A 32 year old female presents with dry cough, progressive dyspnea, fatigue, and low-grade fever for several months. She also reports painful red nodules over both shins and redness of the eyes. Chest X-ray demonstrates bilateral hilar lymphadenopathy. Laboratory investigations reveal elevated serum ACE and hypercalcemia. Lung biopsy shows non-caseating granulomas. Diagnosis?
Diagnosis is pulmonary sarcoidosis.
1. Definition
Sarcoidosis is a chronic multisystem granulomatous disorder of unknown etiology characterized by formation of non-caseating granulomas in affected organs.
2. Etiology
- Unknown etiology
- Abnormal immune response in
genetically susceptible individuals
- Environmental and infectious triggers may contribute
3. Pathophysiology
- T helper cell mediated immune
activation
- Formation of non-caseating granulomas
with epithelioid histiocytes
- Activated macrophages produce
1-alpha hydroxylase
- Increased conversion of vitamin
D to 1,25 dihydroxyvitamin D3
- Resultant hypercalcemia and
hypercalciuria
- Chronic inflammation may progress to pulmonary fibrosis
4. Clinical Features
4.1 Pulmonary Features
- Dry cough
- Progressive dyspnea
- Chest pain
- Wheezing
- Fatigue
4.2 Extrapulmonary Features
- Erythema nodosum
- Anterior uveitis
- Fever
- Arthralgia
- Parotid enlargement
- Hepatosplenomegaly
- Peripheral lymphadenopathy
5. Lofgren Syndrome
An
acute presentation of sarcoidosis characterized by the triad of:
- Fever
- Erythema nodosum
- Bilateral hilar lymphadenopathy
It is associated with a good prognosis
6. Diagnosis
Diagnosis
is based on:
- Compatible clinical and
radiologic findings
- Histologic evidence of
non-caseating granulomas
- Exclusion of other granulomatous diseases such as tuberculosis and fungal infections
6.1 Laboratory Findings
- Elevated serum ACE levels
- Hypercalcemia
- Increased 1,25 dihydroxyvitamin
D3 levels
- Elevated ESR
6.2 Bronchoalveolar Lavage
- Elevated CD4/CD8 ratio
- CD4/CD8 ratio >3.5 is supportive of diagnosis
6.3 Imaging Findings
Chest X-ray / CT Scan
- Bilateral hilar lymphadenopathy
- Bilateral paratracheal
lymphadenopathy
- Pawnbroker’s sign
HRCT Chest
- Galaxy sign
- Reticulonodular infiltrates
- Fibrotic changes in advanced disease
6.4 Histology
- Non-caseating granulomas
- Epithelioid histiocytes
- Multinucleated giant cells
7. Staging of Pulmonary Sarcoidosis
Stage I
- Bilateral hilar lymphadenopathy
only
Stage II
- Bilateral hilar lymphadenopathy
with pulmonary infiltrates
Stage III
- Pulmonary infiltrates without
hilar lymphadenopathy
Stage IV
- Pulmonary fibrosis
8. Differential Diagnosis
- Tuberculosis
- Fungal infections
- Berylliosis
- Lymphoma
- Hypersensitivity pneumonitis
9. Treatment
9.1 Observation
- Many asymptomatic or mild cases
undergo spontaneous remission
- Observation alone may be appropriate in mild disease
9.2 Medical Treatment
- Corticosteroids are first-line
therapy for symptomatic or progressive disease
- Methotrexate may be used as a
steroid-sparing agent
- Azathioprine may be used in
refractory disease
- Infliximab may be considered in severe refractory cases
10. Prognosis
- Many patients undergo
spontaneous remission
- Lofgren syndrome has excellent
prognosis
- Advanced pulmonary fibrosis may lead to chronic respiratory failure
11. Key Clinical Insight
Young adult with bilateral hilar lymphadenopathy, erythema nodosum, uveitis, hypercalcemia, and non-caseating granulomas strongly suggests sarcoidosis
12. Key Exam Points
- Non-caseating granulomatous
disease
- Bilateral hilar lymphadenopathy
is the classic radiologic finding
- Elevated ACE levels are
supportive but nonspecific
- Hypercalcemia occurs due to
increased vitamin D activation by macrophages
- Lofgren syndrome consists of
fever, erythema nodosum, and bilateral hilar lymphadenopathy
- CD4/CD8 ratio >3.5 in
bronchoalveolar lavage supports diagnosis
- Corticosteroids are first-line
treatment for symptomatic disease
- Stage IV disease is associated with pulmonary fibrosis
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