Abdominal pain or belly pain can occur due to several underlying pathologies. While some of these are minor and do not lead to serious damage, some may be a symptom of a life-threatening underlying condition.

Classification according to severity

The causes of abdominal pain may be classified according to their severity and level of urgency in management. These are outlined as below:-

Emergencies

True emergencies that might lead to life-threatening consequences if not managed urgently:-

• Rupture of abdominal or thoracic aorta aneurysm
• Ectopic pregnancy
• Diabetic ketoacidosis
• Myocardial infarction or heart attack
• Peritonitis or inflammation of the membrane like layer within the abdomen
• Perforation of the stomach wall due to a peptic ulcer

Urgent conditions

Urgent conditions that require treatment within a few hours of onset:-

• Appendicitis
• Cholecystitis or gall bladder stones leading to inflammation of the gall bladder
• Pancreatitis or inflammation of the pancreas
• Intestinal obstruction or blockage of the intestines
• Peptic ulcer
• Sickle cell crisis seen in individuals with Sickle cell anemia
• Renal colic
• Injury to the abdominal structures including spleen and liver
• Urinary retention or inability to pass urine for several hours leading to painful collection of urine within the bladder

Non-urgent causes of abdominal pain

Non-urgent causes of abdominal pain include:-

• Constipation
• Gastritis
• Gastroenteritis
• Hepatitis
• Irritable bowel syndrome
• Urinary tract infection
• Dysmenorrhoea
• Endometriosis
• Hernia
• Ovarian cyst
• Pelvic inflammatory disease

What causes abdominal pain?

Abdominal pain can start due to a pathology of any of the structures within the abdomen or the abdominal wall. The pain may also originate from the chest, back, or pelvis and may be felt in the abdomen. For example, patients with heart attacks or severe lung infection pneumonia sometimes complain of upper abdominal painrather than chest pain.

Classification according to site of origin

Causes of abdominal pain may also be classified according to the site of origin. Some of the common causes include:-

Those originating in the chest

• Pneumonia (lung infection)
• Collection of fluid and inflammation within the membranes surrounding the lungs or pleurisy
• Pulmonary embolism that is caused by blood clots to the lungs
• Myocardial infarction (heart attack)
• Inflammation of the rib cartilages or Costochondritis

Those originating from the abdominal wall or from the skin over the belly

• Shingles or herpes zoster infection
• Injury to the abdomen
• Muscle pull or sprains of the abdomen muscles
• Nerve irritation over the abdomen
• Hernias
• Scars

Those originating from the upper abdomen organs

• Peptic and duodenal ulcers
• Esophagitis  and gastroesophageal reflux disease
• Gastritis
• Pancreatitis
• Cholecystitis and Choledocholithiasis  which indicates obstruction of the bile duct with passage of gall stones
• Hepatitis
• Infection or inflammation of the colon or colitis

Those due to diseases and disorders of the abdominal organs

• Non-ulcer dyspepsia
• Irritable bowel syndrome
• Cancers including liver cancer, bile duct or gall bladder cancer, Pancreatic cancer, Stomach cancer, Lymphoma etc.
• Crohn’s disease
• Diverticulitis or inflammation of pouches that form in the colon
• Appendicitis

Those due to problems of the urinary tract

• Kidney stones 
• Tumors and cancers of the kidneys or bladder 
• Urinary tract infection

Those due to gynaecological problems in women

• Ovarian cysts
• Infection of the fallopian tubes or salpingitis
• Ectopic pregnancy 
• Fibroid of the uterus
• Cancers and tumors of the ovaries, uterus and cervix
• Endometriosis
• Pelvic inflammatory diseases