Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of a person's abdominal pain can be quite difficult, because so many diseases can result in this symptom.
Abdominal pain is traditionally described by its chronicity (acute or chronic), its progression over time, its nature (sharp, dull, colicky), its distribution (by various methods, such as abdominal quadrant (left upper quadrant, left lower quadrant, right upper quadrant, right lower quadrant) or other methods that divide the abdomen into nine sections), and by characterization of the factors that make it worse, or alleviate it.
Due to the many organ systems in the abdomen, abdominal pain is a concern of general practitioners/family physicians, surgeons, internists, emergency medicine doctors, pediatricians, gastroenterologists, urologists and gynecologists. Occasionally, patients with rare causes can see a number of specialists before being diagnosed adequately (e.g., chronic functional abdominal pain).
Types and mechanisms
· The pain associated with inflammation of the parietal peritoneum is steady and aching, and worsened by changes in the tension of peritoneum caused by pressure or positional change. It is often accompanied by tension of the abdominal muscles contracting to relieve such tension.
· The pain associated with obstruction of the hollow viscera is often intermittent or "colicky"
· The pain associated with abdominal vascular disturbances (thrombosis or embolism) can be sudden or gradual in onset, and can be severe or mild. Pain associated with the rupture of an abdominal aortic aneurysm may radiate to the back, flank, or genitals.
· Pain that is felt in the abdomen may be "referred" from elsewhere (e.g., a disease process in the chest, like a subdiaphragmatic abscess, may cause pain in the abdomen), and abdominal processes can cause radiated pain elsewhere (e.g., gall bladder pain—in cholecystitis or cholelithiasis—is often referred to the shoulder).
· Parietal peritoneal inflammation
· Due to infection: perforated appendix in appendicitis, pelvic inflammatory disease
· Due to chemical irritation: perforated gastric or peptic ulcer; pancreatitis, mittelschmerz, ruptured ectopic pregnancy
· Miscellaneous (familial mediterranean fever)
· Inflammation of bowel wall crohn's disease, ulcerative colitis, microscopic colitis, diverticulitis, gastroenteritis
· Allergic: lactose intolerance, celiac sprue
· Autoimmune: sarcoidosis, vasculitis
· Mechanical obstruction of hollow viscera such as the small intestine, the large intestine (e.g. By intussusception), the biliary tree (e.g. By gallstones), or the ureter (e.g. By urinary calculi)
· Vascular disturbances (leading to ischemia): embolism, thrombosis, vascular rupture, torsional occlusion (volvulus), sickle cell anemia, left renal vein entrapment
· Abdominal wall injury/disruption: mesenteric traction, muscle trauma, muscular infection, diverticulosis (rare)
· Distention of visceral surfaces such as the hepatic or renal capsule
· Referred pain from the thorax (pneumonia, coronary occlusion), the spine (radiculitis secondary to arthritis), genitals (testicular torsion)
· Metabolic disturbance: lead poisoning, black widow spider bite, uremia, diabetic ketoacidosis, porphyria, c1-esterase inhibitor deficiency, adrenal insufficiency
· Neurogenic pain: tabes dorsalis, herpes zoster, lyme disease (lyme radiculitis or bannwarth syndrome)
· Functional pain, irritable bowel syndrome (affecting up to 20% of the population, IBS is the most common cause of recurrent, intermittent abdominal pain)
Acute abdomen can be defined as severe, persistent abdominal pain of sudden onset that is likely to require surgical intervention to treat its cause. The pain may frequently be associated with nausea and vomiting, abdominal distention, fever and signs of shock.
Selected causes of acute abdomen
· Traumatic : blunt or perforating trauma to the stomach, bowel, spleen, liver, or kidney
· Inflammatory :
· Infections such as appendicitis, cholecystitis, pancreatitis, pyelonephritis, pelvic inflammatory disease, hepatitis, mesenteric adenitis, or a subdiaphragmatic abscess
· Perforation of a peptic ulcer, a diverticulum, or the caecum
· Complications of inflammatory bowel disease such as Crohn's disease or ulcerative colitis
· Small bowel obstruction secondary to adhesions caused by previous surgeries, intussusception, hernias, benign or malignant neoplasms
· Large bowel obstruction caused by colorectal cancer, inflammatory bowel disease, volvulus, fecal impaction or hernia
· Vascular: occlusive intestinal ischemia, usually caused by thromboembolism of the superior mesenteric artery