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Question 1
Correct
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A 49-year-old male presents to the GP for a routine blood check and follow-up. He has a medical history of angina, hypertension, asthma, and hyperlipidemia. Upon reviewing his medications, it is noted that he is taking fenofibrate, a drug that reduces triglyceride levels and increases the synthesis of high-density lipoprotein (HDL). What is the mechanism of action of this medication?
Your Answer: Activation of PPAR receptor resulting in increase lipoprotein lipase (LPL) activity
Explanation:Fibrates activate PPAR alpha receptors, which increase LPL activity and reduce triglyceride levels. These drugs are effective in lowering cholesterol.
Statins work by inhibiting HMG-CoA reductase, which reduces the mevalonate pathway and lowers cholesterol levels.
Niacin, also known as vitamin B3, inhibits hepatic diacylglycerol acyltransferase-2, which is necessary for triglyceride synthesis.
Bile acid sequestrants bind to bile salts, reducing the reabsorption of bile acids and lowering cholesterol levels.
Apolipoprotein E is a protein that plays a role in fat metabolism, specifically in removing chylomicron remnants.
Understanding Fibrates and Their Role in Managing Hyperlipidaemia
Fibrates are a class of drugs commonly used to manage hyperlipidaemia, a condition characterized by high levels of lipids in the blood. Specifically, fibrates are effective in reducing elevated triglyceride levels. This is achieved through the activation of PPAR alpha receptors, which in turn increases the activity of LPL, an enzyme responsible for breaking down triglycerides.
Despite their effectiveness, fibrates are not without side effects. Gastrointestinal side effects are common, and patients may experience symptoms such as nausea, vomiting, and diarrhea. Additionally, there is an increased risk of thromboembolism, a condition where a blood clot forms and blocks a blood vessel.
In summary, fibrates are a useful tool in managing hyperlipidaemia, particularly in cases where triglyceride levels are elevated. However, patients should be aware of the potential side effects and discuss any concerns with their healthcare provider.
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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 49-year-old man with recently diagnosed hypertension has a left adrenal gland phaeochromocytoma and is scheduled for a laparoscopic left adrenalectomy. Which of the following structures is not directly associated with the left adrenal gland?
Your Answer: Splenic artery
Correct Answer: Lesser curvature of the stomach
Explanation:The left adrenal gland is slightly bigger than the right and has a crescent shape. Its concave side fits against the medial border of the upper part of the left kidney. The upper part is separated from the cardia of the stomach by the peritoneum of the omental bursa. The lower part is in contact with the pancreas and splenic artery and is not covered by peritoneum. On the front side, there is a hilum where the suprarenal vein comes out. The gland rests on the kidney on the lateral side and on the left crus of the diaphragm on the medial side.
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 hepato-renal 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 3
Correct
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A 6-year-old girl is brought to her pediatrician by her father. Her father reports that for the past 5 days, she has been experiencing swelling in her lower limbs. The girl is otherwise healthy, has not had any recent illnesses, and her blood pressure during the visit was normal. The results of her urinalysis are as follows:
Leucocytes: Negative
Nitrites: Negative
Urobilinogen: Negative
Proteins: 3+
Blood: Negative
Ketones: Negative
Glucose: Negative
What is the most probable diagnosis?Your Answer: Minimal change disease
Explanation:The boy’s symptoms are typical of nephrotic syndrome, which is characterized by a triad of proteinuria, hypoalbuminaemia, and oedema. Oedema is usually seen in the lower limbs, and proteinuria may cause frothy urine. Minimal change disease, focal segmental glomerulosclerosis, and membranous nephropathy are examples of nephrotic syndrome. Minimal change disease is a common cause of nephrotic syndrome, and it is characterized by effacement of the podocyte foot processes, which increases the permeability of the glomerular basement membrane and causes proteinuria.
It is important to differentiate nephrotic syndrome from nephritic syndrome, which is characterized by the presence of protein and blood in the urine. Nephritic syndrome typically presents with haematuria, oliguria, and hypertension. Alport syndrome is not a correct answer as it causes nephritic syndrome, and it is a genetic condition that affects kidney function, hearing, and vision. IgA nephropathy is also an incorrect answer as it causes nephritic syndrome and is typically associated with upper respiratory tract infections. A careful history is required to distinguish it from post-streptococcal glomerulonephritis, another cause of nephritic syndrome that occurs after a streptococcal infection.
Understanding Nephrotic Syndrome and its Presentation
Nephrotic syndrome is a condition characterized by a triad of symptoms, namely proteinuria, hypoalbuminaemia, and oedema. Proteinuria refers to the presence of excessive protein in the urine, typically exceeding 3g in a 24-hour period. Hypoalbuminaemia is a condition where the levels of albumin in the blood fall below 30g/L. Oedema, on the other hand, is the accumulation of fluid in the body tissues, leading to swelling.
Nephrotic syndrome is associated with the loss of antithrombin-III, proteins C and S, and an increase in fibrinogen levels, which increases the risk of thrombosis. Additionally, the loss of thyroxine-binding globulin leads to a decrease in total thyroxine levels, although free thyroxine levels remain unaffected.
The diagram below illustrates the different types of glomerulonephritides and how they typically present. Understanding the presentation of nephrotic syndrome and its associated risks is crucial in the diagnosis and management of this condition.
[Insert diagram here]
Overall, nephrotic syndrome is a complex condition that requires careful management to prevent complications. By understanding its presentation and associated risks, healthcare professionals can provide appropriate treatment and support to patients with this condition.
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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: Division of the ligament of Treitz
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 68-year-old man visits the clinic with a complaint of persistent hiccups that have been ongoing for 5 days. During the consultation, he mentions feeling increasingly fatigued over the past 7 months. Apart from these issues, he reports no other health concerns. After conducting some blood tests, you discover that he is experiencing renal failure, and his potassium levels are at 6.2 (normal range is 3.5-5 mmol/l). You urgently advise him to go to the hospital, and upon arrival, the medical team requests an ECG to check for signs of hyperkalaemia. What is an ECG indication of hyperkalaemia?
Your Answer: Prominent U waves
Correct Answer: Wide QRS complexes
Explanation:Hyperkalaemia can be identified on an ECG by the presence of broad QRS complexes, which may appear bizarre and form a sinusoidal waveform. Other signs include tall-tented T waves and small or absent P waves. Asystole can also occur as a result of hyperkalaemia.
On the other hand, hypokalaemia can be identified by ECG signs such as small or inverted T waves, ST segment depression, and prominent U waves. A prolonged PR interval and long QT interval may also be present, although a short PR interval may suggest pre-excitation or an AV nodal rhythm.
In the case of a patient presenting with hiccups, persistent hiccups may indicate uraemia, which can be caused by renal failure. Fatigue is another common symptom of renal failure, which is also a common cause of hyperkalaemia.
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 6
Incorrect
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A 56-year-old man presents to the outpatient cardiology clinic complaining of fatigue and weight gain. He has been diagnosed with type II diabetes for 14 years and has been taking metformin to control his blood sugar levels. An echocardiogram reveals a globally dilated left ventricle with a reduced ejection fraction of approximately 30%, and his NT-proBNP level is 1256 (<125 pg/mL). The healthcare provider decides to initiate empagliflozin therapy due to its cardioprotective effects in patients with heart failure with reduced ejection fraction. What is the primary mechanism of action for this new medication?
Your Answer: Descending loop of Henle
Correct Answer: Proximal convoluted tubule
Explanation:Glucose reabsorption within the nephron is mainly concentrated in the proximal convoluted tubule.
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 7
Incorrect
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At which of the following locations is the highest amount of water absorbed?
Your Answer: Right colon
Correct Answer: Jejunum
Explanation:The small bowel, specifically the jejunum and ileum, is the primary location for water absorption in the gastrointestinal tract. While the colon does play a role in water absorption, its contribution is minor in comparison. However, if there is a significant removal of the small bowel, the importance of the colon in water absorption may become more significant.
Water Absorption in the Human Body
Water absorption in the human body is a crucial process that occurs in the small bowel and colon. On average, a person ingests up to 2000ml of liquid orally within a 24-hour period. Additionally, gastrointestinal secretions contribute to a further 8000ml of fluid entering the small bowel. The process of intestinal water absorption is passive and is dependent on the solute load. In the jejunum, the active absorption of glucose and amino acids creates a concentration gradient that facilitates the flow of water across the membrane. On the other hand, in the ileum, most water is absorbed through facilitated diffusion, which involves the movement of water molecules with sodium ions.
The colon also plays a significant role in water absorption, with approximately 150ml of water entering it daily. However, the colon can adapt and increase this amount following resection. Overall, water absorption is a complex process that involves various mechanisms and is essential for maintaining proper hydration levels in the body.
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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 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: Furosemide
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 9
Incorrect
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A 55-year-old male presents to the emergency department with a high fever and fatigue. He does not have any history to offer. On examination, he is noted to have splinter haemorrhages and conjunctival pallor. His observations show him to be pyrexial at 39°C. A pansystolic murmur is audible throughout the praecordium, and an echocardiogram reveals vegetations. He is diagnosed with infective endocarditis and initiated on a triple antibiotic therapy of gentamicin, vancomycin and amoxicillin. The following U&E results are noted at admission:
Na+ 140 mmol/L (135 - 145)
K+ 4.0 mmol/L (3.5 - 5.0)
Bicarbonate 25 mmol/L (22 - 29)
Urea 4.0 mmol/L (2.0 - 7.0)
Creatinine 75 µmol/L (55 - 120)
However, following three days of inpatient treatment, the patient becomes anuric. A repeat set of U&Es reveal the following:
Na+ 145 mmol/L (135 - 145)
K+ 5.0 mmol/L (3.5 - 5.0)
Bicarbonate 25 mmol/L (22 - 29)
Urea 12.0 mmol/L (2.0 - 7.0)
Creatinine 150 µmol/L (55 - 120)
What is the likely mechanism of gentamicin causing this patient’s kidney injury?Your Answer: Pre-renal hypoperfusion
Correct Answer: Renal cell apoptosis
Explanation:AKI can be attributed to gentamicin due to its ability to induce apoptosis in renal cells. Therefore, patients who are prescribed gentamicin should undergo frequent monitoring of their renal function and drug concentration levels. While there are other potential causes of acute kidney injury, none of them are linked to aminoglycoside antibiotics.
Understanding the Difference between Acute Tubular Necrosis and Prerenal Uraemia
Acute kidney injury can be caused by various factors, including prerenal uraemia and acute tubular necrosis. It is important to differentiate between the two to determine the appropriate treatment. Prerenal uraemia occurs when the kidneys hold on to sodium to preserve volume, leading to decreased blood flow to the kidneys. On the other hand, acute tubular necrosis is caused by damage to the kidney tubules, which can be due to various factors such as toxins, infections, or ischemia.
To differentiate between the two, several factors can be considered. In prerenal uraemia, the urine sodium level is typically less than 20 mmol/L, while in acute tubular necrosis, it is usually greater than 40 mmol/L. The urine osmolality is also higher in prerenal uraemia, typically above 500 mOsm/kg, while in acute tubular necrosis, it is usually below 350 mOsm/kg. The fractional sodium excretion is less than 1% in prerenal uraemia, while it is greater than 1% in acute tubular necrosis. Additionally, the response to fluid challenge is typically good in prerenal uraemia, while it is poor in acute tubular necrosis.
Other factors that can help differentiate between the two include the serum urea:creatinine ratio, fractional urea excretion, urine:plasma osmolality, urine:plasma urea, specific gravity, and urine sediment. By considering these factors, healthcare professionals can accurately diagnose and treat acute kidney injury.
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This question is part of the following fields:
- Renal System
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Question 10
Incorrect
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An 80-year-old woman is recuperating in the hospital after undergoing a right hemicolectomy. She has a medical history of hypertension, hypercholesterolemia, and a previous pulmonary embolism. On the fifth day following the surgery, she experiences confusion and has a NEWS2 score of 7, leading to suspicion of sepsis and initiation of the sepsis 6 protocol. The following day, she is diagnosed with AKI, with a sudden rise in serum creatinine and potassium levels.
Which medication(s) should be discontinued due to the risk of exacerbating renal function?Your Answer: Atenolol
Correct Answer: Gentamicin
Explanation:Aminoglycosides, such as gentamicin, should be discontinued in cases of AKI as they may exacerbate renal function. Gentamicin may have been prescribed to treat suspected sepsis. Other medications that should be stopped for the same reason include NSAIDs, ACE inhibitors, angiotensin II receptor antagonists, and diuretics. Atenolol is safe to continue in AKI, but not recommended for use in asthma. Atorvastatin is also safe to continue in AKI, but not during pregnancy or breastfeeding. Paracetamol is generally safe to continue in AKI and is also safe during pregnancy and breastfeeding, unlike NSAIDs.
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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