Sarcoidosis

Sarcoidosis is a granulomatous inflammatory condition. Granulomas are nodules of inflammation full of macrophages. The cause of these granulomas developing is unknown.

It is usually associated with chest symptoms but also has multiple extra-pulmonary manifestations such as erythema nodosum and lymphadenopathy. Symptoms can vary dramatically from asymptomatic (in up to 50%) to severe and life threatening.

There are two spikes in incidence, in young adulthood and again around age 60. Women are affected more often and it occurs more frequently in black people compared with other ethnic groups.

TOM TIP: The typical MCQ exam patient is a 20-40 year old black female presenting with a dry cough and shortness of breath. They may have nodules on their shins suggesting erythema nodosum.

 

Organs Affected

Sarcoidosis can affect almost any organ in the body. The most commonly affected are the lungs so sarcoidosis is usually managed by respiratory physicians.

Lungs (affecting over 90%)

  • Mediastinal lymphadenopathy
  • Pulmonary fibrosis
  • Pulmonary nodules

Systemic Symptoms

  • Fever
  • Fatigue
  • Weight loss

Liver (affecting around 20%)

  • Liver nodules
  • Cirrhosis
  • Cholestasis

Eyes (affecting around 20%)

  • Uveitis
  • Conjunctivitis
  • Optic neuritis

Skin (affecting around 15%)

  • 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

Heart (affecting around 5%)

  • Bundle branch block
  • Heart block
  • Myocardial muscle involvement

Kidneys (affecting around 5%)

  • Kidney stones (due to hypercalcaemia)
  • Nephrocalcinosis
  • Interstitial nephritis

Central nervous system (affecting around 5%)

  • Nodules
  • Pituitary involvement (diabetes insipidus)
  • Encephalopathy

Peripheral Nervous System (affecting around 5%)

  • Facial nerve palsy
  • Mononeuritis multiplex

Bones (affecting around 2%)

  • Arthralgia
  • Arthritis
  • Myopathy

 

Lofgren’s Syndrome

This is a specific presentation of sarcoidosis. It is characteristic by a triad of:

  • Erythema nodosum
  • Bilateral hilar lymphadenopathy
  • Polyarthralgia (joint pain in multiple joints)

 

Differential Diagnosis

  • Tuberculosis
  • Lymphoma
  • Hypersensitivity pneumonitis
  • HIV
  • Toxoplasmosis
  • Histoplasmosis

 

Blood Tests

  • Raised serum ACE. This is often used as a screening test.
  • Hypercalcaemia (rasied calcium) is a key finding.
  • Raised serum soluble interleukin-2 receptor
  • Raised CRP
  • Raised immunoglobulins

 

Imaging

  • Chest xray shows hilar lymphadenopathy
  • High resolution CT thorax shows hilar lymphadenopathy and pulmonary nodules
  • MRI can show CNS involvement
  • PET scan can show active inflammation in affected areas

 

Histology

The gold standard for confirming the diagnosis of sarcoidosis is by histology from a biopsy. This is usually done by doing bronchoscopy with ultrasound guided biopsy of mediastinal lymph nodes.

The histology shows characteristic non-caseating granulomas with epithelioid cells.

Tests for other organ involvement

  • U&Es for kidney involvement
  • Urine dipstick or urine albumin-creatinine ratio to look for proteinuria indicating nephritis
  • LFTs for liver involvement
  • Ophthalmology review for eye involvement
  • ECG and echocardiogram for heart involvement
  • Ultrasound abdomen for liver and kidney involvement

 

Treatment

  • No treatment is considered as first line in patients with no or mild symptoms as the condition often resolves spontaneously.
  • Oral steroids are usually first line where treatment is required and are given for between 6 and 24 months. Patients should be given bisphosphonates to protect against osteoporosis whilst on such long term steroids.
  • Second line options are methotrexate or azathioprine
  • Lung transplant is rarely required in severe pulmonary disease

 

Prognosis

Sarcoidosis spontaneously resolves within 6 months in around 60% of patients. In a small number of patients it progresses with pulmonary fibrosis and pulmonary hypertension, potentially requiring a lung transplant. Death in sarcoidosis is usually when it affects the heart (causing arrhythmias) or the central nervous system.

 

Last updated March 2019
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