Musculoskeletal History

A meticulous rheumatologic history is the foundation of accurate diagnosis (Table 7-1). The exact location that the patient complains about should be given careful attention. Muscle, bone, and tendon or ligament insertion pain (enthesitis) may be interpreted as joint pain unless the clinician asks specifically for the parent or child to describe the symptoms. Often it is helpful for the clinician to ask the child to point with one finger to the site of maximal discomfort.

Table 7-1 Distinguishing Features of the Rheumatologic History

The patient’s age and gender serve as initial guides to a possible etiology. The clinician must then try to discern whether musculoskeletal symptoms are inflammatory or mechanical. Pain that involves swelling, morning stiffness, warmth, redness, and improvement with movement is indicative of inflammation. Pain that is worse at the end of the day, worse with activity, and lacking persistent swelling is more mechanical in nature.

A history of prior illnesses, medications, immunizations, trauma, and bites, and the acuteness of symptoms, can be a clue to diagnosis. Joint pain (arthralgia) is a common symptom of childhood. However, the symptoms associated with inflammatory joint pain (arthritis) are uncommon in the pediatric population. In children with arthritis, the duration and pattern of the symptoms can be telling. Acute migratory arthritis affecting large and small joints is seen in acute rheumatic fever (ARF). Arthritis resolving within a few weeks is consistent with a reactive arthritis (i.e., Streptococcus, Epstein-Barr virus, parvovirus B19). An additive arthritis persisting for more than 6 weeks is consistent with a chronic form of arthritis (i.e., juvenile idiopathic arthritis [JIA]). The chronic arthritides cause indolent and persistent joint changes. Joint stiffness, or gel phenomenon, can be seen not only in the morning, but also after a child has napped or been immobile in a vehicle. As the day progresses, the child with chronic arthritis may become more limber and may even appear normal.

Differences in the quality and duration of arthritis exist among the various rheumatoid diseases. The arthritis in patients with systemic lupus erythematosus (SLE) may feature less swelling with more intense pain, whereas the arthritis of children with JIA is characterized by more stiffness and swelling and less pain. The joint pain of the patient with SLE may be intermittent in nature. The joint stiffness of JIA is usually a daily occurrence without treatment. The joints of ARF can also be distinguished from those of JIA by the presence of exquisite pain that is out of proportion to physical findings. A rapid response to nonsteroidal antiinflammatory drugs further supports a clinical impression of ARF.

A careful family history can be helpful. Children with an extensive family history of autoimmune diseases in their first-degree relatives are at slightly greater risk for developing a rheumatologic condition. Because these diseases are complex genetic traits, there is often little direct genetic linkage. Some diseases such as psoriasis, SLE, acute rheumatic fever, and autoimmune thyroiditis have a stronger genetic penetrance than other rheumatic diseases. Other conditions have little or no penetrance. A child with first-degree relatives with adult rheumatoid arthritis is not at increased risk for developing juvenile idiopathic arthritis.

Physical Examination of the Musculoskeletal System

The only way to confirm the diagnosis of JIA is to demonstrate arthritis by physical examination of the joints. The elucidation of joint inflammation by examination may be the only indication of a rheumatic disease. Because most joints are near the surface of the body, the examiner has an excellent opportunity to obtain significant information about many diseases. A rheumatologic diagnosis requires a thorough joint examination and meticulous general physical examination with special attention to the skin, mucous membranes, nail beds, and muscles.

The physical examination begins with observation of the child and parents walking from the waiting area to the examination room. The physician notes the general appearance of the patient and interactions among family members. Nutritional status and an incremental graph of height and weight must be carefully documented. Certain skin and mucous membrane changes provide valuable information (Table 7-2). Muscle strength must be evaluated first by attempting to elicit a Gowers sign (Fig. 7-1) and then by testing resistance capacity of individual muscle groups and grading them on a standard scale (Table 7-3).

Table 7-2 Mucocutaneous Signs of the Rheumatic Diseases

Figure 7-1 Gowers sign. The child begins in a prone position and is asked to stand. The child is unable to rise without rolling over and progressively pushing to the knees and using hands to push up to a standing position.

Table 7-3 Standard Muscle Strength Grading

The hallmark of a good physical examination of the musculoskeletal system is a careful examination of the joints, consisting of inspection, palpation, and measurement of each joint’s range of motion. The examiner should develop a standard order for examining joints and follow the same pattern so that no joints are missed. Large effusions are easily felt and often ballotable; synovial hypertrophy may be more subtle and has a doughy, spongy, boggy feel. Synovial outpouchings are common in children with arthritis and can resemble ganglion cysts, especially in the wrists and ankles. A ganglion cyst does not cause pain. In children with arthritis the findings may be subtle and often appreciated only because of pain or decreased range of motion.

Temporomandibular Joint

The temporomandibular joint (TMJ) permits three types of motion: (1) opening and closing of the jaw, (2) anterior and posterior motion, and (3) lateral or side-to-side motion; each type should be carefully measured. Careful observation of the TMJ may reveal micrognathia, a clue to the diagnosis of JIA (Fig. 7-2).

Figure 7-2 Micrognathia. Note the underdevelopment of the jaw and retracted chin. This occurs in patients with juvenile idiopathic arthritis.

Cervical Spine

In children the neck can be extended so that the head can touch the back and flexed so that the chin touches the chest; 90-degree rotation and 45-degree lateral bending in each direction is also normal (Fig. 7-3).

Figure 7-3 A child’s neck normally can be extended so that the head touches the back (A), flexed so that the chin touches the chest (B), rotated 90 degrees (C), and tilted laterally 45 degrees (D).

Shoulder

The shoulder is usually involved only in severe polyarticular JIA. It is an extremely complicated joint, but range of active motion can be conveniently tested by having the child perform three simple maneuvers (Fig. 7-4). These maneuvers require 180 degrees of abduction, 45 degrees of adduction, 90 degrees of flexion, and 45 degrees of external rotation of the glenohumeral joint and related articulations.

Figure 7-4 Testing range of motion of the shoulder. A, Place hand behind head and touch opposite shoulder (external rotation and abduction). B, Place back of hand behind the back and touch opposite scapula. C, Place hand on opposite shoulder. (Movements in B and C test internal rotation and adduction.)

Elbow

The examiner must distinguish swelling in the olecranon bursa from involvement of the true elbow joint. The elbow is frequently affected in all forms of JIA and is the most common upper extremity joint affected in spondyloarthropathy. Range of motion of the elbow is easily tested (Figs. 7-5 and 7-6).

Figure 7-5 Supination and pronation of the elbow. The elbow should be held flexed at 90 degrees and against the body. A, The fist is held in a neutral vertical position and then B, rotated 90 degrees in pronation and C, 90 degrees in supination.

Figure 7-6 A, The elbow should extend from 0 degrees with the arm held down and B, flex to 150 degrees.

Wrist and Hand

Children do not require much extension to perform most activities of daily living and thus can lose strength and mobility in the wrist, which may go unnoticed. The wrist is frequently affected in childhood arthritis, and thus a careful range of motion examination is essential. Normal is 70 degrees of extension, 80 degrees of flexion (Fig. 7-7), 20 degrees radially, and 30 degrees to the ulnar side.

Figure 7-7 The wrist should extend to 70 degrees (A) from a neutral position (B) and flex to 80 degrees (C).

Metacarpophalangeal (MCP) joints extend 30 degrees and flex 90 degrees. Normal range of motion for the proximal interphalangeal (PIP) joints is illustrated in Figure 7-8.

Figure 7-8 The metacarpophalangeal joints can extend 30 degrees (A) and flex 90 degrees (B). Note the normal range of motion for the proximal interphalangeal joints (C).

Hip

The normal hip examination consists of 45 degrees of abduction and 20 degrees of adduction (Fig. 7-9) with the knee bent 20 degrees. The hip can extend 30 degrees, externally rotate to 45 degrees, and internally rotate to 35 degrees. An increase in lumbar lordosis may be the first sign of decreased hip flexion. Normally, hip flexion reaches to about 135 degrees (Fig. 7-10).

Figure 7-9 The normal hip can be adducted 20 degrees.

Figure 7-10 The normal hip can be flexed 135 degrees.

Knee

The knee is the joint most commonly involved in childhood arthritis. Swelling of the knee may be diffuse or localized to the suprapatellar bursa, which communicates with the true knee joint, or to the gastrocnemius-semimembranosus bursa (Baker cyst) (Fig. 7-11), which may dissect down the leg. The patella must be carefully evaluated for “roughening of the undersurface” indicative of chondromalacia patellae, which is not uncommon in teenage girls. Normal knee range of motion is illustrated in Figure 7-12.

Figure 7-11 Arthrogram demonstrates communication of Baker’s cyst with synovial cavity of the knee joint.

Figure 7-12 Normal knee range of motion extends from 10 degrees of hyperex-tension (left knee) to 130 degrees of flexion (right knee).

Foot and Ankle

The foot and ankle can offer valuable clues to the diagnosis of arthritis in childhood. Evidence of Achilles tendinitis or plantar fasciitis can suggest a spondyloarthropathy. First metatarsophalangeal (MTP) joint involvement is also a strong clue to the diagnosis of a spondyloarthropathy. Normal ranges of motion of the true ankle joint and subtalar joint are illustrated in Figure 7-13, and decreased range of motion is common in oligoarticular JIA.

Figure 7-13 The ankle normally can flex to 20 degrees (A) and extend to 45 degrees (B). Inversion occurs to 30 degrees (C), and eversion occurs to 20 degrees (D).

Careful flexion and extension of all interphalangeal joints of the feet must be evaluated, especially the first MTP joint (80 degrees of extension to 35 degrees of flexion). The MTP joints should be squeezed enough to wrinkle the skin.

Leg Length

Leg length discrepancy (Fig. 7-14) is common in JIA because of hyperemia of an affected joint and subsequent overgrowth. Compensatory scoliosis may also develop.

Figure 7-14 Leg length is measured from the anterosuperior iliac spine to the medial malleolus.

Thoracic Spine/Lumbar Spine/Sacroiliac Joints

The entire spine including all spinous processes should be carefully palpated to elicit tenderness. Flexion, extension, and lateral motion of the spine should be measured, using S1 as the focal point. Thirty degrees of extension and 50 degrees of lateral motion are normal. Careful examination of the sacroiliac joints (Fig. 7-15) may give an important clue to the diagnosis of a spondyloarthropathy in an adolescent. Chest expansion, occiput-to-wall, and finger-to-floor measurements (Fig. 7-16) are useful in monitoring patients with inflammatory back disease. To detect limitation of forward flexion of the lumbar spine, the Schober test is quite useful. The patient is asked to stand erect, and the skin overlying the spinous process of the fifth lumbar vertebra (usually at the level of the “dimples of Venus”) and another point 10 cm above in the midline are marked. The patient is asked to maximally bend the spine forward without bending the knees. If the lumbar spine is mobile, the distance between the two points increases by 5 cm or more; that is, the distance between the two points becomes equal to or greater than 15 cm. An increase of 4 cm or less indicates decreased mobility of the lumbar spine.

Figure 7-15 Clinical tests for sacroiliitis. A, Application of direct pressure by thumbs over the sacroiliac joints to elicit tenderness. B, With knee flexed and hip flexed, abducted, and externally rotated, downward pressure is applied on the flexed knee and the contralateral anterosuperior iliac spine. C, Compression of the pelvis with patient lying on side. D, Patient lying supine, with flexed knee pushed maximally toward the opposite shoulder. E, Anterosuperior iliac spines forced laterally apart.

Figure 7-16 With feet together, the child bends forward. The measurement from floor to fingertip is recorded and compared with subsequent examination.

Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in children. JIA is a broad term that is used to describe chronic arthritis in children. The group of diseases placed under the JIA rubric combines diverse entities, generally divided into seven categories: (1) oligoarthritis (persistent or extended), (2) polyarthritis (rheumatoid factor negative), (3) polyarthritis (rheumatoid factor positive), (4) enthesitis-related arthritis (ERA), (5) psoriatic arthritis, (6) systemic arthritis, and (7) undifferentiated arthritis. The JIA onset type is based on the disease presentation during the first 6 months of illness. The presenting subtype of JIA may differ from the child’s ultimate disease course. Of note, no laboratory tests, such as a positive anti-nuclear antibody or rheumatoid factor, are required to make a diagnosis of JIA.

The incidence of JIA is approximately 10 cases per 100,000 population per year. The prevalence of JIA is approximately 100 per 100,000 population. JIA in the United States is estimated to affect more than 300,000 children.

The first clear description of these entities was presented by George Still in 1897. He postulated multiple etiologies for childhood arthritis, and this concept is still supported today. All forms of JIA feature inflammation of the synovial tissue as one of the cardinal features. Synovium is usually hypertrophied, and joint effusions may occur. On physical examination (Fig. 7-17), joint swelling, loss of normal anatomical landmarks, tenderness, decreased joint mobility (Fig. 7-18), warmth, erythema, and joint deformity may be noted. It is typical for the child with JIA to have more joint stiffness than pain. Symptoms often develop gradually over a period of weeks or months before evaluation. Morning stiffness is often reported. The duration of morning stiffness correlates well with the degree of inflammation in children with JIA. Immobility and weather changes may exacerbate symptoms, although they have no impact on the underlying inflammatory component of the disease. Although arthralgia alone can be the initial presentation of JIA, the diagnosis cannot be confirmed without the presence of arthritis on physical examination.

Figure 7-17 Juvenile idiopathic arthritis (JIA). A, Erythema of the knee in a patient with systemic-onset JIA (Still disease). B, Swelling and inflammation of the small joints of the hands in a patient with polyarticular JIA. Note the inability to fully extend the fingers. C, Swelling of the right thumb interphalangeal joint. D, Right knee swelling in a patient with pauciarticular JIA.

Figure 7-18 Oligoarticular juvenile idiopathic arthritis. A, A 2-year-old girl with arthritis of the left knee. Note that the left lower extremity is bent at the knee as she bears weight on the extended right lower extremity. B, A closer look at the knees reveals left knee swelling. C, The left knee can be extended only to 35 degrees (secondary to a flexion contracture).

Despite objective signs of arthritis, the patient with JIA may not experience pain. When inflammation persists for a long enough period of time, destruction of the articular surface and bony structures may occur (Fig. 7-19). Because of the poor regenerative properties of articular cartilage, these deformities are usually permanent. Fortunately, most cases of JIA are not associated with permanent joint deformity.

Figure 7-19 Juvenile idiopathic arthritis. Demineralization of the left femur and tibia with soft tissue swelling and hypertrophy of the epiphyses secondary to hyperemia.

Psoriatic Arthritis

Psoriatic arthritis is diagnosed in a child with arthritis and psoriasis. Criteria are also met when a child with arthritis has two of the three findings: dactylitis (“sausage digit”), nail pitting (or onycholysis), or psoriasis in a first-degree relative. Whereas the forms of arthritis previously discussed have weak genetic penetrance, psoriasis and its related disorders are often found through a given family’s pedigree. A patient may often present to their physician with just dactylitis of one or multiple toes. In such a situation, in addition to a detailed joint examination, a detailed skin and nail examination should be performed (Fig. 7-20). Special attention should be paid to the scalp, the umbilicus, posterior ears, gluteal cleft, and shins.

Figure 7-20 Psoriatic arthritis. A, Erythematous plaques with silver scale. B, Dactylitis (sausage toe) of the bilateral third and fifth toes. C, Diffuse nail pitting.

Systemic Arthritis

Systemic arthritis (Still disease) accounts for approximately 10% of all children with JIA. Fever, rash, irritability, arthritis, and visceral involvement dominate the clinical presentation. The patient’s temperature usually rises to greater than 39° C, and this often occurs twice daily in a double quotidian pattern. Chills are associated with fever, but rigors rarely occur. Although the late afternoon is a typical time for a temperature rise, many other patterns may occur. Other manifestations of systemic arthritis, such as rash and joint symptoms, may wax and wane during febrile periods. A helpful clinical feature during the febrile phase is one subnormal temperature during every 24-hour period, which suggests JIA.

The rash of JIA is macular, 2 to 6 mm in diameter, evanescent, and salmon or red in color, with slightly irregular margins (Fig. 7-21). An area of central clearing often exists. The rash usually occurs on the trunk and proximal extremities, but it may also be distal in distribution, with palms and soles affected. Although the rash generally does not produce discomfort, some older patients report pruritus. Superficial mild trauma to the skin, exposure to warmth, and emotional upset may precipitate the rash (Koebner phenomenon). Arthritis may not occur invariably at the onset of systemic arthritis, and thus the diagnosis may not be readily apparent. When fever of unknown origin is the sole initial presentation of systemic arthritis, it must remain a diagnosis of exclusion until the clinician observes inflammatory arthritis during the physical examination. Arthralgia and myalgia can be prominent early, as can hepatosplenomegaly and lymphadenopathy. Serositis, pleuritis, pericarditis, hyperbilirubinemia, liver enzyme elevation, leukocytosis, and anemia are supporting clinical features. About 50% of patients with systemic arthritis progress to having chronic inflammatory arthritis, which often is destructive (Fig. 7-22).

Figure 7-21 Systemic-onset juvenile idiopathic arthritis. A and B, The rash is erythematous, macular, and often evanescent. It can be more prominent during periods of fever. Featured on trunk and extremities.

Figure 7-22 Systemic-onset juvenile idiopathic arthritis (JIA). The femoral head from a 13-year-old girl with a hip replacement shows significant bony erosion. Patients with systemic and polyarticular JIA are more likely to suffer joint destruction than are patients with oligoarticular juvenile idiopathic arthritis.

Extraarticular Manifestations

Patients with JIA are at risk of developing iridocyclitis (or uveitis). Although photophobia, eye pain, and erythema can occur, uveitis is often asymptomatic. For that reason, children with oligoarticular and polyarticular JIA must receive slit-lamp examinations frequently.

The first clinical sign of uveitis is cellular exudate in the anterior chamber. If the uveitis is left untreated, synechiae (adhesions) between the iris and lens may develop, leading to an irregular and poorly functioning pupil (Fig. 7-23). Further along in the clinical course, band keratopathy (calcium deposits in the cornea) (Fig. 7-24) may occur, as well as cataracts or glaucoma. For these reasons, strict adherence to the recommendations for eye examination outlined in Table 7-4 is necessary to help prevent visual loss in these children. Ophthalmologic complications do not parallel the activity of the arthritis.

Figure 7-23 Iridocyclitis. An irregular pupil in a patient with oligoarticular juvenile idiopathic arthritis. Note synechiae projecting posteriorly toward the lens.

Figure 7-24 Band keratopathy. Note the calcium deposits in the Bowman layer in this patient with juvenile idiopathic arthritis.

Table 7-4 Recommended Frequency of Ophthalmologic Examinations in Juvenile Idiopathic Arthritis

Linear growth retardation may occur in the child with active JIA, especially with systemic or polyarticular disease. The degree of growth retardation and the ultimate prognosis for reaching adult height are related to the severity and duration of inflammation and the use of corticosteroids. Treatment with steroid-sparing agents such as nonsteroidal antiinflammatory drugs (NSAIDs), disease-modifying agents (i.e., methotrexate), and biologic agents (i.e., etanercept, adalimumab, and infliximab) is currently preferred compared with the heavy steroid usage of the past. Oligoarticular arthritis can present with bizarre growth abnormalities, usually confined to leg length discrepancy or an enlarged hand or foot related to refractory ankle or wrist involvement. During early illness, bony development may be advanced; later in the course of the illness the opposite may be true. Premature epiphyseal fusion may occur.

Cardiac involvement occurs in more than one third of patients with systemic arthritis. Pericarditis, myocarditis, and endocarditis occur, with pericarditis being the most common. Chest pain, a friction rub, tachycardia, dyspnea, and supportive chest radiograph, electrocardiogram, and echocardiographic findings may occur. These episodes may last for weeks to months and are usually associated with a generalized flare of disease. Various other extraarticular manifestations including hepatosplenomegaly and lymphadenopathy are particularly common in systemic arthritis.

Patients with systemic arthritis are at risk for developing a potentially fatal disorder called macrophage activation syndrome (MAS). Patients present with a toxic appearance, fever, hepatosplenomegaly, lymphadenopathy, and mucosal bleeding. If not recognized early, MAS can progress to hepatic failure, encephalopathy, and disseminated intravascular coagulation. Laboratory testing that supports a diagnosis of MAS includes evidence of hepatitis and coagulopathy. In addition, the white blood cell count, hemoglobin, and platelet counts are depressed with a normal or low sedimentation rate (Table 7-5). Diagnosis is confirmed by bone marrow aspiration demonstrating activated macrophages engulfing surrounding cells (Fig. 7-25).

Table 7-5 Characteristics of Macrophage Activation Syndrome in Patients with Systemic-onset Juvenile Idiopathic Arthritis

Acutely ill with bruising, purpura, mucosal bleeding Hepatosplenomegaly Lymphadenopathy Decrease in white blood cell count, hemoglobin, and platelet count Decrease in erythrocyte sedimentation rate Elevation of alanine aminotransferase, aspartate aminotransferase, prothrombin time, partial thromboplastin time, fibrin split-products, ferritin, and triglycerides Decrease in fibrinogen, clotting factors Tissue biopsy (i.e., bone marrow, liver) may demonstrate active phagocytosis by macrophages

Modified from Cassidy JT, Petty RE: Textbook of pediatric rheumatology, ed 5, Philadelphia, 2005, WB Saunders.

Figure 7-25 Macrophage activation syndrome (MAS). Bone marrow aspirate shows activated macrophages with foamy cytoplasm engulfing surrounding erythrocytes and neutrophils.

(Courtesy Alexi Grom, MD, Cincinnati, Ohio.)

Differential Diagnosis

Because JIA is a clinical diagnosis, strict clinical criteria have been established to make the diagnosis. Most authors suggest the presence of objective joint findings (arthritis) for a minimum of 6 consecutive weeks coupled with the exclusion of other causes of arthritis in children (Table 7-6).

Table 7-6 Differential Diagnosis of Juvenile Idiopathic Arthritis

Systemic Onset

Systemic lupus erythematosus Kawasaki syndrome Acute rheumatic fever Henoch-Schönlein purpura Polyarteritis nodosa Dermatomyositis Systemic sclerosis Inflammatory bowel disease Malignancy (leukemia, neuroblastoma) Lyme disease Viral syndrome Familial Mediterranean fever

Polyarticular Onset

Systemic lupus erythematosus Psoriatic arthritis Hypermobility syndrome Enthesitis syndrome Reactive arthritis

Oligoarticular Onset

Septic joint (monoarthritis) Reiter syndrome Juvenile ankylosing spondylitis Pigmented villonodular synovitis Psoriatic arthritis Lyme disease

Because of its destructive nature, pyogenic arthritis (e.g., staphylococci, streptococci, Haemophilus influenzae) must be ruled out in any child with active joint disease, especially monoarthritis. The intensely red and tender joint should raise suspicion of a bacterial pathogen. This combined with systemic symptoms of infection (fever, chills, malaise, rigors) should prompt the clinician to perform an arthrocentesis early in the course of the illness.

Lyme arthritis can mimic oligoarticular JIA. This spirochetal form of arthritis is tick-borne and usually affects the knee, elbow, or wrist in a monoarthritic pattern with spontaneous exacerbations and remissions. Malaise, fever, myalgia, lymphadenopathy, headache, meningismus, and weakness also may occur in the first phase of the illness. The distinctive rash, known as erythema migrans (Fig. 7-26), begins as an erythematous macule or papule. After this clears, the borders of the lesion expand to form an erythematous circular lesion that can be as large as 30 cm in diameter. These lesions can initially occur singly but can progress to multiple lesions over the legs, arms, and trunk. Other manifestations of Lyme disease include neurologic complications such as seventh nerve palsy, meningitis, radiculoneuritis, and the cardiac manifestations of heart block and myopericarditis. Bilateral Bell’s palsy or seventh nerve paralysis even more strongly suggests the diagnosis of Lyme disease.

Figure 7-26 Lyme disease. The lesion of erythema migrans may be a large erythematous macule with central clearing, occurring singly or multiply.

Other infections cause a reactive arthritis that dissipates in less than 6 weeks. Salmonella, Shigella, Yersinia, and Campylobacter organisms should also be considered. A multitude of viruses cause arthritis. These include rubella; hepatitis B; adenovirus; and herpesviruses including Epstein-Barr virus, cytomegalovirus, varicella zoster, and herpes simplex. Parvoviruses, mumps, and enteroviruses including echovirus and coxsackievirus are associated with acute polyarthritis and occasionally have been recovered from joints. Other viruses result in reactive arthritis and may not infect the joint directly.

Poststreptococcal phenomena include acute rheumatic fever (ARF) and poststreptococcal reactive arthritis. In ARF, Jones criteria are met. The child must be monitored for cardiac sequelae such as valvulitis and congestive heart failure. In poststreptococcal reactive arthritis, Jones criteria are not met. Arthritis will resolve but arthralgia can last for 6 months. The joint pain may be axial and affect the spine. In both cases, children are given prophylactic antibiotics to try and prevent future streptococcal infections.

Malignancies such as neuroblastoma and leukemia may present with musculoskeletal pain. More careful evaluation generally reveals bone pain. Sickle cell disease, particularly in the form of dactylitis, can have prominent digital involvement. Hemophilia, tuberculosis, and gonorrhea infection must be considered in the patient with arthritis. Differential diagnoses of JIA are proposed in Table 7-6.

Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multisystem auto-immune disease with a myriad of clinical presentations. SLE may present in an insidious fashion and hence escape early diagnosis, or it may present acutely and progress rapidly, leading to the patient’s demise. Frequently, children will present with nonspecific constitutional symptoms, such as fever, diffuse alopecia, weight loss, fatigue, and evidence of diffuse body inflammation with lymphadenopathy and hepatosplenomegaly. All organ systems have the potential to become involved, but the most common are skin, musculoskeletal, and renal systems in pediatric SLE (pSLE). As with other collagen vascular diseases, the etiology of SLE is unknown. Because of the large number of serologic markers known to occur in SLE, it is considered by many to be the prototype of autoimmune diseases. To increase diagnostic accuracy, the American College of Rheumatology (ACR) revised its classification criteria of lupus (Table 7-7). This classification, which combines clinical and serologic markers, is highly sensitive and specific for the diagnosis of this disease, reaching almost 100% sensitivity and specificity when 4 of the 11 criteria are present; however, the criteria are not meant for the clinical application of diagnosis and should be used as a study guide rather than applied to the clinical arena.

Table 7-7 Criteria for the Classification of Systemic Lupus Erythematosus*

* Four of 11 criteria provide a sensitivity of 96% and a specificity of 96%.

† Any one item satisfies this criterion.

The word lupus, which means wolf, alludes to the erosive nature of the rash of SLE (“wolf bite”) (Fig. 7-27). This feature of the disease was critical to the diagnosis of SLE until the discovery of the lupus erythematosus (LE) cell in 1948. The LE cell represents a healthy neutrophil that has phagocytosed the nuclear debris of a nonliving cell that has been coated with antibody. The antibody is directed against deoxyribonucleoprotein (DNP), which is made up of both DNA and histones. The presence of this serologic marker for lupus greatly expanded the recognized clinical entity of SLE. Although the LE preparation has proved to be of historical interest, time has shown that it is a nonspecific immunologic phenomenon and has no specificity with respect to the diagnosis of SLE; hence, although it was included in the ACR 1982 criteria, it was not included in the ACR 1997 criteria.

Figure 7-27 Systemic lupus erythematosus. A, Malar rash of systemic lupus erythematosus. Erythema, erosion, and atrophy are present. Note sparing of nasolabial folds. This patient also has a rash involving the forehead and chin. B, Lateral view shows ear involvement.

SLE accounts for 10% of patients with rheumatic diseases and for less than 5% of children seen in pediatric rheumatology practices. The incidence is estimated at 0.5 per 100,000 children per year. From prevalence data, it has been inferred that there are between 5000 and 10,000 children with SLE in the United States. The disease is rare in children younger than the age of 5 years. Before menarche, the boy-to-girl ratio is equal. After menarche, the ratio of affected girls to boys approaches 8 : 1. African Americans and Asians are more commonly affected than the white population.

The incidence of other connective tissue diseases is higher among family members of patients with SLE. Hematologic malignancies and immunodeficiencies are also reported in increased frequency among the relatives of patients with SLE. These well-described phenomena may reflect a genetic alteration of immunity or, as some researchers suggest, the effects of a transmissible agent. The high incidence of the disease in girls supports the role of hormonal factors as contributing or modulating agents in the pathogenesis of SLE. Other investigators suggest the influence of viruses, sunlight, and emotional stress on those developing lupus.

Although immunologic markers contribute to making the diagnosis of SLE, a high index of suspicion is necessary to obtain these studies. The early symptoms are often nonspecific and sometimes go unrecognized as harbingers of serious disease. Fever, fatigue, malaise, anorexia, and weight loss may be the only symptoms. In the adolescent population these symptoms may be all the more difficult to interpret. Conversely, this multisystem disease may present with a plethora of physical findings and the presentation may be so dramatic that the diagnosis is readily apparent. The most common organ manifestations at disease presentation in pSLE are musculoskeletal, cutaneous, renal, and hematologic.

Cutaneous manifestations of SLE occur at some time during the course of the disease in 80% of affected individuals. There are a variety of cutaneous findings including a malar rash, photosensitive rash, palmar erythema (Fig. 7-28), annular erythema, vasculitic skin lesions with nodules or ulcerations, Raynaud phenomenon and associated ulceration, alopecia, and discoid lupus. Isolated discoid lupus is rarely seen in children, but when it occurs is usually without systemic manifestations. The same holds true for subacute cutaneous lupus, which is uncommon, presenting as a serpiginous-like photosensitive erythematous rash associated with positive SS-A (anti-Ro) antibody. The most frequent skin manifestations of SLE are malar rash and photosensitive rash. The classic malar or butterfly rash is a maculopapular rash distributed over the cheeks (malar eminences) and extending over the bridge of the nose, while sparing the nasolabial folds (see Fig. 7-27). The malar rash is photosensitive in 30% of the patients. In general, sun exposure may not only exacerbate the skin disease but also cause a systemic flare of disease, theoretically through large exposure of the immune system to intracellular proteins through massive apoptosis of damaged skin cells. Therefore, appropriate sun protection and avoidance is strongly encouraged. An annular photosensitive rash is frequently associated with the “Sjögren syndrome antibodies” anti-Ro (SS-A) and anti-La (SS-B). The typical morphology of the rash of lupus is defined as reddish purple and raised with a whitish scale (Fig. 7-29). When the scale is removed, the underlying skin often shows “carpet tack–like” fingers on the unexposed side of the scale itself. Carpet tacking is caused by the contouring of the scale into the skin follicles. These finger-like projections on a scale strongly suggest the diagnosis of lupus. Vasculitic rashes are more violaceous and may be associated with nodules, ulceration, and palpable purpura (Fig. 7-30). These lesions are commonly found in an acral distribution, and typically result in postinflammatory hyperpigmentation. Discoid lupus, although uncommon (5% to 10% of patients with pSLE), leaves the most damage with follicular plugging and scarring. Mucosal erosions and ulcers of the oral cavity and nasal mucosa are part of lupus as well, with the most well-recognized manifestation being the “silent” large violaceous ulceration of the hard palate (Fig. 7-31). Alopecia occurs in 20% of patients and may present as broken hair shafts or patchy, red, scaling areas on the scalp, which may eventually scar and cause permanent hair loss (Fig. 7-32). Other reported mucocutaneous findings are livedo reticularis (lacy, fishnet appearance of the skin), urticaria, atrophy, and telangiectasia. The presence of livedo reticularis may be the clinician’s only clue to an associated hypercoagulable state manifested by anti-phospholipid antibodies. This tendency can be diagnosed by obtaining a lupus anticoagulant panel, a functional assay that includes a partial thromboplastin time (PTT), anti-cardiolipin antibodies, and anti–β₂-glycoprotein antibodies. Although anti-phospholipid antibody syndrome (APS) can occur as an entity alone, it is commonly associated with SLE. APS is defined as a hypercoagulable state characterized by both positive laboratory findings of anti-phospholipid antibodies and clinical findings of a variety of venous and arterial thromboses and recurrent fetal loss.

Figure 7-28 Systemic lupus erythematosus. Palmar erythema.

Figure 7-29 Systemic lupus erythematosus. A, Note the localized erythematous rash in a nonmalar distribution. B, The rash of SLE often has a slight white scale.

Figure 7-30 Systemic lupus erythematosus. Purpuric, ulcerative, and necrotic skin lesions of cutaneous vasculitis.

Figure 7-31 Systemic lupus erythematosus. “Silent” ulceration of the hard palate.

Figure 7-32 Systemic lupus erythematosus. Scarring alopecia.

The heart is often significantly involved in patients with lupus. Although the pericardium is involved most commonly, the myocardium and the endocardium may also be of clinical importance. Pericarditis with associated pericardial effusion can be painless and may present only as cardiomegaly on a chest radiograph (Fig. 7-33) or as pericardial effusion on an echocardiogram. However, chest pain may be noted, especially on deep inspiration and when lying down. Auscultation of a friction rub signifies pericarditis. Although pericarditis is usually mild, it can progress to life-threatening cardiac tamponade. If the myocardium is affected, life-threatening complications including dysrhythmias, heart failure, and infarction can result. Libman-Sacks endocarditis is the term given to the verrucous projections of fibrinoid necrosis in the endocardium. These lesions rarely cause clinical symptoms, although the presence of a murmur raises suspicion of endocardial disease. The mitral valve is most commonly involved, although aortic and tricuspid valves may be similarly affected. The presence of Libman-Sacks endocarditis should also alert the clinician to the possibility of an underlying anti-phospholipid antibody syndrome. The major cardiac morbidity associated with SLE, which is gaining more recognition in the adolescent pediatric SLE population, is premature atherosclerosis. Several factors contribute to the risk of atherosclerosis, including chronic inflammatory processes, altered endothelial function, lipid abnormalities, nephritis, and proteinuria. Monitoring and controlling classic Framingham risk factors in addition to factors attributable to lupus are critical for long-term morbidity.

Figure 7-33 Systemic lupus erythematosus. Large pericardial effusion with associated cardiac tamponade physiology in teenage female. Pleural effusions are also present.

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