What could be causing sharp aching pain in the left upper quadrant and side pain at and below the ribs that worsens after standing all day?

Sharp Aching LUQ Pain Worsening After Prolonged Standing

Your symptoms are most consistent with painful rib syndrome (also called slipping rib syndrome), a musculoskeletal condition affecting the lower costal margin that is frequently misdiagnosed and often leads to unnecessary testing and procedures. 1, 2

Clinical Diagnosis

The diagnosis of painful rib syndrome requires three specific features that you should assess:

• Pain in the lower chest or upper abdomen - typically located at or below the costal margin, which matches your LUQ and side pain distribution 2
• A tender spot on the costal margin - palpate systematically along your lower ribs, particularly the tips of ribs 8-10 and the floating ribs (11-12), pressing firmly to identify a specific point of maximal tenderness 2, 3
• Reproduction of pain with pressure - pressing on the tender spot should recreate your typical pain, confirming the diagnosis 2, 4

The positional nature of your pain (worsening after standing all day) is characteristic, as painful rib syndrome is movement and posture-dependent 1, 4. This occurs because prolonged standing or certain positions cause the lower ribs to impinge on intercostal nerves and soft tissue 5, 3.

Why This Diagnosis Fits

• Demographics: 70% of cases occur in women with a mean age of 48 years 2
• Postural aggravation: The pain worsens with specific positions and activities, improving with rest 1, 4
• Location: Left-sided upper quadrant pain at the rib margin is a classic presentation 1, 2
• Chronicity: The intermittent nature suggests a mechanical rather than inflammatory or infectious cause 2

Critical Pitfall to Avoid

Do not pursue extensive imaging or invasive procedures without first performing a thorough physical examination of the costal margin. This condition accounts for 3% of general medical/gastroenterology referrals, yet 43% of patients undergo extensive (and negative) investigations before diagnosis, and 8% even undergo unnecessary cholecystectomy 2. This is a safe clinical diagnosis requiring no investigation when the three diagnostic features are present 2.

When Imaging IS Indicated

However, you should obtain CT abdomen and pelvis with IV contrast if any of the following red flags are present 6:

• Fever or leukocytosis - suggests inflammatory or infectious process requiring urgent evaluation 6
• Inability to reproduce pain with palpation - if pressing the costal margin does not recreate your symptoms, alternative diagnoses must be excluded 2
• Constitutional symptoms - weight loss, night sweats, or progressive worsening despite conservative measures 6
• Abdominal distension or inability to pass gas/stool - suggests bowel obstruction 7

The American College of Radiology rates CT abdomen/pelvis with IV contrast as 8/9 (usually appropriate) for evaluating LUQ pain when clinical features suggest intra-abdominal pathology, as it alters diagnosis in 49% of cases with nonlocalized abdominal pain 8, 6. Plain radiography has very limited diagnostic value and should not be obtained 6.

Management Approach

If painful rib syndrome is confirmed by physical examination:

• Explanation and reassurance - understanding the benign nature of the condition is the most critical intervention, as the pain is real but not dangerous 1, 4
• Posture modification - avoid positions that aggravate symptoms, particularly prolonged standing or leaning forward 1, 4
• NSAIDs - for symptomatic relief during acute flares 3
• Physical therapy - may help with postural correction and core strengthening 3

Expected Course

In a 4-year follow-up study, 70% of patients still had some pain, but all except 3 had learned to live with it 2. Despite firm diagnosis, 33% were re-referred by their general practitioners for additional evaluation, but all further investigations were negative 2. The condition does not progress to serious disease - all deaths in the cohort were from unrelated causes 2.

Alternative Diagnoses to Consider

If the physical examination does not confirm painful rib syndrome, the differential diagnosis for LUQ pain includes:

• Splenic pathology - though typically presents with more acute, severe pain 6
• Renal pathology (nephrolithiasis, pyelonephritis) - usually associated with flank radiation and urinary symptoms 6
• Gastric or pancreatic disease - typically associated with postprandial symptoms or epigastric radiation 6
• Musculoskeletal strain - but would not have a specific tender point on the costal margin 2