Vomiting with abdominal pain and fever

The vomiting is usually unrelated to eating.

Some differential diagnoses and typical outline evidence

Gastroenteritis	Suggested by: diarrhoea, ↑bowel sounds.
	Confirmed by: stools for WBC and culture.
	Management: OHCM p556.
Food poisoning	Suggested by: associated with diarrhoea, eating companions affected.
	Confirmed by: stools for WBC and culture, cultures of vomitus, food and blood.
	Management: OHCM p556.
Urinary tract infection	Suggested by: dysuria, frequency, abnormal dipstix.
	Confirmed by: MSU microscopy and culture. (US scan for possible anatomical abnormality.)
	Management: OHCM p262.
Acute appendicitis, mesenteric adenitis	Suggested by: RLQ pain anorexia, low grade fever.
	Confirmed by: RLQ guarding or right sided rectal tenderness.
	Management: OHCM p476.
Hepatitis A or B	Suggested by: RUQ pain, jaundice.
	Confirmed by: ALT ↑↑ and bilirubin ↑, hepatitis serology.
	Management: OHCM p576.
Toxic shock syndrome	Suggested by: use of tampons, high fever, vomiting and profuse watery diarrhoea, confusion, skin rash, hypotension, myalgia.
	Confirmed by: cultures of blood, stool, vaginal swab for Staphylococcus and toxin. Thrombocytopenia on FBC. ↑CPK.
	Management: OHCM p590.
Pneumonia (lower lobe)	Suggested by: cough, dyspnoea, fever.
	Confirmed by: CXR shows consolidation. Sputum and blood cultures. Serology if atypical.
	Management: OHCM p172.
Pelvic inflammatory disease	Suggested by: lower abdominal pain, fever, vaginal discharge.
	Confirmed by: high vaginal swab, elevated ESR and CRP. FBC: leucocytosis, pelvic ultrasound, ±laparoscopy.
	Management: OHCS p286.
Haemolytic uraemic syndrome	Suggested by: haematuria, fever, confusion.
	Confirmed by: FBC: thrombocytopaenia, fragmented RBCs on blood film, renal failure on U&E.
	Management: OHCM p282.
Malaria	Suggested by: recent travel to malaria zone, periodic paroxysms of rigors, fever, sweating, nausea.
	Confirmed by: Plasmodium in blood smear.
	Management: OHCM pp560–2.