sarcoidosis

Question 1

definition of sarcoidosis

Answer 1

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. It has a bimodal age distribution with 2 peaks in the third and fifth decades. The clinical course is often heterogeneous and unpredictable.

• diagnosis of exclusion of granulomatous lung diseases, including tuberculosis and histoplasmosis.
• Carries a mortality of 1% to 6%.
• Poorer prognosis if black ancestry, chronic pulmonary involvement, lupus pernio, or chronic hypercalcaemia.
• Spontaneous remissions occur in 55% to 90% of patients with stage I, 40% to 70% of patients with stage II, and about 20% of patients with stage III disease, but no remissions are expected in stage IV.

Question 2

different systems that can be affected

Answer 2

Systemic sarcoidosis: multisystem involvement, sometimes with chronic fatigue
Pulmonary sarcoidosis: lungs involved in >90% of patients; further classified into stages I, II, III, and IV
Cutaneous sarcoidosis: plaques; lupus pernio
Ocular sarcoidosis: anterior uveitis is most common
Cardiac sarcoidosis: 5% of patients; various types of heart block; cardiomyopathy later in course; if pulmonary arterial hypertension occurs can be debilitating
Neurosarcoidosis: <10% of patients; headaches; seizures.

Question 3

signs and symptoms

Answer 3

• non productive cough
• dyspnoea (gradual onset)
• chronic fatigue
• arthralgia (Pain in knees, ankles, and wrists but No synovial thickening on examination.)
• wheezing, rhonchi (Bronchospasm, due to airway hyper-reactivity.)
• lymphadenopathy (Nodes are enlarged and non-tender. Cervical, submandibular nodes are often involved.)
• photophobia, red painful eye, blurred vision (uveitis)
• erythema nodosum (usually in lower extremities) (GOOD PROGNOSIS)
• lupus pernio (POOR PROGNOSIS)
• conjunctival nodules
• facial palsy

Question 4

risk factors

Answer 4

• 20-40 y/o
• family history of sarcoidosis
• scandinavian origin

weak:

• female
• non smoker
• black ancestry (US): uveitis
• puerto rico origin: lupus pernio
• european origin: erythema nodosum

Question 5

investigations

Answer 5

1s investigations:
CXR => hilar and/or paratracheal adenopathy with upper lobe predominant, bilateral infiltrates; pleural effusions (rare) and egg shell calcifications (very rare) may be seen
FBC => anaemia, leukopenia (secondary to splenic and/or bone marrow involvement)
serum urea, creatinine => renal involvemtn
serum calcium (Due to dysregulated production of calcitriol by activated macrophages and granulomas.) => hypercalcaemia
liver enzymes => Asymptomatic aminotransferase (AST and ALT) elevation possible.
PFTs => chronic/obstructive/mixed picture in lung function
ECG => possible conduction defects
PPD (purified protein derivative of tuberculin) (test for TB) => negative

Question 6

other differentials to rule out

Answer 6

• berrylliosis (history of exposure - aerospace or nuclear industries. Abnormal beryllium lymphocyte proliferation assay on serum or bronchoalveolar lavage fluid)
• NSCLC (lung mass on CXR. malignant cells on biopsy)
• TB (Positive PPD. Smear or culture positive for TB. Caseating granulomas on lung biopsy.)
• lymphoma (hodgkin’s and non hodgkin’s) (Biopsy of mediastinal lymph nodes shows features of lymphoma.)
• histoplasmosis (Fungus isolation on silver stain from lung biopsy. Positive urinary Histoplasma antigen.The most common finding on CXR is pulmonary nodules; can also
  present as infiltrates, lymphadenopathy, fibrosis, and thickened pleura.)