Sarcoidosis Flashcards
Define sarcoidosis
Systemic granulomatous disease of unknown aetiology, characterised by non-caseating granulomas which can affect any organ/
Commonly the lungs and the intrathoracic lymph nodes.
What is the relevant epidemiology of sarcoidosis?
Peak incidence between 40-50yrs
7 per 100,000 person years
Less common than TB
What is the aetiology of sarcoidosis?
Unclear - suggests a combination of genetic and environmental factors which trigger an aberrant immune response in susceptible individuals.
1. Infectious agents - mycobacteria and propionibacteria
2. Enviro/occu exposure - molds, organic and inorganic
3. Genetic predisposition - HLA alleles
3 times more common in people of Black African ethniciity
What is the relevant underlying aetiology of sarcoidosis?
- Antigen presentation - antigen exposure triggers APCs to activate CD4+ T helper cells
- Th1 and Th17 develop, secretes pro-inflammatory cytokines
- Granuloma formation - macrophages are recruited, transform in epitheliod cells and multinucleated giant cells - non-caesating granuloma, isolate antigens stimulus limiting damage
- Fibossis of granuloma - decrease organ funcation
How is sarcoidosis classified by organ involvement?
Pulmonary sarcoidosis - lungs - acute or chronic
Extrapulmonary - commonly skin, eyes, lymph nodes, liver heart and nervous system - can be more than one at once
What is the radiological classification (Scadding staging) of sarcoidosis?
Stage 0 = normal CXR
Stage 1 - bilateral hilar lymphadeonpathy
Stage 2 - BHL with pulmonary infiltrates
Stage 3 - pulmonary infiltrates without BHL
Stage 4 = pulmonary fibrosis
How can sarcoidosis be classified based on symptomatology?
Lofgren syndrome - acute onset of erythema nodosum, bilateral hilar lymphadenopathy and arthralgia or arthritis.
Heerfordts syndrome - parotitis, anterior uveitis, fever and facial nerve palsy
Chronic sarcoisis - 2+yrs, pulmonary fibrosis
Silent sarcoidosis - incidental diagnosis and lacks symptoms
What are the non-specific symptoms of sarcoidosis?
Fatigue, weight loss, arthalgia and fever
How does sarcoidosis affect the respiratory system?
90%
Persistent dry cough
Dyspnea on exertion or chest discomfort.
Bilateral hilar lymphadenopathy
Restrictive lung disease - may also show obstructive
How does sarcoidosis present in the skin?
25% of patients
eryhema nodosum - tender red nodules on naterior shins
Lupus pernio - violaceous skin lesions on the nose and cheeks.
What are the less common systems affected in sarcoidosis?
Uveitis - often followed by conjunctivitis and scleritis.
Cardio - conduction abnormalities, left ventricular dysfunction or sudden cardiac death
Neuro - cranial nerve palsy, seizures, headaches, or psychiatric symptoms
MSK - arthralgia and arthritis
Endocrine - hypercalcemia (inc VD due to active macrophages)
Hepatomegaly
Splenomegaly
What are the first line investigations for sarcoidosis?
Bloods - FBC, renal function, LFT, serum calcium, serum ACE
Chest radiography - for staging - CXR then CT is required
Pulmonary function tests - restrictive
Tissue biopsy - for definitive diagnosis
Other organ specific investigations based on signs and symptoms
What treatment is required for sarcoidosis?
If asymptomatic or mild - no treatment - spontaneous remission
Symptomatic or progressive - corticosteroids as first line - 20-40mg prednisolone
Second line immunosuppressants - methotrexate, azathioprine and mycophenolate mofetil
Refractiy or severe - biological therapies - adalimumab
Close monitoring of organ function with targeted treatment when needed
What factors are associated with a poor prognosis from sarcoidosis?
- Insidious onset, symptoms >6months
- Absence of erythema nodosum
- Extra-pulmonary manifestations
- CXR - stage 3-4 features
- People of Black African ethnicity
