Nephrology

Question 1

Diagnosis of microscopic hematuria

Answer 1

> 5 WBC/hpf

Question 2

Evaluation of microscopic hematuria

Answer 2

• Unless patient has symptoms, do not get aggressive initially!
• Repeat UA in 2 weeks
• If hematuria present on repeat UA, evaluated for systemic symptoms and check family history.
• First step of work-up = Urine Ca:Urine Cr. *If this answer is not an option, consider RUS, serum BUN/Cr, coags, CBC (for plts), ANA, anti-DS DNA, complement levels or ESR.

Question 3

Interpretation of UrCa:UrCr ratio

Answer 3

• If >0.25, evaluate for hypercalcuria

- If < 0.25, get RUS

Question 4

What are you looking for on RUS in patient with microscopic hematuria?

Answer 4

• Ureteropelvic junction (UPJ) obstruction ( = dilated calyces on US)
• If dilated calyces are noted, confirm with MAG3/furosemide scan. If reveals delayed excretion = UPJ obstruction.

Question 5

Confirmative testing for UPJ obstruction (after RUS)

Answer 5

• MAG3/furosemide scan showing delayed excretion

Question 6

Laboratory findings in renal failure

Answer 6

• Elevated creatinine & BUN
• Elevated urine sodium (tubules dysfunctional)
• Normocytic anemia (decreased EPO production)
• Vitamin D deficiency
• Hypocalcemia
• Elevated phosphorous
• Metabolic acidosis (due to bicarb loss & increased H+ excretion)
• FeNa >2%

Question 7

How to calculate fractional excretion of sodium

Answer 7

• *You NaCr! Pee NaCr!**

- FeNa = [(UNa/UCr)/(PNa/PCr)]

Question 8

Interpretation of FeNa

Answer 8

• < 1% = prerenal disease with low renal perfusion

- > 2% = tubular or glomerular damage

Question 9

Acrostic to remember Hemolytic Uremic Syndrome

Answer 9

• *HAT**
• Hemolytic anemia
• Acute renal failure
• Thrombocytopenia

Question 10

Acrostic to remember TTP-HUS

Answer 10

• *FAT RN**
• Fever
• Anemia
• Thrombocytopenia
• Renal failure
• Neurologic symptoms

Question 11

Most common cause of primary glomerulonephritis

Answer 11

IgA nephropathy

Question 12

Timing of previous infections in PSGN

Answer 12

• Strep throat 2-3 weeks prior

- Skin infection 4-6 weeks prior

Question 13

Lab findings with PSGN

Answer 13

• Low C3
• NORMAL C4
• +/- renal impairment

Question 14

Lab findings with MPGN

Answer 14

• Low C3 AND LOW C4 (as opposed to low C3 and normal C4 with PSGN)

Question 15

Biopsy findings with PSGN

Answer 15

Lumpy, bumpy IgG deposits

Question 16

Biopsy findings with IgA nephropathy

Answer 16

IgA and IgG mesangial deposits (and C3)

Question 17

IgA nephropathy

Answer 17

• Recurrent episodes of hematuria
• Hematuria may worsen with URI or GI illnesses
• In between episodes, may see microscopic hematuria
• NO complement abnormalities!!!!

Question 18

Diagnosis of IgA nephropathy

Answer 18

• Renal biopsy showing IgA and IgG mesangial deposits (and C3)

Question 19

Diagnosis of PSGN

Answer 19

• Diagnosis based on clinical history + evidence of preceding strep infection (i.e. strep throat, skin infection, elevated streptococcal antibodies)