Chapter 13. Neuropharmacology
A 35-year-old right-handed man presents to the emergency department (ED) with a 2-day history of a severe headache, confusion, and slurred speech. On arrival, his temperature is 37.5°C, blood pressure is 132/68 mm Hg, heart rate is 96 bpm, and respiratory rate is 19 breaths/min. His neurologic examination is notable for lethargy and inattention. He underwent a lumbar puncture, which revealed glucose of 50 mg/dL and protein of 150 mg/dL and a white blood cell count of 170 cells/μL with a lymphocytic predominance. His magnetic resonance imaging (MRI) scan is shown below. Which statement is true regarding treatment for his condition?
Sequential images of axial FLAIR MRI at the level of the upper pons and lower midbrain.
A. Dexamethasone 40 mg daily for 4 days is a useful adjunctive treatment for improved functional outcome in this condition.
B. Acyclovir should be administered intravenously at a dose of 2 mg/kg of actual body weight and administered every 8 hours for one week.
C. Acute tubular necrosis is a common renal side effect of treatment.
D. If antivirals are begun within 4 days of onset of the illness in an awake patient, survival is greater than 90%.
E. Quantitative polymerase chain reaction (PCR) testing should guide antiviral treatment duration.
D. Herpes simplex virus (HSV) is the most common cause of sporadic acute encephalitis and, if left untreated, confers >70% mortality. However, early treatment can improve mortality and morbidity associated with the infection. Appropriate treatment with intravenous acyclovir at a dose of 10 mg/kg of ideal body weight (in cases of significant obesity, adjusted body weight can be used to calculate dose) should be administered every 8 hours for 3 weeks. Hydration should be administered concomitantly with acyclovir treatment in order to prevent crystal nephropathy, the most common cause of renal toxicity, although acute tubular necrosis or acute interstitial nephritis can occur as well. Although HSV PCR is an important diagnostic test and may remain persistently positive for up to 2 weeks after initiation of treatment, the potential correlation of viral load with prognosis or other clinical features of disease remains uncertain. Although there are animal data and limited case report data regarding use of adjunctive corticosteroids, as yet, there are no significant large human data supporting the use of dexamethasone in this setting. The German Trial of Acyclovir and Corticosteroids in HSV Encephalitis (GACHE) is an ongoing large randomized controlled trial testing the hypothesis that adjuvant dexamethasone 40 mg daily for 4 days confers a survival and functional outcome improvement.
A 26-year-old man is admitted to the hospital with rapidly ascending weakness after ...