Medication Summary
Patients with depressed mental status may have documented or suspected increased intracranial pressure (ICP). Administer diuretics or corticosteroids to decrease pressure while planning more definitive actions. Administer this therapy preferably in consultation with a neurosurgeon.
H1- receptor antagonists
Class Summary
These agents may suppress vestibular responses through an effect in the CNS; however, the mechanism remains unknown. Some investigators believe this action is mediated primarily by central anticholinergic activity.
Dimenhydrinate (Dramamine, Dimetabs, Dymenate, Triptone)
A 1:1 salt of 8-chlorotheophylline and diphenhydramine, thought to be particularly useful in treatment of peripheral vertigo. Diminishes vestibular stimulation and depresses labyrinthine function through central anticholinergic activity.
Diphenhydramine (Benadryl, Bydramine, Hyrexin)
Used for treatment and prophylaxis of vestibular disorders.
Promethazine hydrochloride (Phenergan)
Used for symptomatic treatment of nausea in vestibular dysfunction.
An antidopaminergic agent effective in treatment of vertigo, blocks postsynaptic mesolimbic dopaminergic receptors in brain and reduces stimuli to brainstem reticular system.
Benzodiazepines
Class Summary
Centrally, these agents inhibit vestibular responses, presumably by potentiating inhibitory GABA receptors.
Diazepam (Valium, Diastat, Diazemuls)
Probably most commonly used benzodiazepine to treat vertigo. Highly lipophilic and undergoes rapid redistribution after administration. Duration of effects in CNS relatively short, which may make it relatively less desirable.
Lorazepam (Ativan)
Sedative hypnotic in benzodiazepine class that has short time to onset and relatively long half-life.
Depresses all levels of CNS, including limbic and reticular formation, probably through increased action of GABA, a major inhibitory neurotransmitter.
Diuretics
Class Summary
Diuretic agents are used as a temporary measure to lower ICP until definitive intervention is performed.
Mannitol (Osmitrol)
Nonreabsorbable solute, decreases water reabsorption in water-soluble portions of nephron. Reduces reabsorption of sodium chloride as well. Perhaps more importantly, does not cross blood-brain barrier. Creates osmotic gradient, drawing water from brain into intravascular compartment. Used to lower ICP in variety of conditions.
Initially assess for adequate renal function in adults by administering test dose of 200 mg/kg IV over 3-5 min. Should produce a urine flow of at least 30-50 mL/h over 2-3 h.
In children, assess by administering same test dose and rate. Should produce a urine flow of at least 1 mL/kg/h over 1-3 h.
Furosemide (Lasix)
Loop diuretic that blocks transport of sodium, potassium, and chloride in thick ascending limb of loop of Henle in kidney. May enhance effect of mannitol and produce greater and more sustained decrease in ICP.
Corticosteroids
Class Summary
These agents are used to decrease brain edema associated with intracranial tumors.
Dexamethasone (Decadron)
Preferred corticosteroid for this purpose because it demonstrates high glucocorticoid potency and minimal mineralocorticoid activity.
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CT scan of a patient with an acute spontaneous cerebellar hemorrhage. The hemorrhage in the right lobe of the cerebellum is partly obscured by bony artifact.
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MRI of a patient with an acute cerebellar hemorrhage less than 24 hours after presentation. MRI allows better resolution than CT scan without bony artifact. MRI is preferred over CT scan for imaging lesions in the posterior fossa.
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CT scan of a patient with a large acoustic neuroma on the right side of the brainstem. The scan was performed after injection of intravenous contrast, which is critical for identifying tumors with CT imaging.
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A CT slice through the brain of a patient with an acoustic neuroma. This slice reveals a level of the brain higher than the acoustic neuroma. The dilated third and lateral ventricles provide gross evidence of obstructive hydrocephalus due to pressure exerted by the tumor on the brainstem. A ventriculostomy, seen as a white circle in the right lateral ventricle, has been placed in an attempt to drain cerebrospinal fluid and relieve the excessive pressure above the brainstem.
