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Neurological differential diagnosis...Vertigo
 

Neurological differential diagnosis...Vertigo

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Neurological differential diagnosis...Vertigo

Neurological differential diagnosis...Vertigo

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    Neurological differential diagnosis...Vertigo Neurological differential diagnosis...Vertigo Document Transcript

    • DIFFERENTIAL DIAGNOSIS OF VERTIGO Synonyms: dizziness, imbalance, disequilibrium www.yassermetwally.com INTRODUCTION Background: Symptoms of vertigo are nonspecific. Vertigo occurs when there is an imbalance or disturbance in vestibular function anywhere in the peripheral or central vestibular system (labyrinth, vestibular nerve, brainstem, cerebellum, cortex). Etiology of vertigo includes familial, infectious, neoplastic, metabolic, toxic, vascular, autoimmune, and traumatic causes. Distinguishing the site and cause of lesion resulting in vertigo is important because some causes of central vertigo can be life threatening and require immediate attention. Pathophysiology: Sensation of balance is the result of appropriate information from vestibular, ocular, and proprioceptive sensory receptors that is properly integrated within the cerebellum and brainstem. Gait, posture, and visual focus during head movement are all dependent on an intact sense of balance. Loss of sensory information, central integration, or output control mechanisms all result in a sense of imbalance. Central causes of vertigo result from a disruption of central integrators (brainstem, cerebellum) or a sensory information mismatch (cortex). Lesions affecting the vestibular nerve or root entry zone (cerebello-pontine angle lesions) result in imbalance by affecting primary vestibular sensory information. Race: There is no racial predilection for CNS causes of vertigo. Sex: Both men and women are equally affected. Age: CNS causes of vertigo typically affect the older population groups because of the associated risk factors of vascular causes of vertigo (hypertension, atherosclerosis, diabetes).  Younger age group is more commonly affected by migraine and multiple sclerosis.  Cerebellar tumors affect a bimodal population - children and adults.  Cerebello-pontine angle tumors typically affect people in the fifth to the eighth decade. CLINICAL History:  CNS causes of vertigo can present in a variety of ways. Vertigo can be sudden and severe in onset and last for days or it may comprise recurrent attacks that last for minutes to hours. Less often central vertigo presents as brief episodes of vertigo brought on by changes in head or body position.  Patient may describe an intense sensation of movement or tilting, or a severe sensation of imbalance; sensation is aggravated by movement and improved by remaining stationary. It is important to discriminate between vertigo (the sensation of movement or spinning) and lightheadedness. Lightheadedness is often a symptom of a metabolic or cardiovascular abnormality.  Cause of vertigo often is revealed by history and physical examination.  In migraine-associated vertigo the patient gives a history of acute-onset vertigo that lasts either minutes to a few hours or many hours to even days. Vertigo may precede, follow, or simultaneously
    • present with the headache (migraine without aura). Vestibular symptoms range in severity from mild to severe. Vertigo may occur with other symptoms of aura (visual and somatosensory paresthesias) before a headache (migraine with aura). Less commonly vertigo is a symptom of basilar migraine. Basilar migraine is suspected when the vertigo is accompanied by binocular visual deficits, diplopia, dysarthria, hearing loss, ataxia, or decreased consciousness.  Patients with presyncopal lightheadedness describe a sensation of wooziness, lightheadedness, or unsteadiness. Sensations result from diffuse cerebral ischemia. Symptoms may occur spontaneously if secondary to cardiac arrhythmia, or can be precipitated by activity (postural hypotension, hyperventilation).  Vertebrobasilar artery (VBA) insufficiency - Vertigo is sudden in onset, lasts only minutes, is associated with nausea and vomiting, and is accompanied by a range of neurological deficits (extremity weakness, numbness, incoordination, dysarthria; diplopia, field defects; tinnitus, hearing loss; loss of consciousness, drop attacks). Few or no residual signs or symptoms remain after the TIA has resolved.  Symptoms and signs of posterior fossa cerebrovascular disease include vertigo, tinnitus, and ataxia. Symptoms may be transient, permanent, recurrent, or isolated. Stroke syndromes involving the posterior circulation are varied depending upon the involved territory. Wallenburg syndrome (lateral medullary syndrome) presents with vertigo, nausea, vomiting, imbalance, ipsilateral facial numbness and weakness, diplopia, dysphagia, and dysphonia. Infarction of the dorsolateral pontomedullary region results in labyrinthine injury (severe vertigo, nausea, vomiting, hearing loss) in addition to the signs and symptoms of Wallenburg syndrome. Cerebellar infarction also presents with severe vertigo, nausea, vomiting, and ataxia. Basilar artery syndrome results from infarction of the pons. Symptoms include vertigo, hearing loss, ataxia, ophthalmoplegia, blindness, and regional sensory losses.  Cerebellar tumors may present with positional vertigo, imbalance while walking and standing, and headaches. Specific features are dependent on tumor location (lateral, medial, ventricular), tumor size, and growth rate. Primary cerebellar tumors typically occur in children. In adults, cerebellar tumor usually results from metastasis.  Temporal lobe tumors may present as recurrent brief attacks of vertigo lasting minutes; it may be followed by transient disorientation, amnesia, and dysphasia.  Brainstem lesions (neoplastic, vascular, posttraumatic) can have vertigo as a presenting symptom. It may be brief or prolonged, depending on the extent of damage to the brainstem structures.  Cerebello-pontine angle (CPA) tumors typically result in disequilibrium or unsteadiness rather than a sensation of vertigo. However, sudden change in tumor size with hemorrhage or disruption of regional blood flow to the labyrinth may precipitate vertigo. Majority of tumors in the CPA are vestibular schwannomas, followed by meningiomas, lipomas, cholesteatomas, and metastatic tumors.  Vertigo is the initial presenting symptom in 5% cases of multiple sclerosis. The vertigo may last several days to weeks; it may be positional in nature and is often associated with facial numbness and weakness, and diplopia.  Posttraumatic vertigo may be peripheral in origin (benign paroxysmal positional vertigo, perilymphatic fistula, labyrinthine concussion, labyrinthine fracture) or central (cerebral concussion). Postconcussion syndrome usually follows a mild head injury. Symptoms are characterized by vertigo, headaches, blurred vision, diplopia, fatigue, and personality changes.
    •  Familial periodic ataxia syndromes represent a rare form of chronic recurring bouts of episodic vertigo. There is a family history of recurrent spells of vertigo. Patients present with recurrent vertigo, prominent nausea and vomiting, diplopia and dysarthria with the spells, and a progressive truncal ataxia. Spells are precipitated by physical exertion or emotional stress. Acetazolamide is effective in controlling episodic vertigo.  Rarely does central nervous system infection cause vertigo. Lyme neuroborreliosis can have vertigo as a presenting feature of Lyme disease encephalopathy.  Psychogenic vertigo is a manifestation of panic or anxiety disorder. Patients will describe a sensation of unsteadiness, vertigo, lightheadedness, and less often nausea and vomiting with the symptoms. Physical:  During asymptomatic periods, patients with migraine-associated vertigo have normal physical examinations. During migraine, patients may exhibit motion-intolerance, diaphoresis, and vomiting. Occasionally nystagmus is observed during an attack; rarely does the migraine include dysarthria, aphasia, hemiparesis, or extremity ataxia.  When symptomatic, a cardiac examination may reveal arrhythmia as the cause of symptoms. If hyperventilation is suspected, having the patient hyperventilate may precipitate the symptoms. Orthostatic changes in pulse and blood pressure should be documented if accompanied by symptoms of lightheadedness.  Direction changing, gaze-evoked nystagmus, and severe truncal ataxia with limb incoordination are findings associated with cerebellar infarction. Lateral medullary infarction also will cause direction- changing nystagmus, but there will be associated signs indicating brainstem damage such as decreased gag reflex, facial numbness, Horner syndrome, and dysphonia. Saccadic eye movements are disrupted; gait is ataxic. Lateral pontomedullary syndrome also presents with nystagmus, defective saccades, and hearing loss.  CPA tumors that cause vertigo will also cause unilateral hearing loss and may present with nystagmus. Nystagmus may be evident only in the dark or with Frenzel glasses, which remove visual fixation. Head thrust test may reveal unilateral vestibular weakness. Large tumors may cause subtle facial weakness, decreased corneal reflex, and facial dysesthesia.  Differentiation between central and peripheral causes of vertigo is facilitated by a precise oculomotor examination. Spontaneous nystagmus that cannot be suppressed with visual fixation; nystagmus that changes direction with gaze; purely vertical, horizontal, or torsional nystagmus; and saccade dysmetria (overshoot and undershoot) are all signs of a potential central abnormality as the cause of vertigo.  Paroxysmal positional nystagmus that is of central origin usually does not fatigue with repeated positioning maneuvers, has no latency of onset, lasts longer than 60 seconds, is often vertical in direction, and may change direction with different head positions.  Vertigo of a panic attack can sometimes be elicited by having the patient hyperventilate. Most patients with psychogenic vertigo do not have any pathological findings on otologic or neurologic examination. Causes:  Central vertigo syndromes resulting from acute vascular events most commonly result from a combination of hypertension and regional atherosclerosis.
    •  Less commonly, arterial dissection secondary to neck extension, rotational injury, or osteoarthritic spurs is the cause of disturbed posterior fossa blood flow.  Migraine and presyncopal lightheadedness are two forms of regional and global ischemia that may present with vertigo or imbalance as the primary symptom. WORKUP Lab Studies:  Few laboratory studies facilitate the diagnosis of central causes of vertigo.  If vertigo is accompanied by prolonged nausea and vomiting, monitoring and replacing fluids and electrolytes in the elderly would be prudent.  In the rare case of suspected neuroborreliosis, serology for Lyme disease with ELISA, Western blot, and lymphocyte antigen stimulation assay would be indicated.  Cerebrospinal fluid should be obtained for Lyme antibody and polymerase chain reaction analysis for Borrelia burgdorferi DNA. Imaging Studies:  Imaging studies are indicated when there is a suspicion that the symptoms are the result of ischemia. MRI and MR angiography are the most helpful studies in assessing posterior circulation disorders and acute infarction. Other Tests:  Formal evaluation with vestibular testing is indicated if the diagnosis is not apparent after obtaining a history and performing a physical examination.  Caloric testing will reveal if there is a unilateral peripheral weakness.  Oculomotor testing can detect saccade, pursuit, and optokinetic disturbances.  Positional testing with infrared oculography can detect nystagmus and clearly define nystagmus patterns.  Complete cardiac and peripheral vascular examination (ECG, Holter, echocardiogram, carotid and vertebral doppler) should be performed if symptoms suggest hypoperfusion, embolic events, or arrhythmia as the cause. TREATMENT Medical Care:  Medical treatment includes supportive care with fluid replacement and vestibular suppressants for intractable vertigo with nausea and vomiting.  Treatment of migraine-associated vertigo includes analgesics and vestibular suppressants. Drugs useful in the treatment of migraine include sumatriptan, propranolol, imipramine, amitriptyline, and
    • nortriptyline and vestibular suppressants diazepam and alprazolam. For further information on the diagnosis and treatment of migraine headache please refer to the chapter Migraine Headache.  Control of hypertension, diabetes, and atherosclerosis is indicated for long-term prevention of further complications. Cardiac arrhythmia should be controlled.  Drugs useful in the treatment of vertebrobasilar insufficiency include aspirin, ticlopidine, pentoxifylline, heparin, and warfarin.  Acetazolamide is indicated for the treatment of familial ataxia syndrome. Surgical Care:  Surgical treatment of central vertigo is limited to urgent posterior fossa decompression of cerebellar and brainstem edema complicating the infarction.  Cerebello-pontine angle tumors are surgically removed on an elective basis. If there is a medical contraindication, radiotherapy for tumor control is an option. MEDICATION The goal of pharmacotherapy is to reduce morbidity and prevent complications. Drug Category: Antihistamines -- Prevent the histamine response in sensory nerve endings and blood vessels. Are effective in treating vertigo. Meclizine (Antivert, Antrizine, Meni-D) -- Decreases excitability of middle ear labyrinth and blocks conduction in Drug Name middle ear vestibular-cerebellar pathways. These effects are associated with therapeutic effects in the relief of nausea and vomiting. Adult Dose 25 mg PO q4-6h <12 years: Not established Pediatric Dose >12 years: Administer as in adults Contraindications Documented hypersensitivity May increase toxicity of CNS depressants, neuroleptics, and Interactions anticholinergics Pregnancy B - Usually safe but benefits must outweigh the risks. Caution in angle-closure glaucoma, prostatic hypertrophy, Precautions pyloric or duodenal obstruction, and bladder neck obstruction Dimenhydrinate (Dimetabs, Dramamine) -- A 1:1 salt of 8 chlorotheophylline and diphenhydramine thought to be useful in the treatment of vertigo. Drug Name Diminishes vestibular stimulation and depresses labyrinthine function through central anticholinergic effects. However, prolonged treatment may decrease rate of recovery of vestibular injuries. Adult Dose 50 mg PO or IM q4-6h or 100 mg supp q8h
    • <2 years: Not established 2-5 years: Up to 12.5-25 mg PO q6-8h; not to exceed 75 mg/24h 6-12 years: 25-50 mg PO q6-8h; not to exceed 150 mg/24h Pediatric Dose >12 years: Administer as in adults Alternatively, 1.25 mg/kg or 37.5 mg/m2 IM qid; not to exceed 300 mg/d Documented hypersensitivity; do not administer to neonates; IV products may contain benzyl alcohol, which Contraindications has been associated with fatal quot;Gasping syndromequot; in premature infants and low birth weight infants Alcohol or other CNS depressants may have additive effect Interactions on dimenhydrinate; may mask ototoxic symptoms, caused by certain antibiotics and irreversible damage may result Pregnancy B - Usually safe but benefits must outweigh the risks. Do not treat severe emesis with antiemetic drugs alone; may contain either sulfites or tartrazine, which may cause allergic-type reactions in susceptible persons; may impede Precautions diagnosis of conditions, such as brain tumors, intestinal obstruction and appendicitis; may obscure signs of toxicity from overdosage of other drugs Drug Category: Anticholinergics -- Work centrally by suppressing conduction in the vestibular cerebellar pathways. Scopolamine (Isopto) -- Blocks action of acetylcholine at parasympathetic sites in smooth muscle, secretory glands and the CNS. Antagonizes histamine and serotonin action. Drug Name Transdermal scopolamine may be the most effective agent for motion sickness. Its use in vestibular neuronitis is limited by its slow onset of action. Adult Dose 0.6 mg PO q 4-6h or 0.5 mg transdermally q3d 6 mcg/kg/dose IM/SC/IV; not to exceed 0.3 mg/dose, or 0.2 Pediatric Dose mg/m2 and repeat q6-8h Documented hypersensitivity; primary glaucoma (including initial stages), pyloric obstruction, toxic megacolon, hepatic Contraindications disease, paralytic ileus, severe ulcerative colitis, renal disease, obstructive uropathy, and myasthenia gravis Antipsychotic effectiveness of phenothiazines may be decreased by coadministration with scopolamine; anticholinergic side effects may be increased by concurrent therapy and phenothiazine dosages should be adjusted as Interactions necessary; coadministration with tricyclic antidepressants, may increase anticholinergic side effects (eg, dry mouth, constipation, urinary retention) due to additive effect (tricyclic antidepressants with less anticholinergic activity may be beneficial) C - Safety for use during pregnancy has not been Pregnancy established. Caution in the elderly because of increased incidence of
    • glaucoma; large doses may suppress intestinal motility and precipitate or aggravate toxic megacolon; anticholinergics may aggravate hiatal hernia associated with reflux Precautions esophagitis; patients with prostatism can have dysuria and may require catheterization; use cautiously in patients with asthma or allergies; a reduction in bronchial secretions can lead to inspissation and formation of bronchial plugs Drug Category: Benzodiazepines -- By binding to specific receptor-sites these agents appear to potentiate the effects of gamma-aminobutyrate (GABA) and facilitate inhibitory GABA neurotransmission and other inhibitory transmitters. These effects may prevent vertigo and emesis. Diazepam (Valium) -- Depresses all levels of CNS (eg, limbic and reticular formation), possibly by increasing Drug Name activity of GABA. Individualize dosage and increase cautiously to avoid adverse effects. Adult Dose 5-10 mg PO/IV/IM q4-6h <6 months: Not recommended >6 months: 0.05-0.3 mg/kg/dose IM/IV over 2-3 min; repeat Pediatric Dose in 2-4 h prn Alternatively, 0.12-0.8 mg/kg/24h PO divided q6-8h; not to exceed 10 mg/dose Documented hypersensitivity; narrow-angle glaucoma; Contraindications children <3 mo Increases toxicity of benzodiazepines in CNS with Interactions coadministration of phenothiazines, barbiturates, alcohols, and MAO inhibitors Pregnancy D - Unsafe in pregnancy Caution with other CNS depressants, low albumin levels, or Precautions hepatic disease (may increase toxicity) Drug Category: Phenothiazines -- Effective in treating emesis possibly due to effects in dopaminergic mesolimbic system. Promethazine (Phenergan) -- For symptomatic treatment of nausea in vestibular dysfunction. Drug Name Antidopaminergic agent effective in treating emesis. Blocks postsynaptic mesolimbic dopaminergic receptors in brain and reduces stimuli to brainstem reticular system. Adult Dose 25-50 mg PO/IM/PR q4-6h <2 years: Not recommended Pediatric Dose >2 years: 0.25-1.0 mg/kg PO/IV/IM/PR 4-6 times/d prn Contraindications Documented hypersensitivity May have additive effects when used concurrently with Interactions other CNS depressants or anticonvulsants; coadministration with epinephrine, may cause hypotension C - Safety for use during pregnancy has not been Pregnancy established. Some of the adverse effects include CNS depression, dry mouth, extrapyramidal symptoms, hypertension, and skin rash Caution in cardiovascular or hepatic disease, seizures,
    • sleep apnea, and asthma; may enhance effects of other Precautions medications that cause CNS depression including alcohol, narcotics, sedatives, hypnotics, etc Prochlorperazine (Compazine) -- May relieve nausea and vomiting by blocking postsynaptic mesolimbic dopamine Drug Name receptors through anticholinergic effects and depressing reticular activating system. Adult Dose 5-10 mg PO/IM q6h 25 mg supp PR q12h 2.5 mg PO/PR q8h or 5 mg q12h, prn; not to exceed 15 mg/d Pediatric Dose 0.1-0.15 mg/kg/dose IM; change to PO as soon as possible IV dosing not recommended for children Documented hypersensitivity; bone marrow suppression, narrow angle glaucoma, severe liver or cardiac disease; comatose patients or patients with large amounts of central Contraindications nervous system depressants in their system (eg, alcohol or barbiturates); do not use in surgery in children <2 y or that weigh <20 lb Coadministration with other CNS depressants or Interactions anticonvulsants may cause additive effects; with epinephrine may cause hypotension Pregnancy D - Unsafe in pregnancy Side effects include CNS depression, blurred vision, and hypotension; neuroleptic malignant syndrome and extrapyramidal dystonic reactions may rarely occur Drug-induced Parkinson’s syndrome or Precautions pseudoparkinsonism occurs quite frequently; akathisia is most common extrapyramidal reaction in elderly; lowers seizure threshold and should be used cautiously in patients with a history of seizures Drug Category: Monoaminergics -- May treat vertigo possibly through modulating the sympathetic system. Ephedrine (Pretz-D) -- Stimulates release of epinephrine Drug Name stores, producing alpha- and beta-adrenergic effects. Adult Dose 25 mg PO q4-6h < 2 years: Not recommended Pediatric Dose 2-5 years: 3 mg q6-8h >5 years: 6.25 mg PO/SC q6-8h Documented hypersensitivity; angle-closure glaucoma, and Contraindications cardiac arrhythmias Theophylline, atropine, or MAO inhibitors may increase toxicity; alpha- and beta-blockers decrease vasopressor Interactions effects of ephedrine; cardiac glycosides and general anesthetics increase cardiac stimulation of ephedrine Pregnancy B - Usually safe but benefits must outweigh the risks. Side effects include excitation, tremulousness, insomnia, nervousness, palpitation, tachycardia, and symptoms associated with sympathetic activation; bladder sphincter
    • spasm can occur and cause transient acute urinary retention; caution in the elderly and patients with diabetes mellitus, Precautions hyperthyroidism, hypertension, cardiovascular disease, prostatic hypertrophy, and cerebrovascular insufficiency FOLLOW-UP Further Outpatient Care:  After the underlying cause of vertigo has been identified and treated, supportive care with vestibular suppressants and antiemetics are indicated for relief of vertigo. BIBLIOGRAPHY  Asmundson GJ, Larsen DK, Stein MB: Panic disorder and vestibular disturbance: an overview of empirical findings and clinical implications. J Psychosom Res 1998 Jan; 44(1): 107-20.  Curless RG, Schatz NJ, Bowen BC, et al: Lyme neuroborreliosis masquerading as a brainstem tumor in a 15-year- old. Pediatr Neurol 1996 Oct; 15(3): 258-60.  Cutrer FM, Baloh RW: Migraine-associated dizziness. Headache 1992 Jun; 32(6): 300-4.  Davies RA, Luxon LM: Dizziness following head injury: a neuro-otological study. J Neurol 1995 Mar; 242(4): 222-30.  Stewart WF, Lipton RB, Celentano DD, Reed ML: Prevalence of migraine headache in the United States. Relation to age, income, race, and other sociodemographic factors. JAMA 1992 Jan 1; 267(1): 64-9.  Welsh LW, Welsh JJ, Jaffe SC, Healy MP: Syndromal vertigo identified by magnetic resonance imaging and angiography. Laryngoscope 1996 Sep; 106(9 Pt 1): 1144-51. THE AUTHOR Professor Yasser Metwally Professor of neurology, Ain Shams University, Cairo, Egypt http://yassermetwally.com