Sarcoidosis

🌟 Sarcoidosis is a systemic inflammatory disease with non-caseating granulomas in multiple organs. Cause unknown, likely due to genetic susceptibility + environmental triggers (infection, dusts, occupational exposures). Most commonly affects lungs + lymph nodes, but can involve almost any system.

ℹ️ About

• Non-caseating granulomatous disease 🧬
• Protean manifestations → lungs, skin, eyes, heart, nervous system, etc.

📊 Epidemiology

• Age of onset: 20–40 years.
• Blacks > Whites; Females > Males.
• Common in African-Americans and Northern Europeans.

🔬 Pathology: Granulomas = macrophages + T cells. Leads to local inflammation, fibrosis, and organ dysfunction.

🧬 Aetiology / Immunology

• Cutaneous anergy: ↓ skin reaction to tuberculin.
• Sequestration of T cells in lungs → ↓ circulating T cells.
• ↑ CD4 cells in bronchi, mildly ↑ B cells in blood.
• Abnormal immune response → granuloma formation.

🩺 Clinical Features (by system)

🫁 Pulmonary Staging (CXR)

• Stage I: Bilateral hilar lymphadenopathy (BHL), no infiltrates
• Stage II: BHL + pulmonary infiltrates
• Stage III: Pulmonary infiltrates only
• Stage IV: Pulmonary fibrosis ± honeycombing

🧪 Investigations

• ↑ ESR/CRP, ↑ ACE, hypercalcaemia (10%).
• Negative tuberculin skin test (anergy).
• Bronchoscopy: cobblestoning; lavage → ↑ CD4:CD8 ratio.
• Biopsy: non-caseating granulomas.
• PFTs: Restrictive pattern, ↓ DLCO.
• HRCT: BHL, ground-glass, fibrosis.
• Gallium-67 scan → “Panda sign” (lacrimal/salivary uptake).
• ECG/tape: arrhythmias, AV block.

⚖️ Differentials

• TB (caseating granulomas – exclude before steroids!) 🧪
• Lymphoma
• Lung cancer with local spread

📈 Prognosis & Indicators

• Good: young age, erythema nodosum, Stage I, Löfgren syndrome.
• Poor: >40 years, Afro-Caribbean, symptoms >6 months, lupus pernio, multi-organ disease, Stage III–IV.

💊 Management

🎯 Exam Pearls

• Löfgren syndrome = acute sarcoid with good prognosis ✅
• Heerfordt syndrome = parotid + uveitis + CN VII palsy
• Exclude TB before giving steroids 🧪
• Lupus pernio = bad prognosis 🚨
• Panda sign = Gallium scan uptake in lacrimal/salivary glands 🐼

3 Clinical Cases - Sarcoidosis 🫁🌍

• Case 1 - Pulmonary sarcoidosis (typical) 🫁: A 34-year-old Afro-Caribbean woman presents with progressive exertional breathlessness and dry cough. CXR shows bilateral hilar lymphadenopathy with reticulonodular shadowing. Spirometry reveals a restrictive pattern and DLCO is reduced. Serum ACE is mildly elevated. Teaching: Pulmonary involvement is the most common presentation (over 90%). The classical CXR finding is bilateral hilar lymphadenopathy ± parenchymal infiltrates. Diagnosis is clinical + histology showing non-caseating granulomas.
• Case 2 - Acute presentation (Löfgren’s syndrome) 🔥: A 28-year-old woman presents with fever, bilateral ankle swelling, painful red nodules over the shins (erythema nodosum), and arthralgia. CXR shows bilateral hilar lymphadenopathy. Teaching: Löfgren’s syndrome (erythema nodosum + bilateral hilar lymphadenopathy + arthritis/arthralgia) is a classic acute presentation. Prognosis is usually excellent with spontaneous resolution in many cases.
• Case 3 - Extrapulmonary sarcoidosis (cardiac) ❤️: A 45-year-old man presents with palpitations, presyncope, and exertional dyspnoea. ECG shows complete heart block. Cardiac MRI demonstrates patchy myocardial infiltration, and biopsy confirms non-caseating granulomas. Teaching: Cardiac sarcoidosis can present with arrhythmias, conduction block, or cardiomyopathy. It is a serious manifestation requiring immunosuppression and sometimes pacemaker/ICD implantation.