Gastroparesis: Clinical Presentation, Workup, and Management

Definition

• Fischer's Mastery of Surgery, 8th ed., p. 2886

Etiology

• Sleisenger & Fordtran's GI and Liver Disease, p. 864

Expected Symptoms

Cardinal symptoms:

• Nausea (most common, often persistent)
• Vomiting - classically occurs 3-4 hours after meals and contains undigested food (vomiting of food eaten the day before is virtually pathognomonic of severe gastroparesis)
• Early satiety
• Postprandial bloating / abdominal fullness
• Abdominal pain

Additional symptoms:

• Weight loss (can be substantial in severe cases)
• Heartburn / GERD-like symptoms
• In diabetics: erratic blood glucose control, unexpected postprandial hypoglycemia (from mismatch between insulin action and delayed nutrient absorption), and recurrent DKA episodes

Physical examination findings:

• Succussion splash (retained gastric contents on auscultation while shaking the abdomen)
• Signs of peripheral neuropathy (in diabetic gastroparesis)
• Signs of malnutrition: cachexia, muscle wasting (in severe disease)
• Yamada's Textbook of Gastroenterology, 7th ed., p. 2317
• Fischer's Mastery of Surgery, 8th ed., p. 2887

Workup / Diagnostic Evaluation

Step 1 - Rule out mechanical obstruction

• Peptic ulcer disease / pyloric stenosis
• Gastric or duodenal neoplasm
• Peptic strictures
• Bezoars (which can form secondary to impaired gastric motility)

Note: Patients with suspected gastroparesis have an increased aspiration risk - plan endoscopy accordingly.

Step 2 - Laboratory studies

• CBC, comprehensive metabolic panel
• HbA1c (assess glycemic control / identify diabetic etiology)
• TSH (hypothyroidism can cause gastroparesis)
• Nutritional markers: prealbumin, transferrin
• Electrolytes (hypokalemia, hypocalcemia can impair motility)
• Exclude metabolic causes: uremia, DKA, hypocalcemia

Step 3 - Exclude offending medications

• Opioids
• GLP-1 receptor agonists (e.g., semaglutide, liraglutide) - these delay gastric emptying significantly
• Alpha-2 adrenergic agonists, calcium channel blockers, anticholinergics

Step 4 - Confirm delayed gastric emptying (Gold Standard)

• Uses a technetium-99m labeled low-fat, 240 kcal solid egg meal
• Scans performed at 0, 1, 2, and 4 hours
• Diagnostic threshold: >10% gastric retention at 4 hours
• The 2025 AGA Clinical Practice Guideline (PMID 40976635) specifically recommends AGAINST 2-hour testing and recommends FOR 4-hour testing

• Wireless motility capsule (SmartPill)
• C-13 octanoic acid breath test
• Antroduodenal manometry (for motility assessment)
• Electrogastrography (EGG)

Management

General measures (all patients):

1. Discontinue offending medications (opioids, GLP-1 agonists, anticholinergics)
2. Optimize glycemic control in diabetic patients (hyperglycemia >220 mg/dL itself worsens gastric motility and blunts prokinetic drug response)

Dietary modification:

• Small, frequent meals (4-6 per day)
• Low fat, low fiber diet
• Blenderized/small particle foods as needed in mild-moderate disease; routinely in severe disease
• Liquid nutritional supplements for moderate-severe disease

Nutritional support:

• Mild: rarely needed
• Moderate: caloric liquids, occasionally percutaneous jejunostomy (PEJ) tube
• Severe: may require PEJ tube or parenteral nutrition (TPN)

Pharmacological Treatment:

• Metoclopramide (dopamine D2 antagonist): 5-10 mg PO before meals and at bedtime; the 2025 AGA guideline conditionally recommends its use. Risk of tardive dyskinesia limits long-term use (FDA black box warning; limit to 12 weeks typically); nasal spray formulation available for severe disease
• Erythromycin (motilin agonist): 125 mg PO bid; useful short-term, particularly during hospitalizations; tachyphylaxis develops with prolonged use

• Ondansetron 4-8 mg TID (PO, sublingual, or IV) - most commonly used
• Promethazine 12.5-25 mg q4-6h PO/PR/IM
• Prochlorperazine 5-10 mg PO/IM
• Aprepitant 40-80 mg (NK1 antagonist) - for severe, refractory nausea
• Mirtazapine 15-30 mg daily - for severe disease with poor appetite

• Nortriptyline 10-25 mg - neuromodulator; evidence for pain and anorexia, though RCT showed no overall benefit in idiopathic gastroparesis
• Acupuncture - may be considered in moderate disease

Procedural / Surgical Options (refractory disease):

• Yamada's Textbook of Gastroenterology, 7th ed., pp. 670-671
• Fischer's Mastery of Surgery, 8th ed., pp. 2886-2889
• Sleisenger & Fordtran's GI and Liver Disease, pp. 863-866

Key 2025 AGA Guideline Takeaways (PMID: 40976635)

1. Use 4-hour GES, not 2-hour, for diagnosis
2. Metoclopramide and erythromycin are the recommended first-line pharmacologic agents
3. Against routine use of: domperidone, prucalopride, aprepitant, nortriptyline, buspirone, cannabidiol as first-line
4. G-POEM and GES should be reserved for patients failing medical therapy
5. Considerable unmet needs remain in gastroparesis treatment

Summary Algorithm

Suspected gastroparesis
        ↓
Rule out obstruction → Upper endoscopy (EGD)
        ↓
Lab workup → CBC, CMP, HbA1c, TSH, nutritional markers
        ↓
Stop offending meds → opioids, GLP-1 agonists
        ↓
Optimize glycemic control (if diabetic)
        ↓
4-hour Gastric Emptying Scintigraphy
        ↓
Confirmed delayed emptying (>10% at 4h)
        ↓
MILD (10-15%)          MODERATE (15-35%)        SEVERE (>35%)
Diet + metoclopramide  + Antiemetics + nutrition  + Domperidone/erythromycin
prn                    support (liquids/PEJ)      + Symptom modulators
                                                  + Consider G-POEM/GES

• Symptoms - cardinal features including the pathognomonic vomiting of undigested food
• Causes - etiology breakdown by prevalence with pathophysiology note
• Workup - stepwise diagnostic approach with the 4-hour scintigraphy thresholds
• Management - severity-stratified treatment ladder from dietary changes through procedural interventions