How should I evaluate and manage nocturnal abdominal pain in a 17‑year‑old female?

Nocturnal Abdominal Pain in a 17-Year-Old Female

In a 17-year-old female with nocturnal abdominal pain, first rule out organic gastrointestinal and gynecologic pathology through targeted history and examination, then consider functional disorders if red flags are absent.

Initial Clinical Assessment

Critical Red Flags to Exclude Immediately

• Weight loss, rectal bleeding, or anemia – these mandate urgent investigation for inflammatory bowel disease or malignancy 1
• Nocturnal symptoms that wake the patient from sleep – this pattern suggests organic disease rather than functional disorders 1
• Fever or signs of acute infection – requires immediate evaluation for appendicitis, pelvic inflammatory disease, or other surgical emergencies 2

Essential History Components

Pain characteristics:

• Exact timing relative to sleep onset and duration 1
• Relationship to menstrual cycle and sexual activity 3, 4
• Relief with defecation or association with bowel habit changes 1
• Associated symptoms: nausea, vomiting, diarrhea, constipation, vaginal discharge 2, 3

Gynecologic evaluation (mandatory in this age group):

• Menarche status and menstrual pattern 4
• Sexual activity history and contraception use 4
• Possibility of pregnancy 4
• History of sexually transmitted infections 4

Dietary and medication history:

• Food intolerances (wheat, dairy products most common) 1
• Recent antibiotic use or dietary changes 5
• Use of NSAIDs or other medications 1

Physical Examination Priorities

Abdominal examination:

• Observe how the patient presents herself – patients with peritonitis appear still and guarded, while those with functional pain may be more comfortable 3
• Localization of tenderness, rebound, guarding 2
• Presence of masses or organomegaly 3

Pelvic examination indicated if:

• Sexually active with vaginal discharge and abdominal pain 4
• Suspicion of pelvic inflammatory disease, ovarian pathology, or ectopic pregnancy 4

Initial Laboratory and Imaging

First-line testing:

• Pregnancy test (urine β-hCG) – performed in 77% of adolescent females with abdominal pain and should be universal 4
• Complete blood count – to assess for anemia, leukocytosis suggesting infection 2
• CRP and WBC – though insufficient alone to discriminate urgent from non-urgent causes, they provide supportive data 2
• Urinalysis – to exclude urinary tract infection 3

STI testing:

• Indicated in sexually active patients, though only performed in 73% of those reporting sexual activity in one study 4
• Include testing for gonorrhea and chlamydia 4

Imaging approach:

• Ultrasound first – preferred initial modality due to high positive predictive value comparable to CT, avoids radiation exposure 2
• CT scan – if ultrasound negative or inconclusive, as CT provides highest sensitivity and specificity for acute abdominal pathology 2
• Conventional radiography has no role – lacks added value beyond clinical assessment 2

Differential Diagnosis Framework

Urgent Conditions Requiring Immediate Action

• Appendicitis (most common surgical emergency in this age group) 2
• Ectopic pregnancy 4
• Ovarian torsion 3, 4
• Pelvic inflammatory disease 4
• Bowel obstruction or perforation 2

Non-Urgent Conditions

• Irritable bowel syndrome – likely if pain relieved by defecation, associated with altered stool frequency/consistency, and symptoms >2 years duration 1
• Functional dyspepsia 1
• Dysmenorrhea 3
• Food intolerances (particularly wheat, dairy) 1, 5
• Eosinophilic esophagitis – consider if history of allergies and treatment-resistant symptoms 5

Management Algorithm

If red flags present (weight loss, bleeding, nocturnal awakening, anemia):

• Proceed directly to imaging (ultrasound then CT if needed) 2
• Gastroenterology or surgical consultation 1
• Consider sigmoidoscopy with biopsies if colonic symptoms present 1

If no red flags and symptoms suggest functional disorder:

• Working diagnosis can be made in primary care based on typical symptoms, normal examination, and absence of sinister features 1
• Confirm diagnosis through observation over time rather than extensive testing 1
• Consider trial of dietary modification (elimination of wheat, dairy) 1, 5

If sexually active with pelvic symptoms:

• Pelvic examination and STI testing mandatory 4
• Empiric treatment for pelvic inflammatory disease if high suspicion 4

Common Pitfalls to Avoid

• Failing to document sexual history – only 52% of adolescent females had sexual history documented in one emergency department study 4
• Assuming functional disorder without excluding organic pathology – nocturnal symptoms that wake from sleep are atypical for IBS and warrant investigation 1
• Racial disparities in evaluation – Black patients were more likely to undergo STI testing and pelvic examination but less likely to receive imaging, suggesting potential bias 4
• Over-reliance on laboratory values alone – CRP and WBC insufficient to discriminate urgent from non-urgent causes without clinical context 2
• Delaying analgesia – opioid administration decreases pain intensity without affecting diagnostic accuracy 2

Follow-Up Strategy

For presumed functional disorders:

• Re-evaluate if symptoms persist beyond expected timeframe or new red flags develop 1
• Diagnosis more likely if female, age <45, history >2 years, and frequent prior visits for non-GI symptoms 1

For organic pathology:

• Antibiotic treatment within first hour if sepsis recognized 2
• Surgical consultation for suspected appendicitis, ovarian torsion, or other surgical emergencies 2