Determining the cause of leg pain in children can be problematic. Children who are talking may have difficulty expressing where the pain is, and in older children the perceived pain can be deceiving. For instance, pain in the knee can actually be due to a problem in the hip. It is important to start with a broad differential diagnosis in order to correctly identify the problem.
Fractures
Fractures to the long bones of the leg are common in school age children, who are likely to experience forceful falls and impacts during sporting activities and play "Nelson's Pediatrics" notes. X-rays can be used to confirm the diagnosis. Children just learning to walk may sometimes break the shinbone with a simple fall; this is called a "toddler's fracture". These may be diagnosed clinically, as they are hard to see on X-rays.
Myositis
Myositis, or inflammation of the muscle, occurs commonly. It can be due to simple overuse, as with strenuous exercise, or may happen with a viral infection such as the flu.
Osetomyelitis
Osteomyelitis is an infection of the bone. There is a rich blood supply to the bones, and infection typically occurs when bacteria are carried into the bone through the blood. The diagnosis is most easily made using MRI, according to "Nelson's Pediatrics." There may be a need to surgically clean the bone, and children will need antibiotics for one to four weeks.
Septic Arthritis
Infections in the joint, or septic arthritis, cause significant leg pain and a warm, red, swollen joint. Children will usually refuse to put any weight on or move the affected leg. This usually happens in kids 5 and younger. X-rays can help, but the diagnosis is officially made by inserting a needle into the joint and removing a sample of joint fluid to look for bacteria and other signs of infection, according to "Nelson's Pediatrics." Treatment requires antibiotics and, at times, surgical cleaning of the affected joint.
Toxic Synovitis
Toxic synovitis can mimic septic arthritis. It is inflammation in the joint without an infection present. Anti-inflammatory medicines like ibuprofen can be helpful for the pain until the synovitis resolves, according to MedlinePlus, a publication of the National Institutes of Health.
Slipped Cap Femoral Epiphysis
Slipped cap femoral epiphysis, or SCFE, happens when the capsule of the hip slips out of place. SCFE is associated with being overweight or having metabolic disease. It can present as groin or knee pain, and typically happens in adolescents. It is fixed by pinning the capsule back to the bone "Nelson's Pediatrics" notes.
Disorders of Blood Supply to the Hip
Two conditions, avascular necrosis of the femoral head and Legg-Calve-Perthes Disease, are caused by disrupted blood flow to the head of the femur. They are characterized by pain in the groin or knee.
Other Benign Causes
Leg pain in children can also be caused by growing pains, injuries such as sprains or strains, or muscle cramps. Most of these will resolve without further treatment and cause no long term consequences, Children's Hospital of Denver notes.
Other Serious Causes
Sometimes leg pain is the first sign of a serious systemic disease. Rheumatologic diseases like lupus, juvenile inflammatory arthritis, and dermatomyositis can begin with leg pain. Certain tumors and malignant cancers such as Ewing's sarcoma, osteochondroma, and osteosarcoma can also have leg pain as the first symptom. Any child with leg pain that seems out of proportion to an injury or that lasts longer than a week should be evaluated by a physician .
References
- Children's Hospital of Denver: Leg Pain
- "Nelson's Pediatrics"; Purushottam Gholve, Harish Hosalkar, Lawrence Wells, Richard M. Lampe, David Horn, Jared Friedman, John Dormans; August 2007.
- MedlinePlus: Toxic Synovitis
- National Cancer Institute: Bone Cancer
- "Pediatric Rheumatology"; Review for the Generalist: Evaluation of Pediatric Hip Pain; Kristin M. Houghton; May 2009
