Lower abdominal pain DDx

Lower abdominal pain – Differential Diagnosis

Common causes

• Gastroenteritis
• Mesenteric adenitis
• Urinary Tract Infection
• Constipation
• Dysmenorrhoea
• Mittelschmerz
• Endometriosis
• Ovarian cyst
• Threatened miscarriage
• Renal colic
• Hernia
• Psychiatric (functional)

Must Not Miss

• ‘Acute’ Abdomen
  • Appendicitis
  • Intestinal obstruction
  • Peritonitis
  • Ectopic pregnancy
• Vascular
  • AAA (Rupture or dissection)
  • Mesenteric ischaemia
• Infection
  • Pelvic Inflammatory Disease
  • Diverticulitis
  • Pyelonephritis
• Malignancy
  • Colorectal cancer
  • Ovarian cancer
  • Endometrial cancer
  • Cervical cancer
• Acute urinary retention
• Testicular Torsion
• Diabetic ketoacidosis

Easily missed

• Crohn’s dis/ Ulcerative colitis
• Sickle cell crisis
• Addison’s disease
• Herpes Zoster

Red flags

• Acute severe pain
• Weight loss
• Systemic features (fever, night sweats, anorexia)
• Rectal bleeding
• Persistent altered bowel habit: age > 50 years
• Anaemia
• Abdominal swelling/mass
• Rectal mass
• Pregnancy
• Raised inflammatory markers
• Known AAA
• Past history of cancer
• Family history of cancer

Investigations to consider

• FBC, CRP/ESR
• U&Es, LFTs, Blood glucose, Bone profile
• Serum amylase
• Urinalysis/MSU
• Pregnancy test
• ECG
• AXR, KUB/ IVU, CXR
• USS (Abdo & Pelvis)
• Small bowel enema
• Barium enema
• Colonoscopy
• CT
• Angiography
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