Chronic use of nasal decongestants, presented with abrupt onset of fever with chills and rigor, diplopia on lateral gaze

 # A 19 year old young girl with previous history of repeated pain over medial canthus and chronic use of nasal decongestants, presented with abrupt onset of fever with chills and rigor, diplopia on lateral gaze, moderate proptosis and chemosis. On examination, the optic disc is congested. Most likely diagnosis is:

A. Cavernous sinus thrombosis

B. Orbital cellulitis

C. Acute ethmoid sinusitis

D. Orbital apex syndrome

The correct answer is:

A. Cavernous sinus thrombosis

Explanation:
The clinical presentation described—abrupt onset of fever with chills, diplopia, proptosis, chemosis, and optic disc congestion—is characteristic of cavernous sinus thrombosis (CST). This condition is often secondary to infections in the medial canthus (commonly from facial infections or sinusitis), which can spread to the cavernous sinus via valveless facial veins.

Key Differentiation:

• B. Orbital cellulitis: Also presents with proptosis and chemosis but typically lacks systemic signs like severe fever with chills and is not associated with optic disc congestion or diplopia on lateral gaze.
• C. Acute ethmoid sinusitis: May cause pain over the medial canthus and fever but does not typically lead to proptosis, chemosis, or optic nerve involvement.
• D. Orbital apex syndrome: Involves cranial nerve deficits (II, III, IV, V, and VI) and visual loss, but the history of prior medial canthus pain and sinusitis with systemic signs strongly points to CST.

Cavernous sinus thrombosis is a medical emergency requiring immediate intervention with antibiotics and sometimes anticoagulation.