GI motility disorders

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Esophageal Dysmotility - Unruly Swallowing

  • Achalasia: Failure of LES to relax + loss of peristalsis.

    • Cause: Degeneration of inhibitory neurons in Auerbach's plexus.
    • Barium swallow shows a "bird-beak" appearance.
    • Manometry is diagnostic: ↑ LES pressure, incomplete relaxation.
  • Diffuse Esophageal Spasm (DES): Uncoordinated, strong contractions.

    • Presents with intermittent chest pain and dysphagia.
    • Barium swallow reveals a "corkscrew" or "rosary bead" esophagus.
    • Manometry: High-amplitude, simultaneous contractions.

Exam Favorite: Chagas disease, caused by Trypanosoma cruzi, can destroy the myenteric plexus, leading to secondary achalasia.

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Gastroparesis - The Stomach on Strike

Delayed gastric emptying without mechanical obstruction. Often linked to poor glycemic control in diabetics.

  • Etiology: Idiopathic (~50%), Diabetes Mellitus (autonomic neuropathy), post-surgical (vagal injury), medications (opioids, anticholinergics).
  • Clinical Features: Nausea, vomiting of undigested food, early satiety, bloating, abdominal pain.
  • Diagnosis: First, rule out mechanical obstruction with EGD. Gold standard is a gastric emptying study (scintigraphy) showing >10% retention at 4 hours.
  • Management:
    • Dietary modification: Small, frequent, low-fat, low-fiber meals.
    • Prokinetics: Metoclopramide, Erythromycin.

⭐ Erythromycin acts on motilin receptors to promote gastric emptying, but its effectiveness can decrease over time due to tachyphylaxis.

Gastric Emptying Scintigraphy in Gastroparesis

Ileus & Pseudo-obstruction - Deceptive Standstills

  • Paralytic Ileus: Functional, non-mechanical bowel hypomotility.
    • Causes: Post-op (common), hypokalemia, sepsis, opiates.
    • Clinical: N/V, absent bowel sounds, no flatus/stool.
    • AXR: Uniformly dilated loops of both small & large bowel.
  • Ogilvie's Syndrome (ACPO): Acute colonic pseudo-obstruction. Massive dilation without a physical blockage.
    • Risk: Elderly, sick patients (trauma, infection).
    • AXR: Cecal diameter >10-12 cm indicates high perforation risk.

⭐ Ogilvie's Syndrome: If conservative management fails, administer IV neostigmine. Must exclude mechanical obstruction first to prevent perforation.

Ogilvie's syndrome: X-ray and CT findings

Irritable Bowel Syndrome - The Sensitive Gut

  • Chronic functional GI disorder characterized by abdominal pain and altered bowel habits. Core pathophysiology involves visceral hypersensitivity and gut-brain axis dysregulation.
  • Diagnosis of Exclusion: Based on Rome IV criteria-recurrent abdominal pain (≥1 day/week in last 3 months) with ≥2 of:
    • Related to defecation
    • Change in stool frequency
    • Change in stool form (Bristol Stool Scale)
  • Subtypes: Predominant constipation (IBS-C), diarrhea (IBS-D), or mixed (IBS-M).
  • Management: Lifestyle/dietary changes (low FODMAP), fiber, antispasmodics, and targeted therapy for constipation or diarrhea.

Alarm features warranting further investigation include rectal bleeding, nocturnal diarrhea, unintentional weight loss, anemia, and age of onset >50 years.

High-Yield Points - ⚡ Biggest Takeaways

  • Achalasia presents with dysphagia to solids and liquids and a "bird's beak" on barium swallow, resulting from the loss of the myenteric plexus.
  • GERD is most often caused by transient LES relaxation; its main complication is Barrett's esophagus, a precursor to adenocarcinoma.
  • Diabetic gastroparesis is a state of delayed gastric emptying without obstruction; treat with metoclopramide.
  • Hirschsprung disease is a congenital aganglionosis of the colon; diagnose with rectal biopsy.
  • Diffuse esophageal spasm appears as a "corkscrew" esophagus on imaging.

Practice Questions: GI motility disorders

Test your understanding with these related questions

A 25-year-old man presents to his gastroenterologist for trouble swallowing. The patient states that whenever he eats solids, he regurgitates them back up. Given this patient's suspected diagnosis, the gastroenterologist performs a diagnostic test. Several hours later, the patient presents to the emergency department with chest pain and shortness of breath. His temperature is 99.5°F (37.5°C), blood pressure is 130/85 mmHg, pulse is 60/min, respirations are 12/min, and oxygen saturation is 99% on room air. On physical exam, the patient demonstrates a normal cardiopulmonary exam. His physical exam demonstrates no tenderness of the neck, a normal oropharynx, palpable crepitus above the clavicles, and minor lymphadenopathy. Which of the following is the best next step in management?

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Flashcards: GI motility disorders

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_____ is an intestinal hypomotility without obstruction that results in constipation and decreased flatus

TAP TO REVEAL ANSWER

_____ is an intestinal hypomotility without obstruction that results in constipation and decreased flatus

Ileus

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