An inguinal hernia is the most common form of hernia.
Presentation
Inguinal hernia presents as a bulge in the groin or the inguinal region or in the scrotum. This bulge becomes appreciable while coughing, straining or standing; meaning it is not constant but is variable depending on the intra-abdominal pressure. Most times the bulge disappears on lying down and is rarely painful.
An asymptomatic hernia presents as a swelling in the inguinal region with a sense of aching. There is no actual pain or tenderness when examined and it is seen that the swelling increases with the increase in abdominal pressure. These are the usual characteristics of an asymptomatic inguinal hernia [10]. If the hernia does not reduce or cannot be manipulated into the abdomen via the fascial defect, then it could be an incarcerated hernia. It is often associated with nausea, vomiting and may have symptoms of blocked bowels.
When the blood supply to a part of intestines entangled in the hernia are obstructed, then it is termed as strangulated hernia. In such cases the patient presents with the symptoms of incarcerated hernia accompanied with toxic appearance as a result of toxicity caused due to gut ischemia. The patient might present with nausea/vomiting, fever and chills since a bacterial infection might supervene on the ischemic bowels of a strangulated hernia.
In infants, the lone symptom could be increased irritability, whereas in older children and adults it is presented by dull aching or burning pain that is aggravated by straining or exercise.
Workup
The diagnosis is generally made by a thorough physical examination. Usually, laboratory studies are not specific for hernia but some of them can be useful as follows:
- Complete blood count: Results aren’t specific, but leukocytosis with left shift can be seen in case of strangulation.
- Electrolytes, blood urea nitrogen levels (BUN), and creatinine levels must be assessed. In case of patients presenting with nausea and vomiting, it is mandatory to determine their hydration status and these tests are a prerequisite for operating hernia.
- Urinalysis: It helps in ruling out any other genitourinary cause leading to groin pain along with hernia.
- Lactate levels: Raised levels can be due to hypoperfusion but normal levels do not rule out strangulation.
Imaging studies
- Radiography: Chest radiograph taken when the patient is standing straight helps to rule out free air under the diaphragm.
- Flat and upright abdominal radiographs help in diagnosing a small bowel obstruction or to know the portion of bowel that is outside the abdominal cavity. Both these radiographs are helpful in cases of suspicious incarcerated or strangulated hernias.
- CT scan: CT scan of abdomen and pelvis along with oral and intravenous contrast helps in detecting various hernias that are otherwise difficult to diagnose by displaying extracoelomic position of the bowel, bladder or internal reproductive organs [11].
- Ultrasonography: It helps in restricting the differential diagnoses for scrotal masses as well as those beneath the inguinal ligament. It also helps in deciding whether to drain or aspirate a nodal abscess if present.
These imaging studies become necessary when the patient’s body habitus prevents physical examination.
Treatment
Conservative
A hernia truss helps in keeping the reducible inguinal hernia in the abdomen. It does not cure the condition but if the pads are hard and invade the hernial opening they can lead to scarring and widening of the hole. Due to the pressure, the trusses can cause injury to the skin or bowel and conceal the signs of an incarcerated and strangulated hernia. The truss also increases the chances of complications like strangulation, degeneration of the spermatic cord and the fascial margins. It might lead to enlargement of the defect thereby making the repair tough [12].
Herniorrhaphy: In this procedure, an incision is made in the groin region to push the protruding intestine back into the abdomen. Then the weakened or damaged muscle is sewed or strengthened and supported with the help of a synthetic mesh.
Laparoscopic hernioplasty: This is a less invasive procedure where the operation is done via many tiny incisions on the abdomen. This procedure causes minimal discomfort and scarring. It helps the patient to recover faster. It is a good option for those who suffer from recurrence of the hernia after the traditional hernia surgery as the surgeon can bypass the scar tissue formed due to the prior repair. It is a better option for bilateral inguinal hernia.
Prognosis
Hernia surgery is quite safe and effective. It has a good prognosis but depending on the site, size, and technique used, few hernias can recur over a period of time.
Once open surgery is done, the patient can get back to routine activities in a week or two, whereas in case of laparoscopic surgery the recovery is faster. After the surgery, patient should keep away from heavy lifting for few weeks so that the muscle and tissues can recover completely.
Etiology
Indirect hernia is a congenital hernia irrespective of the patient’s age.
Direct inguinal hernias occur due to increased pressure within the abdomen, aging, stress or strain weakening the abdominal muscles around the inguinal canal, exertion during bowel movements, heavy lifting, obesity, pregnancy, chronic coughing and sneezing, prior surgeries over lower abdomen that may weaken abdominal muscles.
Epidemiology
Around 10% of the population develops some form of hernia during their life [1]. From about 1 million abdominal hernia repairs, 770,000 cases are of inguinal hernia repair [2] [3] [4]. A lifetime risk of developing inguinal hernia is more in men i.e. 27% whereas in women is just 3% [5].
Of all the inguinal hernias 50% are indirect whereas 25% are direct [6]. Indirect inguinal hernias are common in premature babies especially those that are born before 32 weeks of gestation [3], whereas direct hernias are seen in older patients due to relaxation of the abdominal wall muscles and thinning of the fascia.
Pathophysiology
Inguinal hernias are divided into two types - direct and indirect.
Direct: This type of hernia generally occurs due to a fault or weakness in the transversalis fascia region of the Hesselbach triangle in the abdomen. This triangle is formed by the inguinal ligament at the base, inferior epigastric arteries on the lateral side and the conjoint tendon medially [7].
Indirect: The indirect inguinal hernia pursues the tract via the inguinal canal. It is the outcome of a persistent processus vaginalis. Origin of the inguinal canal is within the abdominal cavity, at the opening of the internal inguinal ring, which is nearly midway between the symphysis pubis and the anterior superior iliac spine (ASIS). From here it goes down together with the inguinal ligament to the external inguinal ring present on the medial side of inferior epigastric arteries. The contents of hernia go downwards into the scrotal sac through the passage of the testicle [6] [8] [9].
Prevention
Rarely inguinal hernias can be prevented, particularly in younger patients. In adults it might be prevented from occurring or recurring by taking following precautions:
- Maintain healthy weight: Overweight causes an increase in the abdominal pressure and thereby increases the risk of developing inguinal hernia. Follow proper diet and exercise regimen to maintain healthy weight. Avoid sudden weight loss by dieting as it leads to weakness of the abdominal muscles due to lack of protein and vitamin intake.
- Quit smoking: Smoking leads to chronic coughing and hence increases the chances of developing hernia.
- Have high fiber diet: This helps in preventing constipation and hence avoids straining while emptying the bowels. Straining for bowels increases the intra-abdominal pressure.
- Take care while lifting heavy weights. While lifting weights bend your knees not the waist.
- Do not depend on a truss: It helps in keeping the hernia in place but does not cure the situation. It can be used for a short time, till you decide about the surgery.
Summary
Inguinal hernia is defined as out-pocketing of the contents of the abdominal cavity through the inguinal canal. This protrusion results into a bulge that can be painful especially when one bends over, coughs or lifts heavy objects.
Inguinal hernias can be classified into direct and indirect inguinal hernia depending on the cause of hernia.
Patient Information
Inguinal hernia is a condition that occurs when the contents of abdomen protrude into the inguinal region of the lower abdomen due to a defect or weakness in the abdominal wall.
Birth defects in the abdominal wall cause direct inguinal hernias while aging and stress or strain that weaken the abdominal muscles leads to indirect inguinal hernia. Both these hernias can be repaired by surgical procedures. If the hernias are left untreated, they may lead to strangulation which is a surgical emergency.
Although hernias are difficult to avoid, but various lifestyle changes like maintaining healthy weight, avoiding crash dieting, high fibre diet, avoid smoking etc can help in recurrence. Wearing truss can help keeping the hernia within the abdomen, but it is not the cure. It gives temporary relief from the symptoms and provides greater confidence while performing any physically demanding activities. Just use them for a short time before surgery.
References
- Ruhl CE, Everhart JE. Risk factors for inguinal hernia among adults in the US population. Am J Epidemiol. 2007 May 15;165(10):1154-61.
- Fitch MT, Manthey DE. Abdominal hernia reduction. In: Roberts JR, Hedges JR. (Eds.) Clinical Procedures in Emergency Medicine. 6th Ed. Philadelphia, WB Saunders, 2014, pp 877- 79.
- Brandt ML. Pediatric hernias. Surg Clin North Am. 2008 Feb;88(1):27-43, vii-viii.
- Rutkow IM, Robbins AW. Demographic, classificatory, and socioeconomic aspects of hernia repair in the United States. Surg Clin North Am. 1993 Jun;73(3):413-26.
- Jenkins JT, O'Dwyer PJ. Inguinal hernias. BMJ. 2008 Feb 2; 336 (7638): 269–272.
- Katz DA. Evaluation and management of inguinal and umbilical hernias. Pediatr Ann. 2001 Dec;30(12):729-35.
- Scherer LR 3rd, Grosfeld JL. Inguinal hernia and umbilical anomalies. Pediatr Clin North Am. 1993 Dec;40(6):1121-31.
- Levine BJ, Nabha S, Bouzoukis JK. Chronic inguinal hernia. J Emerg Med. 1999 May-Jun ;17(3):515-6.
- Matthews RD, Neumayer L. Inguinal hernia in the 21st century: an evidence-based review. Curr Probl Surg. 2008 Apr;45(4):261-312.
- Mizrahi H, Parker MC. Management of asymptomatic inguinal hernia: a systematic review of the evidence. Arch Surg. 2012 Mar;147(3):277-81.
- Toms AP, Dixon AK, Murphy JM, Jamieson NV. Illustrated review of new imaging techniques in the diagnosis of abdominal wall hernias. Br J Surg. 1999 Oct;86(10):1243-9.
- Purkayastha S, Chow A, Athanasiou T, Tekkis P, Darzi A. Inguinal hernia. Clin Evid (Online) 2008 Jul 16;2008 pii: 0412.