Guidance for the gastrointestinal evaluation and management of iron deficiency in Sub-Saharan Africa

BACKGROUND

Over 30% of the world's population is anaemic, with a significant proportion of these being iron deficient. As iron deficiency (ID) anaemia in men and post-menopausal women is mostly caused by gastrointestinal blood loss or malabsorption, the initial evaluation of a patient with ID anaemia involves referral to a gastroenterologist. The current drive towards patient blood management in sub-Saharan Africa (SSA)prescribes that we regulate not only the use of blood transfusion but also the management of patients in whom the cause of iron loss or inadequate iron absorption is sought. Recommendations have been developed to: (i) aid clinicians in the evaluation of suspected gastrointestinal iron loss and iron malabsorption, and often a combination of these; (ii) improve clinical outcomes for patients with gastrointestinal causes of ID; (iii) provide current, evidence-based, context-specific recommendations for use in the management of ID; and (iv) conserve resources by ensuring rational utilisation of blood and blood products.

METHOD

Development of the guidance document was facilitated by the Gastroenterology Foundation of Sub-Saharan Africa and the South African Gastroenterology Society. The consensus recommendations are based on a rigorous process involving 21 experts in gastroenterology and haematology in SSA. Following discussion of the scope and purpose of the guidance document among the experts, an initial review of the literature and existing guidelines was undertaken. Thereafter, draft recommendation statements were produced to fulfil the outlined purpose of the guidance document. These were reviewed in a round-table discussion and were subjected to two rounds of anonymised consensus voting by the full committee in an electronic Delphi exercise during 2022 using the online platform, Research Electronic Data Capture. Recommendations were modified by considering feedback from the previous round, and those reaching a consensus of over 80% were incorporated into the final document. Finally, 44 statements in the document were read and approved by all members of the working group.

CONCLUSION

The recommendations incorporate six areas, namely: general recommendations and practice, Helicobacter pylori, coeliac disease, suspected small bowel bleeding, inflammatory bowel disease, and preoperative care. Implementation of the recommendations is aimed at various levels from individual practitioners to healthcare institutions, departments and regional, district, provincial and national platforms. It is intended that the recommendations spur the development of centre-specific guidelines and that they are integrated with the relevant patient blood management protocols. Integration of the recommendations is intended to promote optimal evaluation and management of patients with ID, regardless of the presence of anaemia.

Prevalence of Helicobacter pylori in children less than three years of age in health facilities in Nairobi Province

OBJECTIVES

To determine the prevalence of Helicobacter pylori in children less than three years of age and to determine socio-demographic correlates of Helicobacter pylori infection in these children.

DESIGN

Cross sectional study.

SETTING

The "well baby clinics", in Nairobi Province.

SUBJECTS

Children less than three years of age.

RESULTS

A total of 195 children were analysed in the study. There were 103 (52.8%) males and 92(47.2%) females giving a male to female ratio of 1.1:1. The mean age was 17.7 months and the median age was 16 months (range 2 weeks to 36 months). H. pylori antigen was found in stool of 89(45.6%) of the children. Low socio-economic status, crowding in the homes and poor sanitation were associated with H. pylori infection.

CONCLUSION

There is a high prevalence rate of H. pylori infection in children less than three years as found in this study which is in agreement with studies done in other developing countries. Family income is associated with H. pylori infection and families with low income are at higher predisposition to H. pylori infection when compared to families with high income.

Role of 5-hydroxytryptamine type 3 receptors in rat intestinal fluid and electrolyte secretion induced by cholera and Escherichia coli enterotoxins

Cholera toxin and Escherichia coli heat labile toxin (LT) induced intestinal secretion has in the past been attributed exclusively to an increase in intracellular cAMP whereas E coli heat stable toxin (ST) induced secretion is mediated through cGMP. Evidence is accumulating on the importance of 5-hydroxytryptamine (5-HT) in cholera toxin induced secretion, but its role in LT and ST is not well established. This study therefore investigated in vivo the effect of 5-HT3 receptor antagonist, granisetron, on intestinal fluid and electrolyte secretion induced by cholera toxin, LT, and ST. Granisetron (30, 75, 150, or 300 micrograms/kg) was given subcutaneously to adult male Wistar rats 90 minutes before instillation of 75 micrograms cholera toxin or 50 micrograms LT in isolated whole small intestine. In situ small intestinal perfusion was performed with an iso-osmotic plasma electrolyte solution (PES) to assess fluid movement. In a second group of animals, granisetron (300 micrograms/kg) was given subcutaneously and two hours later small intestinal perfusion with PES containing 200 micrograms/l ST was performed. Cholera toxin induced net fluid secretion (median -50.1 microliters/min/g (interquartile range -59.5 to -29.8)) was found to be dose dependently decreased or abolished by granisetron (plateau effect at 75 micrograms/kg: 18 (-7.8 to 28), p < 0.01). Granisetron in high dose (300 micrograms/kg), however, failed to prevent LT or ST induced secretion (-52 (-121 to -71) v -31 (-44 to -18), and (-39 (-49 to 17) v (-22 (-39 to -3)), respectively). Sodium and chloride movement paralleled that of fluid. In conclusion, these data show that 5-HT and 5-HT3 receptors play an important part in cholera toxin induced secretion but are not involved in E coli heat stable or heat labile toxin induced secretion.

Role of 5-hydroxytryptamine in intestinal water and electrolyte movement during gut anaphylaxis

Exposure of sensitised intestine to specific allergen is known to produce appreciable reduction in water and electrolyte absorption. The mediators participating in this process have not been fully characterised. The effects of the 5-hydroxytryptamine2 (5-HT2) and 5-HT3 receptor antagonists, ketanserin and granisetron, respectively, on water movement during intestinal anaphylaxis were studied. Hooded Lister rats (120-150 g) were sensitised to ovalbumen and 14 days later, intestinal water and electrolyte movement was assessed at 10 minute intervals by in situ jejunal perfusion with a plasma electrolyte solution (PES) or PES containing 20 mg/l ovalbumen. Within 20 minutes of exposure to PES+ovalbumen, net water secretion that could be completely prevented by the mast cell stabilising agent doxantrazole occurred compared with absorption with PES alone (median -20 microliters/min/g (interquartile range -43 to -5), n = 11), v (107 (86 to 113), n = 10; p < 0.01). Pre-treatment with subcutaneous ketanserin 200 micrograms/kg (n = 7) or granisetron 300 micrograms/kg (n = 8) partially inhibited the secretory response to PES+ovalbumen (18 (11 to 48) and 13 (6 to 32) respectively; both p < 0.01 compared with PES+ovalbumen control). After 40 minutes perfusion with PES+ovalbumen, the changes in water movement were less pronounced 24 (-3 to 43) and neither ketanserin or granisetron had any effect (ketanserin: 48 (28 to 87), granisetron: 41 (32 to 83); NS). In all experiments, sodium and chloride movement paralleled that of water. Thus, the profound water secretion that occurs in the early stages of intestinal anaphylaxis is partly 5-HT dependent because it can be reversed by 5-HT2 and 5-HT3 receptor antagonists. Other mediators must also be involved, especially in the late phase of anaphylaxis.

Ambient-temperature-stable molecular biology reagents

We have processed biological materials to generate several reagents that are ambient temperature stable and ready to use. Stabilized biomolecules in a glassy matrix of carbohydrate polymers offer water-soluble reagents for complex molecular biology applications. This approach is particularly useful for reagent systems composed of enzymes, nucleotides and other components dispensed in single-use aliquots. Reconstitution of the glassy matrix delivers buffered enzymes and/or nucleotides for restriction, modification, sequencing and/or amplification of nucleic acids. These ambient-temperature-stable reagents allow a high level of reproducibility as they minimize the potential for pipetting errors. They also provide advantages in shipping, storage and subsequent handling. Added convenience includes elimination of setup time, cross contamination and refrigeration. Applications of ambient-temperature-stable biological reagents for routine molecular biology methods are presented.