What can cause severe diffuse abdominal pain in a patient with Postural Orthostatic Tachycardia Syndrome (POTS)?

Severe Diffuse Abdominal Pain in a 21-Year-Old with POTS

In a 21-year-old with POTS presenting with severe diffuse abdominal pain, you should systematically evaluate for disorders of gut-brain interaction (DGBI), gastroparesis, mast cell activation syndrome (MCAS), hypermobile Ehlers-Danlos syndrome (hEDS), and functional defecation disorders, as these conditions frequently overlap with POTS and can cause significant gastrointestinal symptoms. 1

Primary Diagnostic Considerations

Disorders of Gut-Brain Interaction (DGBI)

• Nausea, abdominal pain, vomiting, diarrhea, bloating, and severe constipation are common in POTS, with nausea, pain, and early satiety being the most predictive of abnormal GI motility 1
• DGBI evaluation should follow a positive symptom-based diagnostic strategy with limited noninvasive testing, similar to the general population 1
• Visceral hypersensitivity and/or dysmotility are common mechanisms underlying these symptoms in POTS patients 1

Gastroparesis and Upper GI Dysmotility

• Timely diagnostic testing of gastric motor functions (gastric emptying and/or accommodation) should be considered earlier in POTS patients with chronic upper GI symptoms, as abnormal gastric emptying may be more common than in the general population 1
• The underlying autonomic dysfunction in POTS predisposes to gastroparesis and perturbations in GI motility 1

Mast Cell Activation Syndrome (MCAS)

• Consider MCAS testing if the patient has episodic symptoms suggesting a more generalized mast cell disorder beyond isolated GI symptoms 1
• Diagnostic approach: Obtain serum tryptase levels at baseline and 1-4 hours following symptom flares; an increase of 20% above baseline plus 2 ng/mL indicates mast cell activation 1
• If MCAS is supported clinically or by laboratory findings, refer to an allergy specialist or mast cell disease research center 1

Hypermobile Ehlers-Danlos Syndrome (hEDS)

• Screen for joint hypermobility using the Beighton score, as hEDS is strongly associated with POTS and GI symptoms 1
• hEDS patients commonly experience abdominal pain, particularly postprandial pain or pain triggered when any food arrives in the gut 1
• The pain in hEDS is often related to visceral hypersensitivity rather than true dysmotility, though dysmotility can occur when POTS or other factors (like opioids) are present 1

Specific Diagnostic Testing Algorithm

Initial Evaluation

• Test for celiac disease earlier in the diagnostic workup, as the risk is elevated in patients with POTS and hEDS, even without isolated diarrhea 1
• Assess for opioid use, as opioids can cause or exacerbate GI dysmotility and should be avoided or withdrawn 1

Lower GI Symptoms

• If constipation or incomplete evacuation is present, perform anorectal manometry, balloon expulsion test, or defecography to evaluate for pelvic floor dysfunction, which has high prevalence in this population, especially rectal hyposensitivity 1

Infection History

• Inquire about recent viral upper respiratory or GI infections, as up to 40% of POTS patients report a preceding infection, including COVID-19 1
• Consider autoimmune evaluation if infection-triggered onset is suspected 1

Management Approach

Symptom-Directed Treatment

• For abdominal pain: Consider acid-suppressive drugs (PPIs, H2 antagonists), antispasmodics (hyoscyamine, dicyclomine, peppermint oil), and neuromodulators (TCAs, SSRIs, SNRIs, pregabalin, gabapentin) based on pain location, type, and frequency 1
• Avoid opiates specifically for abdominal pain treatment 1
• For nausea/vomiting: Use antiemetics (ondansetron, promethazine, prochlorperazine, aprepitant) and prokinetics (metoclopramide, domperidone, erythromycin, prucalopride) 1

POTS-Specific Management

• High salt diet, copious fluids, and postural training are essential for all POTS patients 2
• Many patients benefit from low-dose beta-receptor antagonists and low-dose vasoconstrictors 2

Multidisciplinary Considerations

• Psychological support with brain-gut behavioral therapies should be incorporated, as studies demonstrate increased rates of anxiety and psychological distress in patients with hypermobility, which may be mediated by autonomic dysfunction 1
• Avoid parenteral nutrition except in life-threatening malnutrition as a temporary bridge to rehabilitative therapies 1

Critical Pitfalls to Avoid

• Do not attribute all symptoms to POTS alone—systematically evaluate for overlapping conditions like hEDS, MCAS, and DGBI 1
• Do not delay gastric emptying studies in POTS patients with upper GI symptoms, as the threshold for testing should be lower than in the general population 1
• Do not prescribe opioids for pain management, as they worsen GI dysmotility and should be withdrawn if already prescribed 1
• Do not overlook pelvic floor dysfunction in patients with constipation or incomplete evacuation 1