Atlas of pathophysiology, 2 Edition

Part II - Disorders

Gastrointestinal Disorders

Inguinal Hernia

A hernia occurs when part of an internal organ protrudes through an abnormal opening in the wall of the cavity that surrounds it. Most hernias occur in the abdominal cavity. Although many kinds of abdominal hernias are possible, inguinal hernias (also called ruptures) are most common. Inguinal hernias may be direct or indirect. Indirect are more common; they may develop at any age, are three times more common in males, and are especially prevalent in infants.

Causes

·   Weak fascial margin of internal inguinal ring

·   Weak fascial floor of inguinal canal

·   Weak abdominal muscles (caused by congenital malformation, trauma, or aging)

·   Increased intra-abdominal pressure (due to heavy lifting, pregnancy, obesity, or straining)

Pathophysiology

In an inguinal hernia, the large or small intestine, omentum, or bladder protrudes into the inguinal canal. In an indirect hernia, abdominal viscera leave the abdomen through the inguinal ring and follow the spermatic cord (in males) or round ligament (in females); they emerge at the external ring and extend down into the inguinal canal, often into the scrotum or labia.

In a direct inguinal hernia, instead of entering the canal through the internal ring, the hernia passes through the posterior inguinal wall, protrudes directly through the transverse fascia of the canal (in an area known as Hesselbach's triangle), and comes out at the external ring.

In an infant, an inguinal hernia commonly coexists with an undescended testicle or hydrocele. In males, during the 7th month of gestation, the testicle normally descends into the scrotum, preceded by the peritoneal sac. If the sac closes improperly, it leaves an opening through which the intestine can slip.

Hernias can be reduced (if the hernia can be manipulated back into place with relative ease), incarcerated (if the hernia can't be reduced because adhesions have formed, obstructing the intestinal flow), or strangulated (part of the herniated intestine becomes twisted or edematous, seriously interfering with normal blood flow and peristalsis and, possibly, leading to intestinal obstruction and necrosis).

Signs and symptoms

Reduced or incarcerated hernia

·   Lump over the herniated area; present when the patient stands or strains; absent when the patient is in a supine position

·   Sharp, steady groin pain when tension is applied to herniated contents; fades when the hernia is reduced

Strangulated hernia

·   Severe pain

Partial bowel obstruction

·   Anorexia

·   Vomiting

·   Pain and tenderness in groin

·   Irreducible mass

·   Diminished bowel sounds

Complete bowel obstruction

·   Shock

·   High fever

·   Absent bowel sounds

·   Bloody stools

Diagnostic test results

·   X-ray confirms suspected bowel obstruction.

·   Complete blood count reveals elevated white blood cell count when bowel obstruction is present.

Clinical Tip

To detect a hernia in a male patient:

·   Ask the patient to stand with his ipsilateral leg slightly flexed and his weight resting on the other leg.

·   Insert an index finger into the lower part of the scrotum and invaginate the scrotal skin so the finger can advance through the external inguinal ring to the internal ring.

·   Tell the patient to cough. If you feel pressure against the fingertip, an indirect hernia exists; pressure felt against the side of the finger indicates that a direct hernia exists.

Treatment

Temporary measures

·   Reduction and a truss

In infants and otherwise healthy adults

·   Herniorrhaphy or hernioplasty

For incarcerated or necrotic hernia

·   Possibly, bowel resection

·   Antibiotics

·   Parenteral fluids

·   Electrolyte replacement

·   Analgesics

P.193

INDIRECT INGUINAL HERNIA

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