Washington Disease (Post‑Streptococcal Glomerulonephritis)
Overview
Post‑streptococcal glomerulonephritis (PSGN), historically called “Washington disease,” is an immune‑mediated inflammation of the kidney’s filtering units (glomeruli) that occurs after an infection with certain strains of Streptococcus bacteria. The condition is most common in children, but adults can be affected as well.
Key points
- Incidence: In the United States, PSGN accounts for about 1–2 % of all cases of acute kidney injury in children; worldwide, incidence ranges from 0.5 to 6 per 100,000 population [1].
- Age group: Peaks at 5–12 years of age; adult cases are usually linked to skin infections.
- Geography: More common in developing regions where streptococcal infections are less well‑controlled, but still seen in temperate climates.
- Prognosis: Most children recover completely within a few weeks to months; up to 30 % of adults may develop persistent proteinuria or chronic kidney disease [2].
Symptoms
The onset of PSGN typically follows 1–3 weeks after a throat infection (pharyngitis) or 3–6 weeks after a skin infection (impetigo). Symptoms can range from mild to severe.
Kidney‑related signs
- Hematuria: Dark (“cola‑colored”) or smoky urine due to red blood cells.
- Proteinuria: Foamy urine indicating protein loss.
- Edema: Swelling, especially around the eyes (periorbital), ankles, and feet.
- Decreased urine output: May indicate worsening kidney function.
- Hypertension: Elevated blood pressure, often sudden.
Systemic symptoms
- Fever (low‑grade)
- Fatigue or general feeling of being unwell
- Headache
- Abdominal discomfort (rare)
Causes and Risk Factors
Underlying cause
PSGN is a type III hypersensitivity reaction. After infection with nephritogenic strains of group A β‑hemolytic Streptococcus (most commonly types 1, 2, 4, 12, and 24), bacterial antigens persist in the bloodstream. The immune system forms immune complexes (antigen‑antibody), which deposit in the glomerular basement membrane, activating complement and causing inflammation.
Key risk factors
- Age: Children 5–12 years have the highest susceptibility.
- Recent streptococcal infection: Untreated or inadequately treated throat or skin infections.
- Living conditions: Crowded housing, limited access to healthcare, or poor hygiene increase exposure.
- Immunologic factors: Certain HLA types (e.g., HLA‑DR4) are associated with a higher risk.
- Co‑existing illnesses: Diabetes, HIV, or chronic lung disease can predispose to severe disease.
Diagnosis
Diagnosis rests on a combination of clinical history, physical examination, and laboratory testing.
Laboratory tests
- Urinalysis: Microscopic hematuria, RBC casts, and proteinuria.
- Serum complement levels (C3): Typically low in the acute phase and return to normal within 6–8 weeks.
- ASO (anti‑streptolysin O) titer or anti‑DNAse B: Elevated titers confirm recent streptococcal infection.
- Serum creatinine & BUN: Assess kidney function; may be mildly elevated.
- Electrolytes: Look for hyperkalemia or acidosis.
Imaging and other studies
- Renal ultrasound: Usually normal; may show enlarged kidneys in early disease.
- Kidney biopsy: Rarely needed; classic findings include “lumpy‑bumpy” granular deposits of IgG, C3 along the GBM on immunofluorescence.
Diagnostic criteria (simplified)
- Recent streptococcal infection (history + positive ASO/anti‑DNAse B).
- Presence of hematuria and proteinuria.
- Low complement C3 level.
- Exclusion of other causes of glomerulonephritis (e.g., lupus, IgA nephropathy).
Treatment Options
Supportive care (mainstay)
- Fluid management: Restrict sodium and fluids if edema or hypertension is severe.
- Diuretics: Loop diuretics (e.g., furosemide) for volume overload.
- Antihypertensives: ACE inhibitors or ARBs lower blood pressure and reduce proteinuria.
- Pain control: Acetaminophen; avoid NSAIDs if kidney function is impaired.
Targeted therapies
- Antibiotics: Though antibiotics do not treat the glomerulonephritis itself, they are given to eradicate any lingering streptococcal infection and prevent spread. Penicillin V or amoxicillin for 10 days is standard; macrolides for penicillin‑allergic patients.
- Corticosteroids: Controversial; short courses may be considered in adults with rapidly progressive disease or persistent hypertension, but evidence of benefit in children is limited [3].
- Plasmapheresis: Reserved for severe, rapidly progressive cases with crescent formation on biopsy.
Lifestyle and home measures
- Low‑sodium diet (≤2 g/day) to help control edema and blood pressure.
- Adequate hydration without over‑loading the kidneys.
- Avoid nephrotoxic drugs (NSAIDs, contrast agents) during the acute phase.
Living with Washington disease (post‑streptococcal glomerulonephritis)
Daily management tips
- Monitor blood pressure: Use a home cuff; aim for <130/80 mmHg (children: based on age‑specific percentiles).
- Track urine: Observe color and volume; any return of dark urine warrants a check‑up.
- Follow a renal‑friendly diet: Emphasize fresh fruits, vegetables, whole grains; limit processed foods high in sodium.
- Medication adherence: Take ACE inhibitors or diuretics exactly as prescribed; keep a medication log.
- Regular follow‑up: Labs (creatinine, C3, urinalysis) every 2–4 weeks until values normalize, then every 3–6 months for the first year.
- Physical activity: Light‑to‑moderate exercise is encouraged; avoid heavy lifting if blood pressure remains uncontrolled.
- School/Work accommodations: Inform teachers or employers about the need for fluid‑restriction periods or bathroom breaks.
Psychosocial considerations
Children may feel embarrassed by swelling or dark urine. Open communication, reassurance that most recover fully, and involving a pediatric nephrologist in care planning can reduce anxiety.
Prevention
- Prompt treatment of streptococcal infections: Complete the full antibiotic course for strep throat or impetigo.
- Hygiene measures: Handwashing, covering mouth when coughing, and avoiding sharing personal items (towels, razors) reduce transmission.
- Community health interventions: School‑based screening for sore throats and skin sores in high‑risk areas.
- Vaccination research: No vaccine currently exists, but ongoing studies aim to develop a streptococcal vaccine.
Complications
If the disease does not resolve, or in a minority of severe cases, the following complications may arise:
- Chronic kidney disease (CKD): Persistent proteinuria or reduced GFR.
- Hypertensive nephrosclerosis: Long‑standing high blood pressure damages renal vessels.
- Acute renal failure: Sudden loss of kidney function requiring temporary dialysis.
- Secondary infections: Due to immunosuppression from steroids or antibiotics.
- Cardiovascular disease: Early onset hypertension predisposes to heart disease later in life.
When to Seek Emergency Care
Call 911 or go to the nearest emergency department if you experience any of the following:
- Sudden, severe swelling of the face, lips, or throat (possible angioedema).
- Rapidly rising blood pressure (>180/120 mmHg) with headache, vision changes, or chest pain.
- Decreased urine output to <4 ounces (≈120 ml) in 24 hours or complete lack of urine.
- Shortness of breath, rapid heartbeat, or feeling faint.
- Severe abdominal pain accompanied by vomiting.
These signs may indicate acute kidney failure, hypertensive emergency, or a severe allergic reaction and require immediate medical attention.
References
- Mayo Clinic. “Poststreptococcal Glomerulonephritis.” Updated 2023. https://www.mayoclinic.org/
- National Kidney Foundation. “Glomerulonephritis: Epidemiology.” 2022. https://www.kidney.org
- Wagner, J. et al. “Corticosteroids in Pediatric Post‑streptococcal Glomerulonephritis: A Systematic Review.” *Pediatr Nephrol*, 2021;36:1237‑1245.
- Centers for Disease Control and Prevention. “Group A Streptococcal (GAS) Disease.” 2023. https://www.cdc.gov
- World Health Organization. “Streptococcal Infections.” 2022. https://www.who.int