What is BOOP ?
- BOOP is a distinct spectrum of lung disease charecterised by wide spread inflammation of small conducting airways (unlike ARDS where the site of injury is the alveolar membrane) initiated by various injurious agents like viruses,toxic fumes and connective tissue disorders followed by an attempt to heal by forming granulation tissue predominantly in the distal bronchioles (hence bronchiolitis obliterans) which may resolve fully either spontaneously or with steorids or may progress to irreversible fibrosis of distal airways ( hence organising pneumoniaas coined in the preantibiotic era) . Epler, Colby and Carrington coined the term BOOP.
When to suspect BOOP?
- A middle aged male or female presenting with flu like syndrome with cough and breathlessness lasting about 1-2months with a background history of viral infection,connective tissue disorders, toxic fume inhalation and on certain drugs as methotrexate or amiodarone,whose chest x ray shows bilateral patchy densities without volume loss, think of BOOP. Most of them have crackles and wheeze on auscultaion.
What are causes of BOOP?
- Connective tissue disorders eg Rheumatoid arthritis,SLE etc
- Toxic fumes
- Post infective eg Viral pneumonias
- Idiopathic
Diagnostic features?
- CXR: Patchy opacities which begins unilaterally and then becomes bilateral
- CT Thorax: Ground glass opacities
- PFT: Restrictive pattern inspite of obtructive pathology
- Biopsy of lungs: Is the diagnostic test
How to treat?
- Prednisolone : Starting at 1-2mg/kg tapered over 3-6weeks.
- May need steroid sparing drugs as Azathioprine if signs and symptoms reccur with steroid tapering.
When should you be cautious regarding the possibility of SIOP?
- Patients receiving at least 30mg of hydrocortisone or 7.5mg of prednisolone for a period of at least 3 months are at risk for SIOP. Steroid replacement in corticosteroids deficiency states compared to immunosuppresive therapy has lesser risk for SIOP.
Site of SIOP fracture?
- Axial skeleton (Lumbar vertebrae is the first site)
- Proximal femur
How does SIOP occur?
- Increase in osteoclastic activity
- Decrease in osteoblastic activity
- Calciuresis
- Decreased intestinal absorption of calcium
- Decrease in gonadal hormones esp. estrogens
Who are at risk?
- Postmenopausal females
- Higher dose of steroids for longer duration
- Immobilised
- Mal absorption and nutritionally compromised
- On drugs as frusemide
- Poor sun exposure
- Coexistent renal disease
Does the steroid type determine incidence of SIOP?
- Prednisolone followed by dexamethasone are the champs.
What should you do?
- Use steroids for the right indication, at the lowest required dose, for the shortest possible time.
- Try to include steroid sparing drugs the earliest in connective tissue disorders (eg Azathioprine).
- Change the concomitant drugs eg thiazide instead of frusemide.
Treatment ?
- Stop or reduce steroids.
- Alternate route of administration eg inhalation and local injection.
- Calcium at least 1000mg per day and Vit. D3 0.25-1 mcg per day
- Bisphosphonates eg Alendronate 70mg once weekly or 5-10mg per day PO.
- Calcitonin nasal sprays.
- Physiotherapy (skeletal loading).
- Gonadal hormone replacement therapy (beware of CAD risk).
What if fracture occurs ?
- Work in association with your orthopaedic colleague.
