A 13-year-old boy with poorly controlled type 1 diabetes (T1D) presents to the emergency department (ED) for evaluation of left ear pain and left facial weakness.
Over the preceding 2 months, he had been evaluated and treated twice at an outside hospital for otitis externa, including a 5-day hospitalization with intravenous (IV) piperacillintazobactam given concern for malignant otitis externa, a rare diagnosis in children, and subsequently completed a course of oral ciprofloxacin and otic corticospinal. He had transient resolution of his symptoms, but for the last 5 days his left ear pain has worsened, and for the last 2 days he has noticed left upper and lower facial weakness. The patient also reports diminished hearing in his left ear and the sensation of left aural fullness.
The boy has not had any recent fevers or chills at home, denies any other regions of weakness, and has not experienced any dizziness or vertigo. There is no recent travel history, but he had been swimming twice in salt water in the summer prior to the onset of his initial symptoms. His most recent hemoglobin A1C was 10.6%, measured 7 months prior to presentation. He has no previous history of otitis media/externa.
Physical exam and ED course
On presentation to the ED, the patient has a temperature of 99.5°F; heart rate of 76 beats per minute; respiratory rate of 20 breaths per minute; blood pressure of 133/77 mmHg; and oxygen saturation of 99% on room air. Blood pressure normalized on repeat measurement. The patient is comfortable and not ill appearing. Left full-facial droop with loss of the ipsilateral nasolabial fold is noted but neurologic exam is otherwise unremarkable.
On examination of the left ear, there is mild anterior displacement of the pinna but no overt skin changes at the mastoid or external ear. There is significant pain with manipulation of the pinna and palpation of the mastoid. The external auditory canal is swollen and occluded with granulation tissue, obscuring the tympanic membrane. Heart, lung, abdominal, and skin exams are unremarkable.
The patient’s white blood cell count is 3860 cells/μL, with 36% neutrophils, 41% lymphocytes, 10% monocytes, and 8% eosinophils. His hemoglobin is 12.4 g/dL and platelets are 425,000/μL. Erythrocyte sedimentation rate is 12 mm/hr. His C-reactive protein is 1.3 mg/dL. Chemistry panel is normal. Urine analysis is normal with no ketonuria or glucosuria.
Computed tomography (CT) scan of the temporal bone with intravenous (IV) contrast is performed that shows findings consistent with acute otomastoiditis on the left with opacification of the left mastoid air cells and middle ear cavity (Figure). The otolaryngology service is consulted and recommends broad IV antibiotic coverage with vancomycin and cefepime and IV dexamethasone for control of swelling and inflammation around the facial nerve. The patient is admitted for further workup and management.
Differential diagnosis of facial nerve palsy
The differential diagnosis for facial nerve palsy in a pediatric patient is quite broad (Table1-3) and can be categorized into genetic, compressive, traumatic, and infectious/inflammatory etiologies. Notably, the facial nerve takes the longest intraosseous course of any cranial nerve and is therefore at increased risk for injury.1 At certain points in its course, the facial nerve occupies up to 25% to 50% of the area of the bony canal; therefore, in the event of swelling and inflammation, the lack of space for expansion in the canal can impede blood flow and further exacerbate nerve damage.
In this case, given the preceding ipsilateral chronic recalcitrant otitis externa in the context of poorly controlled T1DM, the team considers progression to an otitis media with subsequent inflammation of the traversing facial nerve to be the most likely etiology of the deficit. This is further supported by the CT findings that are consistent with the diagnosis of acute otomastoiditis. Of note, otitis media is the most common cause of facial nerve palsy in children, except in areas where Lyme disease is endemic.1
Given this patient’s presentation, a concurrent compressive etiology such as tumor could not be excluded as a cause of obstruction contributing to the chronic external ear infection. The patient’s age of presentation makes a genetic cause unlikely, and the lack of preceding trauma or instrumentation make a traumatic cause unlikely as well. There is no evidence to support an alternate infectious etiology.