Sarcoidosis

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Sarcoidosis

Heterogenous multisystem/systemic non-infectious inflammatory noncaseating granulomatous polymorphic disease of unknown aetiology – can affect almost every organ (primarily lung and lymphatic system). Prevalence of about 1.4/100 000 (Japan), 20/100 000 (UK) 65/100 000 (Sweden). Most often affects females (9:1). Diverse clinical presentation and course  early recognition is a challenge (delayed diagnosis is common).

Pathophysiology is the development of widespread noncaseating granuloma in response to a non-specific stimulus  due to abnormal immune response. Thought to be due to various antigens activating T-cells in those that are genetically predisposed  helper T cells attract monocytes  granuloma formation. In blood there is evidence of depressed cellular immunity and increased humoral immunity.

Most common presentation is young woman between ages of 20 and 40 with bilateral hilar lymphadenopathy on chest x-ray, pulmonary infiltration (lungs affected in 90%) and eye and skin lesions (in 25% and usually occur early; small papules of variable colours; annular plaques). May have history of asthma, skin rash, arthritic symptoms – may have abnormal chest x-ray. Up to a third present with nonspecific fever, malaise and weight loss. Skin sensitivity to tuberculin is reduced or absent.

A granulomatous arthritis develops late in the disease (affects ~5%) – commonly knee or ankle. Other musculoskeletal manifestations include bone cysts, osteolytic lesions, chronic myopathy and tenosynovitis. Visser et al (2002) that the joint symptoms started symmetrically in 75% in large joints of the leg – ankle affected in 98%. Most were treated with NSAID’s and course of arthritis in most was self limiting.

Several sets of criteria for diagnosis have been proposed, but none have universal acceptance.

Up to 5% develop a peripheral neuropathy.

Nail dystrophy has been reported (Cox & Gawkrodger, 1988) – subungual hyperkeratosis can occur and may be associated with underlying bone disease – on x-ray, usually a sclerosis and/or distal tuft resorption and maybe cystic lesions ( dactylitis). Onychogryphosis of the toenails has been reported in a case as being the presenting feature of sarcoidosis – the changes to the nail resembled onychomycosis (dystrophy, hyperkeratosis and onycholysis) – x-rays showed distal resorption of the distal phalanges – sarcoidosis was confirmed with a chest x-ray (hilar adenopathy).

Heel pain has also been reported and has been reported as being the presenting complaint in 2 of 50 patients . The heel may be acutely painful due to sarcoid bone lesions, that may need MRI to be demonstrated .

Treatment:
Many do not need treatment  resolve, but 20-30% have residual lung damage.
Symptomatic management eg bronchodilators for respiratory diseases (eg asthma); NSAID’s for joint symptoms; topicals for skin disease.
If severe  corticosteroids or immunosuppressives.

Lofgren’s syndrome:
• triad of acute arthritis (typically ankles, knees, wrists), erythema nodosum and bilateral adenopathy in those with sarcoidosis
• responds well to corticosteroids (80% resolve within 2 years)

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