"The time is out of joint": Pain, paresthesias, and weakness in a preadolescent
Your patient is a 10-year-old Latino girl brought to the clinic by her very concerned mother. The complaint is leg and joint pain—severe enough to make walking difficult. The visit comes after your colleague at the clinic saw the girl about a month ago for an unusual rash described in the record as a brownish, linear, papular eruption, possibly urticaria pigmentosa. He prescribed hydroxyzine.
Three weeks later, you read, your colleague saw the girl again, this time for a complaint of pain in the left wrist, symptoms of a common cold, and a barky cough of approximately two weeks' duration. She complained that she was feeling generally tired. He prescribed azithromycin for suspected Mycoplasma infection. Examination of the hands and arms was unremarkable. He instructed the mother to watch for joint swelling.
QD: Pain and a long nap
Now, five days after that last visit, the patient has returned with pain in the back, legs, and small joints of the fingers. Walking is difficult, she tells you. There is still a slight cough. She does not have a fever and does not complain of a sore throat or ocular or urinary symptoms. There is no nausea, vomiting, diarrhea, or constipation.
The girl denies weight loss or diminished appetite. She does complain of generalized fatigue and increased sleepiness: She takes a three-hour nap every day after school! You begin by taking the history.
Your patient is in the fourth grade and, her mother reports, is a good student. She lives with her mother and a younger, school-age brother. Her parents have been separated for about nine months; the father is involved in his children's life on an almost daily basis, the mother reports. She denies a history of domestic violence in the family.
The medical history is noncontributory. The girl was delivered at term. She has no history of hospitalization, surgery, or serious illness; has been fully immunized; and does not have known drug allergies. Hydroxyzine and azithromycin are her only medications over the past several months. She has had no recent exposure to ticks, has not been camping, and has not traveled recently. She has had no recent illnesses other than "colds" and "coughs" and no gastrointestinal problems.
The family history is positive for osteoarthritis on the maternal side, and a maternal grandmother who has rheumatoid arthritis.
On physical examination, your general impression is of a well-nourished, well-developed, slightly obese girl who is not in acute distress. The earlier rash over the left forearm is barely noticeable.
Height is at the 50th percentile for age; weight, between the 75th and 90th percentiles. Vital signs are unremarkable: Blood pressure, 107/59 mm Hg; pulse, 69/min; temperature, 97.3°F; and respiratory rate, 22/min. The ear, nose, and throat exam is benign. Oral mucosa is moist and without lesions. There is no conjunctival injection. Bilateral red reflexes are clear. Heart sounds are normal; no heart murmur is heard. Breath sounds are clear. The abdomen is soft and nontender; bowel sounds are present; and you do not palpate any masses or hepatosplenomegaly.
The genitalia are normal and Tanner Stage I. You note no cervical, axillary, or inguinal lymphadenopathy. The neck is supple without thyromegaly.
The patient expresses pain in the metacarpophalangeal and interphalangeal joints of both hands and describes pain in almost all other joints—neck, spine, and large and small joints of the extremities, including shoulders, hips, elbows, and knees. On thorough examination of those joints, you cannot detect swelling, erythema, effusion, or increased warmth over the skin—the tenderness she expresses over the metacarpophalangeal and interphalangeal joints by palpation notwithstanding. The pain is elicited in all small finger joints by passive motion, by wrist movements, and by examination of the large joints of the lower extremities, including knees and hips. She appears to have hyperflexible finger joints. Gait is guarded but there is full range of motion in all joints.
Much pain, no findings
You know that joint complaints are common in children and, in most cases, transient. Arthritis, defined as swelling of a joint or limitation of motion accompanied by heat, pain and tenderness, is much less common than arthralgia (simple joint pain). Disorders of periarticular inflammation may mimic arthritis.
Causes of arthritis and periarticular disorders
A number of thoughts come to mind about the differential diagnosis (see the table - не включена, Алон) in this patient—thoughts that are confounded by the constellation of symptoms. Could this be juvenile rheumatoid arthritis? Should you consider connective tissue disease, such as systemic lupus erythematosus (SLE)? Lack of a true arthritis or systemic or constitutional symptoms (other than the fatigue), plus the absence of fever, however, cast doubt on these possibilities.
What about inflammatory bowel disease, which can present with arthritis? Even if swelling of a joint were documented, it would likely affect only a few large joints—not all joints of the body.
Chronic active hepatitis can present with arthralgia, confined to single joints, but often several joints are involved, usually the large ones.
A migratory polyarthritis may be seen in mycoplasmal infection; this is an interesting possibility, considering that the girl has had a cough and a urticarial rash, although an atypical one.
What about Sch?nlein-Henoch purpura? The rash associated with this vasculitis of unknown cause—purpuric, petechial, or, occasionally, urticarial—is characteristic and most prominent on the lower extremities, although it sometimes occurs on the arms and face, and rarely, on the trunk. Arthralgias, with periarticular swelling involving a few joints, occur in approximately 40% of cases. Abdominal pain, nephritis, hypertension, and unusual areas of edema are common. Your patient's mother insists that she has noted intermittent swelling of her daughter's hands and feet, but you cannot appreciate this or other symptoms of Sch?nlein-Henoch purpura.
Hypermobility syndrome? Alone, this is not likely to affect all joints of the body at the same time.
Hypersensitivity arthritis—so-called serum sickness—caused by a drug or virus and accompanied by joint swelling, is a possibility. The condition can also be associated with edema of the hands and feet and urticarial rash.
Reactive arthritis after pharyngitis or gastrointestinal infection crosses your mind. This can involve single or multiple joints, and can be migratory. Other than the cold that the mother reported early this month, the girl has not had a sore throat or any GI problems.
Your diagnosis, for now, is generalized arthralgia, possibly postviral or of other infectious cause. You turn to basic laboratory work: complete blood count, erythrocyte sedimentation rate, C-reactive protein, comprehensive metabolic profile, urinalysis, antinuclear antibody titers, rheumatoid factor, anti-streptolysin O titer, and parvovirus titers. You also order radiographs of the hands and both hips.
You advise ibuprofen for pain and recommend follow-up in one week.
Most of the lab results arrive on a Friday afternoon. Other than an elevated anti-streptolysin O (ASO) titer of 718 and a positive antinuclear antibody (ANA) titer of 1:160 in a speckled pattern, the tests are normal, including an ESR of 12 mm/hr and C-reactive protein <0.4 mg/L. Some nitrates are noted on urinalysis. The metabolic profile shows that liver function is normal; only the CO2 is slightly low at 18.6 mEq/L. All films are read as normal by the radiologist.
In light of the elevated ASO titer, you elect to treat the girl with a 10-day course of amoxicillin—lack of evidence of poststreptococcal arthritis notwithstanding. When you call the mother with results, she reports that the girl's pain is intensifying, and you also prescribe acetaminophen with codeine for relief over the weekend.
"Born to set it right"?
Your patient returns to the clinic on Monday. She is now unable to walk well without assistance and is brought into your office in a wheelchair! She complains of dizziness, and tells you that she has had "a hard time breathing" and that "it hurts to cough."
Such an abrupt change in mobility is of major concern. You consider other explanations. Is the pain of muscular origin—myalgias or myositis? Perhaps this is dermatomyositis or scleroderma—given the history of an unusual linear-looking rash and pain on palpation over the extremities.