How to manage a 16-year-old patient with abdominal pain and unilateral eye redness?

Management of a 16-Year-Old with Abdominal Pain and Unilateral Eye Redness

This presentation requires simultaneous evaluation of two distinct organ systems—the abdomen and the eye—as the combination is atypical and suggests either two separate pathologies or a systemic inflammatory condition such as inflammatory bowel disease (IBD) with extraintestinal manifestations.

Immediate Assessment Priorities

Abdominal Pain Evaluation

Obtain vital signs immediately to identify hemodynamic instability, fever, tachycardia, or hypotension, which indicate potential organ failure requiring urgent intervention 1.

Key discriminating features in the history:

• Pain migration to the right lower quadrant with fever and positive psoas sign strongly suggests appendicitis 1
• Vomiting before pain onset makes appendicitis less likely 1
• Prior abdominal surgery raises concern for adhesive small bowel obstruction 2
• Chronic diarrhea, bloody stools, or weight loss suggest IBD with possible associated uveitis 3

Physical examination must identify:

• Localized peritonitis or generalized peritoneal signs 2
• Rebound tenderness, guarding, or rigidity 4
• Psoas sign or obturator sign 1

Eye Examination Priorities

Severe ocular pain, significant photophobia, decreased vision, or history of trauma are warning signs demanding immediate ophthalmological consultation 5.

Critical red flags requiring emergent ophthalmology referral:

• Vision loss or decreased visual acuity 6
• Severe pain not relieved with topical anesthetics 6
• Corneal involvement (keratitis) 6
• Distorted pupil suggesting iritis or acute glaucoma 6, 5
• Copious purulent discharge 6

Diagnostic Imaging Strategy

For Abdominal Pain in a 16-Year-Old

Ultrasound is the first-line imaging modality for suspected appendicitis in pediatric patients, given its high sensitivity (86-94%) and lack of radiation exposure 2.

• If ultrasound is non-diagnostic or equivocal, proceed to MRI without and with IV contrast rather than CT, as MRI has sensitivity of 94% and specificity of 94% for appendicitis while avoiding radiation 2
• CT abdomen/pelvis with IV contrast should be reserved for cases where MRI is unavailable or contraindicated 2
• Do NOT delay imaging for oral contrast, as it provides no diagnostic benefit and delays care 1

Laboratory Testing

Obtain complete blood count, C-reactive protein, and lactate if concerned for bowel ischemia or sepsis 1.

• Leukocytosis, metabolic acidosis, and elevated serum amylase are associated with perforation 2
• Lactate elevation suggests mesenteric ischemia or sepsis 1

Differential Diagnosis Framework

Abdominal Pain Considerations

The most common causes in adolescents with right lower quadrant pain:

• Appendicitis (most common surgical cause) 2
• Right ovarian pathology (torsion, cyst rupture) in females 2
• Inflammatory bowel disease (Crohn's disease with terminal ileitis) 2
• Mesenteric adenitis 2
• Ureteral stone 2

Eye Redness Considerations

Unilateral red eye with systemic symptoms raises concern for:

• Anterior uveitis/iritis (associated with IBD, HLA-B27 conditions) 6, 5
• Infectious conjunctivitis (viral or bacterial) 6
• Keratitis 6, 5
• Acute angle-closure glaucoma (if severe pain and vision changes) 6, 5

Consider Systemic Inflammatory Conditions

The combination of abdominal pain and unilateral eye inflammation should prompt consideration of inflammatory bowel disease with extraintestinal manifestations, particularly anterior uveitis, which occurs in 5-10% of IBD patients 3.

Treatment Algorithm

Step 1: Stabilize and Assess Severity

• Establish IV access and initiate fluid resuscitation if signs of sepsis or dehydration 1
• Provide early analgesia without compromising diagnostic accuracy 3, 1
• Do NOT routinely administer antibiotics for undifferentiated abdominal pain 1

Step 2: Imaging-Based Diagnosis

• Perform ultrasound of right lower quadrant first 2
• If ultrasound non-diagnostic, proceed to MRI abdomen/pelvis 2
• Obtain ophthalmology consultation for slit-lamp examination to evaluate for anterior chamber inflammation, corneal involvement, or elevated intraocular pressure 6, 5

Step 3: Definitive Management Based on Findings

If appendicitis confirmed:

• Surgical consultation for appendectomy 2
• Initiate antimicrobial therapy covering aerobic/facultative Gram-negative bacteria, Gram-positive streptococci, and obligate anaerobes 3

If IBD suspected (chronic symptoms, bloody diarrhea, weight loss, uveitis):

• Gastroenterology referral for colonoscopy and tissue diagnosis 3
• Ophthalmology management of uveitis with topical steroids 6

If simple conjunctivitis:

• Broad-spectrum topical antibiotics (erythromycin or polymyxin B-trimethoprim) 6

Critical Pitfalls to Avoid

• Do not dismiss the eye findings as unrelated—systemic inflammatory conditions like IBD commonly present with both GI and ocular manifestations 3
• Do not delay ophthalmology referral if vision is affected, severe pain is present, or pupil is distorted 6, 5
• Do not use CT as first-line imaging in a 16-year-old when ultrasound and MRI are available 2
• Do not administer antibiotics empirically without confirmed infection or sepsis 1
• Elderly patients may have normal labs despite serious infection, but this patient is young—however, maintain high suspicion if vital signs are abnormal 1

When to Involve Specialists

Surgical consultation is needed for:

• Signs of peritonitis 1
• Confirmed appendicitis on imaging 2
• Hemodynamic instability despite resuscitation 1
• Free air on imaging 1

Ophthalmology consultation is needed for:

• Any vision changes 6, 5
• Severe pain not relieved with topical anesthetics 6
• Suspected uveitis, keratitis, or glaucoma 6, 5
• Distorted pupil 6

Gastroenterology consultation is needed if:

• Chronic or recurrent abdominal pain with systemic features 3
• Suspected IBD based on history and examination 3