Sarcoidosis (RESP) Flashcards
Define sarcoidosis.
Chronic granulomatous multisystem disorder of unknown aetiology
Which body systems are most commonly affected in sarcoidosis? (3)
- lungs
- skin
- eyes
What is sarcoidosis a diagnosis of exclusion of?
Granulomatous lung diseases, including TB and histoplasmosis
What is sarcoidosis characterised by?
Accumulation of lymphocytes and macrophages
Formation of non-caseating granulomas (collection of histiocytes) in the lungs and other organs
What body systems are involved in >90% of patients with sarcoidosis?
Lungs and lymph nodes
Describe the epidemiology of sarcoidosis.
- F>M
- 10x more likely in African-Americans
- bimodal peak incidence:
- 25-35 years old
- 50-65 years old
What is the aetiology of sarcoidosis?
Unknown - hypotheses suggest genetic, immunological and infectious causes
HLA-DRB1 and DQB1 alleles
Describe the pathogenesis of sarcoidosis.
- unknown antigen presented on MHC-II complexes on macrophages to CD4+ T lymphocytes
- these accumulate and release cytokines
- leads to formation of non-caseating granulomas in organs
What are the clinical features of sarcoidosis? (12)
- chronic dry cough
- dyspnoea
- wheezing
- rhonchi
- swinging fever
- chronic fatigue
- facial nerve (Bell’s) palsy
- arthralgia - pain in knees, ankles and wrists
- erythema nodosum - rash on shin
- lupus pernio - indurated purple rash on face, nose, ears
- lymphadenopathy - cervical and submandibular lymph nodes
- anterior uveitis - red painful eye, photophobia, blurred vision
What pulmonary symptoms may be seen in sarcoidosis? (4)
- chronic dry cough
- dyspnoea (SOB)
- wheezing
- rhonchi
What skin symptoms may be seen in sarcoidosis? (2+1)
- lupus pernio - purple indurated rash of face, nose and ears (and terminal phalanges)
- erythema nodosum - rash on shin
- (maculopapular eruptions)
What eye symptoms are seen in sarcoidosis? (3+3)
Anterior uveitis:
- red painful eye
- photophobia
- blurred vision
(keratoconjunctivitis sicca, glaucoma, papilloedema)
What cardiac symptoms may be seen in sarcoidosis? (5)
- arrhythmias
- heart block
- pericarditis
- cardiomyopathy
- congestive heart failure
What symptom is pathognomonic for sarcoidosis?
Lupus pernio - indurated purple rash on face, nose and ears
What electrolyte disturbance can occur in sarcoidosis and why?
Hypercalcaemia - granuloma produces ectopic 1-alpha-hydroxylase, macrophages inside the granulomas cause an increased conversion of vitamin D to its active form (1,25-dihydroxycholecalciferol)
What syndromes are associated with sarcoidosis? (3)
- Lofgren’s syndrome - acute form of disease characterised by bilateral hilar lymphadenopathy, erythema nodosum, fever and polyarthralgia
- Mikulicz syndrome - enlarged parotid and lacrimal glands due to sarcoidosis, TB or lymphoma
- Heerfordt’s syndrome (uveoparotid fever) - parotid enlargement, fever and uveitis secondary to sarcoidosis
What are some risk factors for sarcoidosis? (4)
- age 20-50 years (binomial age distribution with 2 peaks 25-35 and 50-65)
- Fx sarcoidosis
- Scandinavian and African origin
- female sex
What are the first-line investigations for sarcoidosis? (7)
- CXR
- FBC
- serum urea
- serum creatinine
- PFTs
- LFTs
- serum calcium
What is the best initial test for sarcoidosis?
CXR
What does CXR show in sarcoidosis? (2)
Bilateral hilar lymphadenopathy
Bilateral pulmonary infiltrates, predominantly in upper lobes
(Pleural effusions - rare)
(Eggshell calcifications - very rare)
What are the stages of sarcoidosis by CXR? (Correlates with likelihood of spontaneous resolution)
- stage 0 - normal
- stage I - bilateral hilar lymphadenopathy
- stage II - bilateral hilar lymphadenopathy PLUS pulmonary infiltrates (and paratracheal node enlargement)
- stage III - pulmonary infiltrates WITHOUT hilar lymphadenopathy
- stage IV - extensive fibrosis with distortion (honeycombing/bulla formation, pleural involvement)
What investigation can be done if suspicious CXR for sarcoidosis?
High resolution CT (check for diffuse lung involvement)
What is the gold-standard investigation for sarcoidosis diagnosis?
Bronchoscopy with lung biopsy –> showing non-caseating granulomas
What does FBC show in sarcoidosis? (2)
- anaemia
- leukopenia - due to lymphocyte sequestration in lungs
