History and exam

Key diagnostic factors

common

groin discomfort or pain with bulge

Patients with inguinal hernia only experience groin discomfort (often described as dull, heaviness, dragging, and sometimes burning) or pain in association with a bulging hernia; groin discomfort or pain is alleviated when the hernia is not bulging.

groin mass

Visible and/or palpable mass or bulge in the groin that may or may not be reducible. Mass or bulge may be soft and pliable. It may also enlarge with standing and with Valsalva manoeuvre (forced expiration through a closed airway). An inguinal hernia lies superomedial to the pubic tubercle.

uncommon

abdominal discomfort or pain

Mid-abdominal discomfort or pain that is poorly localised and associated with an inguinal bulge, but which improves when the bulge is reduced, is indicative of small bowel on stretch in the hernia sac.

Other diagnostic factors

uncommon

acute abdomen

Tender, distended abdomen with absent bowel sounds indicates a strangulated hernia.

nausea and vomiting

If bowel obstruction present. Patients may present with dehydration and sometimes altered mental status.

constipation

If bowel obstruction present.

Risk factors

strong

male sex

Although inguinal hernia can occur in both sexes, the disorder predominantly affects men (male:female ratio is 7-9:1).[15][11]

The lifetime risk of inguinal herniation is estimated to be 27% for men and 3% for women.[15]

older age

The incidence of inguinal hernia (especially the direct type) increases with age.[12][13][14][11]  One case series carried out in Jerusalem found a lifetime prevalence rate of nearly 50% for inguinal hernia in men aged 75 years and over.[13] In a UK study of 30,000 inguinal hernia repairs, around 25% of procedures (both emergency and elective) were performed in patients aged 65 years and older.[15]

There is a progressive weakening of elastic and elastin-related fibres in the transversalis fascia of older patients.[29] In older patients, circulating proteolytic activity rises as the levels of matrix metalloproteinase inhibitors falls.

family history

There is a familial predisposition to all abdominal wall hernias, including inguinal hernia.[17][18] The mode of transmission appears to be autosomal dominant with incomplete penetrance.

Fibroblasts cultured from the skin of patients with groin hernia produce procollagen, which is rich in type III collagen and lacks the strength to support the abdominal wall enough to resist herniation.[30]

prematurity

Congenital inguinal hernias are very common among preterm babies. Up to one third of male preterm babies with birth weight less than 1500 g require a hernia operation by the age of 8 years.[31]

abdominal aortic aneurysm (AAA)

Patients with AAA are more prone to developing inguinal hernia than the general population.[32][33] Inguinal hernia is twice as common in patients with AAA compared to arteriopaths with Leriche syndrome.[34]

AAA is associated with increased leukocytosis and reduced anti-proteolytic activity.[35] Patients have a persistently elevated proteolytic activity even after repair of the aneurysm.[36] Increased proteolytic activity is a systemic response to the effects of smoking, which is a risk factor for AAA.

defective transversalis fascia

A defective transversalis fascia, which is the final barrier preventing inguinal hernia, predisposes to hernia formation.

Risk factors for defective transversalis fascia are the same as for inguinal hernia (i.e., male sex, old age, smoking, family history).

chronic bronchitis or emphysema

Chronic coughing increases intra-abdominal pressure.[37]

Marfan syndrome

Marfan syndrome is a connective tissue disorder that may predispose to hernia formation.[19][22]

Ehlers-Danlos syndrome

Ehlers-Danlos syndrome is a connective tissue disorder that may predispose to hernia formation.[20][22]

lathyrism

Lathyrism is a neurotoxic disease caused by ingestion of certain types of legumes. This disease is associated with connective tissue abnormalities and groin herniation.[21]

weak

smoking

Heavy smoking leads to a generalised defect in connective tissue turnover in the groin, which can result in inguinal hernia formation.[38] Smoking is associated with decreased alpha-1 antitrypsin activity as well as elevated serum elastolase.[38] Smoking also activates leukocytes, which in turn lead to elevated levels of zymogen proteases. Stimulated leukocytes and toxins induce peripheral collagenolysis.

Cigarette smoking has also been found to be a risk factor for recurrences after inguinal herniorrhaphy and is twice as common in patients whose repair fails.[39] Smokers have a 2-fold increase in the risk of recurrence at 2 years after groin herniorrhaphy.[40]

heavy lifting

Specific lifting episodes are the cause of an inguinal hernia in less than 10% of patients.[41] In general, heavy lifting does not predispose to hernia formation, but rather brings the patient's attention to the hernia. Lifting and straining do not cause the weakness or degeneration of the inguinal floor. Professional weightlifters do not have an excessive incidence of inguinal hernias.[41][42]

pregnancy

Stretching of the abdominal wall and increased intra-abdominal pressure caused by pregnancy can make previously undetected small indirect hernias clinically evident.[42]

ascites

Stretching of the abdominal wall and increased intra-abdominal pressure caused by ascites (e.g., from liver cirrhosis) may increase the risk of inguinal hernia.[43]

prostatectomy

Prior radical prostatectomy increases the risk of inguinal hernia.[28]

appendectomy

Possibly due to injury to transversalis fascia, as well as injury to the segmental innervation to the inguinal musculature.[44]

benign prostatic hypertrophy

Increased intra-abdominal pressure caused by benign prostatic hypertrophy may increase the risk of inguinal hernia. (More likely, it makes patients aware of a hernia already present.)

urethral stricture

Increased intra-abdominal pressure caused by urethral stricture may increase the risk of inguinal hernia. (More likely, it calls attention to a hernia already present.)

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