Sarcoidosis

From Ganfyd

A chronic condition characterised by non-necrotising granulomas of unknown aetiology. The term sarcoid invented in 1899 by dermatologist Caesar Boeck.

Clinical Features

Diverse with peak incidence in the third decade. There is variation with race and latitude. One of the causes of hilar lymphadenopathy and hypercalcaemia. It is rarely possible to be sure of the diagnosis on clinical grounds without histological evidence, unless a patient presents with Löfgren's syndrome. About 5% get sarcoid of the nervous system (neurosarcoidosis).

Respiratory

Respiratory symptoms present in about 90% of cases.

• Dyspnoea
• Wheeze or fine anterior crackles sometimes
• Sometimes normal chest on examination
• Clubbing is rare

Systemic

• Fatigue and malaise is actually very common (two thirds)
• Lymphadenopathy

Skin

• Erythema nodosum
  • Lofgren's syndrome has excellent prognosis
• Lupus pernio

Ocular

• Uveitis - important as posterior uveitis easy to miss without slit lamp examination and present in over 10%
  • Heerfordt's syndrome

Nervous system

Rare but serious.

• Mengio-encephalitis
• Isolated nerve palsy
• Neuropathy

Renal

Important as always in differential of:

• Nephritis
• Renal stones

Cardiac

Important as potentially life threatening

• Arrhythmias

Musculoskeletal

• Arthralgia in less than 1%

G/I tract

Rarely involved

• Hepatosplenomegaly
• Intrahepactic cholestasis
• Portal hypertension

Differential diagnosis

• Tuberculosis
• Berylliosis
• Common variable immunodeficiency
• Secondary disease especially when steroids used in treatment:
  • Whipple's disease
  • Tuberculosis yet again

Investigations

• FBC
• ECr
• Calcium
• Immunoglobulins - mainly to exclude common variable immunodeficiency - in sarcoid will have activated immune response
• Serum ACE is nonspecific and not useful in monitoring disease activity and interpretation is now understood to be modified by polymorphisms. Accordingly it is deprecated
• Chest X-ray
• Urine cells & protein
• Spirometry if chest symptoms
• ECG for arrhythmia or conduction abnormalities
• Slit lamp in proven patients to exclude posterior uveitis
• Biopsy is almost always the only way to define the diagnosis. (Gold standard).

Histological Features

Non-caseating granulomata.