DEFINITION OF THE COMPLAINT
Children refuse to walk because of pain, neuromuscular weakness, and certain mechanical factors. The list of possible etiologies in this regard is very extensive, consisting of both benign and life-threatening conditions. A systematic approach examining these causes is necessary to ensure a comprehensive evaluation.
A normal gait is a “smooth, mechanical process that advances the center of gravity with a minimum expenditure of energy.” The stance phase is the time period when the heel strikes the ground bearing the individual’s weight and the ball of the other foot leaves the ground. This requires very strong abductor muscles to stabilize the pelvis. In addition, the swing phase is defined as the time when the foot leaves the ground until the next heel strike.
There are many types of abnormal walking patterns. An antalgic gait is the pattern adopted to minimize pain. With this pattern, the patient will shorten the stance or weight-bearing phase on the affected limb, thereby minimizing the amount of time exerted on the painful limb. This will also result in a shortened stride length. A patient with a fracture, soft tissue injury, or infection, will use an antalgic gait. Circumduction is the pattern followed to shorten a limb and improve limb clearance. This is commonly seen when there is excessive joint stiffness secondary to spasticity or a leg-length discrepancy. A Trendelberg gait is when the muscles on one side of the pelvis are weak causing pelvic instability; when both sides are involved a waddling gait is observed. An unsteady gait is suggestive of the presence of ataxia. A steppage gait is seen in cases of peripheral neurologic weakness. The foot slaps the ground as the patient walks due to decreased ankle dorsiflexion.
COMPLAINT BY CAUSE AND FREQUENCY
When a child refuses to walk the most common causes may vary based on a child’s age (Table 16-1). The primary causes of limp, such as pain, weakness, and mechanical factors, can be further grouped by the following mechanisms: trauma, infectious, inflammatory, congenital, developmental, neurologic, neoplastic, hematologic, metabolic, and non-organic (Table 16-2).
TABLE 16-1. Common causes of refusal to walk in childhood by age.
TABLE 16-2. Causes of abnormal gait in childhood by mechanism.
When evaluating a child who refuses to walk or a child with an abnormal gait, a thorough history and physical examination is crucial. Consideration of the patient’s age, duration of symptoms, and the presence of systemic complaints allow the examiner to develop the appropriate differential diagnosis for the problem. The following list of questions may be helpful in guiding one to the ultimate diagnosis:
• Is the child’s refusal to walk due to pain?
—Trauma is the most common etiology that will result in a child refusing to walk. This may be due to repetitive or overuse injuries, accidental injury, or child abuse. Clues to differentiating between accidental and abuse-related injuries include understanding the mechanism of the injury. Does the explained mechanism for the incident seem appropriate for the developmental age of the child?
Pain may be present because of inflammation and swelling in the bone or joint. Septic arthritis and osteomyelitis are other common causes for limping. A child with juvenile idiopathic arthritis (JIA) or reactive arthritis also complains of pain in his joints and may refuse to walk. Referred pain should also be considered. Commonly, a child with pathology in the hip will complain of knee or medial thigh pain. A child with appendicitis may refuse to walk due to referred pain from the abdomen. Back pain may also present with abnormal gait.
When a child is unable to walk, but denies the presence of pain, one must look hard for neuro-muscular, metabolic, congenital, and developmental abnormalities. Developmental dysplasia of the hip may result in a limblength discrepancy and abnormal walking pattern.
• How did the symptoms evolve? Was there a sudden or gradual onset?
—In some cases, the parents will notice that the child initially develops an abnormal gait and as symptoms worsen will ultimately refuse to walk. A more gradual onset of symptoms suggests the presence of an inflammatory condition or mechanical cause from overuse. In other cases, a child abruptly is unable to walk which may suggest the presence of an injury or septic joint.
• Are there any associated symptoms?
—The presence of other symptoms including fever, weight loss, abdominal pain, diarrhea, and rash may be suggestive of other etiologies. Children with leukemia will commonly complain of bone pain as well as weakness, malaise, and fever. A child with undiagnosed inflammatory bowel disease may have diarrhea, weight loss, as well as isolated joint swelling. Systemic JIA presents commonly with fever, weight loss, and rash in a school-aged child.
• Is there the presence of joint swelling and erythema?
—Associated signs of infection, including toxic appearance, fever, chills, and joint redness, swelling, warmth, and decreased mobility, accompany septic arthritis. Many inflammatory etiologies will also present with joint swelling and increased joint warmth.
• How would you characterize the limp?
—Does the child refuse to walk due to the presence or absence of pain? Is the child’s abnormal walking pattern trying to minimize the amount of time spent on the involved leg? Is the child able to weight bear? Abnormalities in the structure of the lower extremity, for example, torsional deformities or leg-length discrepancies also cause an abnormal walking pattern. In addition, any abnormalities in the muscle such as an increase in tone or the presence of contractures will generate an abnormal walking pattern. A child may also refuse to walk due to neuromuscular weakness. Weakness may be found in the muscle, due to a problem with the peripheral nerves or due to disease within the central nervous system.
• Are there localizing signs on physical examination of the child?
—If pain is present, try to localize it to the area of maximum tenderness. Point tenderness on a painful extremity is highly suggestive of an infection or acute injury. Point tenderness in a febrile child requires an evaluation for osteomyelitis. Tenderness over the epiphyseal growth plate in addition to a history of trauma increases the possibility of a Salter-Harris type 1 fracture.
• Is the pain referred?
—The child may have an acute abdomen or torsion of the testes and may refuse to walk to minimize pain. A child with back pain will also have trouble walking due to pain or neurologic weakness. In addition, knee and medial thigh pain is commonly associated with hip pathology.
• Do symptoms vary with the time of day?
—Rheumatologic disorders are associated with the gelling phenomenon. Symptoms are worse in the morning and improve during the course of the day. When neuromuscular weakness is the etiology, the symptoms tend to progress throughout the day. Pain due to tumors is persistent.
The following cases illustrate the approach to a patient who refuses to walk.
1. Sawyer J, Kapoor M. The limping child: a systematic approach to diagnosis. Am Fam Physician. 2009;79(3):215-224.
2. Hill D, Whiteside J. Limping in children: differentiating benign from dire causes. J Fam Pract. 2011;60(4):193-197.
3. Barkin R, Barkin S, Barkin A. The limping child. J Emerg Med. 2000;18(3):331-339.
4. Tse S, Laxer R. Acute limb pain. Pediatr Rev. 2006;27(5):170-179.
5. Fleisher GR, Ludwig S. Textbook of Pediatric Emergency Medicine. Philadelphia: Lippincott Williams & Wilkins; 2010.