Intermittent Fevers and Inability to Bear Weight in a 7-Year-Old Boy

A 7-year-old boy presented to a community emergency department (ED) in the late spring with a swollen right ankle and refusal to weight bear. Four weeks prior, he began having intermittent fevers (once weekly, up to 38.7°C axillary) and nonspecific pain involving the neck, shoulders, back, arms, and legs. He also had a nonspecific macular rash over the torso. This prompted his parents to bring him to a walk-in clinic where he was diagnosed with a viral upper respiratory illness after the physician identified an erythematous throat. Three weeks after his symptoms began, he sought medical care after developing a new painful and swollen left ankle. An ankle radiograph was normal, and he was diagnosed with a left ankle sprain. Two days later, his left ankle swelling resolved, but the right ankle became warm, painful, and swollen. He also developed a new cough and rash over his chest and was eventually referred to the emergency department by his family physician to rule out septic arthritis. On examination, he had a temperature of 37.3°C, heart rate of 102 beats/min, respiratory rate of 20 breaths/min, and oxygen saturation of 100% in ambient air. He appeared well and nontoxic. The right ankle was swollen with a decreased range of motion. There were no overlying skin changes. The left ankle and other extremities were normal on examination. His oropharynx and tympanic membranes were clear. There was a grade 2/6 systolic ejection murmur noted over the left sternal border. Auscultation of his chest was clear, and his abdomen was soft and nontender without masses. He had gone camping in central Ontario during the preceding week but reported no insect or mosquito bites. There was no recent travel outside of the country. There was no history of sore throat, rhinorrhea, vomiting, diarrhea, or abdominal pain. His medical history was remarkable for Kawasaki’s Disease at 2 years of age without coronary artery involvement and a benign heart murmur. He was born at 36 weeks gestation without complication. He had no known allergies. His immunizations were up to date. There was no family history of autoimmune disease or immunodeficiency. He was discharged from the emergency department with the diagnosis of reactive arthritis, and bloodwork was ordered for the following day. Laboratory studies revealed a white blood cell count of 8.7 × 109/L (normal) with 53% neutrophils, 38% lymphocytes, 5% monocytes, and 4% eosinophils; hemoglobin of 109 g/L(normal); platelets of 729 × 109/L (elevated); C-reactive protein of 76.7 mg/L (elevated); and erythrocyte sediment rate of 28 mm/h (elevated). Urinalysis was normal, and the urine culture showed no growth. Further testing including a throat culture, antistreptolysin O titer, and echocardiogram helped establish the diagnosis. For Denouement see P. 86. DENOUEMENT Continued from P. 85. The child was referred to our pediatric clinic, where he was assessed 3 days after his emergency department visit. On examination, he was well appearing with a faint, irregular lace-like rash on each of his left and right inner thighs. A grade 2/6 systolic murmur was again appreciated over the left lower sternal border. No nodular lesions were appreciated affecting the skin, and there was no arthritis. His oropharynx was clear without tonsillar erythema or exudate, and no evidence of cervical lymphadenopathy. His neurologic examination was normal without choreoathetoid movements. His throat culture grew Streptococcus pyogenes, and his antistreptolysin O titer (ASOT) was 2002 IU/mL. His blood culture showed no growth. Borrelia burgdorferi serology was nonreactive. A 12-lead ECG showed normal sinus rhythm. His echocardiogram identified trace aortic, trace mitral, and mild tricuspid valve regurgitation. Mild mitral prolapse was present on a repeat echocardiogram performed by a pediatric cardiologist. A left ventricle false tendon was present, and coronary artery diameters were within normal limits. He was diagnosed with acute rheumatic fever (ARF) based on fever, migratory polyarthritis involving the ankles, (suspected) erythema marginatum, valvulitis, and evidence of S. pyogenes infection (positive throat culture and elevated ASOT). He was started on a 10-day course of amoxicillin and was referred to infectious disease and rheumatology at the local tertiary pediatric center, where he was subsequently started on prophylactic penicillin V. He was also seen by pediatric cardiology who recommended physical activity restrictions based on his echocardiogram findings. ARF is a nonsuppurative, postinfectious complication of S. pyogenes pharyngitis.1 While the incidence and prevalence of ARF and rheumatic heart disease have declined in Europe and North America over the past 5 decades, the burden of disease remains significant among children in developing countries, where overcrowding and limited access to health care persist.2,3 Furthermore, certain strains of Streptococcal pyogenes carry higher risks of rheumatogenicity.4 The exact pathogenesis of ARF remains unclear but is believed to be mediated by molecular mimicry and involves the adaptive immune system.5 The severity of ARF is determined by a combination of genetic susceptibility, environmental factors, and the virulence of the infecting organism.6 The diagnosis requires evidence of a preceding streptococcal infection, such as a positive throat culture for group A β-hemolytic streptococci, rapid streptococcal antigen test, or an elevated antistreptolysin O or antideoxyribonuclease B titers.1,7 This must be accompanied by the presence of 2 major manifestations or 1 major and 2 minor manifestations of the Jones criteria. The major criteria include migratory polyarthritis, carditis, erythema marginatum, Sydenham chorea, and subcutaneous nodules. The minor criteria include arthralgia, fever, first-degree heart block, and elevated inflammatory markers. The exception to the rule arises when there is isolated chorea, carditis with history of acute group A β-hemolytic streptococci infection, and recurrent ARF.1,7 The differential diagnosis for ARF includes reactive arthritis, juvenile idiopathic arthritis, Lyme disease, serum sickness, and other drug reactions.7 Secondary antibiotic prophylaxis has been shown to significantly reduce the risk of ARF recurrence and progression to severe rheumatic heart disease.8 Intramuscular benzathine penicillin is superior to oral penicillin in reducing the recurrence risk and streptococcal pharyngitis according to a Cochrane review but is less practical and can be associated with allergic reactions.9 In regions with high incidence of ARF or for situations where adherence to oral antibiotics is a concern, intramuscular benzathine penicillin administered every 3–4 weeks is warranted.5 Oral penicillin V is appropriate for individuals where a risk of recurrence of ARF is low and compliant with medications. Macrolides, such as azithromycin, are indicated in patients who are allergic to penicillin.9 The American Heart Association recommends that patients with a diagnosis of rheumatic fever with carditis and residual heart disease remain on secondary antibiotic prophylaxis for 10 years after their last episode of ARF or until 40 years of age. After that time, lifelong prophylaxis can be reserved for high-risk patients. For individuals with ARF with carditis without residual heart disease, prophylaxis is recommended for 10 years or until 21 years of age. In patients with ARF without carditis, prophylaxis is recommended for 5 years or until 21 years of age. When determining duration of prophylaxis, the longer of the 2 scenarios outlined previously should be selected. The decision to discontinue prophylaxis should be made jointly with the patient after careful discussion of the potential risks and benefits of treatment.8 Our patient met the modified Jones criteria for ARF, given a positive throat culture which grew Streptococcus pyogenes, a markedly elevated ASOT, and the presence of 3 major Jones criteria including migratory polyarthritis, erythema marginatum, and carditis.10 He also had 3 of the minor Jones criteria including fever, polyarthralgias, and elevated C-reactive protein. After the diagnosis was made, he had intermittent arthralgias for 1 month before his symptoms were resolved. He remains on oral penicillin V prophylaxis until at least 21 years of age based on current recommendations.9 At the 6-month cardiology follow-up, his echocardiogram showed no further evidence of valvulitis and he was permitted to resume full activity. He is scheduled for annual echocardiograms and cardiology follow-up, we well as annual infectious disease follow-ups at the tertiary pediatric center. Clinicians seldom encounter ARF in developed countries where the incidence has dramatically decreased. This case illustrates a case of ARF occurring in the absence of travel in a developed country, highlighting the importance of maintaining a healthy level of suspicion of this rare condition.

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