North American Veterinary Licensing Examination (NAVLE) Practice Test

In a cat with acute onset exophthalmos and painful eye palpation, what is the most likely diagnosis?

1. Orbital neoplasia

2. Retrobulbar abscess

3. Anterior uveitis

4. Glaucoma

The correct answer is: Retrobulbar abscess

Acute onset exophthalmos, accompanied by painful eye palpation, strongly suggests a retrobulbar abscess as the most likely diagnosis. This condition occurs when there is an accumulation of pus in the retrobulbar space, leading to swelling and a protruding eye. The pain upon palpation occurs due to inflammation and pressure on surrounding tissues and nerves, which is characteristic of abscess formation. In this scenario, the rapidity of the onset is also a significant factor, as retrobulbar abscesses can develop quickly following infections, trauma, or dental disease that can allow bacteria to spread to the area behind the eye. The clinical signs of exophthalmos will typically be accompanied by other symptoms such as swelling of the eyelid or the presence of a fever, which can often accompany such an infection. While orbital neoplasia can also cause exophthalmos, it usually has a more gradual onset and is less commonly associated with acute pain during palpation. Anterior uveitis primarily affects the internal structures of the eye and is characterized by changes in appearance of the eye and discomfort, but does not typically result in exophthalmos. Glaucoma can result in a swollen eye and pain, but it usually produces