WBR1096
| Author | PageAuthor::Chetan Lokhande |
|---|---|
| Exam Type | ExamType::USMLE Step 3 |
| Main Category | MainCategory::Inpatient Facilities |
| Sub Category | SubCategory::Neurology, SubCategory::Infectious Disease, SubCategory::Pediatrics |
| Prompt | [[Prompt::An 11-month-old previously healthy African American female from Haiti comes to Emergency room(ER) with generalized tonic clonic seizures with 1-day history of lethargy, fever and altered mental status. Enroute to hospital, emergency medical team intubated her and gave a dose of diazepam, with no remission. In the ER 1 more dose of diazepam was given and patient was transferred to ICU for further management, where vitals were within normal limits. Overnight EEG showed a pattern of status epileptics. The patient was medically paralyzed and put on a ventilator. Complete blood count, other labs and CT scan all are within normal limits. She was given a dose of quinine for malaria, but stopped due to negative thick and thin smear. A Lumbar puncture was done which revealed:
CSF Glucose 60 mg/dl What is the most common cause?]] |
| Answer A | AnswerA::HSV-1 |
| Answer A Explanation | AnswerAExp::The CSF picture in this case points out to a viral encephalitis more specific to Herpes encephalitis. High protein and low/normal glucose is specific for viral meningitis. |
| Answer B | AnswerB::Cerebral Malaria |
| Answer B Explanation | [[AnswerBExp::This is the incorrect answer as thick and thin smear were both negative. Quinine was started as an empirical therapy as the patient is an immigrant from Haiti where malaria is endemic. It should be stopped immediately as son as thick and thin smear are negative.]] |
| Answer C | AnswerC::Tubercular meningitis |
| Answer C Explanation | [[AnswerCExp::TB meningitis is the incorrect answer as it presents in CSF as low glucose and high protein and mixed cells < 300/mm³]] |
| Answer D | AnswerD::Meningococcal meningitis |
| Answer D Explanation | [[AnswerDExp::Acute bacterial meningitis has the CSF picture of low glucose, high protein and high cells high, often > 300/mm³.]] |
| Answer E | AnswerE::Neurocysticercosis |
| Answer E Explanation | AnswerEExp::Neurocysticercosis also presents with similar complaints and CSF picture. It is the wrong answer because CT scan is negative for any abnormalities. CT scan is very sensitive for neurocysticercosis and cysts will be seen on the CT scan. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Herpes simplex encephalitis (HSE) is a rare, but severe viral infection of the human central nervous system. It is estimated to affect at least 1 in 500,000 individuals per year.[1] The majority of cases of herpes encephalitis are caused by herpes simplex virus-1 (HSV-1), the same virus that causes cold sores. 57% of American adults are infected with HSV-1, which is spread through droplets, casual contact, and sometimes sexual contact, though most infected people never have cold sores. About 10% of cases of herpes encephalitis are due to HSV-2, which is typically spread through sexual contact. About 1 in 3 cases of HSE result from primary HSV-1 infection, predominantly occurring in individuals under the age of 18; 2 in 3 cases occur in seropositive persons, few of whom have history of recurrent orofacial herpes. Approximately 50% of individuals that develop HSE are over 50 years of age.
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. The electrical activity of the brain changes as the disease progresses, first showing abnormalities in one temporal lobe of the brain, which spread to the other temporal lobe 7–10 days later. Imaging by CT or MRI shows characteristic changes in the temporal lobes (see Figure). Definite diagnosis requires testing of the cerebrospinal fluid (CSF) by a lumbar puncture (spinal tap) for presence of the virus. The testing takes several days to perform, and patients with suspected Herpes encephalitis should be treated with acyclovir immediately while waiting for test results. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::HSV-1 Encephalitis |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |