Young woman w/ subacute SOB = broad differential
- Pulmonary ddx: Chronic infections if HIV-infected (PCP, PTB), 1° Ciliary dyskinesia, CF, thoracic endometriosis (sx worse q3-4weeks, hemoptysis), PE (OCP?), LAM, sarcoidosis
Posted 05/29/16 03:56:52 PM by Matthew Cummings
Hypersensitivity pneumonitis (HP): ILD caused by ongoing inhalation of antigen to which individual has been sensitized
- Antigens classically from moldy hay/grain (farmers), birds, hot tubs/humidifiers, spray paint (autoworkers)
- Reversible if antigens avoided and treated early, but can progress to fibrotic disease if continued exposure
Posted 05/29/16 03:57:11 PM by Matthew Cummings
HP clinically presents with repeated episodes of fever/cough/SOB or progressive SOB if fibrotic disease
- No accepted diagnostic criteria but presence of 6 findings highly predictive (PPV >95%): antigen exposure, +precipitating antibodies, recurrent symptomatic episodes w/ onset ~4-6 hours after exposure, crackles, weight loss
Posted 05/29/16 03:57:41 PM by Matthew Cummings
High-resolution CT chest in HP: findings variable, range from GGO, centrilobular nodules w/ mosaic attenuation --> fibrosis in chronic HP
- GGO differential? bacterial PNA (also PCP), inflammatory exudate (viral infection, auto-immune disease), blood (alveolitis/vasculitis), fluid (pulmonary edema)
Posted 05/29/16 03:59:39 PM by Matthew Cummings
Bronchoscopy in HP: BAL classically w/ lymphocytosis, abnormal CD4/CD8 ratio --> bx with noncaseating granulomas
Posted 05/29/16 04:00:13 PM by Matthew Cummings
Differential diagnosis for HP:
- Acute: Pneumonia, sarcoidosis (also w/ nodules, noncaseating granulomas, BAL lymphocytosis)
- Chronic: difficult to distinguish from other ILDs (NSIP, IPF)
Posted 05/29/16 04:00:56 PM by Matthew Cummings
HP treatment: often good prognosis if treated early
- Antigen avoidance is #1
- Systemic steroids (e.g. 1mg/kg prednisone)
- Disease can progress despite avoidance if already into fibrotic phase (no role as of yet for anti-fibrotics in HP)
Posted 05/29/16 04:02:11 PM by Matthew Cummings
For further reading...
Posted 05/29/16 04:06:50 PM by Matthew Cummings
Created by Christopher Kelly
Know a hypochondriac? Get them the best-selling book 'AM I DYING?!: A Complete Guide to Your Symptoms, and What to Do Next'
The information on the website does not constitute official guidelines except where explicitly stated.
It is not meant to replace the advice of a health professional.