groin pain

introduction

there are a multitude of causes of groin pain
the ED clinician needs to systematically exclude the more serious causes such as abdominal aortic aneurysm (AAA), strangulated groin herniae +/- bowel obstruction, and acute scrotal pain or swelling such as torsion testes
the patient with a past history of renal colic who presents with flank pain radiating to the groin is most likely to have renal colic again
the elderly patient with no obvious groin or hip pathology should have a abdominal aortic aneurysm (AAA) excluded with US or CT scan.
finally, don't forget to check the legs for major arterial or venous thrombosis

aetiology

groin herniae
lymphadenopathy
local abscess
referred pain from the abdomen:
neuropathic pain +/- numbness:
- high lumbar disc prolapse - radicular pain
- ilioinguinal nerve neuropraxia
  - T12/L1 nerve
  - emerges near the lateral border of the psoas major muscle
  - goes inferior through the anterior abdominal wall, being sub-peritoneal and anterior to the quadratus lumborum muscle until it reaches the iliac crest
  - goes through the transverse abdominis and the internal oblique muscles
  - becomes superficial by passing through the superficial inguinal ring anterior to the spermatic cord
  - supplies:
    - transverse abdominis and the internal oblique muscles
    - sensation from the anterior surface of the scrotum and root of the penis in males or labia majora and mons pubis in females, and a small area of the upper anteromedial thigh
  - patients suffering from ilioinguinal neuralgia will often be forced into a bent-over position to alleviate some of the pain
  - some patients may have referred pain causing bladder pain, dyspareunia and nocturia
  - aetiology of damage:
    - surgical trauma - inguinal hernia repair, appendicectomy, laparoscopy, etc
    - iatrogenic - femoral catheterisation
    - trauma - blunt or lower external oblique aponeurosis disruption (hockey players)
    - stretch during pregnancy
    - idiopathic entrapments - paravertebral area; iliac crest; rectus border; inguinal;
- iliohypogastric nerve neuropraxia
  - L1 nerve starts its course on the posterior abdominal wall, emerging from the upper border of the psoas major muscle then crosses obliquely to the anterior abdominal wall, running between the anterior abdominal muscles
  - passes through external oblique
  - supplies:
    - transversus abdominis, internal abdominal oblique, conjoint tendon.
    - sensation inguinal / suprapubic region and posterolateral aspect of gluteal region
- genital branch of genitofemoral nerve neuropraxia
- meralgia paresthetica - lateral cutaneous nerve of the thigh
- herpes zoster (shingles) - dermatomal
hip pain - pain on int/ext rotation of hip joint
extensive DVT
groin injuries:
- impact injuries
  - fracture pelvis
  - exacerbate pre-existing inguinal herniae
  - bladder, testicular or urethral straddle injuries
  - hip pointer
    - a contusion to the iliac crest, the surrounding soft-tissue structures, or the greater trochanter of the femur
  - meralgia paresthetica
- hip hyperextension injury
  - strain or avulsion of the sartorius muscle from the ASIS
- groin strain
  - generally involve either the iliopsoas muscle, the adductor group, or the gracilis muscle
  - pain usually radiates down medial aspect of thigh
  - may result from falling, running, quickly changing directions, as well as kicking or doing the splits (and may be strained during coitus with excessive abduction)
- osteitis pubis / gracilis syndrome
  - a chronic injury that causes radiologically evident resorption of the bone or cartilage of the pubic symphysis due to childbirth, pregnancy (relaxin effect), trauma or repetitive stress from kicking, lifting, running, or jumping
  - may cause:
    - loss of flexibility in the groin region, dull aching pain in the groin
    - a sharp stabbing pain when running, kicking, changing directions, or when standing up or getting out of a car
- rectus abdominis strain
  - fairly common in skaters, hockey players, and swimmers (especially breaststrokers)
- sportsman's “hernia” / Gilmore groin
  - characterized by chronic groin pain that is associated with a dilated superficial inguinal ring
  - controversial syndrome, the definition, therefore, is any condition that causes persistent unilateral pain in the groin without a demonstrable hernia
  - pain is located near the pubic tubercle, maximal on the evening of vigorous exercise or on the morning afterward, and exacerbated by activities that increase the intra-abdominal pressure
- stress fractures
  - femoral neck or pubic rami
- avulsion fractures
  - generally occur in adolescents and young adults
  - history of severe, sudden-onset, and well-localized pain
- femoroacetabular impingement
  - thought to result from abnormal contact stress and joint damage around the hip, most notably from prolonged sitting, leaning forward, getting in and out of a vehicle, or performing a pivoting motion in sports