Abdominal pain


Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Since the abdomen contains most of the body's vital organs, it can be an indicator of a wide variety of diseases. Given that, approaching the examination of a person and planning of a differential diagnosis is extremely important.
Common causes of pain in the abdomen include gastroenteritis and irritable bowel syndrome. About 15% of people have a more serious underlying condition such as appendicitis, leaking or ruptured abdominal aortic aneurysm, diverticulitis, or ectopic pregnancy. In a third of cases, the exact cause is unclear.

Signs and symptoms

The onset of abdominal pain can be abrupt, quick, or gradual. Sudden onset pain happens in a split second. Rapidly onset pain starts mild and gets worse over the next few minutes. Pain that gradually intensifies only after several hours or even days has passed is referred to as gradual onset pain.
One can describe abdominal pain as either continuous or sporadic and as cramping, dull, or aching. The characteristic of cramping abdominal pain is that it comes in brief waves, builds to a peak, and then abruptly stops for a period during which there is no more pain. The pain flares up and off periodically. The most common cause of persistent dull or aching abdominal pain is edema or distention of the wall of a hollow viscus. A dull or aching pain may also be felt due to a stretch in the liver and spleen capsules.

Causes

The most frequent reasons for abdominal pain are gastroenteritis, irritable bowel syndrome, urinary tract problems, inflammation of the stomach and constipation. In about 30% of cases, the cause is not determined. About 10% of cases have a more serious cause including gallbladder or pancreas problems, diverticulitis, appendicitis and cancer. More common in those who are older, ischemic colitis, mesenteric ischemia, and abdominal aortic aneurysms are other serious causes.

Acute abdomen

is a condition where there is a sudden onset of severe abdominal pain requiring immediate recognition and management of the underlying cause. The underlying cause may involve infection, inflammation, vascular occlusion or bowel obstruction.
The pain may elicit nausea and vomiting, abdominal distention, fever and signs of shock. A common condition associated with acute abdominal pain is appendicitis. Here is a list of acute abdomen causes:

Surgical causes

Source:

Inflammatory

Source:
  • Viscero-visceral referral: happens when one organ with afferent nerves close to another organ is sensitized or inflamed
  • Viscero-somatic referral: any pain in the viscera that causes pain in the muscle, bone, and skin
  • Somatic-visceral referral: pain in the skin, muscles, and bone that causes referred pain in the viscera

    Medical causes

Source:
Acute pancreatitis.
Sickle cell anemia.
Diabetic ketoacidosis.
Adrenal crisis.
Pyelonephritis.
Lead poisoning.
Familial Mediterranean fever.

Gynecological causes

Source:
Pelvic inflammatory disease and abscess.
Ectopic pregnancy.
Hemorrhagic ovarian cyst.
Adnexal or ovarian torsion.

By system

A more extensive list includes the following:
The location of abdominal pain can provide information about what may be causing the pain. The abdomen can be divided into four regions called quadrants. Locations and associated conditions include:
Abdominal pain can be referred to as visceral pain or peritoneal pain. The contents of the abdomen can be divided into the foregut, midgut, and hindgut. The foregut contains the pharynx, lower respiratory tract, portions of the esophagus, stomach, portions of the duodenum, liver, biliary tract, and the pancreas. The midgut contains portions of the duodenum, cecum, appendix, ascending colon, and first half of the transverse colon. The hindgut contains the distal half of the transverse colon, descending colon, sigmoid colon, rectum, and superior anal canal.
Each subsection of the gut has an associated visceral afferent nerve that transmits sensory information from the viscera to the spinal cord. The visceral sensory information from the gut traveling to the spinal cord, termed the visceral afferent, is non-specific and overlaps with the somatic afferent nerves, which are very specific. Therefore, visceral afferent information traveling to the spinal cord can present in the distribution of the somatic afferent nerve; this is why appendicitis initially presents with T10 periumbilical pain when it first begins and becomes T12 pain as the abdominal wall peritoneum is involved.

Diagnosis

A thorough patient history and physical examination is used to better understand the underlying cause of abdominal pain.
The process of gathering a history may include:
  • Identifying more information about the chief complaint by eliciting a history of present illness; i.e. a narrative of the current symptoms such as the onset, location, duration, character, aggravating or relieving factors, and temporal nature of the pain. Identifying other possible factors may aid in the diagnosis of the underlying cause of abdominal pain, such as recent travel, recent contact with other ill individuals, and for females, a thorough gynecologic history.
  • Learning about the patient's past medical history, focusing on any prior issues or surgical procedures.
  • Clarifying the patient's current medication regimen, including prescriptions, over-the-counter medications, and supplements.
  • Confirming the patient's drug and food allergies.
  • Discussing with the patient any family history of disease processes, focusing on conditions that might resemble the patient's current presentation.
  • Discussing with the patient any health-related behaviors that might make certain diagnoses more likely.
  • Reviewing the presence of non-abdominal symptoms that can further clarify the diagnostic picture.
  • Using Carnett's sign to differentiate between visceral pain and pain originating in the muscles of the abdominal wall.
After gathering a thorough history, one should perform a physical exam in order to identify important physical signs that might clarify the diagnosis, including a cardiovascular exam, lung exam, thorough abdominal exam, and for females, a genitourinary exam.
Additional investigations that can aid diagnosis include:
If diagnosis remains unclear after history, examination, and basic investigations as above, then more advanced investigations may reveal a diagnosis. Such tests include: