18. Main symptoms and syndromes of lower gastrointestinal disorders

Covers the main symptoms of lower gastrointestinal disorders, including abdominal pain, diarrhoea, constipation, bloating, tenesmus, and melena versus haematochezia, followed by clinical syndromes such as irritable bowel syndrome, inflammatory bowel disease, colorectal cancer, diverticular disease, malabsorption, gastroenteritis, colonic obstruction, and haemorrhoids with anal fissures. It closes with key physical signs on palpation, anorectal inspection and auscultation. Diarrhoea is split into secretory, osmotic, inflammatory and fatty types.

Inside: 4 sections · 9 labelled pictures · 14 flashcards · 3 min

Topic 17 of 30 in the MU Sofia syllabus for Internal Medicine (Practical) (Medicine, Year 3). The free AceMed note covers it in 4 sections, about 446 words (3 min of reading), with 14 flashcards.

I. Main Symptoms of Lower GI Disorders

Lower GI disorders involve the small intestine (distal ileum), colon, rectum, and anal canal. Symptoms reflect abnormalities in absorption, motility, inflammation, or obstruction.

1. Abdominal Pain

Often crampy or colicky.

Localized to lower quadrants (especially left lower quadrant in sigmoid colon diseases).
Seen in inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), diverticulitis, or obstruction.

2. Diarrhea

Defined as ≥3 loose stools per day.
Can be:
Secretory (e.g., bacterial toxins),
Osmotic (e.g., lactose intolerance),
Inflammatory (e.g., IBD),
Fatty/malabsorptive (e.g., celiac disease).
May contain blood, mucus, or pus in infections or colitis.

3. Constipation

Infrequent (<3/week), hard stools or difficult defecation.
Can be functional (diet, low activity) or organic (tumors, strictures).
Common in elderly and opioid users.

4. Flatulence and Bloating

Due to gas accumulation from malabsorption or bacterial overgrowth.
Seen in IBS, celiac disease, lactose intolerance.

5. Tenesmus

Painful, ineffective urge to defecate.

Common in rectal inflammation, proctitis, ulcerative colitis, rectal cancer.

6. Melena and Hematochezia

Melena (black tarry stools): Seen in right-sided or slow upper GI bleeding.
Hematochezia (bright red blood per rectum): Typical in left-sided colon lesions, hemorrhoids, diverticulosis, or colorectal cancer.

7. Weight Loss

Seen in chronic diseases: IBD, colorectal cancer, malabsorption.