Choanal atresia is characterized by:

Choanal atresia is a congenital condition that is primarily defined by a blockage or obstruction at the back of the nasal passage, which can occur due to either a bony or a membranous barrier. This occlusion prevents the normal airflow from the nose to the throat, leading to breathing difficulties, especially in newborns, who primarily breathe through their noses. This condition is crucial to recognize in a clinical setting as it can cause severe respiratory distress in infants, often requiring immediate medical intervention.

The other options provided do not accurately describe choanal atresia. While excessive mucus production might be associated with various nasal conditions or infections, it is not the primary characteristic of choanal atresia. Congenital heart defects are unrelated to this nasal obstruction, and a rise in intracranial pressure pertains to neurological conditions rather than anatomical nasal issues. Understanding the specific nature of choanal atresia is critical for diagnosis and subsequent management of affected infants.