Abdominal pain

A 14 year old girl was referred by her general practitioner with a two week history of abdominal pain, nausea, and vomiting. At presentation the pain had become localised to the right iliac fossa. No bowel or urinary symptoms were reported. Her last menstrual period had started one week previously.

Ten days previously, she had been seen by the paediatrics team with symptoms of diarrhoea, frequency, and dysuria associated with a dull suprapubic ache. On the basis of these symptoms and a positive nitrate urine dipstick, a diagnosis of urinary tract infection was made and a five day course of trimethoprim prescribed.

On general examination she seemed mildly dehydrated, with a pulse of 115 beats/min and a respiratory rate of 24 breaths/min. Her temperature was 37.1°C, and her blood pressure was 122/92 mm Hg. Abdominal examination showed tenderness in the right iliac fossa with localised guarding and rigidity, tympanic percussion, and reduced bowel sounds. Examination of other systems was unremarkable. Urine dipstick and pregnancy testing were negative, and capillary blood sugar was 3.9 mmol/L. Blood investigations showed haemoglobin at 13.3 g/L (reference range 11.5-16 g/dL, total white blood cell count 17.7 x 10⁹/L (4.0-11.0 x 10⁹), mean corpuscular volume 82.3 fl (76-96 fl), platelets 561 x 10⁹/L (150-400 x 10⁹), sodium 138 mmol/L (135-145), potassium 4.4 mmol/L (3.5-5.0), urea 7.5 mmol/L (2.5-6.7), and creatinine 57 µmol/L (79-118).