What causes abdominal pain that worsens when standing and how should it be managed?

Abdominal Pain That Worsens When Standing

Abdominal pain that worsens with standing is most commonly caused by abdominal wall pain, particularly anterior cutaneous nerve entrapment syndrome (ACNES), which should be diagnosed using the Carnett test and confirmed with local anesthetic injection. 1

Diagnostic Approach

Primary Consideration: Abdominal Wall Pain

The key distinguishing feature is pain that stays the same or worsens when the abdominal muscles are tensed (positive Carnett test), which strongly suggests abdominal wall rather than visceral origin. 1

Specific examination findings to look for:

• Small, localized tender spot at the lateral edge of the rectus abdominis muscle 1
• Pain that can be elicited by physical movement or position changes 2
• Pain provoked by digital palpation in a circumscribed area 2
• Increased pain intensity when abdominal muscles are contracted 2

Anatomic locations by frequency: 2

• Semilunar line (most common - 71% of cases)
• Linea alba between xiphoid and umbilicus
• Within the rectus muscle itself (often associated with exercise)
• Along the costal arch

Critical Red Flags to Exclude First

Before diagnosing functional or abdominal wall pain, you must rule out life-threatening conditions that can present with positional pain:

Immediate CT angiography is required if: 3, 4

• Severe pain out of proportion to physical examination findings (suggests mesenteric ischemia with 30-90% mortality)
• Sudden onset with hypotension (ruptured abdominal aortic aneurysm with >50% mortality)
• Tachycardia as an early warning sign, even before other symptoms develop
• Peritoneal signs (rigidity, rebound tenderness, guarding)

CT abdomen/pelvis with IV contrast is preferred imaging if any red flags are present, as it alters diagnosis in 49% and management in 42% of cases. 3

Confirmation of Abdominal Wall Pain

Diagnostic injection is both confirmatory and therapeutic: 1

• Local anesthetic injection at the point of maximal tenderness
• ≥50% pain improvement confirms the diagnosis
• Point-of-care ultrasonography can guide the injection and rule out hernias or other wall pathology 1

Management Algorithm

For Confirmed Abdominal Wall Pain (ACNES)

First-line treatment: 1

• Local injection with anesthetic plus corticosteroid
• Overall response rate: 70-99%
• Reassurance and patient education about the benign nature

For refractory cases:

• Repeat injection if initial response was partial (up to 2 injections total) 1
• Surgical neurectomy for cases requiring more than 2 injections - this generally resolves the pain 1

Associated Risk Factors to Address

Mechanical strain contributors: 2

• BMI >30 (chronic inflation of abdominal wall by fat pads)
• Repeated forceful contractions during exercise
• Chronic straining during defecation with bloating
• These cause strain at anatomically predestined sites

Psychological factors: 2

• Anxiety and depression are frequently associated (not causative, but consequence of chronic unexplained pain)
• Symptom-specific anxiety develops from repeated negative workups

Critical Pitfalls to Avoid

Do not order extensive visceral workups once abdominal wall pain is confirmed - this leads to expensive, unnecessary testing and increases patient anxiety. 2, 1

Do not ignore tachycardia - it is the most sensitive early warning sign of surgical complications and should trigger urgent investigation before assuming benign wall pain. 3

Conventional radiography has limited diagnostic value and should not be relied upon for diagnosis. 3

Negative ultrasound does not rule out severe pathology - CT should be considered if clinical suspicion for visceral disease persists. 3

When Functional Bowel Disease Is the Cause

If abdominal wall pain is excluded and chronic recurrent pain is associated with bowel habit changes, relieved by defecation, with onset at least 6 months prior, consider IBS. 3

For IBS-related pain: 5, 3

• Antispasmodics (NNT shows benefit with RR 0.67; 95% CI 0.55-0.80)
• Tricyclic antidepressants for frequent or severe pain (work through neuromodulatory mechanisms independent of psychotropic effects)
• Avoid opioids - risk of dependence, narcotic bowel syndrome, and increased mortality

Psychological therapies are effective: 5, 3

• Cognitive-behavioral therapy (strong recommendation, low quality evidence)
• Gut-directed hypnotherapy (strong recommendation, low quality evidence)
• Consider referral if symptoms persist after 12 months of drug treatment