Sarcoidosis is a multisystem granulomatous disorder of unkown etiology that is characterized by the presence of non caseating granulomatous granulomas.
Etiology:
– common in northern parts of Europe; severe among west Indian and Asian backgrounds
– common in spring and summer
– Genetic susceptibility is supported by familial clustering; a range of class II HLA alleles confer protection from, or susceptibility to, the condition.
– May be associated with common variable immunodeficiency
– Age: occurs often in young adults but not <18 years
– Sex: women>male
Pathology:
– Like other diffuse parenchymal diseases, it commonly affects the lungs but can affect any organs(skin, extra thoracic lymph nodes, eyes, liver spleen, parotid glands, phalengeal bones)
– Fibrosis can occur in 20% of cases
– Hypercalcemia may be present reflecting increased formation of calcitriol by alveolar macrophages.
Clinical features:
– Asymptomatic: abnormal chest X- ray (~30%) or abnormal LFT
– Respiratory symptoms: cough and dyspnoea
– Constitutional symptoms: fatigue, fever, night sweats, weight loss
– Erythema nodusum and arthralgia (~20-30%)
– Ocular symptoms(~5-10%): anterior uveitis, Sicca Syndrome, lacrimal gland enlargement
– Skin sarcoid(including Lupus pernio)
– Superficial lymphadenopathy
– Others: hypercalcemia, diabetes insipidus, cranial nerve palsies, cardiac arrhythmias, nephrocalcinosis
– Lofgren’s syndrome- erythema nodusum, hilar lymphadenopathy and uveitis.
Investigations:
– CBC: lymphopenia
– Chest radiography:
• Stage 1: BHL(bilateral hilar lymphadenopathy) (usually symmetrical); paratracheal node often enlarged
Often asymptomatic but may be associated with erythema nodosum and arthralgia. Majority of cases resolve spontaneously within 1 year.
• Stage 2: BHL and parenchymal infiltrates
Patients may present with breathlessness or cough. The majority of cases resolve spontaneously
• Stage 3: parenchymal infiltrates without BHL
Disease less likely to resolve spontaneously
• Stage 4: pulmonary fibrosis
Can cause progression to ventilatory failure, pulmonary hypertension and cor pulmonale
– LFT: deranged
– Serum Angiotensin converting enzyme(ACE): non specif marker of the disease activity and monitors clinical course
– Serum calcium: may be elevated (reflecting increased formation of calcitriol 1.25-dihydroxyvitamin D by alveolar macrophages)
– Serum uric acid: may be elevated (in cases of nephrocalcinosis)
– Pulmonary function test: shows restrictive defect accompanied by impaired gas exchange
– Exercise test: may reveal oxygen desaturation
– Brochoscopy: cobblestone appearance in the mucosa
– Bronchial and trans bronchial biopsy: usually show non caseating granuloma
– Bronchoalveolar lavage fluid: increased CD4:CD8 T cells ratio
– HRCT chest: reticulonodular opacities followed by a perilymphatic distribution centered on bronchovascular bundles and the sub pleural areas.
– PET scanning: for detection of extrapulmonary diease
Treatment:
– Acute illness with erythema nodosum: NSAIDs or short term corticosteroid therapy (if symptoms are severe) which may follow a spontaneous remission.
– Systemic corticosteroids for 6 months: if there is no evidence of organ damage; can also be given in hypercalcemia, pulmonary impairment and renal impairment
– Topical steroids: in cases of uveitis
– Severe disease: immunosuppressant drugs like methotrexate and azathioprine or specific tumor necrosis factor alpha(TNF α) inhibitors
– In cutaneous sarcoid with limited pulmonary involvement: chloroquine, hydroxychloroquine or low dose thalidomide
– Avoid strong sunlight as it may precipitate hypercalcemia and endanger renal function
– In severe lung damage: consideration of single lung transplantation
Bad prognostic factors:
– Age> 40 years
– Afro –Carribean ethnic origin
– Persistent symptoms for >6 months
– Involvements of more than 3 organs
– Lupus pernio and stage 3/4 chest X ray
Contributor- Dr. Bidhata Rayamajhi
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