Postmortem Intestinal Sampling in Malawi

Erika Feutz | 2020

Advisor: Grace C. John-Stewart

Research Area(s): Global Health, Maternal & Child Health

Background In LMICs, undernutrition is the leading underlying cause of child mortality, which remains unacceptably high. Environmental enteric dysfunction (EED), a prevalent condition in areas with lack of access to hygiene and safe sanitation could be a significant contributor to undernutrition. To better understand the role of EED in child undernutrition and mortality, accurate cause of death ascertainment is crucial. Minimally invasive tissue sampling (MITS) is a validated technique for assigning cause of death, but the current procedure lacks gastrointestinal interrogation. We aimed to assess the utility of postmortem endoscopically obtained intestinal biopsies, as autolysis may preclude its usefulness, and to adapt an EED histopathologic scoring system to assess upper intestinal disease severity and an inflammatory bowel histopathologic disease scoring system to measure lower intestinal disease severity. Methods MITS in Malawi (MiM) recruited children who died during inpatient admission at Queen Elizabeth Central Hospital in Blantyre, Malawi. Eligibility criteria included age (1 week-59 months) and admission diagnosis (acute illness or malnutrition). Upon death, the standard MITS procedure was conducted after upper and lower endoscopies to collect three duodenal and one colonic and one rectal sample, respectively. These were formalin fixed, prepared into paraffin blocks, sectioned, and stained with hematoxylin and eosin (H&E). Two independent pathologists assessed degree of autolysis on each H&E slide and a gastrointestinal pathologist applied the 11-parameter upper and 4-parameter lower intestinal histopathologic scoring system to measure intestinal disease severity. Results Twenty-eight post-mortem endoscopic procedures were completed. We were able to obtain duodenal, colonic, and rectal samples in 25, 6, and 25 cases. Some degree of autolysis was found in nearly all intestinal samples (n=99 (98%)), though complete autolysis was rare (n=11 (11%)). We found increasing tissue autolysis in more distally located intestinal tissues. Tissue autolysis in the rectum was negatively associated with age (PR=0.991; 95%CI: 0.987, 0.995). We found no associations between tissue autolysis and any other variables of interest, including postmortem time interval and body refrigeration time. Chronic inflammation was prevalent in both the upper and lower intestinal tissues (average scores: 1.9 and 2.0, respectively), although acute inflammation was not present in any of the tissues. We also identified a low density of Paneth and goblet cells in the upper intestine (average scores: 2.5 and 2.2 respectively). Conclusions Postmortem endoscopic biopsy is feasible, despite high levels of autolysis. Autolysis was not found to be dependent on body refrigeration or postmortem time interval, but did vary based on intestinal site, possibly related to increasing microbial colonization in more distal segments of the intestinal tract. We identified duodenal chronic inflammation and reduced Paneth and goblet cell densities, which are features of EED. Severe rectal chronic inflammation was also seen, including in children as young as 6 weeks old. These data warrant further investigation and confirmation but point to the utility of including intestinal sampling as part of the MITS procedure.