When Invasive Meningococcal Disease Presents Abdominally
Invasive meningococcal disease doesn’t always present with the classic symptoms of stiff neck and headache—for a small subset of IMD patients, the abdomen is where the disease shows itself.
When we hear about invasive meningococcal disease (IMD), usually presenting as meningitis or septicemia, we typically don’t think about abdominal symptoms. As meningitis is an inflammation of the brain and spinal cord and septicemia is a blood infection, symptoms of IMD often include fever, stiff neck, and headache. However, scientific evidence is showing a definite increase in cases of IMD that include abdominal symptom; in fact, many of these cases include only abdominal symptoms. Because IMD kills 135,000 individuals worldwide each year, it’s imperative that clinicians be able to recognize it no matter what form it takes.
Realizing that some cases of IMD present in what we think of as an atypical way, a group of scientists conducted a retrospective study to determine the frequency of abdominal presentation and discern what the impact of that might be. The team, comprised of researchers from Institut Pasteur and Bicetre Hospital, both in Paris, examined the records of nearly 12,000 patients logged in the database of the French National Reference Centre for Meningococci between 1991 and 2016. They eventually identified 105 patients, with a mean age of 19, in which IMD presented abdominally.
For nearly two-thirds of these patients, the sole symptom experienced was abdominal pain; one-quarter had gastroenteritis and 11% experienced only diarrhea. In one-fifth of the cases, the presenting abdominal pain and its specific location in the lower right quadrant led to abdominal surgery on suspicion of appendicitis. Notably, 24% of these patients died, a much higher fatality rate than that of all IMD cases (10.4%). Also of interest was the fact that the rate of abdominal-only presentation has increased significantly since 2014, corresponding with the rise of a particular subgroup of the meningococcal bacteria known as Group W, even though the overall rate of abdominal presentation of IMD remains relatively low.
The mystery of why some cases of IMD present abdominally remains. “[This is] not fully known yet,” Muhamed-Kheir Taha, MD, PhD, a scientist at the Institut Pasteur and the lead researcher of this study, told Contagion ®. “The mechanisms rely on both the host and the microorganism. Our work suggests that some strains may be more associated than others in provoking these abdominal forms.” The study included a genomic analysis that helped isolate a few meningococcal genes that seem especially associated with inflammatory response; the researchers hypothesize that this inflammation may cause symptoms that mimic appendicitis.
Is the higher fatality rate of IMD patients who undergo abdominal surgery due to time wasted while doctors believe they’re dealing with appendicitis? “Yes, the delay of the management of the IMD is the major reason for this higher fatality,” Dr. Taha said. “IMD is a medical emergency that requires...identification and immediate management [with] antibiotic treatment.”
Dr. Taha and his team would like health care providers to be aware of the possibility that abdominal pain is IMD. “We aim to inform physicians that IMD is one differential diagnosis of abdominal pain with fever,” he said. “In particular, this may be helpful in decision making when other early signs are found, [such as] cold extremities, leg pain, or abnormal skin coloration. All these signs and symptoms appear relatively early—within 8 hours of the onset of the disease. This is of interest when the median time of hospitalization is currently 19 hours after the onset of the disease.”
Laurie Saloman, MS, is a health writer with more than 20 years of experience working for both consumer- and physician-focused publications. She is a graduate of Brandeis University and the Medill School of Journalism at Northwestern University. She lives in New Jersey with her family.