Abdominal pain, also called stomach ache, refers to any pain that occurs between the chest and pelvis. As it is the region that contains the most organs throughout the body, the abdomen is prone to pain due to a multitude of causes and diseases. The large number of possible diagnosis often make the abdominal pain a challenge for the doctors.
Most of the time, an abdominal pain is a benign and self-limiting event. Almost everyone has, at least once, experienced a mild pain in the belly that has disappeared spontaneously, without medical treatment.
However, when an abdominal pain is severe or has other associated symptoms, such as fever, vomiting, lethargy or bloody diarrhea, specialized medical treatment becomes necessary.
In this article, we will address the main causes of abdominal pain. Do not attempt to use this text for purposes of self-diagnosis. The correct diagnosis of an abdominal pain can be difficult even for doctors.
- If you are looking for information on abdominal pain during pregnancy, read: MAIN CAUSES OF ABDOMINAL PAIN DURING PREGNANCY.
Abdominal and pelvic organs
All of the organs within the abdominal and pelvic cavities are possible sources of abdominal pain. Sometimes, organs in the thoracic region may also cause abdominal pain, such as the heart or the lungs.
The abdominal organs that are common sources of abdominal pain are: liver, gallbladder, pancreas, stomach, kidneys, and intestines.
In the pelvic region, the possible sources of abdominal pain are as follows: ovaries, fallopian tubes, uterus, bladder, prostate, rectum and sigmoid (the part of the large intestine that is closest to the rectum and anus).
The illustrations below demonstrate two different ways to anatomically divide the abdomen. These divisions serve to facilitate the description and the interpretation of the physical examination made by the doctor.
When we look at the abdomen from the front of the body, it can be broken down into nine main regions, almost like a Tic-tac-toe with lines running both horizontally and vertically.
LOCATION OF ABDOMINAL PAIN
Due to the type of innervation of most abdominal organs, the brain is often not able to locate the exact focal point of pain. Therefore, most conditions in the abdominal or pelvic organs cause diffuse pain, or pain in the umbilical region. Exceptions include the kidneys, gallbladder, ovaries or appendix, which tend to generate a more lateralized pain, in the hypogastric, lumbar or iliac regions.
In the illustration below, it is possible to see how the main abdominal and pelvic organs end up presenting pain in regions that are very close together.
Therefore, although the location of the pain helps, this is generally not enough to come to the proper diagnosis. In addition to the location, it is also important to evaluate other characteristics of the pain, such as: type (burning, colic, spasm, pressure, etc.), duration, intensity, associated symptoms (i.e. vomiting, diarrhea, fever or jaundice), aggravating factors or triggers, if the pain radiates or not, etc.
Usually, an abdominal pain does not indicate any serious condition. Most of the time the pain is related to intestinal cramps due to the consumption of fatty foods, mild virus gastroenteritis or food poisoning. A mild abdominal pain that is short lived, or lasts only a few hours, usually derive from gas-filled dilated bowels. Anxiety can also cause short-term abdominal pain, by increasing the gas content in the intestines.
A severe or incapacitating abdominal pain that lasts several hours ou days or that is associated with vomiting, fever and/or lethargy is cause for concern.
COMMON CAUSES OF PAIN ON THE RIGHT SIDE OF THE BELLY – RIGHT ABDOMEN
The right abdomen region is divided in two: the upper-right and lower-right quadrants.
The main causes of pain in the upper-right quadrant of the abdomen derive from the liver and the gallbladder, particularly biliary colic caused by gallstones or cholecystitis. Conditions that are associated with inflammation of the liver, such as hepatitis, can also cause pain in this region.
Additionally, lesions in the lower portion of the right lung may also cause abdominal pain on the right side.
The most common reason for a pain that is located in the lower-right quadrant of the abdomen is an intestinal disorder, particularly appendicitis. In women, disorders of the ovaries, such as ovarian cysts, are also very common. An ectopic pregnancy in the right fallopian tube is another possible cause.
Occasionally, a testicle disease, or a kidney stone that has migrated to the lower ureter, may manifest with pain in the lower abdominal quadrant (left or right).
Muscle pain should be considered if the patient had recently made strenous exercise.
COMMON CAUSES OF PAIN IN THE MID-ABDOMEN – PIT OF THE STOMACH
Pain in the center of the belly, is usually triggered by stomach problems. Gastritis or peptic ulcers are the most common causes. Pancreas diseases, such as pancreatitis, often cause severe abdominal pain throughout the entire upper part of the abdomen, possibly even radiating to the back.
Both stomach and pancreas problems can cause pain which can be described as originating at the bottom of the belly. Muscle pain can also affect this region.
Pain resulting from acute myocardial infarction may, in some cases, radiate to the central region of the abdomen, and may initially be confused with a stomach problem.
COMMON CAUSES OF PAIN IN THE LOWER ABDOMEN – HYPOGASTRIUM
Abdominal pain located at the bottom of the belly, also known as the hypogastrium or hypogastric region, usually originate in the bladder or, in the case of women, in the uterus.
Bladder infection (cystitis) and menstrual cramps are the most common causes.
Gastroenteritis or food poisoning may also cause pain in this area, but the pain is usually more widely spread throughout the abdomen.
Pregnancy is not associated with pain but with an uterine discomfort. However, in the case of an ongoing miscarriage, severe cramping may occur.
COMMON CAUSES OF PAIN ON THE LEFT SIDE OF THE BELLY – LEFT ABDOMEN
As on the right side, the abdomen on the left side is divided in two quadrants: the upper-left and the lower-left quadrants.
On rare occasions, the spleen, an organ located below the ribs on the left side of the abdomen, may cause abdominal pain. But the most common source for the upper-left quadrant pain is the stomach.
Also, problems at the base of the left lung, as well as a heart attack, can originate pain in the upper-left quadrant of the belly.
Conversly, within the central and lower regions of the left abdomen, bowel problems are often the main determinants for the pain, particularlly gastroenteritis and diverticulitis.
In women one must always bear in mind the gynecological sources, such as ovary diseases or an ectopic pregnancy.
MAIN CAUSES OF ABDOMINAL PAIN
We will now briefly address the main conditions that most often cause abdominal pain.
1. GASTRITIS AND PEPTIC ULCER
Upper abdominal disconfort or burning pain is the most prominent symptom in patients with peptic ulcers or gastritis. The pain may be worse between meals and at night, when the stomach is empty.
Pain limited to the epigastric region, usually associated with bloating, abdominal fullness, heartburn, or nausea is often classified as dyspepsia.
Elderly patients with dyspepsia and anemia must always be investigated for duodenal ou gastric ulcers.
2. CHOLECYSTITIS AND GALLSTONES
Gallstones usually don’t cause any symptoms and typically don’t need treatment. However, if a gallstone lodges in the outlet of the gallbladder causing an obstruction, biliary colic may arise.
The typicall symptoms of biliary colic are:
- Sudden and rapidly intensifying pain in the upper right portion of the abdomen.
- This pain is sharp and radiates to the right shoulder or to the back, between the shoulder blades.
- The pain usually worsens after a fatty meal.
- Nausea or vomiting.
A prolonged obstruction can lead to inflammation of the gall bladder, known as cholecystitis, which may cause severe abdominal pain and fever.
3. ACUTE PANCREATITIS
Inflammation of the pancreas, known as acute pancreatitis, is usually caused by a gallstone obstructing the pancreatic duct or by prolonged and heavy consumption of alcohol.
The symptoms of acute pancreatitis are:
- Upper abdominal pain that radiates into the back.
- The pain usually worsens after a fatty meal or alcohol intake.
- Swollen and tender abdomen.
- Nausea and vomiting.
4. ACUTE HEPATITIS
Hepatitis refers to an inflammation of the liver. It’s often caused by a viral infection, such as hepatitis A virus (HAV), hepatitis B virus (HBV) and hepatitis C virus (HCV). It can also arise for a number of other reasons, such as autoimmune diseases, medications, drugs, toxins, and alcohol.
Acute hepatitis usually causes a persistent dull pain in the right hypochondrium, and is often accompanied by:
- Flu-like symptoms.
- Dark urine.
- Pale stool.
- Poor appetite.
- Jaundice – yellowish pigmentation of the skin and the eyes due to high bilirubin levels.
- Enlarged liver.
5. KIDNEY STONES
A kidney stone may be asymptomatic until it passes into your ureter. When the stone gets stuck in the ureter, the patient begins to feel an excruciating pain, known as renal colic. Some people who’ve experienced renal colic compare the pain to getting stabbed with a knife.
Typical renal colic symptoms are:
- Severe pain in the side and back, that radiates to the lower abdomen and groin.
- Pain that comes in waves.
- Bloody urine.
- Nausea and vomiting.
If the stone is stuck in the ureter near the bladder, the pain may be located in the hypogastric or iliac region, radiating to the scrotal sack.
Appendicitis is an inflammation of the appendix. Abdominal pain is the most common symptom and is reported in nearly all cases of appendicitis.
The pain is initially periumbilical with subsequent migration to the right lower quadrant as the inflammation progresses. Nausea and vomiting typically follow the onset of pain. Fever and abdominal tenderness can also occur.
Diverticulitis is inflammation or infection of small pouches, called diverticula, that develop along the walls of the intestines.
Abdominal pain is the most common symptom. In 70% of cases it occurs in the lower left side of the abdomen. The pain lasts for several days, and is usually accompanied by a fever.
Other common symptoms of diverticulitis include: nausea, vomiting, constipation or diarrhea.
When inflammation of a diverticulum occurs in the ascending part of the large intestine (on the right), the symptoms may be very similar to those of an appendicitis.
8. ACUTE GASTROENTERITIS
Acute gastroenteritis is defined as diarrheal disease of rapid onset that is usually accompanied by nausea, vomiting, fever, or abdominal pain. Common findings on physical examination of patients with acute gastroenteritis include diffuse abdominal tenderness.
Bacterial gastroenteritis can cause bloody diarrhea, a condition known as dysentery.
Intestinal parasites are also a frequent cause of abdominal pain, which may or may not be associated with diarrhea.
9. MENSTRUAL CRAMPS (DYSMENORRHEA)
Menstrual cramps usually starts one to two days before the onset of menstrual bleeding. The pain is usually crampy and intense, but may be a continuous dull ache. It is usually confined to the lower abdomen. Although the pain is usually strongest in the midline, some women also have severe back or thigh pain.
Symptoms such as nausea, sweating, headache, diarrhea and dizziness may be associated.
10. OTHER CAUSES
In addition to the causes described above, several others can also cause abdominal or pelvic pain, including:
- Tumors in the abdominal or pelvic organs.
- Intestinal obstruction.
- Intestinal ischemia.
- Abdominal aortic aneurysm.
- Urinary tract infection.
- Abdominal hernias.
- Diabetic ketoacidosis.
- Inflammatory bowel disease.
- Ovarian diseases.
- Ectopic pregnancy.
- Uterine leiomyomas (fibroids).
- Hepatic abscess.
- Sickle cell anemia.
- Polycystic kidney disease.
CAUSES OF ABDOMINAL PAIN ORIGINATING OUTSIDE THE ABDOMEN
Some conditions affecting organs outside the abdomen can also cause abdominal pain. These situations are often caused by atypical presentations of thoracic diseases. The most common are:
- Myocardial infarction.
- Hiatus hernia.
- Pleural effusion.
WHAT IS PERITONITIS?
The abdominal organs are not floating loosely within the abdominal cavity. They are fixed and wrapped in a vascularized and innervated membrane known as peritoneum.
Peritonitis refers to an inflammation of the peritoneum, which is often caused by bacterial infection. It is a sign of a serious illness in the abdomen. Left untreated, peritonitis can rapidly spread into the blood, resulting in multiple organ failure and death.
Since it is highly innervated, the peritoneum usually hurts a lot when it is inflamed. The symptoms of peritonitis are typically severe abdominal pain, that is worsened by any movement or abdominal examination, fever, nausea and vomiting.
Peritonitis is a potential complication of numerous diseases, such as appendicitis, diverticulitis, intestinal perforation, cholecystitis, etc. Treatment usually involves antibiotics and, in most cases, surgery.
HOW TO DIAGNOSE AN ABDOMINAL PAIN
In most cases, the evaluation of an abdominal pain begins with a physical examination, blood tests and an abdominal and pelvic ultrasound. In some cases, the doctor may also use a computerized tomography scan.
When the doctor suspects that the abdominal pain is arising from a hollow organ, such as the stomach or colon, an upper digestive endoscopy or colonoscopy are the techniques of choice for the diagnosis.