Case: A preteen with headache and seizures

You've enjoyed the first week on your general pediatrics rotation. While discussing the finer learning points of the week's cases with your team of medical students and fellow residents, your attending receives a page from a local emergency department (ED) physician. She is troubled by a previously healthy 11-year-old boy who has been under her care for the past several hours.

The boy was brought in by his parents who have been concerned about a constellation of symptoms, including a rash, fever, and mental status changes, following a recent camping trip. While being evaluated in the emergency room, the boy's right eye started to twitch and then deviated to the left. This was followed immediately by a tonic-clonic seizure that lasted three minutes, and resolved with administration of IV lorazepam. A computed tomography (CT) scan of the boy's head was unremarkable. The lumbar puncture opening pressure was normal, and his cerebrospinal fluid was normal. The emergency physician has given the boy a dose of ceftriaxone. She would like to transfer the boy to your service for further evaluation and treatment.

Your team is excited by the prospect of an infectious disease investigation, and you discuss the differential diagnosis based on the history you have heard by telephone. The list includes: insect-borne infections including Lyme disease, Rickettsia, and arboviral encephalitis, herpes encephalitis, and cat scratch disease. Additionally, you wonder if he could have vasculitis. You briefly discuss the work-up of this differential but decide to see the patient before determining what to order.

Yesterday he developed a severe headache, anorexia, nausea, vomiting, and diarrhea. This morning he became disoriented, complained of difficulty seeing, bumped into furniture, and appeared to be hallucinating. During the drive to the ED, his parents noted that he became more confused, and then unresponsive for a few minutes.

Patient history

He has no significant past medical or surgical history. His birth and developmental history are normal. He is on no regular medications, but he is currently taking azithromycin and a decongestant. He has no known drug allergies.

While on a camping trip, his father noticed a large, unengorged tick crawling on him. No one had seen any attached ticks. He has not had any recent exposure to illness.

His family history is significant: a cousin with seizures secondary to brain trauma, and a paternal grandmother with hypertension diagnosed at age 17. His parents noticed he developed several pink patches located on his arms, neck, and cheeks in the ED after his lumbar puncture. It resolved within a few minutes. The emergency physician did not see the rash, but said it was probably from the morphine he received prior to the procedure. He also had a pruritic rash three and a half weeks ago, which had been diagnosed as scabies by his primary pediatrician. He had a sore throat four weeks ago; a rapid strep test at that time was negative.

His vital signs are currently 52.3 kg (75% to 90%), 100.8° F (38.2° C), heart rate 82 BPM, respiratory rate 25 BPM, pulse oximetry 95% on room air, and blood pressure (BP) 142/104. Generally he is awake, alert, oriented, and answering questions appropriately.

By your observations, he currently has no evidence of vision changes or hallucinations. You find no rash. On cardiac auscultation, he has a grade 2/6 systolic murmur. He has no cough during exam, and he breathes effortlessly. His lung fields are clear to auscultation. His HEENT exam (head, ears, eyes, nose, throat), including funcuscopic, gastrointestinal, neurologic, and musculoskeletal examinations, are unremarkable. He is Tanner stage I. You make a note that his initial elevated BP measurement needs to be repeated.