Evaluation of Patients with Pathologic Vestibular Vertigo The evaluation depends on whether a central etiology is suspected (Table 22-2). If so, MRI of the head is mandatory. Such an examination is rarely helpful in cases of recurrent monosymptomatic vertigo with a normal neurologic examination. Typical BPPV requires no investigation after the diagnosis is made (Table 22-1). Vestibular function tests serve to (1) demonstrate an abnormality when the distinction between organic and psychogenic is uncertain, (2) establish the side of the abnormality, and (3) distinguish between peripheral and central etiologies. The standard test is electronystagmography (calorics), where warm and cold water. | Chapter 022. Dizziness and Vertigo Part 5 Evaluation of Patients with Pathologic Vestibular Vertigo The evaluation depends on whether a central etiology is suspected Table 22-2 . If so MRI of the head is mandatory. Such an examination is rarely helpful in cases of recurrent monosymptomatic vertigo with a normal neurologic examination. Typical BPPV requires no investigation after the diagnosis is made Table 22-1 . Vestibular function tests serve to 1 demonstrate an abnormality when the distinction between organic and psychogenic is uncertain 2 establish the side of the abnormality and 3 distinguish between peripheral and central etiologies. The standard test is electronystagmography calorics where warm and cold water or air are applied in a prescribed fashion to the tympanic membranes and the slow-phase velocities of the resultant nystagmus from the two are compared. A velocity decrease from one side indicates hypofunction canal paresis . An inability to induce nystagmus with ice water denotes a dead labyrinth. Some institutions have the capability of quantitatively determining various aspects of the VOR using computer-driven rotational chairs and precise oculographic recording of the eye movements. CNS disease can produce dizzy sensations of all types. Consequently a neurologic examination is always required even if the history or provocative tests suggest a cardiac peripheral vestibular or psychogenic etiology. Any abnormality on the neurologic examination should prompt appropriate neurodiagnostic Treatment Treatment of acute vertigo consists of bed rest 1-2 days maximum and vestibular suppressant drugs such as antihistaminics meclizine dimenhydrinate promethazine tranquilizers with GABA-ergic effects diazepam clonazepam phenothiazines prochlorperazine or glucocorticoids Table 22-3 . If the vertigo persists beyond a few days most authorities advise ambulation in an attempt to induce central compensatory mechanisms despite the short-term discomfort
