What should I do for a [AGE]-year-old male experiencing sharp abdominal pain under the umbilical area, should I proceed with imaging?

Sharp Abdominal Pain Below the Umbilicus in a Male: Imaging Decision

For a male patient with sharp abdominal pain below the umbilicus, proceed with ultrasound of the right lower quadrant as the initial imaging modality, followed by CT abdomen and pelvis with IV contrast if ultrasound is non-diagnostic or equivocal. 1, 2

Initial Clinical Assessment

Before ordering imaging, perform a focused physical examination looking for:

• Fever, tachycardia, or signs of peritonitis (rebound tenderness, guarding) which suggest acute appendicitis or other surgical emergencies 3
• Psoas sign or migratory pain to the right lower quadrant which increases likelihood of appendicitis 3
• Palpable mass at or near the umbilicus which could indicate incarcerated umbilical hernia, even in the absence of visible bulging 4, 5

Risk Stratification Determines Imaging Approach

Low Clinical Risk Patients

• If clinical assessment and laboratory data suggest low risk for appendicitis, imaging for appendicitis is not required initially 3
• Consider plain radiography to identify alternative causes such as constipation or lower lobe pneumonia 3

Intermediate to High Clinical Risk Patients

Start with ultrasound as the preferred initial imaging:

• Ultrasound has sensitivity of 82-99% and specificity of 94-96% for appendicitis 6, 1
• Avoids radiation exposure 1
• Can identify alternative diagnoses including mesenteric adenitis, urinary tract pathology, or incarcerated hernia 6

If Ultrasound is Non-Diagnostic

Proceed immediately to CT abdomen and pelvis with IV contrast:

• CT has sensitivity of 95% and specificity of 94% for appendicitis 2
• CT changes diagnosis in 49% of patients and alters management in 42% of cases with nonlocalized abdominal pain 2
• Single-phase IV contrast-enhanced CT is sufficient; do not order CT without and with contrast as this doubles radiation exposure without improving diagnostic accuracy 3
• CT from L2/L3 through the pubic symphysis is adequate for diagnosing appendicitis and most alternative diagnoses 3

Alternative Imaging: MRI

Consider MRI without IV contrast if:

• Ultrasound is equivocal and you want to avoid radiation 1
• MRI has sensitivity of 86-98% and specificity of 94-97% for appendicitis 6, 1
• However, MRI is limited by cost and availability 2

Critical Pitfalls to Avoid

• Do not rely on plain radiography alone for diagnosis of acute abdominal pain—it has limited diagnostic value and rarely changes management 2, 7
• Do not skip imaging in obese patients even without visible umbilical bulging, as incarcerated umbilical hernias can be "invisible" and present with periumbilical pain 4
• Do not delay CT if the patient is clinically deteriorating while pursuing additional non-diagnostic tests 2
• Do not order CT without and with contrast as a first-line study—this provides no additional diagnostic benefit and doubles radiation exposure 3

Laboratory Workup

Obtain simultaneously with imaging:

• Complete blood count with absolute neutrophil count and C-reactive protein 6
• Urinalysis to rule out urinary tract infection or pyelonephritis 6

Specific Differential Diagnoses to Consider

Given the periumbilical/infraumbilical location in a male:

• Acute appendicitis (most common surgical cause) 3
• Incarcerated umbilical or paraumbilical hernia (can occur without visible bulging, especially in obese patients) 4, 5
• Mesenteric adenitis (often follows viral infection) 6
• Small bowel obstruction 3
• Urinary tract infection or pyelonephritis 6
• Lower lobe pneumonia with referred pain 6