Functional dizziness: diagnostic keys and differential diagnosis

Abstract

Dear Sirs,In the 1990s, 9 % of neurological inpatients were found to have functional (then called psychogenic or somatoform) rather than structural neurological disorders of the nervous system as the primary cause of admission [1]. This is a conservative figure, since secondary and minor pseudoneurological symptoms were not included; other studies later found up to 18-20 % [2]. In a further study, it was reported that 61 % of patients referred to a neurology service had at least one medically unexplained symptom, and 35 % fulfilled the diagnostic criteria for an ICD-10 somatoform disorder [3].Functional dizziness is one of the most frequent functional disorders in adult in-and outpatients. In a tertiary referral dizziness unit, it accounted for 19.5 % of 17,700 adult outpatients; thus, it is the second most common diagnosis after benign paroxysmal positional vertigo [4]. The frequencies vary for different countries and study designs: 2.5 [5], 16 [6], and 23 % [7] have been reported. Functional dizziness is also a relevant diagnosis in children. Its frequency peaks at 21 %, and it is an important differential diagnosis for migrainous vertigo, which has the highest frequency (39 %) in childhood [8].

Falls and fear of falling in vertigo and balance disorders: A controlled cross-sectional study

“…Sociodemographic and clinical characteristics, medical diagnoses and onset of disease were retrieved from the medical records. According to the final diagnosis after complete clinical assessment, patients were assigned to one of the following diseasespecific groups: (1) unilateral vestibular disorders including unilateral vestibular hypofunction (difference of 25% in slow phase eye velocity between right and left sides on the caloric tests using the Jongkees's formula), benign paroxysmal positional vertigo (BPPV), Menière's disease (at least "probable" according to the American Academy of Otolaryngology-Head and Neck Surgery [24]), vestibular paroxysmia (at least "probable" according to Hüfner et al [19], and perilymphatic fistula; (2) bilateral vestibular failure (< 5 • /sec of slow phase eye velocity in response to bithermal caloric tests in all four tests and a bilateral pathological head-impulse test); (3) peripheral neuropathy (reduced vibrotactile thresholds of < 4/8 using a 64-Hz tuning fork at the lateral malleolus and absent ankle jerk reflexes); (4) combined peripheral disorders (unilateral/bilateral vestibular loss and peripheral neuropathy); (5) cerebellar disorder (cerebellar ataxia and/or cerebellar oculomotor disturbance; scale for the assessment and rating of ataxia = SARA 2); (6) brainstem ocular motor disorders (pathological central nystagmus, horizontal or vertical gaze palsy, hypermetric saccades, internuclear ophthalmoplegia); (7) vestibular migraine (at least "probable" according to Lempert et al [23]; (8) Parkinsonian syndromes including Parkinson's disease, progressive supranuclear palsy (PSP), multisystem atrophy (MSA), corticobasal degeneration (CBD), dementia with Lewy bodies; and (9) functional dizziness (according to Brandt et al [4]). Patients were excluded in case of insufficient information from medical records, a diagnosis that could not be allocated to one of the groups, two or more differential diagnoses, concomitant orthopedic/neurological disease with motor impairment, or non-ambulatory status.…”

Psychogenic Dizziness: An Important but Overlooked Differential Diagnosis in the Workup of the Dizzy Patient

“…Many patients with nonspecific dizziness and vague symptoms may have an underlying psychiatric disorder. 1,4 Although neurologic, vestibular, and cardiac diseases are common causes of dizziness, it is important to recognize that psychiatric disorders are quite pervasive and a common cause as well. Studies in a variety of health care settings, including primary care clinics, 5 emergency departments, 6 and specialized dizziness clinics, 7 indicate that psychiatric disorders are present in approximately 15% of patients presenting with dizziness.…”

Functional (psychogenic) vertigo

“…Представляется, что аналогично другим функциональным расстройствам (например, «функциональной диспепсии», «функциональной кардиалгии» и пр.) термин, предложенный T. Brandt [18], -«функциональное ГК» (ФГК), является предпочтительным, он используется в настоящем обзоре.…”

“…По данным T. Brandt и соавт. [18], нетипичными для ФГК являются следующие симптомы: 1) частые эпизодические приступы невестибулярного ГК со светлыми промежутками (без приступов); 2) тошнота и рвота во время приступа; 3) вестибулярное ГК с тенденцией к падению; 4) вестибулярное и невестибулярное ГК с нарушениями слуха; 5) позиционный характер ГК; 6) высказываемое пациентами подозрение, что причиной ГК является психологический стресс.…”