Epidemiology
- Prevalence: affects 0.05-1.5% of the population
- Age: usually occurs in <40 y/o’s
- Sex: M:F ratio is 10:1
- Females tend to have milder and more peripheral disease with fewer radiographic changes in spine
- Race: rare in non-whites
- Genetic Factors: >90% of whites with ankylosing spondylitis are HLA-B27 positive
Physiology
- Immunologic Mechanism
- Cardinal Site of Disease: vertebral column -> leads to development of fibrosis and ossification -> eventual ankylosis of vertebral joints
- Decreased Ventilation to Lung Apices: may predispose changes that develop in this area
Diagnosis
- Spine X-Rays: bilateral sacroiliitis
Clinical Manifestations
Cardiovascular Manifestations
Ophthalmologic Manifestations
Pulmonary Manifestations (typically insidious onset)
Apical Interstitial Lung Disease with or without Apical Fibrobullous Disease
- Epidemiology
- Apical interstitial lung disease is the most common pattern of lung involvement: 30% of cases have upper zone fibrosis
- Fibrobullous changes are less common, being seen in 1-2% of cases
- Apical interstitial changes usually progress to fibrobullous changes over time
- Although usually occurs in long-standing ankylosing spondylitis cases, subclinical pulmonary involvement is common early in the course of the disese
- Diagnosis
- CXR/Chest CT: apical reticulonodular infiltrates or fibrobullous changes (often mimicking those seen in TB): usually bilateral
- Apices may be secondarily infected or retracted
- FOB: subclinical lymphocytic alveolitis may be seen
- Open Lung Biopsy
- Pneumonic-like process: patchy round cell or fibroblastic infiltration progressing to extensive fibrosis
- Dense pleural fibrosis is usually associated with parenchymal fibrosis
- Bronchiectasis: may be seen
- Bullous changes may be seen
- Clinical
Asymptomatic or may present with cough, sputum, dyspnea, absence of clubbing
- Pulmonary Superinfection (with TB, atypical mycobacteria, or Aspergillus fumigatus): may complicate the apical fibrobullous changes
- Aspergillus fumigatus is isolated from 60% of cases with apical cavitation
- Hemoptysis: may result from apical cavitary disease
- Treatment
- No treatment has been proven to prevent apical fibrosis: it is typically resistant to corticosteroid therapy
- Bronchial artery embolization: may be necessary to control hemoptysis
- Avoid surgial resection of Aspergilloma unless bleeding is refractory: due to high risk of post-op bronchopleural fistula and empyema
Pleural Disease
- Clinical
- Apical Pleural Thickening: early finding in ankylosing spondylitis
- Pleural Calcifications
- Pleural Effusion (see Pleural Effusion-Exudate, [[Pleural Effusion-Exudate]]): rare
- Usually exudate with normal glucose (but empyema has been reported)
- Pleuritis
Spontaneous Pneumothorax (see Pneumothorax, [[Pneumothorax]])
- Physiology: may occur due to rupture of apical bullae
Atelectasis (see Atelectasis, [[Atelectasis]])
Chronic Aspiration Pneumonia (see Aspiration Pneumonia, [[Aspiration Pneumonia]]):
Thoracic Cage Immobility
- Physiology: costovertebral spondylosis (which may occur in advanced cases)
- Diagnosis
- ABG: minimal gas exchange abnormalities
- PFT’s: fixation of thorax at high volume and decreased chest wall compliance (although ankylosing spondylitis generally does not usually lead to significant pulmonary dysfunction)
- Expiratory flow rates: normal
- TLC (and VC): slight-moderate decrease
- FRC and RV: normal-slightly increased
- Clinical
Bronchocentric Granulomatosis (see Bronchocentric Granulomatosis, [[Bronchocentric Granulomatosis]])
Scar Lung Carcinoma (see Lung Cancer, [[Lung Cancer]])
- Clinical
- Adenocarcinoma
- Squamous Cell Carcinoma
Mediastinal Fibrosis (see xxxx, [[xxxx]])
Cricoarytenoid Arthritis (see Cricoarytenoid Arthritis, [[Cricoarytenoid Arthritis]]): has been reported
- Clinical
- Upper Airway Obstruction
- Acute Respiratory Failure
- Cor Pulmonale
Renal Manifestations
Rheumatologic Manifestations
- Arthritis of Peripheral Joints (see Arthritis, [[Arthritis]]): 33% of cases
- Atlantoaxial Instability (see Atlantoaxial Instability, [[Atlantoaxial Instability]])
- Spine Arthritis (see Arthritis, [[Arthritis]]): back pain and morning stiffness (that improves with exercise) are common
Other Manifestations
- Fatigue (see Fatigue, [[Fatigue]])
- Low-Grade Fever (see Fever, [[Fever]])
- Weight Loss (see Weight Loss, [[Weight Loss]])
Treatment
- Corticosteroids (see Corticosteroids, [[Corticosteroids]])
- Pulmonary apical fibrotic changes are typically steroid-resistant
References
- Pulmonary involvement in ankylosing spondylitis. Ann Rheum Dis. 1986 September; 45(9): 736–740
- Lung findings on high-resolution computed tomography in idiopathic ankylosing spondylitis–correlation with clinical findings, pulmonary function testing and plain radiography. Rheumatology (1997) 36 (6): 677-682