Sarcoidosis

How is sarcoidosis diagnosed?

Diagnostic Tests

Workup should achieve 4 things:¹

• Histologic confirmation of sarcoidosis
• Assessment of extent and severity of organ involvement
• Assessment of disease stability or likelihood to progress
• Determine if therapy will be beneficial to the patient

• Patient evaluation
• Histology and immunological screening
• Chest X-ray
  • Used to determine stage of disease¹
• Computed Tomography (CT) scans

A comprehensive evaluation for all patients should include:¹

• Symptom evaluation
• Patient history (occupational and environmental exposure)
• Physical exam and routine eye exam
• Posteroanterior chest X-ray
• PFTs: spirometry and DL_co
  • Most likely to indicate functional impairment
  • Can uncover both restrictive and obstructive defects
• Baseline assessment
  • Instrumental to monitor improvement or deterioration of lung disease

Pulmonary sarcoidosis is typically found by abnormal chest X-ray, often incidentally.⁹

• Typically bilateral mediastinal adenopathy if asymptomatic — if symptomatic, most commonly dyspnea, cough, nonspecific chest discomfort, crackles⁴
• If wheezing is present, this is often a sign of fibrosis³

Symptomatic patients display:

• Dyspnea, cough, chest pain¹ :— 1/3 to 1/2 patients¹
• Lung crackIes¹ :— less than 1/5 patients¹
• Clubbing is rare¹

Other Symptoms⁴

• Fatigue
• Malaise
• Weakness
• Weight Loss
• Low-grade Fever
• Anorexia

• Symptoms depend on the site and degree of involvement, varying over time
• Can range from spontaneous remission to chronic indolent illness
• It is common for patients with sarcoidosis to not have presenting symptoms

LABORATORY AND PHYSICAL EXAMINATIONS

• Peripheral blood counts¹
  • White blood cells
  • Red blood cells
  • Platelets
• Serum chemistries¹
  • Calcium
  • Liver enzymes
  • Creatinine
  • Blood Urea Nitrogen (BUN)
• Urine analysis¹
• Electrocardiogram (ECG¹)
• Tuberculin skin test¹
  • CT scans may be recommended in some patients pending results

HISTOLOGY

Common Histologic and Immunologic Findings:

Histologic: Transbronchial Lung Biopsy (TLB)

• Performed in presence of a compatible clinical picture¹
• Should be cultured for fungi and mycobacteria to exclude other diagnoses⁴
• Mediastinoscopy may be favorable to TLB¹⁰

Immunologic Features:¹

• Depression of cutaneous delayed-type hypersensitivity
• Heightened T helper cell type 1 (TH1) immune response at sites of disease
• Circulating immune complexes, along with signs of B cell hyperactivity, may also be found

CHEST X-RAY

Chest X-rays are used to determine the stage of disease:

Stage 0 - Normal chest X-ray¹

Stage I - Bilateral hilar lymphadenopathy; may be accompanied by paratracheal adenopathy; parenchymal granulomas upon lung biopsy¹

Stage II - Bilateral hilar adenopathy accompanied by pulmonary infiltration¹

Stage III - Pulmonary infiltration without bilateral hilar lymphadenopathy¹

Stage IV - Pulmonary fibrosis evidenced by honeycombing, hilar retraction, bullae, cysts, and emphysema¹

CT SCANS

Typically only used in the following instances:¹

• Atypical clinical and/or chest radiograph findings
• Detection of complications due to lung disease
• Normal chest radiograph, but clinical suspicion of disease

Classic Findings¹

• Widespread small nodules with bronchovascular and subpleural distribution
• Thickened interlobular septae
• Architectural distortion
• Conglomerate masses

CT Scan: Classical Findings

The CT scans of 80 patients were evaluated by Abehsera and colleagues.¹¹

• Fibrotic sarcoidosis and bronchial distortion (marked by traction bronchiectasis and airway angulation), linear scarring, and honeycombing were found¹¹
• Extent and type of fibrosis in sarcoidosis varies, which may account for the variety of clinical findings and outcomes^3,11

• Although fibrosis is often upper- and middle-lobe predominant, the distribution of fibrosis may be somewhat pattern specific³
• In the study by Abehsera et al, honeycombing was observed more frequently in the upper lobes, and lower lung involvement was more common for diffuse linear fibrosis¹¹
• Regular follow-up of patients with ground-glass opacities may be warranted, even when there are minimal pulmonary symptoms initially³

Less Common Findings by CT Scan

• Honeycombing¹
• Cyst formation and bronchiectasis¹
• Alveolar consolidation¹