This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Gradenigo's syndrome is due to ? 
Select and explain. 
A. Mastoiditis, B. Petrositis, C. Sigmoid sinus thrombophlebitis, D. Labyrinthitis
B: Petrositis
Answer: B: Petrositis 
Explanation: Ans. is 'b' i.e., Petrositis Petrositis Infection of mastoid and middle ear may be complicated by the spread of infection within the temporal bone into petrous apex. Petrositis is an extension of infection from middle ear and mastoid to the petrous pa of the temporal bone. Gradenigo's syndrome is the classical presentation and consists of a triad of : - External rectus palsy (VIth nerve/abducent nerve palsy) causing diplopia. Deep seated orbital or retroorbital pain (Vth nerve involvement). Persistent ear discharge due to ipsilateral acute or chronic otitis media. Associated symptoms of otitis media are also present e.g., conductive deafness. Other symptoms are fever, headache, vomiting, and sometimes neck rigidity. Some patient may get facial paralysis and recurrent veigo due to involvement of facial and statoacoustic nerves.