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A 2-year-old boy was seen in the emergency department for fever and a left-sided limp. The child’s mother said he had a poor appetite and had felt feverish for 3 days, but had been drinking and urinating normally. She was treating him with acetaminophen. He did not have a runny nose, cough, congestion, vomiting, or diarrhea. There was no history of trauma or exposure to sick contacts or a daycare facility. A day earlier, the child would not bear his full weight on his left leg and was limping. He also had a red, bumpy rash on both of his legs. The child had not been seen by a pediatrician before coming to the emergency room.
The child was born full term and had not been previously hospitalized. He was generally very active and ate a balanced diet. He had no known allergies and was up to date with all of his vaccinations. There were no pets in the home and there was no report or sign of a tick bite. The mother smoked cigarettes. There was no family history of any significant disorder.
The child was alert, well developed, and in no respiratory distress. His temperature was 36.8°C (98.3°F); heart rate, 94 beats/min; respiratory rate, 24 breaths/min; blood pressure, 92/65 mm/Hg; and oxygen saturation, 100% while breathing room air. He had an erythematous, papular, non-pruritic rash on both legs and favored the left leg. He flinched when his left foot was touched.
Serous otitis media was seen on the left side. His pharynx appeared erythematous with white exudates. Cervical lymphadenopathy was also present, more prominent on the left side. Auscultation detected a benign musical heart murmur. There was no splenomegaly and his abdomen was soft. Ultrasonography of the hips showed bilateral joint effusion, slightly more pronounced on the left than the right, possibly related to toxic synovitis or septic arthritis. Radiographs of the left lower extremity found no fracture or dislocation between the hip and foot.
A complete blood count showed 20% atypical lymphocytes and decreased values for mean corpuscular volume and mean corpuscular hemoglobin. C-reactive protein level was 2.9 mg/dL (normal 0-1.0 mg/dL) and erythrocyte sedimentation rate was elevated to 40 mm/hr (normal 0-20 mm/hr). A mononucleosis-spot test was positive and an EBV test was ordered. The EBV serology results were:
• EBV capsid IgG - negative (<10)
• EBNA - negative
• EBEA (early antigen) - negative
• EBV capsid AB (IgM) - strongly positive (>160)
The patient was admitted overnight for observation and given supportive care. He ate and drank well during the stay. The limp and rash had improved by the next morning and he was discharged in stable condition without medication. The disease course of EBV mononucleosis is typically 4 to 6 weeks but the symptoms may only be present for a brief period of time.
Epstein Barr virus infection can involve any body system, as seen in this case. The erythematous papular rash is thought to be directly caused by the virus and develops in approximately 3% to 15% of persons with infectious mononucleosis. The rash is seen more frequently if an antibiotic like amoxicillin is administered, which in our case, it was not.
Transient synovitis of the hip is relatively common in young children and presents with pain and limitation of motion in of the hip. It can be treated with conservative therapy and the prognosis is usually excellent with full recovery; however, the rate of recurrence is up to 15%. To our knowledge, this is the first report of bilateral transient synovitis of the hip in a child with Epstein Barr viral infection.
• Transient synovitis of the hip associated with a rash and cervical lymphadenopathy in a young child should prompt inclusion of EBV infection in the differential diagnosis.
• In a young child, EBV infection may be overlooked since it is considered a disease seen most commonly in adolescents.
• Children with EBV infection are more likely than adults to present with abdominal pain, otitis media, and recurrent tonsillopharyngitis before or after infectious mononucleosis.
• An asymptomatic carrier is usually the source of EBV infection in young children.
• Leach CT, Sumaya CV. Epstein-Barr Virus. In: Cherry J, Kaplan S, Demmler-Harrison G, Steinbach W. Feigin and Cherry’s Textbook of Pediatric Infectious Diseases. Philadelphia, PA:Saunders;2009:2043-2071.
• Jenson HB. Epstein-Barr Virus. Pediatr Rev. 2011;32:375-384.
• Tse SM, Laxer RM. Approach to acute limb pain in childhood. Pediatr Rev. 2006;27:170-180.