Gastroenterology · Motility Disorders
The facts most likely to be tested
Diabetes mellitus is the most common systemic cause of gastroparesis due to autonomic neuropathy affecting the vagus nerve.
Patients typically present with postprandial fullness, early satiety, nausea, vomiting, and upper abdominal pain.
The gold standard diagnostic test is a 4-hour scintigraphic gastric emptying study showing delayed emptying of solids.
Upper endoscopy (EGD) is mandatory prior to diagnosis to rule out mechanical gastric outlet obstruction or peptic ulcer disease.
First-line management involves dietary modifications including small, frequent meals that are low in fat and fiber.
Metoclopramide is the primary prokinetic agent used for symptom relief, but it carries a black box warning for tardive dyskinesia.
Erythromycin acts as a motilin receptor agonist and is the preferred agent for acute exacerbations requiring intravenous therapy.
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A 54-year-old female with a 15-year history of poorly controlled type 2 diabetes mellitus presents to the clinic with a 3-month history of nausea, bloating, and vomiting occurring shortly after meals. She reports feeling full after only a few bites of food. Physical examination reveals epigastric tenderness without guarding or rebound. An upper endoscopy is performed and shows only retained food particles in the stomach with no evidence of a mass or stricture.
What is the most appropriate next step in the diagnostic evaluation of this patient?
4-hour scintigraphic gastric emptying study
The patient's clinical presentation and negative EGD for mechanical obstruction strongly suggest gastroparesis, which is confirmed by demonstrating delayed gastric emptying on scintigraphy.
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Etiology / Epidemiology
Most common in diabetes mellitus (autonomic neuropathy) and post-viral syndromes.
Clinical Manifestations
Classic postprandial fullness, early satiety, and vomiting undigested food hours after eating.
Diagnosis
Gastric emptying scintigraphy showing >10% retention at 4 hours is diagnostic.
Treatment
Metoclopramide is the first-line prokinetic; tardive dyskinesia is the major limiting factor.
Prognosis
Chronic condition requiring glycemic control and nutritional support to prevent weight loss.
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Epidemiology & Etiology
The most frequent cause is diabetic gastroparesis due to vagus nerve damage. Other etiologies include post-surgical complications (e.g., vagotomy) and idiopathic cases often following a viral prodrome. It is significantly more common in women.
Pertinent Anatomy
The stomach requires coordinated contraction of the antrum and relaxation of the pylorus for emptying. Damage to the myenteric plexus disrupts this motility, leading to stasis.
Pathophysiology
Hyperglycemia impairs gastric smooth muscle function and damages the interstitial cells of Cajal, which act as the stomach's pacemaker. This results in delayed gastric emptying without mechanical obstruction. Chronic stasis leads to the formation of bezoars.
Clinical Manifestations
Patients present with early satiety, postprandial nausea, and vomiting of undigested food. Physical exam may reveal a succussion splash on abdominal auscultation. Red flags include weight loss, anemia, or hematemesis, which mandate ruling out malignancy.
Diagnosis
Exclude mechanical obstruction first via EGD or CT. The gastric emptying scintigraphy (solid-phase) is the gold standard. Retention of >60% at 2 hours or >10% at 4 hours confirms the diagnosis.
Treatment
Initial management focuses on small, frequent meals low in fat and fiber. Metoclopramide is the primary prokinetic, but use is limited to <12 weeks due to tardive dyskinesia. Erythromycin is an alternative for acute flares but causes tachyphylaxis.
Prognosis
Complications include malnutrition, electrolyte imbalances, and erratic blood glucose control. Patients may require jejunal feeding tubes if oral intake is insufficient.
Differential Diagnosis
Peptic ulcer disease: pain relieved by food/antacids
Gastric outlet obstruction: visible peristalsis and metabolic alkalosis
Cyclic vomiting syndrome: episodic, stereotypical vomiting cycles
Eating disorders: history of purging or body dysmorphia
Functional dyspepsia: normal gastric emptying study