Nephrology and Urology

Question 1

Calculate maintenance water requirement

Answer 1

• 100 mL/kg/day for first 10kg
• 50 mL/kg/day for second 10kg
• 20 mL/kg/day for each additional kg

Question 2

Maintenance sodium

Answer 2

2-3 mEq/kg/day

Question 3

Maintenance potassium

Answer 3

2 mEq/kg/d during infancy but decreases with age

Question 4

Classification of dehydration by serum sodium concentration

Answer 4

• Hyponatremic dehydration (Na less than 130 mmol/L)
• Isonatremic dehydration (Na 130-150 mmol/L)
• Hypernatremic dehydration (Na greater than 150 mmol/L)

Question 5

Classification of degree of dehydration

Answer 5

• Mild dehydration 3-5%
• Moderate dehydration 7-10%
• Severe dehydration greater than 12%

Question 6

2 phases of parenteral rehydration

Answer 6

Emergency phase: restore or maintain the intravascular volume to ensure perfusion of vital organs

• 20 mL/kg bolus
• Same for all patients regardless of the initial sodium level

Repletion phase: more gradual correction of the patient’s water and electrolyte deficits

• Acute onset of hyponatremic or isonatremic dehydration generally have their fluid and electrolyte deficits replaced over 24hrs; chronic hyponatremia should be corrected much more slowly
• Hypernatremic dehydration - over 48 hrs to minimize the risk of cerebral edema that may accompany rapid fluid correction

Question 7

Principle behind oral rehydration therapy

Answer 7

Intestinal absorption of sodium and other electrolytes is enhanced by the active absorption of glucose (coupled co-transport mechanism). This coupled co-transport process of intestinal absorption continues to function normally during secretory diarrhea, whereas other pathways of intestinal absorption of sodium are impaired.

Question 8

Infectious causes of hematuria

Answer 8

• UTI

- Hemorrhagic cystitis (adenovirus)

Question 9

Hematologic causes of hematuria

Answer 9

• SCD
• SC trait
• Thrombocytopenia
• Thrombosis (renal artery or vein)

Question 10

Metabolic causes of hematuria

Answer 10

• Hypercalcemia

Question 11

Structural causes of hematuria

Answer 11

• Tumor
• Obstruction
• Stones
• Vascular malformations

Question 12

Glomerular diseases that cause hematuria

Answer 12

• IgA nephropathy
• Henoch-Schonlein purpura
• Poststreptococcal glomerulonephritis
• Alport’s syndrome

Question 13

Benign transient proteinuria

Answer 13

Associated with vigorous exercise, fever, dehydration, and congestive heart failure

Question 14

Orthostatic proteinuria

Answer 14

• Increased urinary protein excretion while upright but not while supine
• Elevated urine TP/CR and normal urine TP/CR
• Benign condition

Question 15

Glomerular proteinuria

Answer 15

Increased permeability of the glomerular capillaries to large molecular weight proteins, as seen in glomerulonephritis

Question 16

Tubular proteinuria

Answer 16

• Decreased reabsorption of LMW proteins by the tubular epithelial cells
• Interstitial nephritis, ischemic renal injury (acute tubular necrosis) and tubular damage resulting from nephrotoxic drugs
• Elevated urinary beta-2 microglobulin, glucosuria and aminoaciduria