can cause negative feedback to suppress the release of gonadotropins, resulting in a significant decrease in serum testosterone levels. This mechanism can be thought of as switching on to switch off. It is important to note that inhibiting the 5 alpha-reductase enzyme and relaxing prostatic smooth muscle are not mechanisms of action for GnRH agonists, but rather for other medications used in the treatment of prostate conditions.
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 27
Incorrect
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A 2-year-old girl presents with recurrent urinary tract infections. During the diagnostic work-up, abnormal renal function is noted and an ultrasound scan reveals bilateral hydronephrosis.
What could be the probable underlying diagnosis?Your Answer:
Correct Answer: Posterior urethral valves
Explanation:A developmental uropathy known as a posterior urethral valve typically affects male infants with an incidence of 1 in 8000. The condition is characterized by bladder wall hypertrophy, hydronephrosis, and bladder diverticula, which are used as diagnostic features.
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 28
Incorrect
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A 44-year-old man presents with a three-week history of leg swelling. He has no past medical history except for a bout of sore throat at the age of 15. He is not on any medications. On examination, his blood pressure is 155/94 mmHg, and he has pitting edema. Urinalysis reveals 4+ protein with no RBC casts. A biopsy confirms the diagnosis of membranous glomerulonephritis.
What is the most probable cause of this patient's condition?Your Answer:
Correct Answer: Anti-phospholipase A2 antibodies
Explanation:The likely diagnosis for this patient is idiopathic membranous glomerulonephritis, which is associated with anti-phospholipase A2 antibodies. While hypertension may be present in patients with nephrotic syndrome, it is not the cause of membranous glomerulonephritis. Secondary causes of membranous glomerulonephritis include malignancy (such as lung cancer, lymphoma, or leukemia) and systemic lupus erythematosus, but there are no indications of these in this patient. Sore throat is associated with post-streptococcal glomerulonephritis and IgA nephropathy, but these are not relevant to this case.
Membranous glomerulonephritis is the most common type of glomerulonephritis in adults and is the third leading cause of end-stage renal failure. It typically presents with proteinuria or nephrotic syndrome. A renal biopsy will show a thickened basement membrane with subepithelial electron dense deposits, creating a spike and dome appearance. The condition can be caused by various factors, including infections, malignancy, drugs, autoimmune diseases, and idiopathic reasons.
Management of membranous glomerulonephritis involves the use of ACE inhibitors or ARBs to reduce proteinuria and improve prognosis. Immunosuppression may be necessary for patients with severe or progressive disease, but many patients spontaneously improve. Corticosteroids alone are not effective, and a combination of corticosteroid and another agent such as cyclophosphamide is often used. Anticoagulation may be considered for high-risk patients.
The prognosis for membranous glomerulonephritis follows the rule of thirds: one-third of patients experience spontaneous remission, one-third remain proteinuric, and one-third develop end-stage renal failure. Good prognostic factors include female sex, young age at presentation, and asymptomatic proteinuria of a modest degree at the time of diagnosis.
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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 having a radical cystectomy for bladder carcinoma. Significant venous bleeding occurs during the surgery. What is the main location for venous drainage from the bladder?
Your Answer:
Correct Answer: Vesicoprostatic venous plexus
Explanation:The urinary bladder is surrounded by a complex network of veins that drain into the internal iliac vein. During cystectomy, the vesicoprostatic plexus can be a significant source of venous bleeding.
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 30
Incorrect
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A 50-year-old man with a history of type 2 diabetes mellitus, bipolar disorder and chronic obstructive pulmonary disease presents for a preoperative assessment for an inguinal hernia repair. His bloods are taken and reveal the following results:
Na+ 125 mmol/l
K+ 3.8 mmol/l
Bicarbonate 24 mmol/l
Urea 3.7 mmol/l
Creatinine 92 µmol/l
As a result of his smoking history, a chest x-ray is ordered and reported as normal. The Consultant inquires about the most probable cause of the hyponatraemia.Your Answer:
Correct Answer: Carbamazepine
Explanation:Carbamazepine, sulfonylureas, SSRIs, and tricyclics are drugs that can cause SIADH. While lithium can lead to diabetes insipidus, it usually occurs with high sodium levels. Elevated antidiuretic hormone levels due to lithium are typically only seen in cases of severe overdose.
SIADH is a condition where the body retains too much water, leading to low sodium levels in the blood. This can be caused by various factors such as malignancy (particularly small cell lung cancer), neurological conditions like stroke or meningitis, infections like tuberculosis or pneumonia, certain drugs like sulfonylureas and SSRIs, and other factors like positive end-expiratory pressure and porphyrias. Treatment involves slowly correcting the sodium levels, restricting fluid intake, and using medications like demeclocycline or ADH receptor antagonists. It is important to correct the sodium levels slowly to avoid complications like central pontine myelinolysis.
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This question is part of the following fields:
- Renal System
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