Severe leg pain can be caused by Achilles tendon problems, an ACL injury, a broken leg, bursitis and a herniated disk, according to Mayo Clinic. Leg pain can also be related to sciatica or gout.
A broken or fractured leg often causes severe pain, states Mayo Clinic. Besides severe pain, an individual with a broken or fractured leg may find it difficult or impossible to walk and experience swelling and bruising. Depending on the severity of the break or fracture, there may also be an obvious deformity in the limb. Achilles tendon issues, such as a tendon rupture and tendinitis, can also cause severe pain. Tendinitis is when the Achilles tendon becomes overused and stressed. Sometimes this can lead to a rupture. While tendinitis can be treated with at-home care, a rupture sometimes requires surgical treatment.
Both sciatica and a herniated disk can cause severe leg pain, although the problem starts at the back, explains Mayo Clinic. Sciatica is a condition where the sciatic nerve that moves from the back down the legs becomes compressed, causing pain in the buttocks and legs. Although a herniated disk in the vertebrae can cause acute leg pain, some people with herniated discs experience no symptoms.