WBR0616

Author	[[PageAuthor::Rim Halaby, M.D. [1] (Reviewed by Serge Korjian)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Neurology
Prompt	[[Prompt::A 32-year-old man is brought to the emergency department for acute change in mental status. According to the wife, the patient has been complaining of a severe headache and high fever that started two days ago. Shortly after admission, the patient begins to seize. He is stabilized with IV lorazepam and valproic acid. Brain MRI of the patient is shown below. Which of the following is most likely to be found in the CSF analysis of the patient? ]]
Answer A	AnswerA::Increased lymphocytes
Answer A Explanation	[[AnswerAExp::The CSF of a patient with herpes encephalitis is characterized by increased lymphocytes.]]
Answer B	AnswerB::Increased neutrophils
Answer B Explanation	[[AnswerBExp::The CSF of a patient with herpes encephalitis is characterized by increased lymphocytes and not neutrophils. Elevated neutrophil levels is found in bacterial infection.]]
Answer C	AnswerC::Decreased glucose
Answer C Explanation	AnswerCExp::The CSF of a patient with herpes encephalitis is characterized by an unchanged level of glucise. Glucose level is decreased in bacterial infection.
Answer D	AnswerD::Increased glucose
Answer D Explanation	AnswerDExp::The CSF of a patient with herpes encephalitis is characterized by an unchanged level of glucise. Glucose level is decreased in bacterial infection.
Answer E	AnswerE::Decreased proteins
Answer E Explanation	[[AnswerEExp::The CSF of a patient with herpes encephalitis is not characterized by decreased proteins level.]]
Right Answer	RightAnswer::A
Explanation	[[Explanation::Herpes simplex encephalitis (HSE) is a rare, but severe viral infection of the human central nervous system. The majority of cases of herpes encephalitis are caused by herpes simplex virus-1 (HSV-1). HSE is thought to be caused by the retrograde transmission of virus from a peripheral site on the face following HSV-1 reactivation, along a nerve axon, to the brain. Most individuals with HSE show a decrease in their level of consciousness and an altered mental state presenting as confusion, and changes in personality. Increased numbers of white blood cells can be found in patient's cerebrospinal fluid, without the presence of pathogenic bacteria and fungi. Patients typically have a fever and may have seizures. Imaging by CT or MRI shows characteristic changes in the temporal lobes as depicted in the image. Definite diagnosis requires testing of the cerebrospinal fluid (CSF) by a lumbar puncture which mainly increased lymphocytes. Patients with suspected herpes encephalitis should be treated with acyclovir immediately while waiting for test results. Educational Objective: Herpes encephalitis can be diagnosed by brain imaging and spinal tap. Brain MRI reveals asymmetrical bilateral enhancement of the temporal lobes, while lumbar puncture reveals increased lymphocytes, unchanged glucose level and normal or elevated opening pressure. References: Image courtesy of Dr Bruno Di Muzio, Radiopaedia.org.([file here]) ]]
Approved	Approved::Yes
Keyword	WBRKeyword::Herpes, WBRKeyword::encephalitis, WBRKeyword::HSV 1
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::