JEANINE RONAN

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).

CLARIFYING QUESTIONS

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.

SUGGESTED READINGS

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.

CASE 16-1

Four-Year-Old Boy

AMY T. WALDMAN

HISTORY OF PRESENT ILLNESS

A 4-year-old Caucasian boy presented to the emergency department after a 1-week history of leg pain. Initially, the pain was described as bilateral, primarily surrounding his knees. However, the pain gradually became more diffuse and consistently woke the patient from sleep. In addition, the parents also noted that their son was more clumsy. He had difficulty walking and was dropping objects from both of his hands. Review of systems was significant for constipation, urinary incontinence, and fatigue. Three weeks ago, the patient had an upper respiratory infection, which had resolved.

MEDICAL HISTORY

There was no significant medical history. He had reached all of his developmental milestones on time, and had been walking since 9 months of age.

PHYSICAL EXAMINATION

T 36.3°C; RR 24/min; HR 120 bpm; BP 120/70 mmHg; Height under 5th percentile; Weight 10th percentile

Initial examination revealed an alert and interactive young boy. His cranial nerve examination was normal for cranial nerves II-XII. Notably, extraocular movements were normal and facial weakness was absent. His neurologic examination was remarkable for decreased strength in his lower extremities and hand grip bilaterally. Deep tendon reflexes were not elicited in the upper or lower extremities. His gait was limited by pain and weakness. The remainder of the examination was unremarkable.

DIAGNOSTIC STUDIES

Laboratory analysis included a normal complete blood count and sedimentation rate. Computed tomography of the head demonstrated mild mucosal thickening of the maxillary sinus. Cerebral spinal fluid demonstrated one WBC/mm³ and 25 RBCs/mm³. Protein was 106 mg/dL and glucose was 69 mg/dL. He was admitted to the hospital for further evaluation.

COURSE OF ILLNESS

What is the most likely diagnosis?

DISCUSSION CASE 16-1

DIFFERENTIAL DIAGNOSIS

The combination of symptoms including weakness, pain, and areflexia suggests a peripheral neuropathy. There are many causes of peripheral neuropathies. Guillain-Barré syndrome (GBS) is the most common cause of acute generalized weakness. However, at the onset of disease, it is difficult to distinguish GBS from its chronic and relapsing variant, chronic inflammatory demyelinating polyneuropathy. Many drugs have been implicated in inducing neuropathies including isoniazid, vincristine, heavy metals (mercury and lead), and organophosphates. While common in GBS, bilateral facial weakness is not often seen in other neuropathies. In patients with bilateral facial weakness and ataxia but normal or hyperactive reflexes, pathology in the brainstem and cerebellum should also be considered. Asymmetric weakness and sensory symptoms along with urinary retention suggests involvement of the spinal cord as is seen in transverse myelitis. Acute paraparesis or quadriparesis also occurs in the setting of a compressive myelopathy. Myopathies may present with similar symptoms but without sensory involvement and reflexes are preserved. An elevated creatine kinase may also be present in myopathies.

DIAGNOSIS

In this case, the physical finding of absent deep tendon reflexes was very important in establishing the proper diagnosis. The elevated cerebrospinal fluid protein with a normal number of white blood cells (cytoalbuminologic dissociation) was also consistent with the diagnosis of GBS. Electromyography (EMG) showed prolonged distal motor latencies in all motor nerves and a slowed conduction velocity that was consistent with a demyelinating process. The diagnosis is Guillain-Barré syndrome. At this point, the patient did not show any signs of respiratory compromise. He was treated with intravenous immunoglobulin (IVIg) and his symptoms gradually improved.

INCIDENCE AND EPIDEMIOLOGY

GBS, the most common cause of acute generalized weakness, occurs in 0.4-1.7/100 000 children. It is an acquired inflammatory disease of the peripheral nervous system. While the exact pathogenesis is unknown, GBS may be mediated by an immune response against myelin antigens of the peripheral nerves, which leads to demyelination and axonal degeneration of motor and sensory nerves. Many cases are postinfectious in which there is a history of gastrointestinal or respiratory illness within 4 weeks of symptom onset. Infections associated with the development of GBS include Campylobacter jejuni, varicella, cytomegalovirus, hepatitis, measles, mumps, and Mycoplasma pneumoniae.

CLINICAL PRESENTATION

The diagnosis of GBS requires areflexia and the presence of progressive motor weakness of more than one limb. The weakness is usually relatively symmetric and typically ascending, although descending weakness can also occur. Mild sensory loss, including paresthesias, numbness, and diminished position and vibratory sensation, is usually present.

Pain is a surprisingly common finding in children. A review of 29 children hospitalized with GBS demonstrated the presence of pain in 79% of cases. However, in many children the presence of pain obscured the proper diagnosis. The pain hindered accurate neurologic examination and usually caused clinicians to initially suspect a rheumatologic or inflammatory disorder. Adults typically classify the pain as a deep lower limb pain, exacerbated by straight leg raises.

Fever is not a common sign. However, there may be signs of autonomic dysfunction including labile blood pressure, tachycardia or bradycardia, as well as bladder or bowel dysfunction. Respiratory failure may be fairly rapid in onset and is seen in 20% of patients.

The Miller-Fisher variant is characterized by ophthalmoplegia, ataxia, and areflexia and is due to a specific IgG directed at a ganglioside.

DIAGNOSTIC APPROACH

The important step in making the diagnosis is to obtain a detailed history and perform a thorough general and neurologic examination.

Lumbar puncture. Cerebrospinal fluid classically demonstrates cytoalbuminologic dissociation (i.e., an elevated protein with only minimal pleocytosis, typically fewer than 10 WBCs/mm³); however, an elevated protein may not be present early in the disease course (i.e., during the first week).

Electromyography (EMG). The diagnosis is usually supported by EMG studies, which demonstrate slowed or blocked motor conduction. Within 2 weeks of illness onset, the EMG is abnormal in approximately 50% of patients; more than 85% of patients with GBS ultimately have an abnormal EMG.

Magnetic resonance imaging (MRI) of the spine. Although not usually required for diagnosis, MRI should be performed if spinal compression or central nervous system inflammation (such as transverse myelitis) is suspected. In patients with GBS, MRI frequently reveals spinal nerve root enhancement.

TREATMENT

GBS should be considered a neurologic emergency due to the potential for respiratory and autonomic failure. Patients with suspected or confirmed GBS must be monitored closely for worsening vital capacity and negative inspiratory force as intubation may be required. While spontaneous recovery may occur within 6 months, patients with respiratory compromise or autonomic dysfunction and those unable to walk are typically treated. Plasmapheresis and intravenous immunoglobulin are the current treatment modalities. While plasmapheresis and IVIg are equally effective, IVIg is often easier to initiate. Side effects of IVIg include fever, headache, vomiting, and meningismus. A recent study concluded that 23% of children may continue to have evidence of mild muscle weakness following IVIg therapy. However, in many cases this weakness had no impact on daily function. Children who were young in age and who had a rapid progression of symptoms were more likely to have long-term weakness. Combination therapy (plasmapheresis followed by IVIg) is not superior to either treatment alone and is not recommended. Corticosteroids are not effective and should not be administered in patients with GBS. Recovery from GBS occurs in a descending manner. Physical therapy should be initiated for all patients to assist with timely recovery.

SUGGESTED READINGS

1. Evans OB, Vedanarayanan V. Guillain-Barré syndrome. Pediatr Rev. 1997;18:10-16.

2. Gordon PH, Wilbourn AJ. Early electrodiagnostic findings in Guillain-Barré syndrome. Arch Neurol. 2001; 58:913-917.

3. Nguyen DK, Agenarioti-Belanger S, Vanasse M. Pain and the Guillain-Barré syndrome in children under 6 years old. J Pediatr. 1999;134:773-776.

4. Vajsar J, Fehlings D, Stephens D. Long-term outcome in children with Guillain-Barré syndrome. J Pediatr. 2003; 142:305-309.

5. Hughes RAC, Wijdicks EFM, Barohn R, et al. Practice parameter: immunotherapy for Guillain-Barré syndrome: report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2003; 61:736-740.

6. Yuki N, Hartung HP. Guillain-Barré syndrome. N Engl J Med. 2012;366:2294-2304.

CASE 16-2

Three-Year-Old Boy

JEANINE RONAN

HISTORY OF PRESENT ILLNESS

A healthy 3-year-old boy presented to the emergency department with significant left ankle swelling and the inability to walk. During the past several months, he has had swelling and tenderness of multiple joints, including his knees, wrists, fingers, and hips. He has also had daily fevers with associated night sweats and an 8-lb weight loss. His mother noted rashes that appeared on his face, back, and chest.

MEDICAL HISTORY

His medical history was unremarkable.

PHYSICAL EXAMINATION

T 38.2°C; RR 24/min; HR 106 bpm; BP 102/64 mmHg; Height 50th percentile; Weight 10th percentile

In general, the boy appeared tired. Musculoskeletal examination revealed multiple painful and swollen joints with limited range of motion, including his right hip, right wrist, and left third digit. His neurologic examination demonstrated intact sensory function and normal deep tendon reflexes. No rash was seen. The remainder of the examination was normal.

DIAGNOSTIC STUDIES

Initial laboratory data revealed a 14 600 WBCs/mm³ with 54% segmented neutrophils, 6% band forms, and 36% lymphocytes. The hemoglobin was 7.9 g/dL and there were 997 000 platelets/mm³. The erythrocyte sedimentation rate was 63 mm/h. Electrolytes, blood urea nitrogen, and creatinine were normal. Liver function tests were normal, except an albumin of 2.9 mg/dL. Blood cultures were subsequently negative. Lyme antibodies and ASO titers were also negative. Radiologic studies were normal including hip and abdominal radiographs.

COURSE OF ILLNESS

Septic arthritis was considered unlikely given the number of joints involved as well as the chronicity of the problem. Throughout the hospital stay the patient continued to have fevers and joint swelling. A salmon colored rash appeared with each temperature elevation and suggested the diagnosis (Figure 16-1).

DISCUSSION CASE 16-2

DIFFERENTIAL DIAGNOSIS

In a child with fever and refusal to bear weight, infectious causes such as septic arthritis and osteomyelitis must be considered. Children with septic arthritis may have systemic symptoms including irritability and malaise. The affected joint acutely appears erythematous, warm, and tender. Range of motion is typically limited due to pain. In more than 90% of cases, only a single joint is affected. Children with acute hematogenous osteomyelitis manifest symptoms for fewer than 2 weeks. On physical examination there is often erythema, edema, and tenderness over the affected bone. However, the degree of tenderness may be out of proportion to the other findings. The femur, tibia, humerus, and fibula are most commonly involved. Laboratory findings in both septic arthritis and osteomyelitis include leukocytosis and elevation of the erythrocyte sedimentation rate and C-reactive protein. Blood cultures are positive in up to 50% of the children with septic arthritis or osteomyelitis.

Acute rheumatic fever (ARF) may also present with fever. In ARF, the arthritis is classically described as a migratory polyarthritis with pain that is out of proportion to the physical findings and responds quickly to antiinflammatory medication. In addition, there must be evidence of a recent group A Streptococcus infection and fulfillment of the Jones criteria (Table 16-3).

Arthritis occurs in late-onset Lyme disease. It should also be considered particularly in areas where Lyme disease is endemic. When occurring, the erythema migrans or bullseye rash develops in early disease and will precede joint swelling. Patients may complain of arthralgias during early-onset disease in addition to fever and generalized malaise. In 80% of cases, Lyme arthritis is monoarticular, typically involving the knee joint, but multiple joints are occasionally involved. The affected joint is erythematous and swollen; pain is relatively mild despite the significant joint effusion.

The constellation of fever, rash, and joint pain also suggests systemic-onset juvenile idiopathic arthritis (JIA). However, in many cases the presentation of systemic-onset JIA can be elusive and is sometimes confused with the presentation of leukemia or lymphoma. The systemic-onset JIA patient may have lymphadenopathy and hepatosplenomegaly. The arthritis and joint symptoms may not be apparent initially.

DIAGNOSIS

In this case, the evanescent salmon colored rash strongly suggested the diagnosis of systemic JIA (Figure 16-1). This rash usually appears while the child is febrile.

INCIDENCE AND EPIDEMIOLOGY

Juvenile idiopathic arthritis is the most common rheumatic disease of childhood. The incidence is 1:10 000, with a prevalence of 1:1000. JIA encompasses a heterogeneous group of disorders. By definition, JIA includes all forms of arthritis that occur before 16 years of age, persists for greater than 6 weeks, and does not have another known etiology. Arthritis is defined as the presence of a joint effusion plus two of the following: decrease range of motion of the joint, increase in warmth, and pain. Based on the symptom characteristics within the first 6 months of illness, the type of JIA is classified into systemic-onset, oligoarticular (persistent and extended), polyarticular (rheumatoid factor positive and negative), psoriatic arthritis, enthesitis related arthritis, and undifferentiated (Table 16-4). Systemic JIA represents about 10% of all cases and is seen equally among boys and girls. There is no peak age of onset and can present any time throughout childhood. In contrast, oligoarticular JIA is the most common, including about 40% of all JIA cases. Oligoarticular JIA occurs more commonly in girls than boys with a 5:1 ratio. Most children with oligoarticular JIA present between 1 and 6 years of age with a peak at 2-4 years. Polyarticular JIA, which comprises about 25% of JIA cases, is also seen more commonly in girls than boys with a 3:1 ratio. Peak onset of polyarticular JIA occurs between 1-4 years of age and 7-10 years of age until adolescence. The remainder of the cases consists of psoriatic arthritis, enthesitis-related (where tendons and ligaments attach to bone) and undifferentiated.

CLINICAL PRESENTATION

The term juvenile idiopathic arthritis encompasses a group of diseases that involve the infiltration and proliferation of the synovial membrane resulting in joint swelling. JIA is a multifactorial autoimmune disease that develops due to host and environmental susceptibility factors. Immune dysregulation produces cytokines with an increase in inflammatory mediators within the synovium. Tissue inflammation causes remodeling, cartilage degradation, and bony erosions. The pain classically includes morning stiffness and gait disturbance, in contrast to patients with musculoskeletal pain due to mechanical or overuse injuries, which worsen with use and improve with rest. Patients with musculoskeletal pain will have worsening of symptoms during the day or with exercise and have no associated joint effusion.

Systemic-onset JIA. Systemic-onset JIA presents with high spiking fevers, salmon-colored rash that begins in the groin or axilla and extends to the trunk and extremities, hepatosplenomegaly, lymphadenopathy, with or without the arthritis. Supporting laboratory data include an elevated white blood cell count, anemia, thrombocytosis, and elevated ferritin level. Signs of disseminated intravascular coagulation are due to the macrophage activation syndrome. The sedimentation rate is typically greater than 80 mm/h. Chronic uveitis or iriditis does not typically occur.

Oligoarticular JIA. In oligoarticular JIA, the patient presents with less than four joints involved. This category is further divided into patients with persistent disease in which less than four joints are involved throughout the disease course and extended diseases in which more joint involvement develops after the first 6 months. The typical patient is a preschool girl with isolated knee swelling and difficulty walking. The arthritis usually involves the knees, ankles, wrists, or elbows, while sparing the hips. These patients are at high risk for uveitis. In patients with a positive antinuclear antibody (ANA), the risk is about 80%. Chronic anterior uveitis can be asymptomatic initially, but the complications include corneal clouding, cataracts, glaucoma, and vision loss. Serial ophthalmologic examinations are crucial in this population. Treatment may include NSAIDs or intraarticular steroid injections. This is the mildest form of JIA and these patients may go into permanent remission.

Polyarticular JIA. Polyarticular JIA affects five or more joints at the time of presentation. The joint distribution is symmetrical involving small and large joints including joints of the hands, the temporomandibular joint, or cervical spine. Polyarticular JIA is further categorized by the presence of rheumatoid factor. Rheumatoid factor positive polyarticular JIA is seen most commonly in adolescent girls and the disease course is similar to adult rheumatoid arthritis. The risk for uveitis is not as great in this category, but if the ANA is positive, these patients are also at risk for the complications with anterior uveitis.

Psoriatic arthritis. Psoriatic arthritis involves the knees, hands, and feet. It is seen in patients with psoriasis or with first degree relatives with psoriasis. Nail changes including pitting and onycholysis are typically seen along with dactylitis.

Enthesitis-related arthritis. Enthesitis-related arthritis encompasses inflammatory bowel disease associated arthritis, in which arthritis may precede other symptoms, reactive arthritis and juvenile ankylosing spondylitis. Enthesitis describes inflammation at the site of tendon and ligament attachment within the joint capsule. Many of these patients are HLA-B27 positive and develop progressive involvement of the sacroiliac joint.

Undifferentiated arthritis. This includes any arthritis that is not further defined by the above definitions.

DIAGNOSTIC APPROACH

When making the diagnosis of juvenile idiopathic arthritis, by definition the patient must have symptoms for a duration of at least 6 weeks. The history and physical examination should be directed at eliciting clues to changes in gait, the presence of joint effusions, and pain in the joints. It is important to examine all joints including the temporo-mandibular joint and cervical spine for subtle changes. Also, associated symptoms including fever, rash, and adenopathy must be assessed. Looking for signs of psoriasis, nail changes, can also have clues to the diagnosis. Growth parameters should be reviewed. An ophthalmologic examination is also very important. Laboratory data may be a helpful adjunct.

Complete blood count. Patients with systemic JIA often have leukocytosis with neutrophil predominance, thrombocytosis, and anemia.

Antinuclear antibody (ANA). Antinuclear antibody studies are not required for the diagnosis of JIA but are helpful in classifying patients. If JIA patients are ANA-positive, their risk for chronic anterior uveitis is higher. Since chronic anterior uveitis is an asymptomatic condition with devastating complications, including cataracts, glaucoma, and loss of visual acuity, these patients require close ophthalmologic follow-up.

Rheumatoid factor (RF). In general, a positive rheumatoid factor is not helpful in making the diagnosis. In most cases of JIA, the test will be negative with the exception of polyarticular JIA in which approximately 15% of children have a positive result. In this instance, a positive rheumatoid factor is important for prognosis, but not required for the diagnosis, as polyarthritis JIA, RF-positive is most closely related to adult rheumatoid arthritis.

Radiographs. Radiographs are normal early in the course of illness. Radiographs will show joint space narrowing, growth abnormalities of the joint, and bony erosions as persistent arthritis will also lead to bone demineralization and loss of articular cartilage.

Other studies. Erythrocyte sedimentation rate and C-reactive protein will be in most cases of JIA.

TREATMENT

The goals of treatment for JIA are to maintain functional mobility, by controlling inflammation and increasing joint range of motion, as well as limiting the side effects of medications and thereby leading to the normal physical, social, and developmental growth of the patient. Nonsteroidal antiinflammatory drugs (NSAIDs) are the first line of therapy for JIA. NSAIDs are directed at treating the pain and symptoms of JIA but these medications are not disease modulating. NSAIDs can be started at the onset of symptoms prior to classifying the arthritis without resulting clouding the diagnosis. Naproxen is commonly used because it is a twice-a-day medication. The chronic use of NSAIDs requires monitoring of certain data including urinalysis, complete blood count, renal, and liver function tests. A particular skin rash called pseudoporphyria is associated with naproxen. This photosensitive eruption results in small facial vesicles that may lead to permanent scar formation.

Other medications are directed at treating the inflammation and thus are disease modulation. Corticosteroids are used particularly in children with systemic JIA who present with high fevers and severe systemic symptoms. The side effects of systemic corticosteroids make them less appealing for chronic control of inflammation, especially in less severe forms of the disease. In patients with oligoarticular JIA, intraarticular injections with triamcinolone hexacetonide may be very effective treatments.

New data suggest that aggressive therapy at the onset of treatment is more effective in minimizing long-term sequelae. Disease-modifying antirheumatic drugs (DMARDs) including methotrexate are particularly useful in patients with oligoarticular JIA, extended disease, and polyarticular JIA. Methotrexate is usually very safe, but it can be associated with liver toxicity requiring monitoring of hepatic function tests every 4-8 weeks, kidney dysfunction, increase risk of infections, and bone marrow suppression. Folic acid supplementation once a week will decrease the incidence of side effects.

A new area of drug research is focused on targeting inflammatory cytokines to turn off the inflammatory cascade. Biological DMARDs are showing increasing promise in reducing symptoms and altering the disease course. These types of medications include TNF-alpha blocking agents, T-cell co-stimulation modulators, Inter-leukin 1 blocking agents, Interleukin 6 blocking agents, and B cell depletion agents.

Physical therapy is also crucial for these patients to maintain the most active possible lifestyle. Vitamin D and calcium supplements should be encouraged.

SUGGESTED READINGS

1. Goldmuntz E, White P. Juvenile idiopathic arthritis. Pediatr Rev. 2006;27(4):24-32.

2. Prakken B, Albani S, Martini A. Juvenile idiopathic arthritis. Lancet. 2011;322(9783):2138-2149.

3. Prince F, Otten M, van Suijlekom-Smit L. Diagnosis and management of juvenile idiopathic arthritis. BMJ. 2011;342(c6434):95-102.

CASE 16-3

Two-Year-Old Boy

JEANINE RONAN

HISTORY OF PRESENT ILLNESS

A 2-year-old boy presented with the chief complaint of refusing to walk. The child was in his usual state of health yesterday and was outside playing with his older brother. While looking outside the mother noted that her son had fallen while running on the grass, but he stood up immediately and continued trying to keep up with his older brothers. Over the remainder of the day he seemed to be acting normally. However, when he woke up this morning there was significant swelling over the right lower leg and he was walking with a limp. There has been no history of fever or viral infections.

MEDICAL HISTORY

The medical history was remarkable. He met all his developmental milestones appropriately.

PHYSICAL EXAMINATION

T 36.9°C; RR 28/min; HR 125 bpm; BP 96/70 mmHg; Height 75th percentile; Weight 50th percentile

In general, the child appeared as a happy, well-developed boy. His physical examination was normal with the exception of the right lower extremity. There was an area of focal swelling and discrete tenderness along the lower third of the tibial shaft. His hip, knee, and ankle examination revealed full range of motion. His neurologic examination was normal; however, he refused to bear weight on his right leg. His skin examination did not demonstrate any bruises or unusual marks.

DIAGNOSTIC STUDIES

Complete blood count revealed 8200 WBCs/mm³

with 54% segmented neutrophils, no band forms 38% lymphocytes, and 8% monocytes. The erythrocyte sedimentation rate and C-reactive protein were normal.

COURSE OF ILLNESS

A radiograph of the right leg revealed the diagnosis (Figure 16-2).

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