Special Operations Forces Medical Handbook

4-18

Follow-up Actions
Return Evaluation: Refer patients that do not improve for specialty care and additional special studies.
Evacuation/Consultation Criteria: Evacuate unstable patients. Consult internist or pulmonologist.

NOTE: Pleurectomy (pleural stripping) in cases of “trapped lung” is a definitive procedure only done by
surgeons when a large scar forms and impairs normal lung function.

Respiratory: Allergic Pneumonitis

COL Warren Whitlock, MC, USA

Introduction: Hypersensitivity pneumonitis begins with allergic lung inammation from repeated inhalation of
dust particles consisting of animal proteins, plant proteins or reactive inorganic compounds. It is different from
inammatory disease of the airways (asthma) in that it diffusely affects the lungs and symptomatically presents
as a sub-acute, progressive or recurrent pneumonia. In cases where the allergen is inhaled repeatedly,
recurrent pneumonia can be sudden and life-threatening. Thermophilic actinomycetes is a mold that causes
several types of hypersensitivity pneumonitis: farmer’s lung or silo ller’s lung (exposure to moldy silos), air
conditioner lung (exposure to moldy air lter) and bagassosis or cotton worker’s lung (inhalation of bers or
moldy cotton). Other types include bird breeder’s lung (inhalation of avian protein, blood or dander), isocyanate
lung (exposure to toluene diisocyanate [TDI] or methylene diisocyanate (MDI) used in polyurethane, plastics
and some spray paints) and washing powder lung (Bacillus subtilis enzymes). Chronic exposure to the allergen
can result in permanent restrictive lung disease.

Subjective: Symptoms
Acute illness (within 6 hours of exposure): cough, dyspnea, malaise, and body aches (mimics an acute
infectious pneumonia).
Chronic illness: progressive condition without acute exacerbation, cough, dyspnea and exercise limitation,
anorexia, weight loss, and fatigue.
Focused History: Quality: Do you get sick after a specific activity or exposure? Do symptoms go away
when on vacation or visiting relatives in a distant city or state? (Diagnose based on history of symptoms
only occurring at work or in a certain environment. Sometimes a patient will need to keep a diary to log all
their activities and exposures.) Duration: How long do your symptoms last? (Generally, pneumonitis start to
improve over 72 hours, unless additional exposure.)

Objective: Signs
Using Basic Tools: Acute illness: Vital Signs: Fever up to 104oF, tachypnea, tachycardia. Inspection: acute
sputum production (clear, white or colored), cyanosis. Auscultation: Fine, mid- to end-inspiratory crackles in
chest. Signs may improve without treatment if removed from the offending antigen.
Chronic illness: Vital Signs: Afebrile or low-grade fever. Inspection: Progressive cyanosis and clubbing of
fingers. Auscultation: Fine, mid- to end-inspiratory crackles in chest; right heart failure with extremity swelling.
Signs will not acutely improve when removed from the offending antigen due to lung scarring from chronic
exposure. Diagnosis can only be made by laboratory testing at this point in the disease.
Using Advanced Tools: CXR: Pneumonia appears as a localized or diffuse infiltration or granulomas in
the peripheral areas of the lung. Pulmonary function studies (if available) may show restriction and reduction
in diffusing capacity of the lung

Assessment:
Denitive diagnosis can only be made by laboratory testing for allergies (hypersensitivity panel).
Differential Diagnosis: Acute illness resembles typical and many atypical pneumonias including inuenza
and mycoplasma
Chronic illness: Non-resolving or recurrent pneumonia, tuberculosis, sarcoidosis, fungal infections, and
Pneumocystis carinii pneumonia with HIV.