Congestive Heart Failure: Orthopnea, PND, associated with edema legs.

Adult respiratory distress syndrome: Non-cardiogenic pulmonary edema. Normal capillary wedge pressure. Leaky pulmonary capillaries.

Chronic Bronchitis: Cough and spit for 3 months for two consecutive years. In most strong smoking history.

Pulmonary Emphysema: Older patient. Progressive shortness of breath over time. Strong smoking history.

Asthma: Intermittent episodes of shortness of breath associated with wheezing. Strong atopic history. Normal in between episodes.

Diffuse Interstitial Lung Disease: Older patient. Progressive shortness of breath associated.

Spontaneous Pneumothorax: Acute onset of shortness of breath, with sharp chest pain.

Acute Pulmonary Embolism: Varied presentation from acute to chronic shortness of breath. With a predisposing situation for thrmboembolic process. High index of suspicion for the diagnosis crucial.

Anxiety with Hyperventilation: Air hunger. Classical complaint of not having enough air and not able to get sufficient air with inspiration. Multiple sighs during interview.