II. Epidemiology

  1. Most common Hernia type
    1. Accounts for 75% of all Hernias
    2. Accounts for 96% Groin Hernias (other 4% are femoral)
    3. Results in 600,000 Inguinal Hernia repairs annually in U.S.
  2. Bilateral in 20% of cases
  3. Gender predisposition: Male by 9 to 1 ratio
  4. Peak age: 40-59 years old
  5. Lifetime risk of Inguinal Herniation: 10%
  6. Children account for 5% of Inguinal Hernia cases
    1. See Inguinal Hernia in Children

III. Risk Factors

  1. Men
    1. Hiatal Hernia (2 fold increased Inguinal Hernia risk)
    2. Normal weight (lower risk in obese men)
  2. Women
    1. Tall height
    2. Chronic Cough
    3. Umbilical Hernia
    4. Older age

IV. Types

  1. Background: Anatomy
    1. See Hesselbach's Triangle
    2. See Inguinal Canal
  2. Indirect Inguinal Hernia (most common in men and women)
    1. Course
      1. Hernia sac passes outside Hesselbach's Triangle
      2. Herniates via Inguinal Canal
        1. Enters through Internal Inguinal Ring (Lateral to inferior epigastric artery)
        2. See Inguinal Canal for anatomic course
        3. Canal carries spermatic cord in men and round ligament in women
      3. May result in Scrotal Hernia in males
      4. More commonly on right in males (due to right Testicle migration lags the left in development)
    2. Pathophysiology
      1. Nonobliterated processus vaginalis (congenital)
      2. Internal abdominal ring weakened fascia
      3. Decreased muscular tone
      4. Increased abdominal pressure
  3. Direct Inguinal Hernia
    1. Hernia sac passes within Hesselbach's Triangle (medial inguinal fossa)
    2. Breaches posterior inguinal wall
    3. Hernia develops medial to inferior epigastric vessels
    4. Pathophysiology
      1. Usually occurs in males
      2. Congenital weakness of medial inguinal fossa musculature in some cases
      3. Acquired deficiency in transversus abdominis muscle

V. Symptoms

  1. Often asymptomatic (especially in direct Hernias)
  2. Groin Pain or (dull sensation)
    1. Intensity varies from mild to severe
    2. Burning or ache may be present
    3. Increased pain with valsalva (coughing, straining, lifting)
  3. Bulging, localized fullness or heaviness in the groin
    1. Progressively larger over time
    2. Increased with upright position and valsalva
    3. Decreased when supine

VI. Signs

  1. See Inguinal Canal Exam (for males)
  2. Palpable defect or swelling may be present
    1. Indirect Hernia may bulge at Internal Inguinal Ring
      1. Look for bulge site at mid-inguinal ligament
    2. Direct Hernia may bulge at External Inguinal Ring
      1. Look for bulge site at pubic tubercle
      2. Occurs just above inguinal ligament
      3. Seen medial and inferior to Indirect Hernia bulge
  3. Distinguishing indirect and direct Hernias difficult
    1. Experienced clinicians are incorrect in 30% of cases
    2. Indirect Inguinal Hernia palpation difficult in women
    3. Inguinal Hernias difficult to palpate in children

VII. Differential Diagnosis

  1. See Groin Pain
  2. See Scrotal Pain
  3. See Groin Swelling
  4. Athletic Pubalgia (Sports Hernia)
    1. Seen in high intensity athletes
    2. Hernia symptoms with no inguinal bulge on examination
    3. Pain reproduced with hip adduction against resistance
  5. Adductor Strain
  6. Osteitis Pubis
    1. Pain at Symphysis Pubis
  7. Testicular Torsion
    1. Especially in young males with unilateral Scrotal Pain

VIII. Imaging

  1. Indications: Imaging is not required in most cases of Inguinal Hernia
    1. Distinguish from other causes of Groin Pain (e.g. Sports Hernia, Hydrocele)
    2. Post-operative pain
  2. Modalities
    1. Inguinal Ultrasound (excellent first-line study)
    2. CT Pelvis
      1. Distinguishes inguinal from Femoral Hernias
    3. MRI Pelvis
      1. Consider in Sports Hernia evaluation

IX. Imaging: Inguinal Ultrasound

  1. Technique: Ultrasound in various patient positions
    1. Supine
    2. Upright
    3. Valsalva Maneuver
  2. Efficacy
    1. High Test Sensitivity: >90%
    2. High Test Specificity: 82-86%
      1. Distinguish Incarcerated Hernia from firm mass

X. Management

  1. Small, first, incidental or minimally symptomatic Hernia
    1. Observation is reasonable
    2. Incarceration rate in 2 years is 0.3%
    3. Fitzgibbons (2006) JAMA 295(3):285-92 +PMID:16418463 [PubMed]
  2. Large or recurrent Hernias
    1. See Herniorrhaphy
    2. Repair is recommended within one month of diagnosis

XI. Complications

  1. Incarcerated Hernia
    1. Painless entrapment of bowel (contrast with the pain and local inflammation of a Strangulated Hernia)
    2. Risk of Small Bowel Obstruction
    3. Reduced with patient lying supine in Trendelenburg position
      1. Examiner holds gentle pressure on the Herniated bulge for up to 15 minutes
      2. Stop and obtain immediate surgical Consultation for strangulation if pain before or during the procedure
  2. Strangulated Hernia
    1. Surgical emergency with vascular compromise and high risk of infarcted bowel

XII. References

  1. Degowin (1987) Diagnostic Examination, p. 489-96
  2. Goroll (2000) Primary Care Medicine, p. 431-4
  3. Stevens (2013) Crit Dec Emerg Med 27(9): 2
  4. Bax (2001) Am Fam Physician 59(4):143-56 [PubMed]
  5. LeBlanc (2013) Am Fam Physician 87(12): 844-8 [PubMed]

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Related Studies

Ontology: Hernia, Inguinal (C0019294)

Definition (NCI) The protrusion of a sac-like structure containing fibroadipose tissue through an abnormal opening in the inguinal region.
Definition (MSH) An abdominal hernia with an external bulge in the GROIN region. It can be classified by the location of herniation. Indirect inguinal hernias occur through the internal inguinal ring. Direct inguinal hernias occur through defects in the ABDOMINAL WALL (transversalis fascia) in Hesselbach's triangle. The former type is commonly seen in children and young adults; the latter in adults.
Concepts Anatomical Abnormality (T190)
MSH D006552
ICD9 550
ICD10 K40 , K40.90
SnomedCT 155738001, 196828002, 44297005, 266440002, 196827007, 266508004, 266510002, 196822001, 196800008, 155744002, 396232000
English Hernia, Inguinal, Hernias, Inguinal, Inguinal Hernia, Inguinal Hernias, HERNIA INGUINAL, Inguinal hernia NOS, Hernia Inguinal, Unspecified inguinal hernia NOS, Unspec inguinal hernia NOS, Unspecified inguinal hernia, inguinal hernia (diagnosis), abdomen hernia inguinal, inguinal hernia, inguinal hernia (physical finding), Hernia inguinal, inguinal hernia NOS, Hernia, Inguinal [Disease/Finding], inguinal hernias, Hernia;inguinal, Inguinal hernias, Inguinal herniae, Hernia - inguinal, Unspecified inguinal hernia (disorder), Unspecified inguinal hernia NOS (disorder), Inguinal hernia NOS (disorder), Inguinal hernia, IH - Inguinal hernia, Inguinal hernia (disorder), hernia; inguinal, inguinalis; hernia, Inguinal hernia, NOS
French HERNIE INGUINALE, Hernie inguinale SAI, Hernies inguinales, Hernie inguinale
Spanish HERNIA INGUINAL, Hernia inguinal NEOM, hernia inguinal no especificada (trastorno), hernia inguinal no especificada, hernia inguinal no especificada, SAI (trastorno), hernia inguinal no especificada, SAI, hernia inguinal, SAI (trastorno), hernia inguinal, SAI, Hernia Inguinal Directa, Hernia Inguinal Indirecta, hernia inguinal (trastorno), hernia inguinal, Hernia inguinal, Hernias inguinales, Hernia Inguinal
Italian Ernie inguinali, Ernia inguinale non specificata, Ernia inguinale
Dutch liesbreuk NAO, hernia; inguinalis, inguinalis; hernia, liesbreuken, liesbreuk, Hernia inguinalis, Liesbreuk
German Leistenbruch NNB, HERNIA INGUINALIS, Leistenbrueche, Hernia inguinalis, Hernie, Inguinal-, Inguinalhernie, Leistenbruch
Portuguese Hérnia inguinal NE, HERNIA INGINAL, Hérnia Inguinal Indireta, Hérnia Inguinal Direta, Hérnia inguinal, Hérnias inguinais, Hérnia Inguinal
Japanese 鼡径ヘルニアNOS, ソケイヘルニア, ソケイヘルニアNOS, 鼠径ヘルニア, 鼡径ヘルニア, ヘルニア-鼠径
Swedish Ljumskbråck
Czech tříselná kýla, Tříselná kýla NOS, Tříselná kýla, Tříselné kýly, hernie inguinální, hernia inguinalis, hernie ingvinální
Finnish Nivustyrä
Korean 샅(서혜)헤르니아
Polish Przepuklina pachwinowa
Hungarian Lágyéksérv k.m.n., Inguinalis hernia, Inguinalis sérvek, Lágyék sérv
Norwegian Brokk i lysken, Inguinalhernie, Hernia inguinalis, Inguinalbrokk, Lyskebrokk, Brokk i inguen, Brokk, inguinal

Ontology: Inguinal Hernia, Direct (C0019295)

Concepts Anatomical Abnormality (T190)
MSH D006552
ICD10 K40
SnomedCT 286968003, 196800008, 261478001, 155741005, 73147001
English Direct hernia, Direct inguinal hernia NOS, direct inguinal hernia (diagnosis), direct groin hernia, direct inguinal hernia, direct hernia, hernia direct, internal inguinal hernia, Direct inguinal hernia NOS (disorder), Direct hernia (qualifier value), Direct inguinal hernia, Internal inguinal hernia, Direct inguinal hernia (disorder), Direct Inguinal Hernias, Hernia, Direct Inguinal, Hernias, Direct Inguinal, Inguinal Hernias, Direct, Direct Inguinal Hernia, Inguinal Hernia, Direct
Dutch directe liesbreuk
German direkter Leistenbruch
Italian Ernia inguinale diretta
Portuguese Hérnia inguinal directa
Spanish Hernia inguinal directa, hernia inguinal directa, SAI (trastorno), hernia inguinal directa, SAI, Direct inguinal hernia NOS, hernia directa (calificador), hernia directa, hernia inguinal directa (trastorno), hernia inguinal directa, hernia inguinal interna
Japanese 直接鼡径ヘルニア, チョクセツソケイヘルニア
French Hernie inguinale directe
Czech Přímá tříselná kýla, hernia inguinalis directa
Hungarian Lágyéki direkt sérv
Norwegian Medialt inguinalbrokk, Medialt inguinalhernie, Direkte inguinalhernie, Hernia inginualis directa, Direkte lyskebrokk, Direkte inguinalbrokk, Medialt lyskebrokk

Ontology: Inguinal Hernia, Indirect (C0019296)

Concepts Acquired Abnormality (T020)
MSH D006552
ICD10 K40
SnomedCT 266509007, 261480007, 286969006, 196800008, 65626001
English Indirect hernia, Oblique hernia, Indirect inguinal hernia NOS, indirect inguinal hernia, indirect inguinal hernia (diagnosis), oblique inguinal hernia, hernias indirect, hernia indirect inguinal, inguinal indirect hernia, external inguinal hernia, indirect hernia, Inguinal hernia - indirect,NOS, Indirect inguinal hernia NOS (disorder), Indirect hernia (qualifier value), External inguinal hernia, Indirect inguinal hernia, Oblique inguinal hernia, Indirect inguinal hernia (disorder), Hernia, Indirect Inguinal, Hernias, Indirect Inguinal, Indirect Inguinal Hernias, Inguinal Hernias, Indirect, Indirect Inguinal Hernia, Inguinal Hernia, Indirect
Dutch indirecte liesbreuk, schuine spier liesbreuk
French Hernie inguinale oblique externe, Hernie inguinale indirecte
German Leistenbruch schiefer Bauchmuskel, indirekter Leistenbruch
Italian Ernia inguinale obliqua, Ernia inguinale indiretta
Portuguese Hérnia inguinal indirecta, Hérnia inguinal oblíqua
Spanish Hernia inguinal indirecta, Hernia inguinal oblicua, hernia inguinal indirecta, SAI, hernia indirecta, hernia indirecta (calificador), hernia inguinal indirecta, SAI (trastorno), hernia inguinal externa, hernia inguinal indirecta (trastorno), hernia inguinal indirecta, hernia inguinal oblicua
Japanese 斜鼡径ヘルニア, 間接鼡径ヘルニア, カンセツソケイヘルニア, シャソケイヘルニア
Czech Nepřímá tříselná kýla, hernia inguinalis indirecta
Hungarian Lágyéki indirekt sérv, Inguinalis ferde hernia
Norwegian Indirekte inguinalhernie, Indirekte lyskebrokk, Indirekte inguinalbrokk, Hernia ingiunalis obliqua, Lateralt inguinalbrokk, Lateralt lyskebrokk, Hernia inginualis lateralis, Hernia inginualis indirecta, Lateralt inguinalhernie

Ontology: Scrotal hernia (C0019319)

Concepts Anatomical Abnormality (T190)
ICD10 K40
SnomedCT 275439008, 196800008, 32665003
Dutch scrotumhernia
French Hernie scrotale
German Skrotalhernie
Italian Ernia dello scroto
Portuguese Hérnia escrotal
Spanish Hernia escrotal, hernia escrotal (trastorno), hernia escrotal
Japanese 陰嚢ヘルニア, インノウヘルニア
English scrotal hernia, scrotal hernia (diagnosis), abdomen hernia scrotal, scrotal hernia (physical finding), scrotum hernia, hernia scrotal, hernia scrotum, hernias scrotum, Scrotal hernia, Scrotal hernia (disorder), Scrotal Hernia
Czech Skrotální kýla
Hungarian Scrotalis hernia