Sarcoidosis

Question 1

Define sarcoidosis

Answer 1

Multisystem granulomatous inflammatory disorder

Question 2

Explain the aetiology/risk factors of sarcoidosis

Answer 2

UNKNOWN

Transmissible agents (e.g. viruses), environmental triggers and genetic factors have all been suggested

Pathogenesis
An UNKNOWN antigen is presented on MH
C class 2 complexes on macrophages to CD4+ T-lymphocytes.

These accumulate and release cytokines

This leads to the formation of non-caseating granulomas in organs

Question 3

Summarise the epidemiology of sarcoidosis

Answer 3

Most common in AFRICANS and SCANDINAVIANS

Can occur at any age but tends to be in adults > 50 yrs

Question 4

Recognise the presenting symptoms and the signs of sarcoidosis

Answer 4

General Symptoms - Fever, Malaise, Weight loss, Bilateral parotid swelling, Lymphadenopathy,Hepatosplenomegaly

Pulmonary Symptoms - Breathlessness, Dry cough, Chest discomfort, Minimal clinical signs

Musculoskeletal Symptoms - Bone cysts (e.g. dactylitis), Polyarthralgia, Myopathy

Eye Symptoms - Keratoconjunctivitis sicca, Uveitis, Papilloedema

Skin Symptoms - Lupus pernio (red-blue infiltrations of the nose, cheeks, ears and terminal phalanges), Erythema nodosum, Maculopapular eruptions

Neurological Symptoms - Lymphocytic meningitis, Space-occupying lesions, Pituitary infiltration, Cerebellar ataxia, Cranial nerve palsies, Peripheral neuropathy

Cardiac Symptoms - Arrhythmia, Bundle branch block, Pericarditis, Cardiomyopathy, Congestive cardiac failure

Question 5

Identify appropriate investigations for sarcoidosis

Answer 5

Bloods - High serum ACE, High calcium, High ESR
FBC - WCC may be low due to lymphocyte sequestration in the lungs
Immunoglobulins - polyclonal hyperglobulinaemia
LFTs - high ALP + GGT

24 hr Urine Collection - Hypercalciuria

CXR
Stage 0 - may be clear
Stage 1 - bilateral hilar lymphadenopathy
Stage 2 - stage 1 with pulmonary infiltration and
paratracheal node enlargement
Stage 3 - pulmonary infiltration and fibrosis

High-Resolution CT Scan - Check for diffuse lung involvement

Gallium Scan - shows areas of inflammation

Pulmonary Function Tests - Low FEV1, FVC shows restrictive picture

Bronchoscopy and Bronchoalveolar Lavage
High lymphocytes
High CD4: CD8 ratio

Transbronchial Lung Biopsy (or lymph node biopsy)
Shows non-caseating granulomas consisting of:
Epithelioid cells (activated macrophages)
Multinucleate Langerhans cells
Mononuclear cells (lymphocytes)