Parkinsonism in essential tremor cases: A clinicopathological study

Abstract

Background Essential tremor and Parkinson's syndrome are two common movement disorders that may co‐occur in some individuals. There is no diagnostic neuropathology for essential tremor, but in PD and other Parkinson's syndrome variants, the neuropathology is well known. The spectrum of Parkinson's syndrome variants associated with essential tremor, their clinical features, and course have not been determined in autopsy‐confirmed cases. Objectives To identify: diagnostic features of essential tremor/Parkinson's syndrome, different Parkinson's syndrome variants, and long‐term clinical profile in such cases. Methods Patients that had an essential tremor diagnosis and a subsequent clinical or pathological diagnosis of Parkinson's syndrome seen in our clinic during 50 years were included. The diagnosis of parkinsonism was made when bradykinesia, rigidity, and resting tremor were all clinically evident. Results Twenty‐one cases were included. All the common variants of parkinsonism co‐occurred with essential tremor. The most common was PD (67%) followed by PSP. The pathological findings were not predicted clinically in 2 cases that had essential tremor/PD and in all 5 essential tremor/PSP cases. Conclusion In most essential tremor/Parkinson's syndrome patients, the main motor features of parkinsonism—bradykinesia, rigidity, and resting tremor—were identifiable. All known degenerative Parkinson's syndrome variants co‐occurred in essential tremor patients. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Essential Tremor as a “Waste Basket” Diagnosis: Diagnosing Essential Tremor Remains a Challenge

“…Patients with ET can during the course of their illness develop signs of dystonia and parkinsonism, and some may even develop a secondary PD (22,23). This is generally a later phenomenon.…”

Reply to: Parkinsonism in essential tremor cases: A clinicopathological study—were they really essential tremor?

“…We appreciate the interest of Mulroy et al in our article . They claim that more than half of our patients did not meet the essential tremor (ET) diagnostic criteria recommended by Bhatia et al When our article is read in conjunction with that statement, their major questions have already been addressed. Their criticism: “ Onset was monomelic in 8 patients.…”

“…Clinical diagnosis made after autopsy information artificially inflates diagnostic accuracy, compared with premortem diagnosis by the same criteria. Table 1 in our article shows findings at baseline, final clinical diagnosis in our clinic, and the clinicopathological diagnosis considering all the information …”

Parkinsonism in essential tremor cases: A clinicopathological study—were they really essential tremor?

“…We read with interest the article by Rajput and colleagues 1 reporting neuropathologic findings in patients with essential tremor (ET) who later developed a parkinsonian syndrome (PS). Nearly one third of ET patients had neuropathologic evidence of a parkinsonian syndrome, primarily Parkinson's disease (PD).…”

“…PD neuropathology was usually correctly predicted on clinical grounds, in contrast to progressive supranuclear palsy pathology, in which all were clinically misdiagnosed as PD. 1 This article raises interesting observations and emphasizes the difficulties of studying conditions such as ET, where both in vivo disease biomarkers and distinct neuropathologic hallmarks are absent.…”