Abstract
Nervus intermedius neuralgia (NIN), also called geniculate neuralgia, is an extremely rare condition whose pain is very similar to that of trigeminal neuralgia but with the distribution of nervus intermedius (1, 2). The pain paroxysms are felt deeply in the auditory canal and the clinical picture is often first interpreted as a manifestation of an otological disease. The new classification of the International Headache Society (3) proposes the following diagnostic criteria: pain paroxysms felt in the depth of the ear, lasting for seconds or minutes, of intermittent occurrence; the presence of a trigger zone in the posterior wall of the auditory canal; and exclusion of a structural lesion. Herpes zoster, temporomandibular joint disease, carcinoma of the nasopharynx, osteoma petrous bone and neuroborreliosis have been reported as causing NIN (4–6). Taking into account both primary and secondary cases, NIN is a condition of adulthood (4).
Case report
A 1-year-old White girl presented with a 4-month history of left auricular pain. According to her mother, the attacks had started suddenly, with no precipitating factor, lasting about 8 s. During attacks, the child cried out and froze in place with the left hand slowly rising to her left ear but not touching it (Fig. 1). The frequency had gradually increased during 2 months, ranging from 10 to 20 attacks per day. There were diurnal and nocturnal attacks. There was no autonomic feature. Perinatal history, developmental milestones and past medical history were unremarkable. Neurological examination was normal. A trial with carbamazepine led to a reduction of frequency of pain attacks (from five to seven attacks daily).
Patient during an attack.
Brain computed tomography showed no abnormality. Brain magnetic resonance imaging disclosed a mass suggestive of a left trigeminal tumour (Fig. 2). Surgery was performed with complete tumour removal. Histopathological examination revealed a schwannoma.
Brain magnetic resonance image showing the lesion.
Following the immediate postoperative period, the patient presented complete relief of her headaches and she remains asymptomatic after 4 years of follow-up. The child's parents approved this publication and signed informed consent.
Discussion
We describe a 1-year-old girl with symptomatic neuralgiform pain secondary to a schwannoma in the ipsilateral trigeminal nerve.
The first consideration in the differential diagnosis of the clinical picture is trigeminal neuralgia (TN). TN is described (3) as: ‘a unilateral disorder characterized by brief electric shock-like pains, abrupt in onset and termination, limited to the distribution of one or more divisions of the trigeminal nerve. Pain is commonly evoked by trivial stimuli including washing, shaving, smoking, talking and/or brushing the teeth (trigger factors) and frequently occurs spontaneously. Small areas in the nasolabial fold and/or chin may be particularly susceptible to the precipitation of pain (trigger areas)’. Since the pain of symptomatic trigeminal neuralgia is indistinguishable from classical trigeminal neuralgia (3), the auriculotemporal area is an unusual pain location in TN.
Neuralgiform pain attacks in the ear resemble glossopharyngeal neuralgia (GN). The pain of GN is similar in quality and characteristics to that of TN, but it occurs in the distribution of the glossopharyngeal nerve (the posterior part of the tongue, tonsillar fossa, pharynx or beneath the angle of the lower jaw and/or in the ear). However, unlike TN, the presence of precipitating factors is essential to the diagnosis of classical or symptomatic GN and there is no trigger factor of pain reported by child's parents.
Anatomical, clinical and surgical studies have clearly shown the involvement of the sensory component of the seventh nerve in what was previous called ‘geniculate neuralgia or neuralgia of the nervus facialis’ (4). The peripheral anastomotic connections of the nervus intermedius with the descending spinal trigeminal and also the VII (postauricular branch), IX (anastomotic branch), X (auricular branch of Arnold), and C II/III (greater auricular nerve) tracts play a pivotal role in the pain mechanism (2). These anatomical relationships could explain a clinical picture such as described in this article, in which a trigeminal schwannoma provoked an intermedius neuralgia-like pain. We could not definitely test criteria B of the IHS classification (3), since the patient, understandably, refused any attempt to touch her ear area.
Tumours of the trigeminal nerve are infrequent; they account for 0.08–0.28% of intracranial tumours and 0.8–8% of intracranial neurinoma (7). Schwannomas of the trigeminal nerve can occur at any age; however, it is a condition much more prevalent in adults, predominating in the fourth and fifth decades (7).
We report a case of secondary intermedius neuralgia-like pain in a young girl due to a trigeminal schwannoma, in whom surgical removal led to complete recovery. This is an interesting case report of a very unusual condition in childhood secondary to a rare intracranial tumour.