AUTHOR AND EDITOR INFORMATION

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

In 1804, Astley Cooper stated,

A hernia is defined as a protrusion of any viscus from its proper cavity. The protruded parts are generally contained in a sac-like structure, formed by the membrane with which the cavity is naturally lined.

Several different types of abdominal wall hernias exist, along with a larger number of associated eponyms. This article reviews the pathophysiology, evaluation, and treatment of most of these hernias from an emergency medicine perspective. Hernias are brought to the attention of an emergency physician either during a routine physical examination or when the patient has developed a complication associated with the hernia.

Pathophysiology

Indirect hernia

An indirect inguinal hernia follows the tract through the inguinal canal. This results from a persistent process vaginalis.

The canal begins in the intra-abdominal cavity at the internal inguinal ring, located approximately midway between the pubic symphysis and the anterior iliac spine. The canal courses down along the inguinal ligament to the external ring, located medial to the inferior epigastric arteries, subcutaneously and slightly above the pubic tubercle. Contents of this hernia then follow the tract of the testicle down into the scrotal sac.

Direct hernia

A direct inguinal hernia usually occurs due to a defect or weakness in the transversalis fascia area of the Hesselbach triangle. The triangle is defined inferiorly by the inguinal ligament, laterally by the inferior epigastric arteries, and medially by the conjoined tendon.

Femoral hernia

The femoral hernia follows the tract below the inguinal ligament through the femoral canal. The canal lies medial to the femoral vein and lateral to the lacunar (Gimbernat) ligament.

Because femoral hernias protrude through such a small defined space, they frequently become incarcerated or strangulated.

Umbilical hernia

The umbilical hernia occurs through the umbilical fibromuscular ring, which usually obliterates by 2 years of age.

Umbilical hernias are congenital in origin and are repaired if they persist in children older than 2-4 years.

Richter hernia

The Richter hernia occurs when only the antimesenteric border of the bowel herniates through the fascial defect.

A Richter hernia involves only a portion of the circumference of the bowel. As such, the bowel may not be obstructed, even if the hernia is incarcerated or strangulated, and the patient may not present with vomiting. Richter hernia can occur with any of the various abdominal hernias and is particularly dangerous, as a portion of strangulated bowel may be reduced unknowingly into the abdominal cavity, leading to perforation and peritonitis.

Incisional hernia

This iatrogenic hernia occurs in 2-10% of all abdominal operations secondary to breakdown of the fascial closure of prior surgery. Even after repair, recurrence rates approach 20-45%.

Spigelian hernia

This rare form of abdominal wall hernia occurs through a defect in the spigelian fascia, which is defined by the lateral edge of the rectus muscle at the semilunar line (costal arch to the pubic tubercle).

Obturator hernia

This hernia passes through the obturator foramen, following the path of the obturator nerves and muscles. Obturator hernias occur with a female-to-male ratio of 6:1, because of a gender-specific larger canal diameter. Because of its anatomic position, this hernia presents more commonly as a bowel obstruction than as a protrusion of bowel contents.

Reducible hernia

This term refers to the ability to return the contents of the hernia into the abdominal cavity, either spontaneously or manually.

Incarcerated hernia

An incarcerated hernia is no longer reducible. The vascular supply of the bowel is not compromised. Bowel obstruction is common.

Strangulated hernia

A strangulated hernia occurs when the vascular supply of the bowel is compromised secondary to incarceration of hernia contents.

Frequency

United States

• Approximately 700,000 herniorrhaphies are performed in the United States each year.
• Approximately 25% of males and 2% of females have inguinal hernias in their lifetimes; this is the most common hernia in males and females.
• Approximately 75% of all hernias occur in the groin; two thirds of these hernias are indirect and one third direct.
• Indirect inguinal hernias are the most common hernias in both men and women; a right-sided predominance exists.
• Incisional and ventral hernias account for 10% of all hernias.
• Only 3% of hernias are femoral hernias.
• Between 10% and 30% of children have an abdominal wall hernia; most hernias of this type close spontaneously by age 1 year.
• The incidence of incarcerated or strangulated hernias in pediatric patients is 10-20%; 50% of these occur in infants younger than 6 months.

International

• Data from developing countries is limited; therefore, an accurate occurrence value is unavailable. Gender and anatomic distribution are believed to be similar.

Mortality/Morbidity

Morbidity is secondary to missing the diagnosis of the hernia or complications associated with management of the disease.

• A hernia can lead to an incarcerated and often obstructed bowel.
• The hernia also can lead to strangulated bowel with a compromised blood supply. Reduced strangulated bowel leads to persistent ischemia/necrosis with no clinical improvement.
• Ensuing surgery to repair the hernia or its complications may leave the patient at risk for future hernias or intra-abdominal adhesions.

Race

• Umbilical hernias occur 8 times more frequently in black infants than in white infants.

Sex

• Approximately 90% of all inguinal hernia repairs are performed on males.
• Reduction of hernias in females may be complicated by inclusion of the ovary in the hernia.
• Femoral hernias (although rare) occur almost exclusively in women because of the differences in the pelvic anatomy.
• The female-to-male ratio of obturator hernias is 6:1.

Age

• Indirect hernias usually present during the first year of life, but they may not appear until middle or old age.
• Direct hernias occur in older patients as a result of relaxation of abdominal wall musculature and thinning of the fascia.
• Umbilical hernias usually occur in infants and reach their maximal size by the first month of life. Most hernias of this type close spontaneously by the first year of life, with only a 2-10% incidence in children older than 1 year.

CLINICAL

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History

Patients with hernias present to the emergency department (ED) secondary to a complication associated with the hernia. Hernias also may be detected in the ED on routine physical examination. However, in relation to the chief complaint, the following issues must be considered:

• Asymptomatic hernia
• • Presents as a swelling or fullness at the hernia site
  • Aching sensation (radiates into the area of the hernia)
  • No true pain or tenderness upon examination
  • Enlarges with increasing intra-abdominal pressure and/or standing
• Incarcerated hernia
• • Painful enlargement of a previous hernia or defect
  • Cannot be manipulated (either spontaneously or manually) through the fascial defect
  • Nausea, vomiting, and symptoms of bowel obstruction (possible)
• Strangulated hernia
• • Symptoms of an incarcerated hernia present combined with a toxic appearance.
  • Systemic toxicity secondary to ischemic bowel is possible.
  • Strangulation is probable if pain and tenderness of an incarcerated hernia persist after reduction.
  • Suspect an alternative diagnosis in patients who have a substantial amount of pain without evidence of incarceration or strangulation.
• Femoral hernia: Medial thigh pain as well as groin pain are possible because of the position of this hernia.
• Obturator hernia
• • Because this hernia is hidden within deeper structures, it may not present as a swelling.
  • The patient may complain of abdominal pain or medial thigh pain, weight loss, or recurrent episodes of bowel or partial bowel obstruction.
  • Pressure on the obturator nerve causes pain in the medial thigh that is relieved by thigh flexion. This same pain may be exacerbated by extension or external rotation of the hip (Howship-Romberg sign).
• Incisional hernia
• • As these are usually asymptomatic, patients present with a bulge at the site of a previous incision.
  • Lesion may become larger upon standing or with increasing intra-abdominal pressure.

Physical

In general, the physical examination should be performed with the patient in both the supine and standing positions, with and without the Valsalva maneuver. The examiner should attempt to identify the hernia sac as well as the fascial defect through which it is protruding. This allows proper direction of pressure for reduction of hernia contents. The examiner should also identify evidence of obstruction and strangulation.

• When attempting to identify a hernia, look for a swelling or mass in the area of the fascial defect.
• • Place a fingertip into the scrotal sac and advance up into the inguinal canal. If the hernia is elsewhere on the abdomen, attempt to define the borders of the fascial defect.
  • If the hernia comes from superolateral to inferomedial and strikes the distal tip of the finger, it most likely is an indirect hernia.
  • If the hernia strikes the pad of the finger from deep to superficial, it is more consistent with a direct hernia.
• A bulge felt below the inguinal ligament is consistent with a femoral hernia.
• Strangulated hernias are differentiated from incarcerated hernias by the following:
• • Pain out of proportion to examination findings
  • Fever or toxic appearance
  • Pain that persists after reduction of hernia

Causes

Any condition that increases the pressure in the intra-abdominal cavity may contribute to the formation of a hernia, including the following:

• Marked obesity
• Heavy lifting
• Coughing
• Straining with defecation or urination
• Ascites
• Peritoneal dialysis
• Ventriculoperitoneal shunt
• Chronic obstructive pulmonary disease (COPD)
• Family history of hernias

DIFFERENTIALS

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Other Problems to be Considered

Groin abscess
Hematoma
Lipoma
Lymphadenitis
Pseudoaneurysm
Spermatocele
Tumor
Undescended or retracted testes
Varicocele

WORKUP

Section 5 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• Complete blood count
• • Test is nonspecific.
  • Leukocytosis with left shift may occur with strangulation.
• Electrolytes, BUN, creatinine levels
• • Assess the hydration of the patient with nausea and vomiting.
  • These tests are rarely needed except as part of a preoperative workup.
• Urinalysis: This test assists with narrowing the differential diagnosis of genitourinary causes of groin pain.

Imaging Studies

• Imaging studies are not required in the normal workup of a hernia.
• Ultrasonography can be used in differentiating masses in the groin or abdominal wall or in differentiating testicular sources of swelling.
• If an incarcerated or strangulated hernia is suspected, the following imaging studies can be performed:
• • Upright chest radiograph to exclude free air (extremely rare)
  • Flat and upright abdominal films to diagnose a small bowel obstruction (neither sensitive or specific) or to identify areas of bowel outside the abdominal cavity
• CT scanning or ultrasonography may be necessary in the following cases:
  • To diagnose a spigelian or obturator hernia
  • Inability to obtain a good examination because of body habitus

TREATMENT

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Emergency Department Care

• Reduction of a hernia
• • Provide adequate sedation and analgesia to prevent straining or pain. The patient should be relaxed enough to not increase intra-abdominal pressure or to tighten the involved musculature.
  • Place the patient supine with a pillow under his or her knees.
  • Place the patient in a Trendelenburg position of approximately 15-20° for inguinal hernias.
  • Apply a padded cold pack to the area to reduce swelling and blood flow while establishing appropriate analgesia.
  • Place the ipsilateral leg in an externally rotated and flexed position resembling a unilateral frog leg position.
  • Place 2 fingers at the edge of the hernial ring to prevent the hernial sac from riding over the ring during reduction attempts.
  • Firm, steady pressure should be applied to the side of the hernia contents close to the hernia opening, guiding it back through the defect.
  • Applying pressure at the apex, or first point, that is felt may cause the herniated bowel to "mushroom" out over the hernia opening instead of advancing through it.
  • Consult with a surgeon if reduction is unsuccessful after 1 or 2 attempts; do not use repeated forceful attempts.
  • The spontaneous reduction technique requires adequate sedation/analgesia, Trendelenburg positioning, and padded cold packs applied to the hernia for a duration of 20-30 minutes. This can be attempted prior to manual reduction attempts.

Consultations

Consult a surgeon for the following reasons:

• Inability to reduce the hernia
• Concern for a strangulated bowel and a patient with a toxic appearance
• Patients with comorbid risks for sedation should have a surgeon present for the initial reduction attempt.

MEDICATION

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For strangulated hernias, start broad-spectrum antibiotics. Antibiotics are administered routinely if ischemic bowel is suspected.

Drug Category: Antibiotics

These agents are to be used if the patient has a strangulated hernia.

FOLLOW-UP

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Further Inpatient Care

• All incarcerated or strangulated hernias demand admission and immediate surgical evaluation.

Further Outpatient Care

• Schedule a follow-up visit with the general surgeon within the next 1-2 weeks for those patients with easily reducible hernias or with hernias found upon physical examination.
• Discharge patients with umbilical hernias with close follow-up care if the defect is less than 2 cm in diameter and the hernia is not incarcerated or strangulated.
• Educate patients to avoid those activities that increase intra-abdominal pressure.
• Educate patients to return for increased pain, inability to reduce hernia, fever, and vomiting.

Deterrence/Prevention

• Counsel the patient on avoidance of activities that increase intra-abdominal pressure, such as straining at defecation or lifting heavy objects.

Complications

• If strangulation of the hernia is missed, bowel perforation and peritonitis can occur.
• Hernias can reappear in the same location, even after surgical repair.

Prognosis

• The prognosis depends on the type and size of hernia as well as on the ability to reduce risk factors associated with the development of hernias.
• The prognosis is good with timely diagnosis and repair.

Patient Education

• Counsel the patient to avoid those activities that increase intra-abdominal pressure, such as straining at defecation and lifting heavy objects.
• Instruct the patient to apply support to the hernia.
• Even with asymptomatic hernias, early repair (ie, before it enlarges) is preferred.

MISCELLANEOUS

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• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Failure to consider the diagnosis of hernia in patients who present with nausea and/or vomiting
• Diagnosing testicular torsion as a hernia (puts the testicle at risk)
• Reducing a strangulated bowel without recognizing it (The hernia will be reduced, but the bowel will remain ischemic.)

Special Concerns

• Pain after reduction of a hernia may indicate a strangulated hernia, requiring further evaluation by a surgeon.

MULTIMEDIA

Section 10 of 11  

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• Workup
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• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Anatomic locations for various hernias
	View Full Size Image
Media type:  Image

REFERENCES

Section 11 of 11

• Authors and Editors
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• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

• Bobrow RS. The hernia. J Am Board Fam Pract. Jan-Feb 1999;12(1):95-6. [Medline].
• Eubanks S. Hernias. In: Sabiston DC Jr, ed. Textbook of Surgery: The Biological Basis of Modern Surgical Practice. 1997. [Medline].
• Ginsburg BY, Sharma AN. Spontaneous rupture of an umbilical hernia with evisceration. J Emerg Med. Feb 2006;30(2):155-7. [Medline].
• Kapur P, Caty MG, Glick PL. Pediatric hernias and hydroceles. Pediatr Clin North Am. Aug 1998;45(4):773-89. [Medline].
• Levine BJ, Nabha S, Bouzoukis JK. Chronic inguinal hernia. J Emerg Med. May-Jun 1999;17(3):515-6. [Medline].
• Manthey, DE. Abdominal hernia reduction. In: Clinical Procedures in Emergency Medicine. 2003.
• Mensching JJ, Musielewicz AJ. Abdominal wall hernias. Emerg Med Clin North Am. Nov 1996;14(4):739-56. [Medline].
• Rutkow IM, Robbins AW. Demographic, classificatory, and socioeconomic aspects of hernia repair in the United States. Surg Clin North Am. Jun 1993;73(3):413-26. [Medline].
• Scherer LR 3d, Grosfeld JL. Inguinal hernia and umbilical anomalies. Pediatr Clin North Am. Dec 1993;40(6):1121-31. [Medline].
• Wants GE. Abdominal wall hernias. In: Schwartz SI, Shires GT, Spencer FC, eds. Principles of Surgery. 6th ed. 1994. [Medline].

Article Last Updated: Jan 3, 2007