Most inguinal hernias can be safely managed in the ED – but beware the zebras that require emergency surgery.
Figure 1: Right-sided swelling over the inguinal canal
A 63-year-old female presented with four days of progressive swelling over her right inguinal area. While initially painless, the patient developed significant discomfort in the days preceding her presentation to the emergency department. She denied fevers, chills, vaginal bleeding, history of vaginal discharge/STDs or urinary symptoms. She was eating and moving her bowels without difficulty. On arrival to the ED, the patient appeared uncomfortable, but was non-toxic and had normal vital signs. Physical exam revealed a 6 cm x 4 cm x 1 cm fullness to the patient’s right inguinal canal. The area was exquisitely tender to touch, but was not red or warm. A bedside ultrasound and computed tomography (CT) were used to confirm the diagnosis.
What's the Diagnosis?
Amyand’s hernia with acute appendicitis.
Presence of the appendix in an inguinal hernia sac is known as Amyand’s hernia. Acute appendicitis inside a hernia sac is a rare clinical entity representing approximately 0.08% of all cases of appendicitis . A retrospective review of 18 patients with Amyand’s hernia found that painful inguinal swelling was the presenting symptom in 83% of patients . In this series, all patients were taken to the operating room with a presumptive diagnosis of incarcerated or strangulated inguinal hernia, and four patients had evidence of appendiceal inflammation and underwent appendectomy. Although the diagnosis of Amyand’s hernia is a zebra, the management of inguinal hernias is bread and butter emergency medicine.
Definition and Classification
Hernias are caused when structures such as muscle, fat or intestines push through the tissues that normally contain them. Hernias are classified as external or internal. External hernias protrude through the abdominal wall and internal hernias push through an internal tissue within a body cavity. Our discussion will focus on the recognition and management of inguinal hernias.
Hernias occur in roughly 5% of the general population and approximately three-fourths of hernias occur in the inguinal region . The inguinal canal is located just superior to the inguinal ligament, between the internal and external inguinal rings.
This canal allows for the passage of the spermatic cord and testicular vasculature from the abdomen into the scrotum. Indirect inguinal hernias are due to a patent processus vaginalis, an embryologic remnant, and pass from the abdomen through the internal inguinal ring, and into the inguinal canal.
In contrast, a direct inguinal hernia is due to a weakness, or a defect, in the transversalis fascia of the abdominal wall. In a direct inguinal hernia, intra-abdominal contents herniate through this fascial defect, instead of through the inguinal canal. Direct inguinal hernias are often due to increased intra-abdominal pressure from heavy lifting or intra-abdominal fluid (i.e. ascites, peritoneal dialysis, etc.) .
Both subsets of inguinal hernias are external hernias, and therefore can often be diagnosed based on clinical examination. Direct inguinal hernias can be recognized by a protrusion or tenderness over the lower abdominal wall superior to the inguinal ligament and medial to the inferior epigastric artery. In contrast, indirect inguinal hernias can be palpated when the examiner inserts a finger into the inguinal canal (through the external ring) during a Vasalva maneuver. Indirect hernias may also be visible in the scrotum if they exit the external inguinal ring. Clinical recognition of both direct and indirect inguinal hernias may be difficult in obese patients, or in patients with small hernia sacs.
Ultrasound is a useful imaging modality when the clinical diagnosis of an inguinal hernia is unclear, with a recent meta-analysis showing ultrasound had a 97% sensitivity and 85% specificity for this diagnosis . The advantages of ultrasound include its increasing availability to most EDs along with its low cost and lack of radiation exposure.
Computed tomography (CT) is an alternative imaging modality when the clinical diagnosis of an inguinal hernia is uncertain in ED patients with lower abdominal pain or swelling. While many inguinal hernias are clinically apparent without any imaging, smaller hernia sacs may be difficult to diagnose with physical exam or ultrasound. Therefore, CT should be considered when there is a clinical suspicion of an inguinal hernia that cannot be confirmed on exam or bedside ultrasound.
The advantages of CT include a better delineation of the anatomic site of the hernia sac and superior resolution of the contents of the hernia (i.e. omentum, bowel, appendix, etc.). Several small studies have examined the utility of CT in the diagnosis of abdominal wall and inguinal hernias. Sensitivities of CT range from 60-83%, while the specificity of CT approaches 100% [5,6].
Figure 2: Bedside ultrasound of the right groin. Axial ultrasound image through the affected area of the right groin, which did not show an obvious abscess or drainable fluid collection.
Management of Reducible Hernias
Unless there is a strong suspicion of a strangulated hernia (discussed below) most patients can have their inguinal hernias successfully reduced in the emergency department. As hernia manipulation can be quite painful, pain meds should be administered prior to manual reduction. If the patient still appears obviously uncomfortable the use of conscious sedation should be strongly considered.
Patients with inguinal hernias should be placed in a Trendelenburg position (supine with the head 20 degrees downward) so that gravity aids in pulling contents of the hernia sac back into the abdominal cavity. The patient should be left in this position for 10 to 20 minutes, as many hernias will spontaneously reduce with this maneuver alone .
If positioning alone is unsuccessful, locate the defect in the abdominal wall and with slow and steady pressure gently push the most proximal contents of the hernia sac through this defect . ￼If initial reduction is unsuccessful, fight the temptation to make repeated attempts as this may increase swelling. Instead, if at first you don’t succeed . . . consult surgery.
Figure 3: Computed tomography image of the abdomen and pelvis. Single-slice coronal CT image showing direct herniation of the appendix through the inguinal canal with appendiceal thickening and inflammation consistent with appendicitis.
Management of Incarcerated and Strangulated Hernias
If reduction is unsuccessful, the hernia is by definition incarcerated (it cannot be reduced to its original position). A true incarcerated hernia may present like a bowel obstruction with vomiting, decreased gas, hyperactive bowel sounds and abdominal pain. As swelling in the incarcerated hernia progresses, the vascular supply becomes compromised resulting in ischemic tissue and a strangulated hernia.
This is a true surgical emergency as ischemic bowel can become gangrenous in as little as five hours  In one study, bowel resection was required in 12% of patients, and patients with incarcerated or strangulated hernias had an overall mortality of 3% .
Incarcerated and strangulated hernias are associated with significant morbidity and mortality, underscoring the need for appropriate and prompt ED management. Emergency department management includes prompt surgical consultation, intravenous fluid resuscitation, analgesia, consideration of parenteral antibiotics for cases of suspected viscous perforation, and prompt transfer to an operating room.
Drs. Easter and Ruygrok are PGY-3 residents at the Denver Health Residency in Emergency Medicine. Dr. Breyer is an Associate Program Director at Denver Health.
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