Estrella, an eighteen-month-old female child who lives in a small North Carolina town, is the only child in the family. Estrella’s mother states she was born at home in the United States but no documentation is available. Her parents are undocumented Mexican agricultural workers who also do home cleaning and repairs during the winter. Although Estrella has apparently not received pediatric medical care, her mother states that in the past she has always eaten well and been healthy. Estrella has been brought to a community free medical clinic by her parents. Her mother states that on the previous day Estrella was irritable and turned away from bright light (had photophobia). She was unwilling to eat, vomited, and felt very warm. This morning Estrella had a convulsion and became lethargic (did not move much). Her parents became very concerned, prompting the visit to the clinic. The clinic was staffed by a physician’s assistant (PA), Jill. Jill notes that Estrella’s height and weight are age appropriate, but her developmental stage is difficult to assess as she is in distress and poorly responsive. On examination, Jill noted that the child was lethargic but could be aroused. She had a fever of 103° F. She cried when her head was turned and appeared to have a stiff neck (nuchal rigidity). Although the “soft spot” on her skull (anterior fontanelle) was almost closed, there appeared to be some bulging of the brain tissue. Jill thought a petechial rash consisting of pinpointlike purple spots was beginning to appear. Jill is concerned about possible signs of a neurological disease (and specifically bacterial meningitis; infection of the meningeal layer of the brain), and these concerns are exacerbated by Estrella’s socioeconomic background. To confirm Jill’s suspicion, a lumbar puncture was required. Jill was inexperienced (and there are some risks to the patient), so the test was deferred until Estrella could be transferred to the pediatric infectious disease division of a regional hospital. At the hospital, CSF obtained by lumbar puncture had elevated protein, reduced glucose, and neutrophils were detected (15 cells per microliter of CSF). Estrella also had an elevated neutrophil count in her blood. The gram-negative diplococcus detected in her CSF was determined to be Neisseria meningitides, confirming a diagnosis of neisserial meningitis. Estrella was admitted to the pediatric ICU where she demonstrated signs of shock and was given IV fluids. She was immediately started on IV antibiotics (initially vancomycin and cefotaxime), which were continued for ten days, after which she was discharged. Estrella’s household contacts (parents) and children in her nursery were treated with prophylactic antibiotics.
Discussion
The classic symptoms of bacterial meningitis are demonstrated in the case; fever, meningeal signs (neck rigidity), bulging fontanelle, photophobia, convulsions, and (had Estrella been able to express herself) undoubtedly headache. Examination of the CSF demonstrated the signs of bacterial meningitis, reduced glucose (said to be related to bacterial consumption), and increased protein (as a result of acute inflammatory changes in the meningeal vasculature). In addition, an elevated blood neutrophil count was indicative of bacterial infection. Detection of gram-negative diplococci in the CSF (and subsequent confirmation by culture) confirmed the organism to be Neisseria, which tends to cause a very rapidly progressive (and potentially lethal) disease. The bacteria colonizes the respiratory system but can spread via the blood in nonimmune individuals. A bacterial endotoxin can result in DIC (see discussion in abnormalities of blood coagulation), a disastrous complication with a very high likelihood of death (or disability if the patient survives). The petechial rash is an indicator of DIC that results from platelet consumption, activation of the coagulation system, and capillary bleeding. Luckily for Estrella, the rash noted by Jill was not related to the disease. Rapid antibiotic therapy is life-saving, and the disease can be spread to contacts (hence, the use of prophylactic antibiotics in contacts). A vaccine is available but not generally used as it has limited effectiveness in young children and is effective only against certain Neisserial strains. The vaccine is used in certain epidemic areas and in individuals who are housed in crowded circumstances (such as students in college dormitories) where it may be required. Another bacterial meningitis caused by Haemophilus influenzae group B (HiB) was formerly quite common in children under the age of five. Incidence of this infection has sharply declined because of highly effective nearly universal childhood vaccination. Jill was concerned because she felt it unlikely that Estrella had been vaccinated for this bacteria (and she suspected it might be the causative agent).
Etiology and Pathogenesis
Bacterial infection with Neisseria meningitides and subsequent meningitis.
Questions
1. Jill had several specific concerns about Estrella’s disease based on socioeconomic background. How would those concerns affect a potential diagnosis?
2. Jill’s parents were agricultural (field) workers who lived in substandard housing. What additional etiologies might be suggested in an acutely sick child who came from such a background?
3. Assume that Estrella did, in fact, demonstrate DIC. What additional symptoms would she demonstrate? What laboratory tests might have been used to detect and monitor for DIC?
4. Under what circumstances might it be reasonable to require HiB immunization? Have you personally been immunized, and if so, why?
5. Several simple clinical tests can be used to demonstrate signs of meningeal disease. What are they, and how are they performed? (Hint: investigate Brudzinski’s sign.)