Undulating Tongue: A Window for Diagnosing Wilson's Disease

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We read with great interest the article by El Otmani et al. in this journal wherein the investigators report on a patient with tongue tremors and undulating movements as a presenting feature of Wilson's disease (WD).1 We report on a similar case of a 10‐year‐old girl with progressive difficulty in oral manipulation of food, with dysarthria for 2 months. She had no history of dysphagia, neuroleptic intake, jaundice, or family history of similar complaints. She had bilateral Kayser‐Fleischer rings and undulating tongue movements when protruded (Video 1). Remaining examination was normal. Routine hemogram, liver, and renal function tests were normal. Serum ceruloplasmin was 9 mg/dL (reference, 20–60); 24‐hour urinary copper was 350 μg (reference, up to 70 μg/24 h). Abdominal ultrasound showed evidence of hepatic cirrhosis. MRI brain showed symmetrical hypointense with surrounding hyperintense T₂/FLAIR (fluid‐attenuated inversion recovery) signals in bilateral caudate nuclei and putamen with blooming on gradient recalled echo (GRE) sequences (Supporting Information Fig. S1).

Unlike the patient reported on by El Otmani et al., our patient exhibited undulating lingual undulation only on tongue protrusion and not at rest. Also, this was the only movement disorder present in our patient whereas the patient reported on by El Otmani et al. demonstrated tremor on tongue protrusion also. Additionally, this patient had resolution of lingual dyskinesia on chelation therapy, although dysarthria was persistent. However, our patient showed only mild response in terms of tongue undulations and none in terms of dysarthria to penicillamine therapy at 4 months (Video 2).

Lingual involvement is a rare, but early, neurological manifestation occurring in 17% of juveniles and 13% of adults suffering from WD.1 Phenomenology varies among dystonia, chorea, bradykinesia, or tremor and is commonly misdiagnosed.1, 2, 3, 4, 5, 6

Isolated lingual involvement in WD has previously been described by Liao et al.2 and Kumar et al.,3 but as irregular contractions and dystonia, respectively. We agree with El Otmani et al. that such arrhythmic, irregular to‐and‐fro tongue movements are best described as “undulating.” Our patient had isolated lingual manifestations, which might be attributable to early presentation in the disease course. All previous cases have reported lingual movements at rest with abnormal imaging findings in both basal ganglia and brainstem (Table 1). However, our patient had these on tongue protrusion with imaging abnormalities limited to the striatum. This makes it the first case reported in the literature where an “undulating tongue” was present on protrusion and in isolation.

Table 1.

Case reports on lingual movements in WD

Serial No.	Authors	Year Published	Movement Disorder of Tongue	Other Neurological Features	MRI Brain Features
1	Topaloglu et al.7	1990	Tongue tremor	None	CT head: normal MRI: not done
2	Liao et al.3	1991	1‐Hz transverse and bilateral contraction, irregular; at rest	None	CT head: normal MRI: not done
3	Kumar et al.4	2005	Tongue dystonia; when tongue was protruded	None	Not mentioned
4	Nagappa et al.5	2014	Undulating tongue; at rest	Dysarthria, dysphagia, drooling, dystonia of upper extremities, pseudobulbar affect	Caudate, putamen, thalamus, central pons, and dorsal midbrain hyperintensities on T2/FLAIR
5	Choudhary et al.6	2015	Limited tongue movements; tremor	Reduced blink rate, rigidity in left upper limb	Caudate, putamen, thalamus, pons and midbrain hyperintensities on T2/FLAIR
6	El Otmani et al.1	2019	Tongue tremor/undulating tongue; at rest	Dysarthria	Caudate and putamen hyperintensities on T2/FLAIR

The exact pathogenesis of lingual movements in WD is debated. They have been likened to semirhythmic repetitive movements observed in anti–N‐methyl‐D‐aspartate receptor encephalitis, where interruption of the forebrain corticostriatal inputs may remove tonic inhibition of brainstem pattern generators.2, 4 Involvement of pontine central tegmental tracts may also play a role.4 The former seems likely in our patient, given that her MRI revealed striatal abnormality sparing the brainstem.

Our case report, along with the one by El Otmani et al., suggests that lingual presentation of WD provides a uniquely early window to identify this eminently treatable condition. Whether this form of lingual involvement is reversible needs further observation.

Author Roles

(1) Research Project: A. Conception, B. Organization, C. Execution; (2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; (3) Manuscript Preparation: A. Writing of the First Draft, B. Review and Critique.

A.A.: 1A, 1B, 1C, 2A, 3A, 3B

D.G.: 1A, 1B, 1C, 2B, 2C, 3B

A.Q.: 1B, 1C, 3B

Disclosures

Ethical Compliance Statement

Ethics clearance from the institution was not required for this letter to the editor. Ethical principles according to the Declaration of Helsinki were followed. Informed patient consent was taken. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this work is consistent with those guidelines.

Funding Sources and Conflicts of Interest

The authors report no sources of funding and no conflicts of interest.

Financial Disclosures for previous 12 months

The authors declare that there are no disclosures to report.

Supporting information

Video 1. Undulating tongue movements seen on protrusion at presentation.

Video 2. Tongue movements seen after 4 months of penicillamine therapy.

Figure S1. MRI brain showed symmetrical hypointense with surrounding hyperintense T₂ (A)/FLAIR (B) signals in bilateral caudate nuclei and putamen with blooming on GRE sequences (C).