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Sarcoidosis

BASICS

  • Definition: Noninfectious, multisystem, granulomatous disease of unknown cause.
  • Classic features: Bilateral hilar adenopathy, pulmonary infiltrates, ocular or skin lesions.
  • Common presentation: ~50% diagnosed asymptomatic (abnormal chest x-ray).
  • Systems affected: Primarily pulmonary, but also cardiovascular, GI, hematologic, endocrine, renal, neuro, derm, ophthalmologic, musculoskeletal.
  • Synonyms: Löfgren syndrome (EN, hilar adenopathy, fever, arthralgias), Heerfordt syndrome (uveitis, parotid enlargement, facial palsy, fever), lupus pernio, Besnier-Boeck disease.

EPIDEMIOLOGY

  • Incidence: ~6/100 person-years.
  • Prevalence: 10–20 per 100,000 (higher in Black Americans, women, Scandinavians, Japanese).
  • Peak age: Women 50–69 yr; men 40–59 yr.
  • Rare in children.

ETIOLOGY & PATHOPHYSIOLOGY

  • Etiology: Unknown; likely exaggerated cell-mediated immune response to unknown antigen(s).
  • Genetics: Familial clustering; MHC region on chr6; higher prevalence in specific populations (Scandinavians, Japanese, Black Americans).
  • Risk factors: Not fully defined.

DIAGNOSIS

Diagnosis requires: 1. Clinical presentation 2. Noncaseating granulomatous inflammation on biopsy (not always required) 3. Exclusion of other diseases

History

  • May be asymptomatic.
  • Nonspecific complaints:
  • Nonproductive cough, SOB, fever, night sweats, weight loss, fatigue, eye pain, chest pain, palpitations, arrhythmias, skin lesions, polyarthritis.
  • Systemic symptoms more likely in age >70.

Physical Exam

  • May be normal.
  • Lungs: wheezing, fine crackles.
  • Extrapulmonary (30%):
  • Eye: uveitis, retinitis, conjunctival nodules, lacrimal gland enlargement
  • CN VII palsy, salivary swelling, arrhythmia, hepatosplenomegaly
  • Rashes: maculopapular, waxy nodular, plaques (lupus pernio), erythema nodosum (Löfgren)
  • Polyarthritis

Differential Diagnosis

  • Infectious: TB, atypical mycobacteria, fungal, Brucella, T. whipplei, tularemia, Bartonella, Coxiella, herpes zoster, Toxoplasma, schistosomiasis, leishmaniasis
  • Lymphoma
  • Autoimmune: vasculitis, Langerhans cell histiocytosis, IBD
  • Hypersensitivity pneumonitis

Diagnostic Tests

  • Labs:
  • CBC, HIV, creatinine, alk phos, transaminases, calcium, vitamin D (25- and 1,25-OH), baseline eye exam, ECG
  • Serum ACE: elevated in >75%, NOT diagnostic
  • Imaging:
  • Chest x-ray (Scadding classification)
    • 0: Normal
    • 1: Bilateral hilar adenopathy
    • 2: Hilar adenopathy + parenchymal infiltrates
    • 3: Parenchymal infiltrates with shrinking hilar nodes
    • 4: Parenchymal infiltrates with volume loss, bronchiectasis, calcification/cyst
  • HRCT: peribronchial disease
  • PET scan: areas of disease activity
  • Cardiac MRI or PET (extracardiac disease/cardiac involvement)
  • Echocardiogram for suspected pulmonary hypertension
  • PFTs: Restrictive pattern, ↓ DLCO
  • Biopsy: Noncaseating granulomas (not always required if classic syndrome present)
  • Preferred: EBUS-guided lymph node sampling
  • Bronchoscopy with biopsy for lung involvement
  • ALERT: Löfgren syndrome (acute sarcoid with bilateral hilar adenopathy, EN, arthritis): no biopsy required, observation only.

TREATMENT

  • Spontaneous remission common.
  • No treatment for asymptomatic individuals or those with stages I–III and mild/normal lung function (monitor closely).
  • Treat if: Cardiac, CNS, renal, ocular involvement, hypercalcemia, worsening lung function/symptoms/radiology.

Medications

  • First Line:
  • Systemic corticosteroids:
    • Prednisone 0.3–0.6 mg/kg (20–40 mg/day) for 4–6 wk
    • Taper if stable, continue 10–20 mg/day for 8–12 mo
    • High-dose (80–100 mg/day) for severe organ involvement
    • Exclude TB before starting
  • Topical/inhaled steroids for mild skin/lung involvement
  • Second Line:
  • Immunosuppressants: Methotrexate, azathioprine, leflunomide, mycophenolate (regular CBC/LFT monitoring)
  • Antimalarials: Hydroxychloroquine/chloroquine (less clear benefit)
  • TNF antagonists (infliximab): Refractory cases

Surgery

  • Lung transplant: For severe, refractory cases

Referral

  • Pulmonology for most
  • Specialist referral based on organ involvement

ONGOING CARE

Monitoring

  • ~23% develop new manifestations in 3 years.
  • Monitor serum calcium, creatinine, alk phos annually.
  • On prednisone: see every 1–2 months.
  • Not on therapy: q3 months for 2 years (Hx, PE, PFT, labs as indicated).
  • On hydroxychloroquine: eye exam q6–12 months.

Patient Education

PROGNOSIS

  • 50%: spontaneous resolution within 2 years.
  • 25%: significant fibrosis, stable after 2 years.
  • 25%: chronic disease (higher in Black Americans).
  • Death rate <5% (higher in Black American women).
  • Prolonged steroid use (>6 mo) = higher chronic disease risk.

COMPLICATIONS

  • Significant respiratory involvement (cor pulmonale)
  • Pulmonary hemorrhage (aspergillosis in damaged lung)
  • Heart: CHF, arrhythmias
  • Eye: rare blindness
  • CNS: serious consequences

ICD-10 CODES

  • D86.89 Sarcoidosis of other sites
  • D86.81 Sarcoid meningitis
  • D86.2 Sarcoidosis of lung with lymph nodes

CLINICAL PEARLS

  • Sarcoidosis = noninfectious, multisystem granulomatous disease of unknown cause, usually young/mid-aged adults.
  • Diagnosis: clinical findings, exclusion of other diseases, noncaseating granulomas on biopsy (not always required).