Primary position upbeat nystagmus associated with amitriptyline use

Abstract

This case illustrates that amitriptyline withdrawal may be responsible for the onset of primary position upbeat nystagmus. This is not a recorded side effect of the drug and it has not been previously reported in the literature. CaseA 42-year-old man was seen in the West Suffolk Eye Department complaining of blurred vision for 5 days. His Snellen visual acuity was 6/60 in the primary position, and on down gaze it improved to 6/6. He had no medical history of eye problems; however, he did suffer from asthma and had had a basal skull fracture in 1996. A computerized tomography scan from 1996 showed right posterior temporal and left subfrontal region gliosis.Eye examination revealed a primary position vertical nystagmus, and the fast phase was up. The nystagmus reduced on down gaze. He had no relative afferent pupillary defect; his eye movements were full; his colour vision, measured with Ishihara plates, was intact; and fundal examination showed no abnormalities. An examination of his central nervous system was normal. A magnetic resonance scan of his brain showed no new changes.He had been taking salbutamol and flixotide inhalers for a number of years to control his asthma. At 6 months before the onset of nystagmus, he had started taking amitriptyline 150 mg once daily, for depression. At 2 weeks before the nystagmus commenced, he reduced his amitriptyline dose down to 100 mg. At 2 weeks after the start of the nystagmus he cut the dose to 50 mg, under the guidance of his GP. The dose was reduced to 25 mg a week later, and stopped after a further week. With the reduction of the drug, he found that his nystagmus gradually resolved.The medicines control agency was informed of a possible association between amitriptyline and the induction of nystagmus; the agency reported two previously documented cases. CommentUpbeat nystagmus is a type of central vestibular nystagmus. It can be caused by lesions from the medulla to the midbrain. It usually increases in up gaze, but not on lateral gaze, and fixation does not dampen it. Causes of upbeat nystagmus include: cerebellar degeneration, multiple sclerosis, infarction of the medulla, tumours, Wernicke's encephalopathy, brain stem encephalitis, Behcet's syndrome, meningitis, congenital, middle ear disease, and drugs. This condition is often seen with medullary lesions; these involve the perihypoglossal nuclei, medial vestibular nuclei, nucleus intercalatus, and the ventral tegmentum. It is also reported in lesions of the anterior vermis of the cerebellum, the brachium conjunctivum, and midbrain.Primary position upbeat nystagmus has been reported secondary to organophosphate toxicity 1 and tobacco. 2 We propose that amitriptyline withdrawal may cause upbeat nystagmus by the following mechanism. Acetylcholine and histamine are found in the vestibular system; acetylcholine is a central vestibular agonist. Amitriptyline blocks histamine and muscarinic acetylcholine receptors and is therefore a vestibular suppressant. We suggest that withdrawal of amitriptyline removes this inhibi...

Spontaneous nystagmus with an upbeat component: Central or peripheral vestibular disorders?

“…Pure UBN and SN with a predominant upbeat component have been reported in patients with brainstem infarction, brainstem hemorrhage, Wernicke's encephalopathy, multiple sclerosis, tumors, episodic ataxia type 2, cerebellar degeneration, Creutzfeldt-Jakob disease, brainstem encephalitis, epilepsy, Behcet's syndrome, Chiari malformation, meningitis, congenital, vestibular migraine (VM), organophosphate toxicity, tobacco, drugs, canalith jam involving the anterior semicircular canal, Meniere's disease (MD), and delayed endolymphatic hydrops (2)(3)(4)(5)(6)(7)(8)(9)(10)(11). SN with a non-predominant upbeat component has been reported in patients with both central and peripheral lesions, including lateral medullary infarction and medial medullary infarction (12,13), and superior vestibular neuritis (VN) (14)(15)(16).…”

“…SN with a non-predominant upbeat component has been reported in patients with both central and peripheral lesions, including lateral medullary infarction and medial medullary infarction (12,13), and superior vestibular neuritis (VN) (14)(15)(16). Few studies have analyzed the topical diagnosis and etiologies of all kinds of SN with an upbeat component and the differences between nystagmus types in peripheral and central vestibular disorders (5)(6)(7)(17)(18)(19)(20). Hence, we retrospectively analyzed the medical history and examination findings in 43 patients with SN with an upbeat component and explored the topical diagnosis, possible etiologies, and mechanism of SN with an upbeat component.…”

Acute isolated vertigo with vertical up-beating nystagmus: A rare case of nucleus intercalatus of Staderini ischemia

“…Possible causes may include spinocerebellar degeneration, Wernicke's encephalopathy, multiple sclerosis, brainstem infarction, brainstem tumor, trauma, and meningitis. PPUN has also been described during organophosphate poisoning, amitriptyline, and tobacco intoxication ( Osborne and Vivian, 2004 ; Sibony et al., 1987 ). In all these cases, however, PPUN is not the only clinical sign of the pathology; other neurological symptoms are often associated.…”