Clinical spectrum of focal dystonias: Experience from a tertiary care center

Abstract

BACKGROUND: There is a paucity of literature in patients with focal dystonia from our country with certain differences in the clinical characteristics as compared to the Western population. OBJECTIVES: The aim of this study was to evaluate the clinical spectrum of patients with focal dystonia attending the neurology outpatient department and of admitted patients in neurology ward of a tertiary care hospital. MATERIALS AND METHODS: All consecutive patients of focal dystonia from October 2017 to September 2019, fulfilling the inclusion criteria were enrolled. Patients were subjected to a detailed history and thorough examination as per a predesigned pro forma. RESULTS: Of a total of 88 patients with focal dystonia, 62.5% were male. Majority of the focal dystonia (51.1%) had late adulthood onset (>40 years). Writer’s cramp was the most common type of focal dystonia (n = 38; 43.2%), but in patients older than 40 years, focal cranial dystonias (n = 28 of 43, 65.1%) were the most common. Oromandibular dystonia and blepharospasm had significantly older mean age of onset compared to focal upper limb (57.0 ± 14.05, 44.9 ± 13.83 vs. 31.5 ± 17.67; P < 0.001, P = 0.032, respectively). Most of the focal dystonias were isolated (87.5%, n = 77) and idiopathic (66%). Among the acquired causes, drugs were the most common (n = 9; 10.1%), followed by perinatal birth insult (n = 4; 4.5%). All of the drug-induced focal dystonias were oromandibular. CONCLUSION: Focal dystonia was more prevalent in males, and it had an earlier age of onset by a decade as compared to the Western population. Writer’s cramp was the most common type of focal dystonia, but in patients older than 40 years, cranial dystonias were the most common. In patients presenting with oromandibular dystonia, a drug history should be carefully sought.

Keywords

• cranial dystonia
• drug-induced dystonia
• focal dystonia
• oromandibular dystonia
• writer’s cramp