The abdomen and pelvis contain many organs and any condition affecting them could cause pain.  The commonest causes are infection/ inflammation, obstruction, perforation, ischaemia (lack of adequate blood flow) and malignancy.  The surrounding tissues, muscles, bone and nerves can also be causing pain.

Causes of abdominal pain:

• Visceral pain:
  • Mild – Common causes include vomiting, constipation, diarrhoea, gastroenteritis, food intolerance and acid reflux disease.  Stress and starvation can also aggravate heart-burn.
  • More serious causes from the bowel include infections like appendicitis and peritonitis, bowel obstruction due to hernias, tumours and adhesions and traumatic injury.  Perforation of gastric or duodenal ulcers, diverticulitis and inflammatory bowel diseases like Ulcerative colitis and Crohns disease can lead on to persistent abdominal pain.  Hiatus hernia and diseases of the oesophagus can also lead on to upper abdominal pain.  Chronic conditions like tuberculosis and sarcoidosis can also present as abdominal pain.  Volvulus or twisting of the bowel and intussusception can also cause pain and obstruction.  Mesenteric ischaemia is a serious condition that needs urgent management.  Ascites is the filling of the abdomen with fluid causing distension and pain.
  •  Other visceral causes include hepatitis, pancreatitis, cholecystitis and cholangitis (infection/inflammation of gall bladder and biliary tree), obstructive jaundice, kidney infection and urinary obstruction due to stones can lead on to upper abdominal pain.

• • Cardiovascular causes including myocardial infarction, angina, heart failure can manifest as abdominal pain.  Abdominal Aortic Aneurysm is a life-threatening swelling of the main blood vessel and leakage from it can present as abdominal pain radiating to the back.
  • Tumours and cancers particularly of pancreas, gall bladder, stomach, carcinoma and sarcomas of the bowel and soft tissue could present with pain but would be associated with other symptoms.
  • Most of the chronic abdominal pains do not have an identifiable cause despite extensive investigations.  Sometimes these can be attributed to medication use or opioid withdrawal, but most are classed as functional disorders and may be identified as part of irritable bowel syndrome (IBS).
  • Myofascial pain: are often missed when presented as abdominal pain.
    • Trigger points in the rectus abdominis and oblique muscles
    • ACNES – abdominal cutaneous nerve entrapment syndrome
    • Psoas muscle spasm
  • Neuropathic pain
    • Shingles and post-herpetic neuralgia
    • Scar pain – this could be post-trauma or post-surgical pain.  Post gall bladder surgery and repair of hernias with mesh is a common cause of persistent pain.  The risk of developing nerve pain is increased if there was post-operative wound infection.
  • Referred pain: This could be from anywhere in the body cavity or surrounding structures.  Spinal pain due to arthritis, disc prolapses and foraminal stenosis can be manifested as abdominal pain.  Tumours and infection of the spine can cause referred pain to the abdomen.  Pleural irritation due to pneumonia or effusion can refer to the abdomen.  Pain from the pelvic viscera including urinary bladder, uterus and ovaries are other causes of referred pain.
  • The pelvis contains the bowel, bladder and reproductive organs and is enclosed in a bony structure with several nerves and plexuses that supply the pelvis and lower limbs as well as blood vessels.  The pelvic musculature is also complex.

Causes of pelvic pain:

• Gynaecological:
  • Menstrual cramps (dysmenorrhoea) or period pains; this is cyclical in nature
  • Mittelschemrz (associated with Ovulation)
  • Pelvic inflammatory disease
  • Endometriosis
  • Uterine masses including fibroids, adenomyosis and cancer
  • Ovarian cysts – rupture, torsion, bleeding
  • Pregnancy and ectopic pregnancy
  • Chronic pelvic pain – vulvodynia, dyspareunia
• Urinary Bladder:
  • Urinary tract infection
  • Sexually Transmitted Diseases
  • Interstitial Cystitis
  • Stones in kidney, ureter or bladder
• Small bowel, Colon and Rectum
  • Chronic constipation
  • Diverticulitis
  • Hernia
  • Anal – Haemorrhoids, Anal fissure, Fistula
• Testicular pain can be due to infection or inflammation (epididymo-orchitis), trauma, ischaemia due to testicular torsion, varicoceles (swollen veins around the testicle) and hydrocele.  Chronic infection of the prostate (prostatitis) can also give rise to pelvic pain in males.
• Myofascial pain: pain arising from the surrounding muscles and ligaments of the pelvis and pelvic floor.  This could be trigger points or conditions like pyriformis syndrome.
• Bony pain:
  • Lumbar spondylosis (osteoarthritis)
  • Joint pains – sacroiliac joint, hip joint
  • Pubic symphysis dysfunction
  • Coccydynia
• Neuropathic pain: Pudendal neuralgia, post-surgical pain
• Referred pain from abdomen and lower limbs

Sudden onset or acute pain especially if you feel unwell could be a serious condition and should seek urgent medical attention to rule out surgical emergency. Chronic pain in the absence of a specific treatment could be complex and needs a full assessment. Common investigations include blood tests, urine and stool studies; imaging tests might include X-rays, Ultrasound scans, CT scan and MRI scans. Internal examination include upper and lower endoscopies, colonoscopy, colposcopy, cysto-ureteroscopy and diagnostic laparoscopy.