Tongue tremor: A rare manifestation of disseminated central nervous system tuberculosis

Dear Sir, A 22-year-old man presented to us with a history suggestive of chronic meningitis in the form of fever and headache for the last 2 months along with occasional episodes of vomiting for the last 2 weeks. He had dysarthria for the last 10 days with some difficulty in swallowing. Five days before admission, the patient developed weakness of all four limbs along with bladder–bowel involvement, leading to him being in a bed-bound state for the next 3 days. On examination, the patient was conscious and oriented with dysarthria. Cranial nerve examination was normal, except for a sluggish response to gag reflex. The patient had mild bulbar dysarthria, and a tongue tremor was interfering with his speech. Neck rigidity and signs of meningeal irritation were present. Motor examination was suggestive of hyporeflexic quadriparesis, while the bilateral plantar responses were mute. A striking finding in the examination was the presence of a tongue tremor, which was present on protrusion of the tongue but subsided at rest [Video 1]. {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1","caption":"","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_ivio8qba"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} Considering the possibility of disseminated tuberculosis, imaging and cerebrospinal fluid (CSF) analysis was performed. Brain magnetic resonance imaging (MRI) was suggestive of mild hydrocephalus, with meningeal enhancement and basal exudates with multiple nodular/ring-enhancing lesions, suggestive of tuberculomas. MRI of the spine showed longitudinally extensive transverse myelitis [Figure 1], areflexic flaccid quadriparesis due to spinal shock. CSF analysis supported tubercular infection as the cell count was 240 with all lymphocytes (100%), and protein was 280 mg/dl with normal sugar and an Adenosine deaminase value of 10 units/l. The mycobacteria growth indicator tube test detected growth of mycobacteria, confirming the diagnosis of central nervous system (CNS) tubercular infection. After starting antitubercular treatment and steroids, the tremor resolved completely within 2 months, and the patient started walking independently after 6 months of treatment.Figure 1:: Brain Imaging of 22 yrs. old boy with Disseminated CNS tuberculosis, A-MRI brain with T1 contrast suggestive of basal exudates with multiple nodular enhancing lesions with dilated temporal horns, B- T2 weighted image screen whole spine showing hyper intensity from cervical to dorsal cord suggesting longitudinally extensive transverse myelitis.The presence of a tongue tremor is commonly described in movement disorders such as chorea, dystonia, parkinsonism, and Wilson's disease and in cases of drug use, essential tremor, physiological diseases, structural diseases, and mitochondrial and psychogenic lingual tremor.[1] The presence of a tongue tremor is a rare finding in infective CNS disorders that were earlier described in neurosyphilis as "candy sign."[2] Keane JR et al.[3] described four cases of cysticercosis with hydrocephalus and jaw and tongue tremor. In addition, these patients have features of parkinsonism. The authors proposed postoperative shunt obstruction and hydrocephalus as possible explanations. We could not find any literature on tongue tremor in such cases of disseminated CNS tuberculosis. In various studies, it was found that CNS tuberculosis in a few cases (0.5%–18.6%) was associated with certain movement disorders and basal ganglia dysfunction, primarily due to vasculitic infarction. Chorea, dystonia, limb tremor, ataxia, hemiballismus, myoclonus, and Parkinson's disease-like presentation are explained in the literature and are mostly attributed to granuloma or infarcts in patients with tuberculous meningitis.[4] The tremor in our patient was an isolated tongue tremor without associated parkinsonian features and orofacial and jaw movements. The tremor in our patient was possibly an "action-induced positional tongue tremor" as they become evident on protrusion of the tongue but disappear when the tongue rests in the mouth.[1] The precise mechanism of the generation of isolated tongue movements is debated. Involvement of the pontine central tegmental tracts and interruption of the tonic inhibition of the brainstem pattern generators from the forebrain corticostriatal inputs were proposed to be the possible explanation of the origin of such a tremor.[5] Furthermore, our patient had hydrocephalus and the presence of multiple tuberculomas in the pons, which supports the suggested possibilities of its origin. To the best of our knowledge, this case is the first report on tongue tremor in CNS tuberculosis. It enlightens the diverse clinical manifestations of CNS tubercular infection. Acknowledgement Nil. Author contribution A. Research project: Conception: AQ, DK, AKT Organization: AQ, PKM, AKS, DK, AKT, TSS Execution: AQ, PKM, AKS, DK B. Statistical analysis: Design: AQ, TSS Execution: AQ, DK Review and Critique: AQ C. Manuscript preparation: Writing of the first draft: AQ, TSS Review and Critique: AQ, PKM, AKS, DK, DK. Ethical compliance statement The authors of this paper state that case report involving human was conducted with due regard to relevant ethical standards and guidelines. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.