Generally a clinical diagnosis
Consider CXR and labs
May have eosinophilia, which suggests an immune mediated component
May have eosinophilia, which suggests an immune mediated component
Acute pulmonary toxicity from crack cocaine
Acute eosinophilic pneumonia
Acute asthma exacerbation
Acute respiratory distress syndrome
Acute asthma exacerbation 
Pulmonary embolism
Synthetic cathinone toxicity
Congestive heart failure