Sarcoidosis

Question 1

Definition

Answer 1

Multisystem granulomatous inflammatory disorder

Question 2

Aetiology

Answer 2

• UNKNOWN

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

Question 3

Pathogenesis

Answer 3

o An UNKNOWN antigen is presented on MHC class 2 complexes on macrophages
to CD4+ T-lymphocytes
o These accumulate and release cytokines
o This leads to the formation of non-caseating granulomas in organs

Question 4

Epidemiology

Answer 4

• Most common in AFRICANS and SCANDINAVIANS

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

Question 5

Presenting symptoms (general)

Answer 5

o Fever
o Malaise
o Weight loss
o Bilateral parotid swelling
o Lymphadenopathy
o Hepatosplenomegaly

Question 6

Presenting symptoms (pulmonary)

Answer 6

o Breathlessness
o Dry cough
o Chest discomfort
o Minimal clinical signs

Question 7

Presenting symptoms (musculoskeletal)

Answer 7

o Bone cysts (e.g. dactylitis)
o Polyarthralgia
o Myopathy

Question 8

Presenting symptoms (eye)

Answer 8

o Keratoconjunctivitis sicca (inflammation of the conjunctivitis and surrounding tissues due to the eyes being dry)
o Uveitis
o Papilloedema

Question 9

Presenting symptoms (skin)

Answer 9

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

Question 10

Presenting symptoms (neurological)

Answer 10

o Lymphocytic meningitis
o Space-occupying lesions
o Pituitary infiltration
o Cerebellar ataxia
o Cranial nerve palsies
o Peripheral neuropathy

Question 11

Presenting symptoms (cardiac)

Answer 11

o Arrhythmia
o Bundle branch block
o Pericarditis
o Cardiomyopathy
o Congestive cardiac failure

Question 12

Investigations (bloods and urine)

Answer 12

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

• 24 hr Urine Collection
o Hypercalciuria

Question 13

Investigations (scan)

Answer 13

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

• High-Resolution CT Scan
o Check for diffuse lung involvement

• Gallium Scan - shows areas of inflammation

Question 14

Investigations (pulmonary)

Answer 14

• Pulmonary Function Tests
o Low FEV1
o FVC shows restrictive picture

• Bronchoscopy and Bronchoalveolar Lavage
o High lymphocytes
o High CD4: CD8 ratio

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