Proteinuria

Signs and Symptoms

  • Fatigue, general malaise, reduced appetite
  • Weight changes
  • Facial swelling (in the mornings) and lower limb swelling (in the afternoon)
  • Symptoms related to rheumatologic conditions (skin rash, joint pain, joint stiffness)
  • Cough, shortness of breath

History
  • Changes in the aspect of the urine (foamy) or color (red, tea-colored)
  • Recent illness (pharyngitis and upper respiratory infections) or frequent episodes of fever (lymphoma, malignancies)
  • Medications and herbal/folk medicines
  • llicit drugs use and risk factors for STD in adolescent and adults (HIV, syphilis)
  • UTI in the past (reflux nephropathy)
  • Family history of renal, rheumatological diseases or hearing loss.

Physical Exam
  • General:
    • Hypertension
    • Growth and development
  • HEENT
    • Periorbital edema
    • Malar rash
  • Chest:
    • Pericardial or pleural effusions
  • Abdomen:
    • Ascites
    • Hepatosplenomegaly
    • Abdominal masses/organomegaly
  • Genitalia:
    • Scrotal edema
    • Ambiguous genitalia (Dennys-Drash syndrome)
  • Skin:
    • Purpuric or petechial rash (leukemia, lymphomas)
    • Pallor (malignancies, chronic renal failure, HUS)
    • Angiokeratomas (Fabry disease)
  • Extremities:
    • Pitting edema
    • Arthralgias/Arthritis
    • Dystrophic nails

Tests

Lab

  • Dipstick testing:
    • Always to be performed in a 1st morning urine sample
    • A negative or trace result in a concentrated urine specimen (specific gravity >1,020) is normal.
  • 24-hour collection of urine for protein:
    • It is indicated for quantification of proteinuria and to confirm the diagnosis
    • Normal range: <100 mg/m2/d or <4 mg/m2/hr
  • Spot ratio for protein/creatinine:
    • Always to be performed in a 1st morning urine sample
    • Normal values are <0.2 in children >2 years of age and <0.5 in children 6–24 months old.
    • It is the simplest method to quantitate proteinuria

Differential Diagnosis

  • Idiopathic nephrotic syndrome:
    • Minimal change nephritic syndrome
    • Mesangial proliferation
    • Focal and segmental glomerulosclerosis
    • Membranous nephropathy
  • Nephrotic syndrome owing to genetic causes:
    • Finnish-type congenital nephrotic syndrome
    • Familial focal and segmental glomerulosclerosis
    • Diffuse mesangial sclerosis
    • Denys-Drash syndrome (nephropathy, Wilms tumor, and genital abnormalities)
  • Acquired glomerular disease:
    • Idiopathic glomerulonephritis (membranoproliferative glomerulonephritis)
    • Lupus-associated nephritis
    • IgA nephropathy
    • Systemic vasculitides
    • Subacute bacterial endocarditis
    • Diabetes mellitus
    • Hypertension
    • Hemolytic uremic syndrome
    • Hyperfiltration secondary to nephron loss (with or without sclerosis)
  • Genetic disorders:
    • Nail-patella syndrome
    • Alport syndrome
    • Fabry disease
    • Glycogen storage disease
    • Cystic fibrosis
    • Hurler syndrome (mucopolysaccharide type-1)
    • แα1-antitrypsin
    • แMitochondrial disorders (usually tubular proteinuria)
    • Gaucher diseas
    • Dent disease (X-linked nephrolithiasis
    • Cystinosi
    • Wilson disease
  • Oncologic/Hematologic:
    • Sickle cell disease
    • Renal vein thrombosis
    • Leukemia
    • Lymphoma
  • Infectious:
    • Post-streptococcal glomerulonephritis
    • HIV-associated nephropathy
    • Hepatitis B and C virus infection
    • Malaria
    • Syphilis (can present as congenital nephrotic syndrome)
    • Pyelonephritis
  • Drugs/Toxins:
    • Bee sting
    • Food allergens
    • Antibiotic-induced interstitial nephritis
    • Penicillamine
    • Gold salts
    • NSAIDs
    • Heavy metals (e.g., mercury, lead)
  • Miscellaneous:
    • Tubular interstitial nephritis
    • Acute tubular necrosis
    • Reflux nephropathy
    • Hypothyroidism
    • CHF