Petrositis

Patients affected by a petrositis typically present with Gradenigo's syndrome, a triad of symptoms involving an abducens nerve palsy, suppurative otitis media and facial pain that follows the distribution of the trigeminal nerve. Nevertheless, not every patient diagnosed with petrositis tends to exhibit all three symptoms upon diagnosis [1] [2] [3]. In cases where petrositis occurs secondary to an otitis media and mastoiditis, fever, otorrhea that persists for more than three weeks, erythema in the region of the mastoid and ipsilateral pain tend to be the symptoms that patients present with, alongside Gradenigo's syndrome [4]. Additional symptoms that may accompany the aforementioned presentation include:

• Facial paralysis, due to extension of the infection to the facial nerve
• Vertigo
• Involvement of the vestibulocochlear, glossopharyngeal or vagus nerve. Symptoms that are elicited may be those of nasal speech, bovine cough or pseudobulbar palsy; the latter occurs in cases where the petrous apex of the temporal bone is bilaterally affected.
• Hearing impairment due to extension of the infection to the labyrinth [5]

Petrositis, if left undiagnosed or untreated, can affect various structures in the vicinity of the temporal bone. If such complications occur, symptoms may vary and include thrombosis of the sigmoid, dural venous or cavernous sinus, thrombotic events of the jugular vein, an epidural or cerebral abscess, a subdural empyema, frank meningitis and loss of orientation or coma.

Diagnosing petrositis initially requires a detailed clinical examination and medical history. Symptoms obtained from the medical history that raises suspicion towards petrositis includes the following:

• Otorrhea, abducens nerve palsy, pain along the distribution of the trigeminal nerve (Gradenigo's syndrome)
• Fever
• Otalgia
• Erythema and pain in the region of the mastoid
• Facial paralysis
• Vertigo
• Pseudobulbar palsy, bovine cough or nasal speech

With regard to the laboratory examinations that can aid towards the diagnosis of petrositis, a complete blood count and biochemical profile are expected to show leukocytosis, an augmented erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP); other pathological findings such as an increased blood glucose or abnormal urea and creatinine levels, can direct the physician towards an underlying condition that predisposes the patient to a petrositis. A sample from the ear suppuration can also be cultured, in order to isolate the pathogen responsible for the infection. The sample can be collected via myringotomy or direct drainage in cases of eardrum perforation.

A computerized tomography (CT) or magnetic resonance imaging (MRI) scan, alongside a single-photon emission computed tomography scan (SPECT) are also able to depict the petrous apex of the temporal bone and diagnose an infection, with the MRI being the imaging modality of choice regarding the differential diagnosis of an infection and a malignant tumor [6] [7]. Finally, a radioisotope bone scan can also be used in the diagnostic approach [7].

1. Mafee MF, Singleton EL, Valvassori GE, et al. Acute otomastoiditis and its complications: role of CT. Radiology. 1985;155 (2): 391-7.
2. Head and neck imaging. Peter MS, Hugh DC, St Louis (eds). Mosby-Year Book, 2003.
3. Chole RA, Sudhoff HH. Chronic otitis media, mastoiditis, and petrositis. In: Flint PW, Haughey BH, Lund VJ, Niparko JK, Richardson MA, Robbins KT, et al., eds. Cummings otolaryngology head and neck surgery. 5th ed. Philadelphia, PA: Mosby; c2010. pp. 1963–1978.
4. Vazquez E, Castellote A, Piqueras J, et al. Imaging of complications of acute mastoiditis in children. Radiographics. 23 (2): 359-72.
5. Lutter SA, Kerschner JE, Chusid MJ. Gradenigo syndrome: a rare but serious complication of otitis media. Pediatr Emerg Care. 2005 Jun;21(6):384–386.
6. Lee YH, Lee NJ, Kim JH, et al. CT, MRI and gallium SPECT in the diagnosis and treatment of petrous apicitis presenting as multiple cranial neuropathies. Br J Radiol. 2005 Oct;78(934):948-51
7. Pedroso JL, de Aquino CC, Abrahao A, et al. Gradenigo's Syndrome: Beyond the Classical Triad of Diplopia, Facial Pain and Otorrhea. Case Rep Neurol. 2011 Feb 15;3(1):45-7. doi: 10.1159/000324179.