In the latest Case Record of the Massachusetts General Hospital, a 28-year-old woman was seen in the emergency department of this hospital because of the acute onset of headache, fever, rash, and myalgias. On examination, she had petechiae on the chest, abdomen, and thighs and a purpuric lesion on the right shoulder.
Neisseria meningitidis is the second most common cause of bacterial meningitis in adults, and most cases occur sporadically.
– What clinical and laboratory findings are often associated with bacterial meningitis?
The following clinical findings are often associated with bacterial meningitis: mental-status changes, a CSF neutrophil count of greater than 1000 cells per cubic millimeter, visible organisms on Gram’s staining, hypoglycorrhachia (a low CSF glucose level), and an elevated CSF protein level. However, it is important to recognize that one or more clinical or laboratory signs or symptoms that are typical of meningitis — such as fever, nuchal rigidity, altered mental status, and a CSF white-cell count of greater than 1000 per cubic millimeter — may be absent in a substantial number of patients with this diagnosis, and the CSF glucose and protein levels may be normal.
– What microbiologic findings are characteristic of Neisseria meningitidis?
Gram-negative diplococci with a coffee-bean shape are characteristic of N. meningitidis.
Figure 3. Microbiologic Study.
Morning Report Questions
Q: Describe some of the features associated with meningococcal meningitis.
A: N. meningitidis is associated with a rapidly progressive, sometimes fulminant illness characterized by sepsis, petechial rash, purpura, and meningitis. Of adults with meningococcal meningitis, 49% seek medical attention less than 24 hours after the onset of symptoms and 64% have a rash, of whom the majority have petechiae and one fourth have purpura, ecchymoses, or both; impaired consciousness may be absent in 49% and Gram’s staining of CSF may be negative for organisms in 11%.
Q: What disorder has been associated with recurrent meningococcal meningitis?
A: A deficiency in one of the terminal complement components, with the exception of C9, has been associated with recurrent meningococcal meningitis. Although low-grade or transient meningococcal bacteremia can be overcome by opsonization and subsequent phagocytosis, higher-grade or persistent bacteremia requires the complement system for eradication. Vaccination is performed in an attempt to boost the early opsonophagocytic response. Ultimately, however, an intact and a sufficient response of the terminal complement components is crucial in overwhelming the defense mechanisms of this microorganism and in protecting against invasive disease. The risk of N. meningitides infection among persons with a terminal complement deficiency is 7000 to 10,000 times as high as the risk among persons without such a deficiency; furthermore, approximately 50% of persons with a terminal complement deficiency who have had N. meningitidis infection have recurrent infections. However, N. meningitidis infection is often milder and associated with lower mortality among persons with a terminal complement deficiency than it is among persons without such a deficiency.