IgA Nephropathy (Berger's disease)

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🧑‍⚕️ IgA nephropathy (Berger’s Disease) is the most common cause of glomerulonephritis worldwide. It typically affects young males and classically presents with frank haematuria following an episode of pharyngitis. ~20% progress to end-stage renal failure (ESRF) over time.

About 📖

• IgA Nephropathy: Accounts for ~40% of GN cases globally.
• Initial presentation often with microscopic haematuria, later progressing to proteinuria.
• Part of the same spectrum as Henoch–Schönlein Purpura (IgA vasculitis).

Aetiology 🔬

• Deposition of IgA in the mesangium, triggering inflammation and glomerular damage.
• Immune-mediated but exact cause unknown.
• Seen in association with chronic mucosal immune stimulation (e.g., recurrent infections, gut/liver disease).

Clinical Features 🚨

• 🔴 Haematuria: Gross, often within 24–48h of an upper respiratory infection (pharyngitis). Classic “synpharyngitic” presentation.
• 💧 Proteinuria: Variable severity; can reach nephrotic levels in some.
• 📈 Hypertension: Common in progressive disease.
• 🦠 Pharyngitis link: Key distinguishing feature from post-streptococcal GN (which presents weeks later, not immediately).

Investigations 🧪

• Urinalysis: Microscopic or visible haematuria, proteinuria, red cell casts.
• Renal Biopsy: Definitive test:
  • Mesangial proliferation + IgA deposition.
  • Crescents → marker of severe disease & poor prognosis.
• Complement: C3/C4 usually normal (helps differentiate from lupus/post-strep GN).
• Serum IgA: May be elevated but not specific.

Associations 🔗

• 🦴 Ankylosing spondylitis
• 🍺 Chronic liver disease (esp. cirrhosis)
• 🌾 Dermatitis herpetiformis (linked to gluten sensitivity)

Management 💊

• 📉 BP Control: ACE inhibitors or ARBs slow progression & reduce proteinuria.
• 💊 Steroids: May be helpful in patients with heavy proteinuria.
• 🛡️ Immunosuppressants: Not routinely beneficial; case-by-case basis.
• 🔄 CKD Care: If progression to ESRF ➝ dialysis or renal transplantation.

Prognosis 📊

• ~20% progress to ESRF within 20 years.
• Poor prognostic factors: male sex, older age, nephrotic syndrome, hypertension, crescentic lesions on biopsy.
• Renal transplantation is effective, but recurrence of IgA deposits can occur in the graft.

Exam Clinical Pearl ✨

If a young man develops visible haematuria immediately after a sore throat, think IgA nephropathy. If haematuria occurs 2–3 weeks later, think post-streptococcal GN.

Cases - IgA Nephropathy (Berger’s Disease)

• Case 1 - Synpharyngitic haematuria 🩸: A 22-year-old man presents with cola-coloured urine that developed 24 hours after a sore throat. No oedema. Urine dip: blood +++, protein ++. Renal biopsy: mesangial IgA deposition on immunofluorescence. Diagnosis: classic IgA nephropathy. Managed with ACE inhibitor and BP control.
• Case 2 - Progressive renal impairment ⏳: A 35-year-old woman with a history of recurrent haematuria is found to have proteinuria (1.5 g/day) and declining eGFR over 2 years. Blood pressure 155/95. Diagnosis: IgA nephropathy with progressive CKD. Managed with aggressive BP control (ACEi/ARB), immunosuppression if high-risk, and nephrology follow-up.
• Case 3 - Rapid progression / overlap 🌐: A 28-year-old man presents with nephritic syndrome (oedema, hypertension, haematuria, rising creatinine). Biopsy: crescentic GN with IgA deposition. Diagnosis: crescentic IgA nephropathy (rapidly progressive). Managed with high-dose corticosteroids and cyclophosphamide.

Teaching Point 🩺: IgA nephropathy is the commonest primary glomerulonephritis worldwide. Classic presentation = synpharyngitic haematuria (haematuria soon after an upper respiratory infection). Prognosis varies: some remain stable, others progress to ESRD. Management focuses on BP control, proteinuria reduction, and immunosuppression in progressive disease.