Related Subjects:
|X linked Agammaglobulinaemia (Bruton)
|X-linked lymphoproliferative disease (Children)
|Chediak Higashi syndrome
|Common variable immunodeficiency
|Severe combined immunodeficiency disorders
|DiGeorge syndrome (thymic aplasia)
|Selective IgA deficiency
|Wiskott-Aldrich syndrome (Children)
|T lymphocytes
📖 About
- 🧬 Common Variable Immunodeficiency (CVID) is a primary immunodeficiency with defective B-cell differentiation → impaired antibody (IgG, IgA ± IgM) production.
- 📊 One of the most common primary immunodeficiencies (1:25,000–50,000) but highly variable in presentation → hence the name.
- 👩🎓 Often presents in adolescence/early adulthood; diagnosis is frequently delayed.
🩺 Clinical Features
- 🌬️ Recurrent respiratory infections: Sinopulmonary infections (pneumonia, sinusitis, otitis media). Chronic infections → bronchiectasis & lung disease.
- ♻️ Autoimmune disease: ~25% (ITP, autoimmune haemolytic anaemia, RA, pernicious anaemia).
- 🍽️ Gastrointestinal disease: Chronic diarrhoea, malabsorption (Giardia), ↑ risk gastric carcinoma & lymphoma.
- 🦠 Lymphoproliferation: Generalised lymphadenopathy, splenomegaly, granulomatous disease (may mimic sarcoid).
- 😴 Fatigue & inflammation are common.
🔎 Investigations
- 🧪 Serum immunoglobulins: ↓ IgG, ↓ IgA, ± ↓ IgM.
- 💉 Functional antibody testing: Poor/absent vaccine responses (pneumococcal, tetanus).
- 🔬 Flow cytometry: Reduced memory B cells, abnormal isotype switching; T-cell abnormalities may coexist.
- 🚫 Exclusion: Rule out secondary causes (nephrotic syndrome, protein-losing enteropathy, drugs like rituximab).
⚕️ Management
- 💉 Immunoglobulin replacement: Lifelong IVIg or SC Ig → reduces infections & prevents organ damage.
- 🦠 Infections: Prompt antibiotics; prophylaxis in selected patients.
- ⚖️ Autoimmunity: Steroids, rituximab, or other immunosuppressants for ITP, AIHA, arthritis.
- 💉 Vaccination: Avoid live vaccines; use inactivated ones (though response may be weak).
- 📅 Monitoring: Lifelong follow-up for bronchiectasis (HRCT, PFTs), lymphoma, gastric cancer, autoimmunity.
💡 Teaching pearl:
CVID is “variable” because it causes more than infections → think autoimmunity, granulomatous disease, and malignancy. Always manage broadly, not just with IVIg.
