Question

A patient had a running nose and pain over the medial aspect of the eye and was being treated with decongestants for many days. He later developed chemosis, proptosis and diplopia on abduction of the right eye with congestion of the optic disc. What is the probable diagnosis?

• A. Acute ethmoidal sinusitis
• B. Orbital cellulitis
• C. Cavernous sinus thrombosis
• D. Orbital apex syndrome

Hint:

Facial/nasal sepsis spreading back, plus chemosis, proptosis, CN VI palsy and a congested disc, means the cavernous sinus.

Answer 1

The Correct Option is C

Step 1: Trace the source of infection. The patient started with a running nose and medial periorbital pain (ethmoid/nasal region) treated only with decongestants. Untreated paranasal sinus and facial infection can spread backward through the valveless facial and ophthalmic veins into the cavernous sinus.
Step 2: List the new signs. He developed chemosis, proptosis, diplopia and a congested (swollen) optic disc. These reflect impaired venous drainage from the orbit plus involvement of the nerves running through the cavernous sinus.
Step 3: Interpret the cranial nerve clue. The cavernous sinus carries CN III, IV, V1, V2 and VI, and the lateral rectus is run by CN VI. Diplopia on abduction means a sixth nerve (lateral rectus) deficit, and CN VI lies most medially within the sinus, so it is often affected. This localizes the lesion to the cavernous sinus.
Step 4: Explain the orbital and disc signs. Thrombosis of the cavernous sinus blocks orbital venous outflow, producing chemosis, proptosis and venous congestion of the optic disc, often becoming bilateral because the two cavernous sinuses communicate.
Step 5: Exclude alternatives. Simple ethmoidal sinusitis would not give cranial nerve palsies or disc congestion. Orbital cellulitis causes proptosis and restricted movements but the painful ophthalmoplegia with disc congestion following spread from the face fits cavernous sinus involvement better, and orbital apex syndrome lacks the prominent venous congestion and the antecedent septic facial source.
Conclusion: The septic source, multidirectional venous congestion, CN VI palsy and congested disc point to cavernous sinus thrombosis.