Right lower quadrant pain at 22:00 with no CT scanner until morning
A 27-year-old woman presents at 22:00 with 14 hours of right lower quadrant pain that began around the umbilicus, anorexia and two episodes of vomiting. She had a normal vaginal delivery 11 months ago, her last menstrual period was 4 weeks ago, and a urine pregnancy test in triage is negative. Temperature 38.1 °C, pulse 98/min, blood pressure 118/72 mmHg. The abdomen is soft with marked tenderness and guarding at McBurney point, positive rebound, and a positive Rovsing sign; pelvic examination shows no cervical motion tenderness and no adnexal mass. White cell count 13,800/mm3 with 82% neutrophils, CRP 46 mg/L, urinalysis shows 5-8 white cells per high-power field without nitrites. Bedside ultrasound describes a blind-ending tubular structure 7 mm in diameter in the right iliac fossa that does not compress, with surrounding hyperechogenicity, and normal ovaries with good Doppler flow. The hospital has a laparoscopy-capable surgeon on call but no CT scanner between midnight and 07:00.
1. List the alternatives you cannot dismiss and state which specific findings favour acute appendicitis over each of them.
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Ruptured corpus luteum or ovarian cyst / ovarian torsion. Both are common at this age and present with acute lower abdominal pain. Against them: the pain migrated from the periumbilical region, the ovaries are normal with preserved Doppler flow, there is no adnexal mass or cervical motion tenderness, and there is fever with neutrophilia and a CRP of 46.
Ectopic pregnancy. Excluded by a negative urine hCG in a patient only 4 weeks from her last period, but if there is any doubt about test sensitivity, send a quantitative serum beta-hCG; a negative serum value rules it out.
Pelvic inflammatory disease or tubo-ovarian abscess. Against: no cervical motion tenderness, no abnormal discharge, unilateral localised signs, and a normal pelvic examination.
Ureteric colic. Against: no colic or loin-to-groin radiation, urine shows white cells without blood or nitrites, and the pain is localised with peritoneal signs.
Mesenteric adenitis or gastroenteritis. Against: no diarrhoea, no generalised tenderness, and localised guarding with a CRP of 46 is disproportionate for a viral illness.
The strongest positive evidence is the combination of migratory pain, anorexia, fever, localised guarding and rebound at McBurney point, leukocytosis with 82% neutrophils, and a non-compressible 7 mm structure with periappendiceal fat stranding on ultrasound. No single item is decisive, but the pattern makes appendicitis the leading diagnosis and makes discharge without further action unsafe.
2. CT is unavailable until 07:00. Do you operate tonight, admit for serial examination, or start antibiotics and scan in the morning? Justify your choice, including the risk you are avoiding and what you tell the patient about a negative operation.
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Proceed to diagnostic laparoscopy tonight, after giving preoperative intravenous antibiotics (for example ceftriaxone plus metronidazole, or cefazolin plus metronidazole) and adequate analgesia and fluids. Reasons:
- Symptom duration is already 14 hours and the clinical picture is high probability (migratory pain, fever, localised peritonitis, leukocytosis, CRP 46, supportive ultrasound). The main risk of delay is perforation, which increases with time from onset and converts a straightforward laparoscopic appendicectomy into a contaminated field with abscess, longer stay and higher morbidity.
- Expectant observation with serial examination is defensible only for an equivocal, low-probability presentation. Here, guarding and rebound in a patient with fever argue against it, and a patient who deteriorates at 04:00 will be operated on emergently in worse condition.
- Antibiotics alone with a morning scan is not appropriate here: the evidence for antibiotics-first is limited to confirmed uncomplicated appendicitis in selected, fully compliant patients, and it does not remove the need for a decision in a patient with a high clinical probability and peritonism.
Counselling about a negative appendicectomy: explain that the clinical diagnosis is not perfect, that a normal appendix is removed in roughly 5-15% of operations when the picture is this strong, and that laparoscopy also allows diagnosis and treatment of the alternatives (torsion, ruptured cyst). Emphasise that delay carries the greater risk of perforation.
3. Laparoscopy shows a gangrenous, unperforated appendix in one patient and a perforated appendix with purulent fluid in the pelvis in another. Give your antibiotic plan for each.
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Both patients: a single preoperative dose given within 60 minutes of incision is prophylaxis and treatment; do not omit it because the diagnosis is uncertain.
Gangrenous but unperforated appendix: this is contamination without established infection. Continue the same agent for no more than 24 hours postoperatively, or stop it at the end of the operation; prolonged courses add resistance and Clostridioides difficile risk without benefit. No drain is needed.
Perforated appendix with purulent fluid: this is established intra-abdominal infection. Perform thorough peritoneal lavage and suction, aspirate pus for culture, and give a therapeutic course of a third-generation cephalosporin plus metronidazole (or piperacillin-tazobactam), continuing intravenously until the patient is afebrile for 24-48 hours with a normalising white cell count and returning bowel function, typically 3-5 days, then oral cover to complete about 7 days if source control was adequate. Escalate or image if fever persists beyond 72 hours (pelvic collection, abscess needing drainage). Consider a drain only for a well-defined abscess, not routinely.
Across both: check tetanus status is irrelevant here, but document the operative findings clearly and review the patient for surgical site infection at discharge.