First Aid - Renal Pathology I

Question 1

What is renal tubular acidosis?

Answer 1

Renal tubular acidosis is a disorder of the renal tubules that leads to non-anion gap hyperchloremic metabolic acidosis

Question 2

What is type 1 renal tubular acidosis, what is it associated with, and what causes it?

Answer 2

Type 1 (distal, pH>5.5) results from a defect in the a-intercalated cells to secrete H+, thus no new HCO3 is generated -> metabolic acidosis. Associated with hypokalemia. Caused by amphotericin B toxicity, analgesic nephropathy, multiple myeloma, and obstruction/congenital abnormalities of the urinary tract.

Question 3

What is type 2 renal tubular acidosis, what is it associated with, and what causes it?

Answer 3

Type 2 (proximal, pH less than 5.5) results from a defect in HCO3 reabsorption in proximal tubule and increased HCO3- excretion -> metabolic acidosis. Associated with hypokalemia. Caused by Fanconi syndrome, lead, aminoglycosides, carbonic anhydrase inhibitors.

Question 4

What is type 4 renal tubular acidosis, what is it associated with, and what causes it?

Answer 4

Caused by hypoaldosteronism, aldosterone resistance, or K+ sparing diuretics. The resulting hyperkalemia impairs ammoniagenesis decreasing buffering capacity and H+ secretion into urine.

Question 5

What do RBC casts indicate?

Answer 5

Glomerulonephritis, ischemia, or malignant hypertension

Question 6

What do WBC casts indicate?

Answer 6

Tubulointerstitial inflammation, acute pyelonephritis, transplant rejection

Question 7

What do fatty (oval fat bodies) casts indicate?

Answer 7

Nephrotic syndrome

Question 8

What do granular (Muddy Brown) casts indicate?

Answer 8

Acute tubular necrosis

Question 9

What do waxy casts indicate?

Answer 9

Advanced renal disease

Question 10

What do hyaline casts indicate?

Answer 10

Nonspecific, may be a normal finding, often seen in concentrated urine samples.

Question 11

What does “focal” disorder mean, and what is one example?

Answer 11

Focal indicates less than 50% of glomeruli are involved, i.e. Focal Segmental Glomerulosclerosis

Question 12

What does “Diffuse” disorder mean, and what is one example?

Answer 12

Diffuse indicates greater than 50% of glomeruli are involved, i.e. Diffuse Proliferative Glomerulonephritis

Question 13

What does “Proliferative” disorder mean, and what is one example?

Answer 13

Proliferative indicates hypercellular glomeruli, ie Membranoproliferative Glomerulonephritis

Question 14

What does “Membranous” disorder mean, and what is one example?

Answer 14

Membranous indicates a thickening of the glomerular basement membrane, i.e. Membranous Nephropathy

Question 15

What does “Primary glomerular disease” mean, and what is one example?

Answer 15

Primary glomerular disease means it involves only the glomerulus (thus a primary disease of the kidney), i.e. Minimal Change Disease

Question 16

What does “Secondary glomerular disease” mean, and what is one example?

Answer 16

Involves glomeruli and other organs, thus a disease of another organ system or a systemic disease that impacts the kidney, i.e. SLE, diabetic neuropathy.

Question 17

Name four diseases of nephritic syndrome

Answer 17

Acute post streptococcal glomerulonephritis, Rapidly progressive glomerulonephritis, Berger disease (IgA glomerulonephropathy), Alport syndrome

Question 18

Name five diseases of nephrotic syndrome

Answer 18

Focal segmental glomerulosclerosis, membranous nephropathy, minimal change disease, amyloidosis, diabetic glomerulonephropathy

Question 19

Name two diseases that are both nephritic and nephrotic

Answer 19

Diffuse proliferative glomerulonephritis, Membranoproliferative glomerulonephritis