Case Studies
Case 2: A deaf young man with poor balance
A 28-year-old man reports increasing tinnitus in his left ear with a tendency to fall to the left. He has no significant previous medical history and on examination he has left sided ataxia, a gaze paresis to the left and sensorineural deafness on that side.
Your Answer:
Correct answer: The lesion is clearly involving the left pons, left side of the brainstem or cerebellum and presumably the 8th cranial nerve on the left given the deafness. It is therefore likely that the lesion is in the cerebellar pontine angle on the left.
Your Answer:
Correct answer: Given the position the most likely cause of this is an acoustic neuroma which is a Schwannoma of the vestibular part of the 8th cranial nerve. There are a number of other lesions in this anatomical location that could give this clinical picture including meningiomas as well as different types of developmental cysts.
Your Answer:
Correct answer: This reflects compression of the left pontine area in particular the pontine paramedian reticular formation which is responsible for horizontal gaze.
Your Answer:
Correct answer: Definitely not. This patient clearly has some problem in the posterior fossa and no lumbar puncture should be undertaken in any patient with a lesion in this region of the neuro axis until imaging has been secured, and if a space occupying lesion is found, no lumbar puncture should be done.
Your Answer:
Correct answer: It is doubtful that any further tests are required outside an MRI scan. Sometimes brainstem auditory evoked potentials can help detect abnormalities within the 8th cranial nerve to help localise the lesion, but in this case it is unlikely to be helpful given that he is deaf.
Your Answer:
Correct answer: No, as acoustic neuromas are rarely inherited. If they are bilateral in nature, however, this implies that they might have a condition called neurofibromatosis type II in which case genetic testing and counselling would be advised.
Your Answer:
Correct answer: Some patients develop malignant middle ear infections where the infection is such that it erodes the bone and destroys the local structures. In younger people this can take the form of cholesteatoma, in older patients especially diabetics it can often start in the external ear and they develop a malignant otitis externa.
Your Answer:
Correct answer: In the case of an acoustic neuroma the only treatment is a surgical removal of the lesion with sacrifice of the 8th cranial nerve. In the case of infection clearly surgical and/or antibiotic therapy is required depending on the extent and nature of the lesion.