Renal, Urinary Systems and Electrolytes III

Question 1

What is the likely diagnosis in a young female with orthostatic hypotension, hyponatremia, and hypokalemia with high urine Na+ and K+?

Answer 1

Diuretic abuse

normally dehydrated patients with hyponatremia and hypokalemia will have reduced urine Na+/K+

Question 2

What is the likely diagnosis in a young female with photosensitivity, headaches, thrombocytopenia, hematuria, and proteinuria?

Answer 2

SLE

Question 3

What is the likely diagnosis in an adolescent with recurrent kidney stones and hexagonal crystals on urinalysis?

Answer 3

Cystinuria

due to defective transport of dibasic amino acids (cystine, lysine, arginine, and ornithine); stones are classically hard and radioopaque

Question 4

What is the likely diagnosis in an afebrile elderly male with BPH who experiences agitation and lower abdominal tenderness 2 days after surgery?

Answer 4

Acute urinary retention

diagnosis is confirmed by bladder ultrasound; treatment is insertion of a Foley catheter

Question 5

What is the likely diagnosis in an elderly diabetic with non-anion gap metabolic acidosis, hyperkalemia, and mild renal insufficiency?

Answer 5

Type 4 (hyperkalemic) renal tubular acidosis

most common in elderly patients with poorly controlled diabetes (damage to the juxtaglomerular apparatus results in hyporeninemic, hyperaldosteronism)

Question 6

What is the likely diagnosis in an elderly patient taking a TCA that develops abdominal pain and suprapubic fullness?

Answer 6

Urinary retention

due to anticholinergic properties of TCAs, which prevents destrusor muscle contraction and urethral sphincter relaxation

Question 7

What is the likely ingested agent in a patient who overdosed and presents with fever, tinnitus, and tachypnea?

Answer 7

Aspirin

causes mixed respiratory alkalosis and anion gap metabolic acidosis

Question 8

What is the likely underlying cause of refractory hypokalemia in an alcoholic patient?

Answer 8

Hypomagnesemia

intracellular Mg2+ typically inhibits potassium secretion by renal outer medullary potassium (ROMK) channels

Question 9

What is the likely underlying etiology of kidney disease with arteriosclerotic lesions of renal arterioles?

Answer 9

Hypertension

hypertension first manifests as nephrosclerosis and evolves to glomerulosclerosis

Question 10

What is the likely underlying etiology of kidney disease with GBM thickening, mesangial expansion, and glomerular sclerosis?

Answer 10

Diabetic nephropathy

Question 11

What is the long-term treatment for severe hypercalcemia (> 14mg/dL or symptomatic)?

Answer 11

bisphosphonates (e.g. zoledronic acid, pamidronate)

symptoms include weakness, GI distress, and neuropsychiatric symptoms

Question 12

What is the most common cause of abnormal hemostasis in patients with chronic renal failure?

Answer 12

Platelet dysfunction

Question 13

What is the most common cause of death in dialysis and renal transplant patients?

Answer 13

Cardiovascular disease

accounts for approximately 50% of all deaths in dialysis patients

Question 14

What is the most common cause of glomerulonephritis in adults?

Answer 14

IgA nephropathy

Question 15

What is the most common extrarenal manifestation of autosomal dominant PKD?

Answer 15

Hepatic cysts

other extra-renal complications include berry aneurysms, valvular heart disease, colonic diverticula, and abdominal wall/inguinal hernia

Question 16

What is the most common form of drug-induced chronic renal failure?

Answer 16

Analgesic nephropathy

suggested by elevated creatinine with urinalysis showing hematuria or sterile pyuria

Question 17

What is the most common malignancy associated with painless hematuria in adults?

Answer 17

Bladder tumors

especially patients age > 35 with a smoking history

Question 18

What is the most common reason for higher incidence of UTIs in females than in males?

Answer 18

Shorter urethral length in females

other predisposing factors include sexual intercourse, recent antibiotic use, spermicidal contraceptives, and close proximity of the urethra to the anus

Question 19

What is the most common type of kidney stone?

Answer 19

Calcium oxalate

Question 20

What is the most important intervention for preventing contrast-induced nephropathy?

Answer 20

Adequate IV hydration

with isotonic bicarbonate or normal saline; acetylcysteine administration may reduce risk as well

Question 21

What is the next step in evaluation of acute kidney injury in an elderly patient with BPH who presents with rising creatinine and urinary urgency without hematuria, weight loss, or elevated PSA?

Answer 21

Renal ultrasound

helps assess for hydronephrosis and other causes of obstruction

Question 22

What is the next step in management for a patient with acute renal failure and oliguria with evidence of significant urine retention?

Answer 22

Bladder catheterization

may also place a catheter if the bladder scan is inconclusive

Question 23

What is the recommended management for a patient with uremic encephalopathy?

Answer 23

Hemodialysis

Question 24

What is the recommended management for an asymptomatic simple renal cyst?

Answer 24

Reassurance (no follow-up required)

Question 25

What is the recommended treatment for a patient with a 4 mm kidney stone (first episode)?

Answer 25

Hydration (\> 2 L fluid intake daily) stones \< 5 mm typically pass spontaneously with conservative management; supportive therapy for pain and nausea may be initiated as well

Question 26

What is the recommended treatment for a patient with metabolic alkalosis and hypokalemia secondary to recurrent vomiting?

Answer 26

IV saline and potassium volume resuscitation with normal saline corrects contraction alkalosis

Question 27

What is the recommended treatment for both type I and type II renal tubular acidosis?

Answer 27

Oral bicarbonate replacement type II RTA may benefit from the addition of a thiazide diuretic as well (mild volume depletion enhances bicarbonate and sodium reabsorption)

Question 28

What is the treatment of choice for euvolemic hypernatremia?

Answer 28

5% dextrose (preferred) or 0.45% saline for free water supplementation

Question 29

What is the treatment of choice for mild hypovolemic hypernatremia?

Answer 29

5% dextrose in 0.45% saline

Question 30

What is the treatment of choice for severe hypovolemic hypernatremia? [...] until euvolemic, then [...]

Answer 30

**0.9% saline** (isotonic) until euvolemic, then **5% dextrose (hypotonic)** patients may also be switched to 0.45% saline instead of 5% dextrose

Question 31

What is the treatment of choice for uremic coagulopathy?

Answer 31

Desmopressin (DDAVP) increases release of factor VIII-vWF multimers from endothelial storage sites; other treatment options include cryoprecipitate or conjugated estrogens (platelet transfusion is not indicated)

Question 32

What is the typical volume state (hypo, eu-, or hyper-volemic) of patients with hypercalcemia?

Answer 32

Hypovolemic due to polyuria (from Ca2+-induced nephrogenic DI) and decreased oral intake; loop diuretics should be avoided as they can worsen volume depletion

Question 33

What is the underlying cause of hypercoagulability in patients with nephrotic syndrome?

Answer 33

Loss of antithrombin III in urine manifests as venous or arterial thrombosis, most commonly renal vein thrombosis

Question 34

What neurological complication is associated with autosomal dominant PKD?

Answer 34

Berry aneurysms however, routine screening is not recommended

Question 35

What psychiatric medication is associated with nephrogenic diabetes insipidus?

Answer 35

Lithium treatment involves salt restriction and discontinuation of lithium

Question 36

What renal pathology is likely present in an asymptomatic patient with the CT below?

Answer 36

Simple renal cyst

Question 37

What screening procedure is useful for detecting cystinuria?

Answer 37

Urinary cyanide nitroprusside test

Question 38

What side effect may thiazide diuretics have on serum Na+ levels?

Answer 38

Hyponatremia

Question 39

What treatment is used for cardiac membrane stabilization in patients with hyperkalemia?

Answer 39

IV calcium infusion (e.g. calcium gluconate or calcium chloride) note: NOT calcium carbonate!

Question 40

What treatment provides the most rapid reduction in serum K+ in patients with hyperkalemia?

Answer 40

IV insulin + glucose results in an intracellular potassium shift (transiently); other options include inhaled beta-2 agonists and sodium bicarbonate

Question 41

What type of acid-base disturbance occurs with vomiting?

Answer 41

hypokalemic, hypochloremic metabolic alkalosis GI fluid is rich in both HCl and KCl, resulting in loss of K+ and Cl-; HCO3- levels rise as a result of H+ loss

Question 42

What type of anti-histamine has anti-cholinergic activity?

Answer 42

1st generation H1-blockers may cause urinary retention, especially in elderly men with BPH

Question 43

What type of cast is characteristic of acute tubular necrosis?

Answer 43

Muddy brown granular cast

Question 44

What type of cast is characteristic of glomerulonephritis?

Answer 44

RBC cast

Question 45

What type of cast is characteristic of interstitial nephritis and pyelonephritis?

Answer 45

WBC cast

Question 46

What type of cast is characteristic of nephrotic syndrome?

Answer 46

Fatty cast

Question 47

What type of casts (2) are characteristic of chronic renal failure?

Answer 47

broad and waxy casts

Question 48

What type of kidney stone commonly affects patients with Crohn disease or other causes of fat malabsorption?

Answer 48

Calcium oxalate stones non-absorbed fat binds Ca2+ in the gut, preventing Ca2+ from binding oxalate (insoluble) and consequently increasing free oxalate (soluble) absorption

Question 49

What type of kidney stone is characterized by needle-shaped crystals on urinalysis and radiolucency?

Answer 49

Uric acid stones radiolucent therefore must be evaluated by abdominal CT, ultrasound, or IV pyelography (not X-ray)

Question 50

Which class of autonomic drugs are associated with hyperkalemia?

Answer 50

Non-selective beta blockers

Question 51

Which class of autonomic drugs may be useful for treating ureteric kidney stones (in addition to IV hydration and analgesics)?

Answer 51

alpha1-blockers (e.g. tamsulosin) acts on the distal ureter to lower muscle tone and reduce reflex ureteral spasm secondary to stone impaction

Question 52

Which classes of anti-hypertensive drugs are associated with hyperkalemia?

Answer 52

ACE inhibitors and ARBs other commonly implicated drugs are non-selective beta blockers, cardiac glycosides, NSAIDs, and K+-sparing diuretics

Question 53

Which diuretics (2) are commonly administered to cirrhotic patients with volume overload and ascites?

Answer 53

furosemide and spironolactone may result in hypokalemia, metabolic alkalosis, and prerenal AKI

Question 54

Which type of hematuria, glomerular or non-glomerular, is associated with gross hematuria and no proteinuria?

Answer 54

Non-glomerular hematuria

Question 55

Which type of hematuria, glomerular or non-glomerular, is associated with microscopic hematuria and proteinuria?

Answer 55

Glomerular hematuria may also have RBC casts and dysmorphic RBCs

Question 56

Which type of nephrotic syndrome is associated with HIV, heroin use, and obesity?

Answer 56

Focal segmental glomerulosclerosis (FSGS)

Question 57

Which type of nephrotic syndrome is associated with Hodgkin lymphoma?

Answer 57

Minimal change disease

Question 58

Which type of nephrotic syndrome is most common in African Americans and Hispanics? ## Footnote [...]

Answer 58

Focal segmental glomerulosclerosis (FSGS) most common type of nephrotic syndrome overall in adults

Question 59

Which type of nephrotic syndrome is most commonly associated with malignancies?

Answer 59

Membranous nephropathy typically solid cancers (e.g. lung, colon, prostate, breast)

Question 60

Which type of nephrotic syndrome is most commonly associated with renal vein thrombosis?

Answer 60

Membranous nephropathy may present acutely with abdominal pain, fever, and hematuria or gradually as worsening renal function and proteinuria in an asymptomatic patient (more common)

Question 61

Which type of nephrotic syndrome is most likely in a patient with rheumatoid arthritis?

Answer 61

Amyloidosis (AA) characterized by amyloid deposits that stain with Congo red and demonstrate apple-green birefringence under polarized light or as randomly arranged fibrils on electron microscopy

Question 62

Which types of nephrotic syndrome (2) are associated with hepatitis B infection?

Answer 62

membranous nephropathy (more common) and MPGN

Question 63

Winter's formula is use to calculate the expected PaCO2 in a patient with metabolic acidosis via the equation: PaCO2 = [...]

Answer 63

PaCO2 = (1.5\*HCO3-) + 8 +/- 2 a patient with a PaCO2 within the expected range suggests adequate respiratory compensation

Question 64

[...] casts are nonspecific and are often seen in concentrated urine samples (can be a normal finding).

Answer 64

**Hyaline** casts are nonspecific and are often seen in concentrated urine samples (can be a normal finding).