WBR0616
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::Neurology |
| Prompt | [[Prompt::A 32 year old male patient was brought by his wife to the emergency department for acute change in mental state. According to the wife, the patient was complaining of a headache and a fever two days ago and today he is confused and disoriented to time, place and person. 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?
 Courtesy of radiopaedia.org]] |
| 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. |
| Approved | Approved::No |
| Keyword | WBRKeyword::Herpes, WBRKeyword::encephalitis, WBRKeyword::HSV 1 |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |