PM Questions Flashcards
Mechanism of action of Spironolactone?
Spironolactone competitively inhibits aldosterone dependant sodium potassium exchange channels in the distal convoluted tubule. This action leads to increased sodium and water excretion, but more potassium retention. The increased excretion of water leads to diuretic and also antihypertensive effects.
Through what mechanism does Spironolactone work?
Spironolactone is an aldosterone antagonist, therefore, acts to inhibit the mineralocorticoid receptor in the cortical collecting ducts.
What is recommended in a renal diet?
Patients with renal failure are advised to adopt a diet which has:
- Low protein
- Low phosphate
- Low sodium
- Low potassium
A 45-year-old patient presents to his physician 6 days after his last appointment. He is concerned that he has been passing very small amounts of urine for the past 3 days. He was started on an gentamicin last week for an infection. His physician is concerned about gentamicin-induced nephrotoxicity.
On examination, no abnormalities are noted. His blood pressure and temperature are normal.
His fractional excretion of urine is greater than 4%.
A urine sample is sent to the lab for microscopy, culture and sensitivity.
What is likely to be seen on microscopy if the physician’s suspicion is true?
The patient was started on gentamicin, a nephrotoxic drug. Reduced urine output after starting a nephrotoxic drug should make one worry about acute tubular necrosis (ATN). Brown granular casts are seen on microscopy of the urine in ATN.
What is the mechanism of action of furosemide?
Furosemide is a loop diuretic that prevents reabsorption of sodium, chloride, and potassium by inhibition of the cotransporter in the thick ascending loop of Henle. This causes significant diuresis.
Inhibits the sodium-potassium-chloride co-transporter.
In IgA nephropathy, there is a proliferation of what cells?
In IgA nephropathy, there is a proliferation of the mesangial cells.
Thickening of the basement membrane occurs in what condition?
Thickening of the glomerular basement membrane occurs in diabetic nephropathy or membranous nephropathy, which are both types of nephrotic syndrome.
What is prescribed as the second line therapy for patients who are unable to tolerate the side effects of statins?
The second line therapy for patients who are unable to tolerate the side effects of statins is ezetimibe.
A 28-year-old woman presents with a 3-day history of dysuria and increased urinary frequency. She denies any vaginal discharge or menorrhagia. Urine dipstick is positive for leukocytes and nitrites. Urine culture grows a urease-bacteria that is identified as Proteus mirabilis. She is treated with antibiotics.
Chronic and recurrent infections with this bacteria predispose patients to which of the following types of renal stones?
Recurrent urease-positive bacteria (eg. proteus mirabilis) infections predispose individuals to struvite renal stones.
Struvite accounts for 15% of stones. It is caused by infections with urease-positive bacteria (e.g. Proteus mirabilis) that hydrolyze urea to ammonia and alkalize the urine. They commonly form staghorn calculi.
Six weeks after the birth of her child, a woman presents with agalactorrhoea, amenorrhoea, intolerance to cold, constipation and weight loss. She suffered a post-partum haemorrhage after delivery. She is subsequently diagnosed with hypopituitarism. What is the likely cause of this?
Sheehan’s syndrome occurs due to pituitary ischaemia secondary to blood loss during or after childbirth. It presents with symptoms consistent with global hypopituitarism, such as agalactorrhoea (prolactin), amenorrhoea (FSH and LH), cold intolerance and constipation (thyroid hormones) and weight loss (steroid hormones).
Complications of spironolactone:
Spironolactone is the drug in question and a known side effect involves breast tissue growth. It is an aldosterone receptor antagonist and interferes with excretion of potassium. Thus it is known as a potassium-sparing diuretic.
Can lead to hyperkalaemia.
Angiotensin II does what to the efferent arteriole?
Angiotensin II causes vasoconstriction of the efferent arteriole to the glomerulus. This is to increase the pressure across the glomerulus and increase filtration fraction, ultimately preserving GFR.
Structures of the hilum of the kidney from anterior to posterior?
The renal veins lie most anteriorly, then artery and ureter lies posteriorly.
What type of testicular tumour presents with gynecomastia?
Leydig cell tumour
Leydig cell tumours are rare testicular sex cord stromal tumours (which also include sertoli cell tumours) which are associated with hormonal activity.
Patients with Leydig cell tumours may present with gynaecomastia before they notice testicular enlargement.
Majority are benign
Histology: eosinophilic cells in columns
Haemolytic uraemic syndrome (HUS) can be a complication following infection with what organism?
E. coli
History of diarrhoea is a big sign.
