Celiac disease or gluten intolerance/sensitivity: Celiac disease is an autoimmune disorder triggered by sensitivity to the gliadin protein in gluten. Gluten-sensitive T-cells attack the intestinal villi. Gluten is a component of wheat, barley, and rye, and it may also be present in some medications, toothpastes, vitamin supplements, and lip balms. It is more prevalent in individuals with Northern European ancestry. Risk is increased in people with HLA-DQA1 and HLA-DQB1.
The disease can present with gastrointestinal (GI) and systemic manifestations beginning in early childhood, including chronic diarrhea, steatorrhea, bloating, abdominal pain, vomiting, weight loss, malabsorption, chronic fatigue, dermatitis herpetiformis, joint pain, iron deficiency anemia, osteoporosis, migraine, depression, ADHD, infertility, miscarriages, short stature, and delayed puberty. Some patients may be clinically asymptomatic.
Biopsy findings include infiltration of the intestinal epithelium with lymphocytes, atrophy and flattening of the intestinal villi, loss of brush border, and hyperplasia of intestinal crypts. Laboratory findings include elevated IgA anti-transglutaminase antibodies (most sensitive), anti-endomysial antibodies (most specific), and anti-gliadin antibodies. Patients with celiac disease are at increased risk of lymphomas and intestinal adenocarcinomas.
Treatment is avoidance of gluten, supplementation for nutrient deficiencies, and steroids or chemotherapy for resistant cases.
Diarrhea: Diarrhea is loose, watery stools more than three times a day.
Medical conditions that can cause diarrhea include hyperthyroidism, carcinoid syndrome, adrenocortical insufficiency, VIPoma, short bowel syndrome, IBD, IBS, ischemic colitis (bloody diarrhea with abdominal pain), lactose intolerance, and medullary carcinoma thyroid. Medications that can cause diarrhea include antibiotics, magnesium- or calcium-based antacids, PPIs, mannitol, lithium, etc. Acidic pH of stool is seen in lactose intolerance.
| Character | Condition seen |
| Non-inflammatory diarrhea with absence of leukocytes in stool | ETEC, B.cereus, S.aureus, Rotavirus, V.cholerae, Giardiasis, Cryptosporidium, Cl.perfringens |
| Inflammatory diarrhea with presence of leukocytes in stool | Non-typhi Salmonella, Shigella, Campylobacter, Shiga toxin producing E.coli, EIEC, Cl.difficile, Entamoeba histolytica, Yersinia enterocolitica |
| Diarrhea plus vomiting | Preformed bacterial toxin, viral illnesses |
| Pregnant women, unpasteurised cheese, raw milk | Listeriosis |
| Afebrile, abdominal pain and bloody diarrhea | Shiga toxin producing E.coli |
| Bloody diarrhea | Salmonella, Shigella, Campylobacter, shiga toxin producing E.coli, E.histolytica, Yersinia, Cl.difficile |
| Camping | Giardia |
| Fried rice | Bacillus cereus |
| Raw or improperly cooked ground beef, seed sprouts | E.coli O157:H7 |
| Raw milk | Salmonella, Campylobacter, Listeria, shiga toxin producing E.coli |
| Seafood, undercooked or raw shellfish | V.cholerae, V.parahaemolyticus |
| Daycare centers or old-age homes | Rotavirus, Cryptosporidium, Giardia, Shigella |
| Hospital admission or recent antibiotic use | Cl.difficile |
| Diarrhea with fever | Campylobacter, Salmonella, Shigella, Yersinia |
| Anal intercourse and proctitis | HSV, Chlamydia, Syphilis, Gonorrhea, Campylobacter, Salmonella, Shigella, E.histolytica, Giardia |
| Rice water stools | V.cholerae |
| Recent travel | ETEC, E.histolytica |
| HIV | Cryptosporidium, Isospora, Microsporidia, CMV, M.avium intracellulare, Listeria |
Appendicitis: Appendicitis is inflammation of the appendix. It is more common in children and young adults.
In many cases, appendicitis begins with luminal obstruction from causes such as fecaliths (hard fecal material), lack of fibre in the diet, or lymphoid hyperplasia. Obstruction blocks secretions, which promotes bacterial overgrowth and infection. The resulting inflammation can weaken the appendiceal wall and may lead to perforation. In some cases, there is no luminal obstruction; instead, ischemia may cause wall damage.
The classic clinical presentation is periumbilical pain (referred pain) that shifts to the right iliac fossa (peritoneal, parietal pain), along with nausea, vomiting, and loss of appetite. Fever may be present; a rising fever suggests peritonitis or impending appendiceal rupture. Histology shows local infiltration with neutrophils.
Symptoms can vary with the position of the appendix. For example, pelvic appendicitis may cause dysuria and increased frequency of urination.
On physical examination, there is tenderness at McBurney point, located in the right iliac fossa at 2/3rd of the distance from the umbilicus on an imaginary line drawn between the umbilicus and the right anterior superior iliac spine. In most patients, this corresponds to the base of the appendix. Rovsing sign may be positive: pain is felt in the right lower quadrant when palpating the left lower quadrant, due to peritoneal inflammation. Rigidity is seen in perforated appendix.
Complications of acute appendicitis include gangrene and perforation with peritonitis. Laboratory findings include raised WBC count with neutrophil leukocytosis and elevated CRP and ESR.
Ultrasound is preferred in children and pregnant women to avoid radiation exposure; it shows an enlarged, non-compressible appendix with periappendicular fluid. CT scan with contrast is the investigation of choice in suspected appendicitis and shows an inflamed appendix; wall thickening and periappendiceal fat stranding are also seen. MRI can be used if clinical suspicion is high but routine investigations are inconclusive.
Diagnostic laparoscopy for suspected appendicitis is recommended for young women (if diagnosis is unclear and you need to differentiate from PID or ectopic pregnancy), the elderly, or other patients with unclear pathology because of its broader diagnostic ability.
Treatment is laparoscopic (preferred) or open appendicectomy along with supplemental antibiotic therapy. IBD involving the appendix may clinically mimic appendicitis and can be differentiated by biopsy findings.
IBS or irritable bowel syndrome: IBS is a functional disorder characterized by recurrent abdominal pain >once/week lasting >6 months, along with a change in the frequency or form of stool, diarrhea, and constipation. Symptoms improve after defecation and are exacerbated by emotional stress or eating. It is more common in young women. Stools may be mucousy but not bloody.
Constipation-predominant IBS is caused by functional obstruction to defecation from pelvic floor dys-synergia, manifested as paradoxical anal contraction on straining. Diarrhea-predominant IBS can be differentiated from IBD by fecal calprotectin levels, which are normal in IBS.
Some cases of IBS may be post-infectious. Intestinal microbiomes may be altered in IBS. Levels of serotonin in the gut and TNF alpha in the blood may be elevated.
Therapy includes dietary modifications, increasing fibre intake, probiotics, biofeedback, managing stress, lubiprostone and linaclotide for constipation, 5HT3 antagonists like alosetron or ondansetron in diarrhea, loperamide, and antidepressants.
Intussusception: Intussusception is telescoping of a segment of intestine into another, causing obstruction. The telescoped segment is called the intussusceptum, while the receiving segment is called the intussuscipiens.
It is more common in small children, usually due to lymphoid hyperplasia from viral infections and following Rotavirus vaccination. Older patients often have underlying masses (such as lipomas or leiomyomas) that act as the leading point of the intussusception. Other associated conditions include cystic fibrosis, polyps, adhesions, Henoch Schonlein purpura, and endometriosis.
The most common type is ileocaecal, followed by ileo-ileal and colo-colic. Clinical features include intermittent abdominal pain, vomiting, and passing mucus and blood-tinged stools (red currant-jelly). Children may pull their legs up to the chest due to pain. Perforation and peritonitis may occur.
A “sausage shaped” mass can be palpated in the abdomen, most commonly in the right hypochondrium, with an empty right lower quadrant (Dance sign). Ultrasound is preferred in children, and CT scan is preferred in adults. Imaging shows a target or doughnut sign with a hyper-echoic core surrounded by a hyp-echoic edematous bowel.
Treatment is by barium or air enema. Non-reducible cases may be treated by surgical reduction. Treatment of intussusception in adults is always by exploratory laparotomy or laparoscopy followed by resection of lead point masses.
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