Nephrology Flashcards
Diagnosis of microscopic hematuria
> 5 WBC/hpf
Evaluation of microscopic hematuria
- 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.
Interpretation of UrCa:UrCr ratio
- If >0.25, evaluate for hypercalcuria
- If < 0.25, get RUS
What are you looking for on RUS in patient with microscopic hematuria?
- Ureteropelvic junction (UPJ) obstruction ( = dilated calyces on US)
- If dilated calyces are noted, confirm with MAG3/furosemide scan. If reveals delayed excretion = UPJ obstruction.
Confirmative testing for UPJ obstruction (after RUS)
- MAG3/furosemide scan showing delayed excretion
Laboratory findings in renal failure
- 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%
How to calculate fractional excretion of sodium
- *You NaCr! Pee NaCr!**
- FeNa = [(UNa/UCr)/(PNa/PCr)]
Interpretation of FeNa
- < 1% = prerenal disease with low renal perfusion
- > 2% = tubular or glomerular damage
Acrostic to remember Hemolytic Uremic Syndrome
- *HAT**
- Hemolytic anemia
- Acute renal failure
- Thrombocytopenia
Acrostic to remember TTP-HUS
- *FAT RN**
- Fever
- Anemia
- Thrombocytopenia
- Renal failure
- Neurologic symptoms
Most common cause of primary glomerulonephritis
IgA nephropathy
Timing of previous infections in PSGN
- Strep throat 2-3 weeks prior
- Skin infection 4-6 weeks prior
Lab findings with PSGN
- Low C3
- NORMAL C4
- +/- renal impairment
Lab findings with MPGN
- Low C3 AND LOW C4 (as opposed to low C3 and normal C4 with PSGN)
Biopsy findings with PSGN
Lumpy, bumpy IgG deposits
Biopsy findings with IgA nephropathy
IgA and IgG mesangial deposits (and C3)
IgA nephropathy
- Recurrent episodes of hematuria
- Hematuria may worsen with URI or GI illnesses
- In between episodes, may see microscopic hematuria
- NO complement abnormalities!!!!
Diagnosis of IgA nephropathy
- Renal biopsy showing IgA and IgG mesangial deposits (and C3)
Diagnosis of PSGN
- Diagnosis based on clinical history + evidence of preceding strep infection (i.e. strep throat, skin infection, elevated streptococcal antibodies)
