sarcoidosis

see also:

• the chest X-ray (CXR)
• respiratory medicine
• wikipedia

• a chronic disease in which granulomas form as nodules in multiple organs, especially lungs and LNs, but also skin (25%), eyes, liver, heart, kidneys
• commonly improves or clears up spontaneously - most have no symptoms after 9 years but 50% have relapses and 10% develop serious disability - usually respiratory failure

• cause is unknown
• one case seems to be clearly related to silica in cat litter ¹⁾

• more common patients who are Black and more common in women

• may be asymptomatic
• symptoms may include chronic fatigue, LOW, aches and pains, arthritis, dry eyes, blurry vision, SOB, dry hacking cough, skin rashes, skin nodules
• Löfgren syndrome: combination of erythema nodosum, bilateral hilar lymphadenopathy and arthralgia
• 90% eventually develop an abnormal the chest X-ray (CXR)
  • 75-90% develop hilar &/or paratracheal LN enlargement
• generalised lymphadenopathy is common, especially cervical nodes
• 5-15% develop pulmonary fibrosis
• anaemia occurs in 4-20%
• 40% develop mild-mod lymphopenia
• 20-30% develop hepatomegaly
• 5% develop symptomatic cardiac disease
• 5% develop neurologic involvement such as cranial nerve palsies, chronic meningitis or peripheral neuropathy
• uveitis
• up to 5% develop parotid involvement which is usually bilateral and may cause xerostomia
• uveoparotid fever - combination of anterior uveitis, parotitis, VII cranial nerve paralysis and fever
• may cause hypervitaminosis D ⇒ compensatory hypoparathyroidism, fatigue, metallic taste, cognitive dysfunction, immune dysfunction
• up to 1/3rd develop hyperprolactinaemia
• some may develop thyroid dysfunction
• association with coeliac disease

• essentially is based on clinical features combined with radiographic features and preferably histology showing non-caseating granulomas.
  • histology of granulomas reveal higher than normal levels of type 1 innate lymphoid cells (ILC1s) ²⁾
  • inhibiting the CXCR4 can inhibit granulomas from forming
• CXR
• lung function tests
• serum ACE is controversial
  • is a marker of sarcoid granuloma burden
  • has poor sensitivity (60%) and specificity for diagnosis though
    • may also be elevated in other conditions such as Gaucher’s disease, disseminated tuberculosis, hyperthyroidism and fungal infections
    • ACE levels are reduced in patients on ACE inhibitors