Tubular Diseases

Question 1

Acute Tubular Necrosis

Answer 1

Damage to the RTE cells from decreased blood flow that causes ischemia (shock) or the presence of toxic substances (including high levels of hemoglobin and myoglobin). Findings include mild proteinuria, microscopic hematuria, RTE cells and RTE cell casts containing tubular fragments; Tubular damage produces hyaline, granular, waxy, and broad casts.

Question 2

Fanconi Syndrome

Answer 2

Generalized failure of tubular reabsorption in the proximal convoluted tubule, substances affected include glucose, amino acids, phosphorous, sodium, potassium, bicarbonate, and water. May be inherited in association with cystinosis and Hartnup disease or acquired through exposure to toxic agents, or seen as a complication of multiple myeloma and renal transplant. Findings include glycosuria with normal blood glucose, low pH due to the failure to reabsorb bicarbonate.

Question 3

Uromodulin Assoc. Kidney Disease

Answer 3

Only protein produced by kidney in the proximal and distal convoluted tubules. An inherited disorder caused by an autosomal mutation in the gene that produces uromodulin. Abnormal uromodulin is still produced by the tubular cells and accumulates, resulting in their destruction. Also causes an increase in serum uric acid, resulting in persons developing gout.

Question 4

Diabetic Nephropathy

Answer 4

Most common cause of end-stage renal disease. Damage to the glomerular membrane occurs as a result of glomerular membrane thickening, increased proliferation of mesangial cells and increased deposition of cellular and noncellular material in the glomerular matrix, resulting in accumulation of solid substances around the capillary tufts.

Question 5

Nephrogenic Diabetes Insipidus

Answer 5

Excessive amounts of urine are excreted.

Inherited as a sex-linked recessive gene or acquired from medications, including lithium and amphotericin B.

Low specific gravity, pale yellow color, and possible false-negative results for chemical tests.

Question 6

Renal Glycosuria

Answer 6

Number of glucose transporters in the tubules is decreased or the affinity of the transporters for glucose is decreased

Question 7

Acute Pyelonephritis

Answer 7

Predominant casts will be WBC, occurs as a result of ascending movement of bacteria from a lower UTI into the renal tubules and interstitium.

Question 8

Chronic Pyelonephritis

Answer 8

Congenital urinary structural defects producing reflux nephropathy are the most frequent cause of chronic pyelonephritis

Question 9

Renal Failure

Answer 9

• Progression to end-stage renal disease causes a
• Decrease in the glomerular filtration rate (less than 25 mL/min)
• Steadily rising serum BUN and creatinine values (azotemia)
• Electrolyte imbalance
• Lack of renal concentrating ability
• Proteinuria
• Renal glycosuria
• Abundance of granular, waxy, and broad casts