Sarcoidosis Flashcards
What is sarcoidosis?
Sarcoidosis is a chronic granulomatous disorder of unknown aetiology, commonly affecting the lungs, skin, and eyes. It is characterised by accumulation of lymphocytes and macrophages and the formation of non-caseating granulomas in the lungs and other organs. Although lungs and lymph nodes are involved in more than 90% of patients, virtually any organ can be involved.
Who is commonly affected by sarcoidosis?
Usually affects adults aged 20–40yrs, more common in women. There are two spikes in incidence, in young adulthood and again around age 60.
African–Caribbeans are affected more frequently and more severely than Caucasians, particularly by extra-thoracic disease.
What is the typical patient who presents with sarcoidosis?
The typical MCQ exam patient is a 20-40 year old black woman presenting with a dry cough and shortness of breath. They may have nodules on their shins suggesting erythema nodosum.
What are the risk factors for sarcoidosis?
- Age 20-40
- FHx of sarcoidosis
- Associated with HLA-DRB1 and DQB1 alleles
What organ systems can be affected by sarcoidosis?
Sarcoidosis can affect almost any organ in the body. The most commonly affected are the lungs so sarcoidosis is usually managed by respiratory physicians.
Extra-pulmonary manifestations:
- Liver
- Eyes
- Skin
- Heart
- Kidneys
- CNS
- PNS
- Bones
How does sarcoidosis affect the lungs?
- Mediastinal lymphadenopathy
- Pulmonary fibrosis
- Pulmonary nodules
What are the systemic symptoms of sarcoidosis?
- Fever
- Fatigue
- Weight loss
How does sarcoidosis affect the liver?
- Liver nodules
- Cirrhosis
- Cholestasis
How does sarcoidosis affect the eyes?
- Uveitis
- Conjunctivitis
- Optic neuritis
How does sarcoidosis affect the skin?
- Erythema nodosum (tender, red nodules on the shins caused by inflammation of the subcutaneous fat)
- Lupus pernio (raised, purple skin lesions commonly on cheeks and nose)
- Granulomas develop in scar tissue
How does sarcoidosis affect the heart?
- Bundle branch block
- Heart block
- Myocardial muscle involvement
How does sarcoidosis affect the kidneys?
- Kidney stones (due to hypercalcaemia)
- Nephrocalcinosis
- Interstitial nephritis
How does sarcoidosis affect the CNS?
- Nodules
- Pituitary involvement (diabetes insipidus)
- Encephalopathy
How does sarcoidosis affect the PNS?
- Facial nerve palsy
- Mononeuritis multiplex
How does sarcoidosis affect the bones?
- Arthralgia
- Arthritis
- Myopathy
What are the signs of sarcoidosis?
- Wheeze
- Rhonchi
- Lymphadenopathy
- Erythema nodosum
- Lupus pernio
- Conjunctival nodules
- Facial palsy
What are the symptoms of sarcoidosis?
- Cough
- Dyspnoea
- Chronic fatigue
- Arthalgia
- Blurred vision
What % of sarcoidosis diagnoses are found incidentally?
In 20–40%, the disease is discovered incidentally, after a routine cxr, and is thus asymptomatic.
What investigations should be ordered for sarcoidosis?
- CXR
- Serum ACE
- Serum calcium
- CRP
- High-resolution CT
- Flexible bronchoscopy with transbronchial lung biopsy
- Skin biopsy
- MRI
- PET scan
Tests for other organ involvement: U&E, urine dipstick, LFTs, opthamology, ECG, echocardiogram and ultrasound.
Why investigate using CXR?
90% have abnormal CXRs with bilateral hilar lymphadenopathy ± pulmonary infiltrates or fibrosis.

What is shown on the CXR?

PA chest radiograph showing bilateral hilar lymphadenopathy. The important differentials for this appearance are: sarcoidosis, tb, lymphoma, pneumoconioses, and metastatic disease. This patient has sarcoidosis but there are no other stigmata (such as the presence of infiltrates, fibrosis, and honeycombing) on this image.
Why investigate serum ACE?
Elevated in about half of patients. This is often used as a screening test.
Why investigae serum calcium?
Due to dysregulated production of calcitriol by activated macrophages and granulomas.
Hypercalcaemia.
Why investigate CRP?
Raised CRP.
