Differentials
Asthma
SIGNS / SYMPTOMS
History of long-standing episodes of cough, wheezing, and/or dyspnoea.
Absence of obvious inhalation exposure.
May co-exist with inhalation injury.
INVESTIGATIONS
Airflow obstruction documented prior to inhalation exposure.
COPD
SIGNS / SYMPTOMS
History of chronic cough, sputum production, and/or dyspnoea.
Absence of obvious inhalation exposure.
Evidence of chronic pulmonary disease (barrel chest, clubbing).
May co-exist with inhalation injury.
INVESTIGATIONS
Chest x-ray demonstrates lung hyperinflation and flattened diaphragm.
Pulmonary function testing reveals large lung volumes (total lung capacity, functional reserve capacity).
Cardiogenic oedema
SIGNS / SYMPTOMS
History of congestive heart failure (CHF), or new-onset chest pain or palpitations.
Examination shows non-pulmonary evidence of CHF (elevated jugular venous pressure, extremity oedema, ascites).
May co-exist with inhalation injury.
INVESTIGATIONS
ECG, cardiac enzymes, or echocardiography suggestive of ischaemia or heart failure.
Head trauma
SIGNS / SYMPTOMS
History of witnessed trauma or fall.
Examination demonstrates soft tissue injury, focal deficit on neurological examination.
May co-exist with inhalation injury.
INVESTIGATIONS
Head CT scan: may show signs of head trauma.
Carboxyhaemoglobin (CO-Hb) level: normal if no co-existent inhalation injury.
Intoxication
SIGNS / SYMPTOMS
History of intoxicant use.
Constellation of symptoms suggestive of specific intoxication.
May co-exist with inhalation injury.
INVESTIGATIONS
Urine toxicology screen: positive for drug use.
Serum ethanol level: positive for ethanol use.
Osmolar gap: increased in alcohol intoxication.
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