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   . 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 . Additional symptoms that may accompany the aforementioned presentation include:
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:
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  . Finally, a radioisotope bone scan can also be used in the diagnostic approach .