Diarrhea & Enterocolitis
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This document discusses various types, causes, and presentations of diarrhea and enterocolitis. It describes the mechanisms and examples of different types of diarrhea including osmotic, inflammatory, secretory, and motility diarrhea. It outlines the clinical presentations of acute watery diarrhea, acute bloody diarrhea, and persistent diarrhea. It discusses infectious causes of diarrhea including viruses, bacteria, and parasites. It also describes inflammatory vs non-inflammatory diarrhea and examples of different types of infectious and non-infectious enterocolitis.
Diarrhea & Enterocolitis
- 1. DIARRHEA & ENTEROCOLITIS Dr. Muhammad Usman Shams
- 3. Types of Diarrhea (Mechanism) Type Mechanism Osmotic Additional water is pulled into GIT; if excessive amounts of solutes are retained in the lumen, water will not be reabsorbed Inflammatory Water and nutrients cannot pass through the inflamed intestinal wall. Motility Contents move too quickly for normal water absorption to occur Secretory Epithelial lining actively secrete more water than they reabsorb
- 5. Tests Relieved by fasting Examples Osmotic Usually >125mOsm /kg Yes Lactase deficiency, Bowel preps e.g. lactulose, Antacids e.g. MgSO4 Secretory <50 mOsm/kg No Bacterial toxins, NET, excessive laxatives Malabsorption Steatorrhea Yes Diverse Inflammatory Culture, CRP, leukocytes No IBD, diverticulitis, invasive infections
- 6. Types of Diarrhea (Clinical) • Acute watery diarrhoea – lasts several hours or days, and includes cholera • Acute bloody diarrhoea –also called dysentery • Persistent diarrhoea –lasts 14 days or longer
- 7. Types of Diarrhea (Infection)
- 8. Types of Diarrhea (Inflammatory vs. Non-inflammatory) Inflammatory Non-inflammatory • Large intestinal disease • Bloody diarrhea with pus and necrotic tissue debris (dysentery) • Feces associated with tenesmus, lower left quadrant pain, and urgency • A smaller volume of excrement that contains more formed elements • Leukocytes and red blood cells easily found in the feces • Small intestinal disease • Watery diarrhea of sudden onset • Nausea and vomiting, cramps, and upper abdominal pain • Copious excrement • Not containing inflammatory cells or blood • EXAMPLES: Typical food poisoning, travelers’ diarrhea and epidemics of cholera.
- 9. Inflammatory Diarrhea Luminal or Invading Viruses Bacteria Protozoa Helminths Immunological mechanisms Complement T-lymphocytes Proteases Oxidants Minimal or severe inflammation Enterocyte damage or death Malabsorption and secretion
- 10. ENTEROCOLITIS –INFECTIOUS (Viral, Bacterial, Parasitic) – NECROTIZING – COLLAGENOUS – LYMPHOCYTIC – AIDS – After BMT – DRUG INDUCED – RADIATION – “SOLITARY” RECTAL ULCER
- 11. INFECTIOUS enterocolitis • VIRAL –Rotavirus (69%), Calciviruses, Norwalk-like, Sapporo- like, Enteric adenoviruses, Astroviruses • BACTERIAL – E. coli, Salmonella, Shigella, Campylobacter, Yersinia, Vibrio, Clostridium difficile, Clostridium perfringens, TB – Bacterial “overgrowth” • PARASITIC – Ascaris, Strongyloides, Necator, Enterobius, Trichuris – Diphyllobothrium, Taenia, Hymenolepsis – Amebiasis (Entamoeba histolytica) – Giardia
- 12. BACTERIAL enterocolitis • Ingestion of bacterial toxins – Staph – Vibrio – Clostridium • Ingestion of bacteria which produce toxins – Montezuma’s revenge (traveller’s diarrhea), E.coli • Infection by enteroinvasive bacteria – Enteroinvasive E. coli (EIEC) – Shigella – Clostridium difficile
- 14. Intestinal biopsy showing Vibrio cholerae causing increased mucous production.
- 15. Mucosal and intraepithelial neutrophil infiltrates are prominent, particularly within the superficial mucosa; cryptitis and crypt abscesses may be seen (vs. UC … crypt architecture is preserved).
- 16. The mucosa is hemorrhagic and ulcerated, and pseudomembranes may be present. The histology of early cases is similar to other acute self-limited colitides, such as Campylobacter colitis, but because of the tropism for M cells, aphthous-appearing ulcers similar to those seen in Crohn disease may occur.
- 17. TYPHOID Perforation at the site of Peyer patches is a serious complication of typhoid fever (gross findings)
- 18. Microgranulomatous reaction (typhoid nodules) seen in the ileal wall (HE)
- 21. C. Enterohemorrhagic E. coli O157:H7 results in an ischemia-like morphology with surface atrophy and erosion. D, Enteroinvasive E. coli infection is a similar to other acute, self-limited colitides. Note the maintenance of normal crypt architecture and spacing, despite abundant intraepithelial neutrophils.
- 26. BACTERIAL OVERGROWTH SYNDROME • One of the main reasons why “normal” gut flora is NOT usually pathogenic, is because, they are constantly cleared by a NORMAL transit time. • BLIND LOOPS • DIVERTICULA • OBSTRUCTION • Bowel PARALYSIS
- 27. PARASITES• NEMATODES (ROUNDWORMS) –Ascaris, Strongyloides, Hookworms (Necator & Anklyostoma), Enterobius, Trichuris • CESTODES (TAPEWORMS) –FISH (DIPHYLLOBOTHRIUM latum) –PORK (TAENIA solium) –DWARF (HYMENOLEPSIS nana) • PROTOZOANS: AMOEBA (ENTAMOEBA histolytica), Giardia lamblia
- 29. Parasites in Surgical Pathology Giardiasis
- 30. Parasites in Surgical Pathology Modified ZN StainModified ZN Stain
- 31. Parasites in Surgical Pathology Appendicectomy
- 32. Parasites in Surgical Pathology
- 34. ACUTE DIARRHEA • With fever and with blood – Shigellosis, Campylobacter, EIEC, C. Perfringens, Salmonella • with fever and without blood – Rotaviruses, Norwalk, salmonella, malaria • without fever and with blood – Amoebiasis, intestinal schistosomiasis, balantidiosis, trichuriasis • without fever and without blood – Cholera, ETEC, staphylococcus, B. cereus, cryptosporidiosis
- 35. CHRONIC DIARRHEA • with fever – Intestinal tuberculosis, visceral leishmaniasis, yersiniosis, HIV infection, CMV • without fever and with blood – Amoebiasis, intestinal schistosomiasis, balantidiosis, trichuriasis, Crohn disease, idiopatic proctocolitis • without fever and without blood – Giardiasis, strongyloidosis, lymphoma, malabsorption syndromes
- 36. Diagnostic clues 1 Feature Potential Pathogen/etiology Afebrile, abdominal pain with bloody diarrhea Shiga toxin-producing Escherichia coli Camping, consumption of untreated water Giardia Extra-intestinal symptoms Yersinia, Campylobacter Exposure to day care centers Rotavirus, Cryptosporidium, Giardia, Shigella Liver abscess Amoebiasis
- 37. Diagnostic clues 2 Feature Potential Pathogen/etiology Hospital admission C. difficile, treatment adverse effect Human immunodeficiency virus infection, immunosuppression Cryptosporidium, CMV, MAI, Listeria Medications or other therapies associated with diarrhea Antibiotics (especially broad- spectrum), laxatives, antacids (magnesium-or calcium-based), chemotherapy, colchicine, pelvic radiation therapy Hospital admission C. difficile
- 38. Diagnostic clues 3 Feature Potential Pathogen/etiology Persistent diarrhea with weight loss Giardia, Cryptosporidium, Cyclospora Pregnancy Listeria Recent antibiotic use C. difficile Rectal pain or proctitis Campylobacter, Salmonella, shigella, E. histolytica, C. difficile, Giardia Travel to developing country Enterotoxigenic E. coli Gas gangrene C. Perfringes
- 40. MISC. COLITIS (OTHER) • NECROTIZING ENTEROCOLITIS (neonate) (Cause unclear) • COLLAGENOUS (Cause unclear) • LYMPHOCYTIC (Cause unclear) • AIDS • GVHD after BMT, as in stomach • DRUGS (NSAIDS, etc., etc., etc.) • RADIATION, CHEMO • NEUTROPENIC (TYPHLITIS), (cecal, caecitis) • “DIVERSION” (like overgrowth) • “SOLITARY” RECTAL ULCER (anterior, motor dysfunction)
- 46. Two days after eating a chicken salad sandwich, a 35-year-old man experiences cramping abdominal pain with fever and watery diarrhea. Physical examination shows mild diffuse abdominal pain on palpation, but there are no masses. Bowel sounds are present. A stool sample is negative for occult blood. He recovers completely within a few days without treatment. Which of the following infectious organisms is most likely to produce these findings? (A) Yersinia enterocolitica (B) Escherichia coli (C) Entamoeba histolytica (D) Salmonella enteritidis (E) Rotavirus
- 47. A lunch party is held at the office at noon on Thursday. Various meats, salads, breads, and desserts that were brought in earlier that morning are served. Everyone has a good time, and most of the food is consumed. By midafternoon, the single office restroom is being used by many employees who have an acute, explosive diarrhea accompanied by abdominal cramping. Which of the following infectious agents is most likely responsible for this turn of events? (A) Escherichia coli (B) Staphylococcus aureus (C) Vibrio parahaemolyticus (D) Clostridium difficile (E) Salmonella enteritidis
- 48. For the past year, a 20-year-old man has had increasingly voluminous, bulky, foul-smelling stools and a 10-kg weight loss. There is no history of hematemesis or melena. He has some bloating, but no abdominal pain. On physical examination, there are no palpable abdominal masses, and bowel sounds are present. Which of the following laboratory findings is most likely to be present on examination of his stool? (A) Increased stool fat (B) Giardia lamblia cysts (C) Occult blood (D) Vibrio cholerae (E) Entamoeba histolytica trophozoites
Editor's Notes
- #12: Rotavirus is the most likely cause of “stomach” flu, especially in kids.
- #13: “Traveller’s diarrhea” usually refers to E. coli infections, but also has a more generic connotation. Which of these 3 conditions is most likely to produce histopathologic mucosal changes and blood in stools?? Ans: Enteroinvasive bacteria
- #14: Rotavirus selectively infects and destroys mature enterocytes in the small intestine.
- #16: Colored …Campylobacter jejuni infection produces acute, self-limited colitis. Neutrophils can be seen within surface and crypt epithelium and a crypt abscess is present at the lower right. Black & White …Rectal biopsy from a patient with Campylobacter colitis.There is increased cellularity of the lamina propria with neutrophils, plasma cells, and eosinophils. Glandular epithelial cells are degenerated and thinned, with loss of goblet cells. A crypt abscess is present. Campylobacter are comma-shaped, flagellated, Gram-negative organisms.
- #17: Mucosal biopsy from a patient with culture-proven Shigella colitis showing loss of surface epithelial cells, presence of a mixed inflammatory cell infiltrate, and numerous crypt abscesses.
- #18: Infection causes Peyer&apos;s patches in the terminal ileum to enlarge into sharply delineated, plateau-like elevations up to 8 cm in diameter. Draining mesenteric lymph nodes are also enlarged. Neutrophils accumulate within the superficial lamina propria, and macrophages containing bacteria, red blood cells, and nuclear debris mix with lymphocytes and plasma cells in the lamina propria. Mucosal shedding creates oval ulcers, oriented along the axis of the ileum, that may perforate. The draining lymph nodes also harbor organisms and are enlarged due to phagocyte accumulation. The spleen is enlarged and soft, with uniformly pale red pulp, obliterated follicular markings, and prominent phagocyte hyperplasia. The liver shows small, randomly scattered foci of parenchymal necrosis in which hepatocytes are replaced by macrophage aggregates, called typhoid nodules, that may also develop in the bone marrow and lymph nodes.
- #20: A scanner view of typhoid perforation edge biopsy showing dense lymphoid hyperplasia in submucosa (H&Ex 40)
- #21: The organisms multiply extracellularly in lymphoid tissue, resulting in regional lymph node and Peyer&apos;s patch hyperplasia and bowel wall thickening.[79] The mucosa overlying lymphoid tissue may become hemorrhagic, and aphthous-appearing ulcers may develop, along with neutrophil infiltrates (see Fig. 17-28B ) and granulomas, increasing the potential for diagnostic confusion with Crohn disease. In Yersinia infection the surface epithelium can be eroded by neutrophils and the lamina propria is densely infiltrated by sheets of plasma cells admixed with lymphocytes and neutrophils.
- #23: Biopsies showed marked injury with prominent lamina propria fibrin deposition and regenerative surface and glandular epithelium. A small vessel shows a fibrin thrombus near the bottom of the biopsy. These changes are those of ischemia and are identical to those caused by enteorhemorrhagic E. coli.
- #24: here is a patchy mucosal process characterised by “caps” of fibrin (fibrin caps (1), (2). The underlying glands are dilated. The fibrinous material appears to have erupted out of the glands. This material (the pseudomembrane) is usually admixed with recognisable cellular debris and neutrophils - not seen here because of the autolysis.
- #25: Fully developed C. difficile–associated colitis is accompanied by formation of pseudomembranes ( Fig. 17-29A , B), made up of an adherent layer of inflammatory cells and debris at sites of colonic mucosal injury.
- #26: The surface epithelium is denuded, and the superficial lamina propria contains a dense infiltrate of neutrophils and occasional fibrin thrombi within capillaries. Superficially damaged crypts are distended by a mucopurulent exudate that forms an eruption reminiscent of a volcano ( Fig. 17-29C ). These exudates coalesce to form the pseudomembranes.
- #27: Bacterial overgrowth syndromes result in, and are caused by, L---O---N---G transit times
- #28: Helminths generally do not produce too much mucosal damage, BECAUSE “a successful parasite never kills its host”. This principle is also true in the business world and the usury trade. If you remember, the loan sharks rarely killed their victims, they just threatened to. Just like banks and credit card companies too.
- #34: Infectious enteritis. A, Histologic features of viral enteritis include increased numbers of intraepithelial and lamina propria lymphocytes and crypt hypertrophy. B, Diffuse eosinophilic infiltrates in parasitic infection. This case was caused by Ascaris (upper inset), but a similar tissue reaction could be caused by Strongyloides (lower inset). C, Schistosomiasis can induce an inflammatory reaction to eggs trapped within the lamina propria. D, Entamoeba histolytica in a colon biopsy specimen. Note some organisms ingesting red blood cells. E, Giardia lamblia, which are present in the luminal space over nearly normal-appearing villi, are easily overlooked. F, Cryptosporidia organisms are seen as small blue spheres that appear to lay on top of the brush border but are actually enveloped by a thin layer of host cell cytoplasm.
- #47: (D) Salmonella enteritidis
- #48: (B) Staphylococcus aureus
- #49: (A) Increased stool fat