Saying the word “meningitis” is a sure-fire way to scare parents of young children or college students. Invasive infections caused by Neisseria meningitidis are rare but serious. Mortality rates can run around 15%; complications include amputations due to tissue necrosis and hearing loss. In short, N. meningitidis infections are nothing to mess around with.
In order to avoid death and extremity loss, the infection needs to be diagnosed early. Trouble is, the early symptoms can be similar to those of a run-of-the-mill viral infection. Some patients do not exhibit the elevated white blood cell count so common in bacterial infections. Without clear signposts to guide the way, how can clinicians catch this fast-moving infection early in its course? A handful of esoteric hematology parameters might hold the key.
Demissie et al recently published this paper in The Pediatric Infectious Disease Journal about using neutrophil counts to diagnose meningococcal infection in children. It’s behind a paywall, but here’s the gist:
-Your automated hematology analyzer needs to report immature white blood cells.
-Using total white blood cell (WBC) counts or total neutrophil counts alone is insufficient.
-The parameters to check are absolute neutrophil count (ANC), immature neutrophil count (INC), and immature-to-total neutrophil ratio (ITR).
-Patients with invasive meningococcal infection (or, the authors also say, a serious bacterial infection) display abnormalities in at least one of the three parameters.
What do you think about these guidelines? Do you think they’d be effective in diagnosing invasive meningococcal infections?