Glomerulonephritis

Background

• Glomerulonephritis (GN) = inflammation of the glomeruli, characterized by hematuria, proteinuria, and often RBC casts
• Presents as nephritic syndrome: hematuria, hypertension, edema, oliguria, mild-moderate proteinuria, elevated creatinine
• Distinguished from nephrotic syndrome (massive proteinuria >3.5g/day, hypoalbuminemia, edema, hyperlipidemia)
• Most common cause in children: post-streptococcal GN (typically self-limited)
• In adults: IgA nephropathy is most common worldwide

Causes of Glomerulonephritis

• Poststreptococcal glomerulonephritis
• Hemolytic-uremic syndrome
• Henoch-Schonlein purpura
• IgA nephropathy
• Lupus nephritis
• Alport syndrome
• Goodpasture syndrome
• Paraneoplastic

Clinical Features

• Cola/tea-colored urine (glomerular hematuria)
• Periorbital or peripheral edema
• Hypertension (often the presenting finding)
• Oliguria
• Recent URI or skin infection 1-3 weeks prior (post-streptococcal)
• Rash + arthralgia (HSP/IgA vasculitis, SLE)
• Fever + bloody diarrhea → anemia + thrombocytopenia (consider hemolytic uremic syndrome)
• Hemoptysis + renal failure (pulmonary-renal syndrome: Goodpasture, granulomatosis with polyangiitis)

Differential Diagnosis

Hematuria

Sources of hematuria.

• Urologic (lower tract)
  • Any location
    • Iatrogenic/postprocedure
    • GU trauma
    • Infection
    • Kidney stone
    • Erosion or mechanical obstruction by tumor
  • Ureter(s)
    • Dilatation of stricture
  • Bladder
    • Transitional cell carcinoma
    • Vascular lesions or malformations
    • Chemical or radiation cystitis
  • Prostate
    • Benign prostatic hypertrophy
    • Prostatitis
  • Urethra
    • Stricture
    • Diverticulosis
    • Foreign body
    • Endometriosis (cyclic hematuria with menstrual pain)
• Renal (upper tract)
  • Glomerular
    • Glomerulonephritis
    • IgA nephropathy (Berger disease)
    • Lupus nephritis
    • Hereditary nephritis (Alport syndrome)
    • Toxemia of pregnancy
    • Serum sickness
    • Erythema multiforme
  • Nonglomerular
    • Interstitial nephritis
    • Pyelonephritis
    • Papillary necrosis: sickle cell disease, diabetes, NSAID use
    • Vascular: arteriovenous malformations, emboli, aortocaval fistula
    • Malignancy
    • Polycystic kidney disease
    • Medullary sponge disease
    • Tuberculosis
    • Renal trauma
• Hematologic
  • Primary coagulopathy (e.g., hemophilia)
  • Pharmacologic anticoagulation
  • Sickle cell disease
• Myoglobinuria - positive blood, no RBCs: rhabdomyolysis
• Hemoglobinuria - positive blood, no RBCs
  • TTP / HUS
  • DIC
  • Mechanical valve emergency
  • Hemolytic anemia
  • Paroxysmal Nocturnal Hemoglobinuria
• Miscellaneous
  • Eroding abdominal aortic aneurysm
  • Malignant hypertension
  • Loin pain–hematuria syndrome
  • Renal vein thrombosis
  • Exercise-induced hematuria
  • Cantharidin (Spanish fly) poisoning
  • Stings/bites by insects/reptiles having venom with anticoagulant properties
  • Schistosomiasis
  • Sickle Cell Trait

Evaluation

• Urinalysis: hematuria, proteinuria, RBC casts (pathognomonic for GN)
• BMP: creatinine, BUN, electrolytes (hyperkalemia from renal failure)
• CBC: anemia (HUS, chronic disease), thrombocytopenia (HUS/TTP, SLE)
• Albumin (reduced in nephrotic features)
• Complement levels: low C3 (post-strep GN, MPGN, lupus), low C3 + C4 (lupus)
• ASO titer, anti-DNase B (post-streptococcal)
• ANA, anti-dsDNA (lupus nephritis)
• ANCA (vasculitis)
• Anti-GBM antibodies (Goodpasture)
• Peripheral smear if HUS suspected (schistocytes)
• CXR if pulmonary-renal syndrome suspected

Management

• Hypertension control: most important acute intervention — risk of hypertensive encephalopathy/seizures
• Fluid/sodium restriction for edema and volume overload
• Diuretics (furosemide) for significant edema or pulmonary congestion
• Treat hyperkalemia if present
• Do not delay empiric treatment for rapidly progressive GN (RPGN) — high-dose IV corticosteroids while awaiting biopsy results
• Nephrology consultation for all suspected GN
• Specific therapy depends on etiology (immunosuppression, plasmapheresis for Goodpasture/ANCA, supportive care for post-strep)

Disposition

• Admit: significant renal impairment, severe hypertension, pulmonary edema, suspected RPGN, HUS
• Discharge: mild post-strep GN with controlled BP and stable renal function — close nephrology follow-up within 24-48 hours
• Return precautions: decreased urine output, swelling, headache, visual changes, blood in urine

See Also

• Hematuria
• Hematuria (peds)
• Nephrotic syndrome
• Hemolytic uremic syndrome