What is the differential diagnosis for a patient with a history of gastroparesis and a gastric electrical stimulator, presenting with emesis, diarrhea, and epigastric pain radiating to the left lower quadrant (LLQ)?

Differential Diagnosis for Emesis, Diarrhea, and Epigastric Pain Radiating to LLQ in a Patient with Gastroparesis and Gastric Electrical Stimulator

In a patient with known gastroparesis and a gastric electrical stimulator presenting with emesis, diarrhea, and epigastric pain radiating to the left lower quadrant, you must first consider mechanical complications from the device itself, followed by gastroparesis disease progression, mimics of gastroparesis, and unrelated acute abdominal pathology.

Device-Related Complications (Priority Consideration)

Given the presence of a gastric electrical stimulator, mechanical complications must be ruled out urgently:

• Small bowel obstruction from electrode strangulation is a documented surgical emergency that can present with abdominal pain, nausea, vomiting, and signs of ileus, even years after device implantation 1
• Device extrusion or migration occurs in approximately 7% of patients with gastric neurostimulators and can cause peritonitis, pain, and gastrointestinal symptoms 2
• Lead displacement or malfunction may cause worsening gastroparesis symptoms or new pain patterns that differ from baseline gastroparesis presentation 3

The radiation of pain to the LLQ is atypical for gastroparesis alone and should raise suspicion for mechanical complications involving the small bowel or device hardware 1.

Gastroparesis-Related Symptom Progression

If device complications are excluded, consider worsening gastroparesis or its known complications:

• Refractory gastroparesis progression typically manifests as severe, persistent nausea and vomiting as the predominant symptoms, though abdominal pain can coexist 4, 5
• Medication-induced exacerbation from opioids or GLP-1 agonists must be excluded, as these can mimic or worsen gastroparesis 4, 5
• Diabetic gastroparesis with poor glycemic control can worsen symptoms, as hyperglycemia itself delays gastric emptying 5

However, diarrhea is not a typical gastroparesis symptom and suggests alternative or concurrent pathology 4.

Gastroparesis Mimics and Overlapping Conditions

The AGA guidelines emphasize several conditions that can mimic or coexist with gastroparesis 4:

• Cyclic vomiting syndrome presents with episodic severe nausea and vomiting but typically lacks the continuous diarrhea pattern 4
• Cannabinoid hyperemesis syndrome should be considered if there is cannabis use history, presenting with severe cyclic vomiting 4
• Narcotic bowel syndrome occurs with chronic opioid use and presents with paradoxical worsening of pain and gastrointestinal symptoms 4
• Functional dyspepsia is distinguished by normal gastric emptying but shares symptom overlap including epigastric pain, bloating, and postprandial fullness 4, 5
• Intestinal pseudo-obstruction can present with symptoms mimicking mechanical obstruction including pain, vomiting, and altered bowel habits 4

Acute Abdominal Pathology (Unrelated to Gastroparesis)

The specific pattern of epigastric pain radiating to LLQ with diarrhea suggests consideration of:

• Small bowel pathology including enteritis, ischemia, or inflammatory bowel disease, particularly given the LLQ radiation and diarrhea
• Colonic pathology such as diverticulitis or colitis affecting the descending/sigmoid colon, which would explain LLQ pain and diarrhea
• Pancreatitis can present with epigastric pain radiating to various locations, though typically to the back, and may cause diarrhea
• Mesenteric ischemia should be considered given the vascular risk factors often present in diabetic gastroparesis patients

Diagnostic Approach

Immediate imaging is essential to exclude mechanical complications from the gastric stimulator, particularly small bowel obstruction from electrode strangulation, which requires emergency surgical intervention 1:

• CT abdomen/pelvis with contrast to evaluate for bowel obstruction, device complications, inflammatory processes, and vascular pathology
• Plain radiographs to assess device position and integrity
• Laboratory evaluation including complete blood count, metabolic panel, lipase, and lactate to assess for infection, inflammation, or ischemia 4

If imaging excludes mechanical complications, proceed with gastroparesis-specific evaluation:

• Review medication list for opioids, GLP-1 agonists, or other gastroparesis-exacerbating agents 4, 5
• Assess glycemic control in diabetic patients 5
• Consider stool studies if diarrhea persists, as this is not explained by gastroparesis alone
• Evaluate for cyclic vomiting syndrome or cannabinoid hyperemesis syndrome based on symptom pattern 4

Critical Pitfall

The most dangerous pitfall is attributing all symptoms to known gastroparesis without considering device-related mechanical complications. Repeated presentations with abdominal symptoms in a patient with an implanted gastric stimulator must raise suspicion for unusual device complications, even years after implantation 1. The combination of pain radiating to LLQ with diarrhea is not typical for gastroparesis and demands exclusion of alternative pathology before attributing symptoms to the underlying motility disorder 4.