Oronasal fistula is a differential diagnosis for nasal discharge with feed material.

• A. Choke
• B. Oronasal fistula
• C. Fungal rhinitis
• D. Sinusitis

Answer: (B)

The key idea is that feed material in nasal discharge signals a direct mouth–nose connection. An oronasal fistula creates an abnormal passage between the oral and nasal cavities, so food particles and saliva from the mouth can move into the nasal passages and appear in nasal discharge. Other conditions like choke, fungal rhinitis, or sinusitis cause nasal discharge through inflammatory or infectious processes but do not establish a channel that lets oral contents enter the nose. Choke leads to regurgitation through the mouth rather than nasal discharge, while fungal rhinitis and sinusitis produce discharge from nasal tissues or sinuses without feeding material entering the nasal cavity. Therefore, observing feed material in nasal discharge most specifically points to an oronasal fistula.