The correct answer is:

Dural sinus thrombosis

Educational Objective:

Understand known complications of mastoiditis.

Key Point:

This patient is presenting with signs and symptoms suggestive of acute mastoiditis. Mastoiditis is an infectious process of the temporal bone, most commonly a complication of acute otitis media. 

Explanation:

Patients present with fever, ear or neck pain, and irritability. On clinical examination they may exhibit swelling or erythema of the retro/postauricular area, point tenderness and protrusion of the auricle with downward displacement from the normal position. 

The organisms most commonly involved in mastoiditis are Streptococcus pneumoniae, Staphylococcus aureus, and S. pyogenes. Pseudomonas aeruginosa is more frequently associated with chronic mastoiditis. 

Diagnosis can be made clinically or with evidence of opacified mastoid air cells with erosion on temporal bone CT. 

The infection can spread through the air cells to the medial portion of the temporal bone leading to cranial nerve VI palsy, meningitis, cerebritis, intracranial abscesses, dural sinus thrombosis, otitis hydrocephalus, and cranial osteomyelitis. Purulent extension into the deep tissues of the upper neck can lead to a bezold abscess. Less severe complications include labyrinthitis, and conductive or sensorineural hearing loss. 

The other choices listed are not known complications of mastoiditis; cavernous sinus thrombosis and cranial nerve III palsy are seen as complications of orbital cellulitis.

References:

Hudgins JD, et al. ENT emergencies. F&L 2016; p 1343.

Tien I, Aschkenasy M. Ear diseases. Baren 2008; 410-1.

Seiden JA. Mastoiditis. 5-min PEM Consult 2012; 608-9.