ITE Nephrology and Hypertension 5 — Questions and Answers
Question 1: A 52-year-old man with diabetes presents with serum creatinine rising from 1.0 to 1.8 mg/dL after starting lisinopril. Renal artery duplex shows elevated resistive indices bilaterally with post-stenotic turbulence. What should be done?
- Discontinue lisinopril and arrange renal artery stenting urgently
- Discontinue lisinopril and pursue further imaging to assess for bilateral renal artery stenosis (Correct answer)
- Continue lisinopril at reduced dose and recheck creatinine in 2 weeks
- Add amlodipine and continue lisinopril
Correct answer: Discontinue lisinopril and pursue further imaging to assess for bilateral renal artery stenosis
A >30% rise in creatinine after ACE inhibitor initiation suggests bilateral renal artery stenosis or stenosis in a solitary kidney; ACE inhibitor should be stopped and vascular imaging pursued.
Question 2: A 28-year-old woman with systemic lupus erythematosus presents with serum creatinine of 2.1 mg/dL, 4+ proteinuria, red cell casts, C3 18 mg/dL (low), and anti-dsDNA titer of 1:640. Kidney biopsy shows diffuse proliferative lesions in >50% of glomeruli. What is the LN class?
- Class III
- Class IV (Correct answer)
- Class V
- Class II
Correct answer: Class IV
Diffuse proliferative lupus nephritis involving >50% of glomeruli is classified as class IV (diffuse) by the ISN/RPS classification.
Question 3: A 68-year-old man on hydrochlorothiazide presents with serum sodium of 122 mEq/L. He appears euvolemic. Urine osmolality is 450 mOsm/kg and urine sodium is 55 mEq/L. TSH and morning cortisol are normal. What is the most appropriate treatment?
- Hypertonic 3% saline infusion
- Discontinue thiazide and fluid restrict to 1 L/day (Correct answer)
- Tolvaptan 15 mg orally
- Normal saline infusion at 125 mL/hour
Correct answer: Discontinue thiazide and fluid restrict to 1 L/day
Thiazide-induced SIADH-like hyponatremia requires stopping the offending drug and fluid restriction; thiazides impair renal diluting capacity making them a common cause.
Question 4: A 44-year-old man with alcohol use disorder presents with acute kidney injury. Urine microscopy shows muddy brown granular casts and renal tubular epithelial cells. FENa is 3.2%. What is the most likely diagnosis?
- Pre-renal azotemia from volume depletion
- Acute tubular necrosis (Correct answer)
- Acute interstitial nephritis
- Rhabdomyolysis-induced AKI
Correct answer: Acute tubular necrosis
Muddy brown granular casts and RTECs on urinalysis with FENa >2% are the hallmark of acute tubular necrosis.
Question 5: A 61-year-old woman with resistant hypertension (BP 158/96 mmHg on ACEI, amlodipine, and chlorthalidone) has plasma aldosterone-to-renin ratio of 35 (ng/dL)/(ng/mL/h). CT adrenals are normal. What is the next step?
- Begin spironolactone empirically
- Adrenal vein sampling (Correct answer)
- Add doxazosin for suspected pheochromocytoma
- 24-hour urine aldosterone collection
Correct answer: Adrenal vein sampling
An elevated ARR with biochemically confirmed primary hyperaldosteronism requires adrenal vein sampling to distinguish unilateral adenoma (surgical) from bilateral hyperplasia (medical).
Question 6: A 75-year-old woman on lithium for bipolar disorder for 30 years presents with nephrogenic diabetes insipidus, CKD stage 4 (eGFR 22), and small echogenic kidneys on ultrasound. What renal pathology is most characteristic of chronic lithium nephrotoxicity?
- Chronic interstitial fibrosis with microcystic tubular changes (Correct answer)
- Focal segmental glomerulosclerosis
- Membranous nephropathy
- Mesangial proliferative glomerulonephritis
Correct answer: Chronic interstitial fibrosis with microcystic tubular changes
Chronic lithium nephrotoxicity causes characteristic cortical and medullary microcysts from distal tubular injury, accompanied by interstitial fibrosis and tubular atrophy.
Question 7: A 40-year-old woman presents with hypertension, hypokalemia, and metabolic alkalosis. Plasma renin is elevated and aldosterone is elevated. Renal artery MRA shows a beaded appearance of the right renal artery mid-segment. What is the diagnosis and preferred treatment?
- Atherosclerotic renal artery stenosis; stenting
- Fibromuscular dysplasia; percutaneous transluminal angioplasty (Correct answer)
- Renal artery aneurysm; surgical repair
- Takayasu arteritis; glucocorticoids
Correct answer: Fibromuscular dysplasia; percutaneous transluminal angioplasty
Fibromuscular dysplasia causing renovascular hypertension in a young woman is best treated with percutaneous transluminal angioplasty, which is curative in many cases.
ITE Nephrology and Hypertension 5
A 52-year-old man with diabetes presents with serum creatinine rising from 1.0 to 1.8 mg/dL after starting lisinopril.
Renal artery duplex shows elevated resistive indices bilaterally with post-stenotic turbulence.
What should be done?