Abdominal sounds

Definition

Abdominal sounds are the noises made by the intestines.

Alternative Names

Considerations

Abdominal sounds (bowel sounds) are made by the movement of the intestines as they push food through. Since the intestines are hollow, bowel sounds can echo throughout the abdomen much like the sounds heard from water-pipes.

The majority of the bowel sounds are harmless and simply indicate that the gastrointestinal tract is working. A doctor can evaluate abdominal sounds by listening to the abdomen with a stethoscope (auscultation).

Although the majority of bowel sounds are normal, there are some instances in which abnormal bowel sounds provide valuable information about the health of the body.

Ileus is a condition in which there is a lack of intestinal activity. Many medical conditions may lead to ileus, but it is important to evaluate it further because gas, secretions, and intestinal contents can build up and rupture the bowel wall. The doctor may be unable to hear any bowel sounds when listening to the abdomen.

Reduced (hypoactive) bowel sounds include a reduction in the loudness, tone, or regularity of the sounds. They indicate a slowing of intestinal activity.

Hypoactive bowel sounds are normal during sleep, and also occur normally for a short time after the use of certain medications and after abdominal surgery. Decreased or absent bowel sounds often indicate constipation.

Increased (hyperactive) bowel sounds are sometimes heard even without a stethoscope. Hyperactive bowel sounds reflect an increase in intestinal activity. This can sometimes occur with diarrhea and after eating.

Abdominal sounds are always evaluated together with symptoms such as:

• Gas
• Nausea
• Presence or absence of bowel movements
• Vomiting

If bowel sounds are hypoactive or hyperactive, along with abnormal symptoms, continued evaluation by a health care provider is important.

For example, absent bowel sounds after a period of hyperactive bowel sounds are significant and can indicate a rupture of the intestines, or strangulation of the bowel and death (necrosis) of the bowel tissue.

Very high-pitched bowel sounds may indicate early bowel obstruction.

Causes

Most of the sounds you hear in your stomach and intestines are due to normal digestion and are no need for concern. Many conditions can cause hyperactive or hypoactive bowel sounds. Most are harmless and require no treatment.

The following are a list of more serious conditions that can cause abnormal bowel sounds.

Hyperactive, hypoactive, or absent bowel sounds:

• Blocked blood vessels prevent the intestines from getting proper blood flow. For example, blood clots can cause mesenteric artery occlusion.
• Mechanical bowel obstruction is caused by hernia, tumor, adhesions, or similar conditions that can block the intestines.
• Paralytic ileus is a problem with the nerves to the intestines. Reduced nerve activity can result from:
  • Blood vessel obstruction
  • Bowel obstruction
  • Chemical imbalances such as hypokalemia
  • Infection
  • Overexpansion of the bowel
  • Trauma

Other causes of hypoactive bowel sounds:

• Drugs that reduce intestinal movements such as opiates (including codeine), anticholinergics, and phenothiazines
• General anesthesia
• Radiation to the abdomen
• Spinal anesthesia
• Surgery in the abdomen

Other causes of hyperactive bowel sounds:

• Crohn's disease
• Diarrhea
• Food allergy
• GI bleeding
• Infectious enteritis
• Ulcerative colitis

References