The anatomic components of the groin consist of the skin, subcutaneous tissue, fascia, lymph nodes, the femoral nerve, arteries and veins, and underneath, the hip bones. With these components in mind, it should be easy to develop a differential diagnosis of groin pain because most of the lesions are inflammatory or traumatic.
The skin is affected by intertrigo, scabies, furuncles, and herpes zoster, among other things. The subcutaneous tissue may be involved by cellulitis and a tuberculous abscess. When the fascia is weak or torn, femoral or inguinal hernias develop. More likely causes of groin pain are inflamed lymph nodes that may be from any venereal disease (such as gonorrhea or chancroid) or infections of other portions of the genitalia. The femoral nerve may be affected by viral neuritis, diabetic neuropathy, and disease of the spine (fracture, disc, or tumors). The femoral artery may be involved by a thrombosis, embolism, or dissecting aneurysm, whereas the vein may be thrombosed. Finally, the underlying hip bones can be involved by any form of arthritis and by infections or metastatic tumors of the bone. Fractures and other traumatic disorders affect the bones of the hip also.
It would be a gross omission if referred pain to the groin were not considered. Pain may be referred to the groin in pyelonephritis, renal colic, regional ileitis, appendicitis, salpingitis, and many other abdominal disorders.
Approach to the Diagnosis
In the approach to the diagnosis of groin pain, a mass or tender structure is usually present in the groin. If the mass is a lymph node, careful examination of the genitalia and lower extremities will often show the cause, but a urethral or vaginal smear and culture may be necessary to show gonorrhea. Investigation of the genitourinary (GU) tract and the GI tract for causes of referred pain is then undertaken. If the mass is reducible, a hernia is likely and referral to a surgeon is in order. Incarcerated hernias, of course, demand immediate referral.
Other Useful Tests
1. Tuberculin test
2. Sonogram (cystic mass)
3. Flat plate of abdomen (hernia with intestinal obstruction)
4. X-ray of hip (fracture, osteomyelitis)
5. CBC (abscess)
6. Bone scan (tumor, osteomyelitis)
7. Angiogram (aneurysm)
8. Phlebogram (saphenous varix)
9. Exploratory surgery (hernia, tumor)
10. Biopsy (tumor)
11. CT scan (tumor, abscess)
Case Presentation #36
A 38-year-old carpenter complained of intermittent pain in his right groin for several months. The pain was so severe he had to quit work for the past 2 weeks. Physical examination failed to disclose a mass in his right groin, but there was slight tenderness on palpation.
Question #1. Utilizing anatomy, what is your differential diagnosis?
Neurologic examination reveals diminished sensation to touch, pain in the right L1 dermatome, and precipitation of the pain by coughing or sneezing.
Question #2. What is your diagnosis now?