What is the clinical presentation of brucellosis in pediatric patients?

Clinical Presentation of Brucellosis in Children

Brucellosis in children typically presents with nonspecific symptoms including fever, malaise, arthralgia, and night sweats, often mimicking other febrile illnesses and leading to diagnostic delays, with bone-joint involvement occurring in approximately 20% of cases and hematologic abnormalities in up to 59% of patients. 1, 2

Primary Clinical Features

Constitutional Symptoms

• Fever is the most common presenting symptom, often prolonged and relapsing in nature 3, 2
• Malaise and lack of appetite are frequently reported initial complaints 2
• Night sweats represent a characteristic but nonspecific finding 2
• Irritability, lethargy, and altered mental status may occur, particularly when neurological involvement is present 4

Musculoskeletal Manifestations

• Arthralgia is a predominant symptom that should raise suspicion for brucellosis in endemic areas 2
• Bone-joint involvement occurs in 20.7% of pediatric cases, with significantly elevated Brucella Coombs gel test titers (≥1/640) and increased ESR in this subgroup 1
• Vertebral osteomyelitis can present as subacute back pain in endemic regions 5

Organ System Involvement

Hematologic Complications

• Hematologic abnormalities are the most common complication, occurring in 59.1% of cases 2
• Anemia is present in 35.6% of patients 1
• Leukopenia occurs in 9.9% of cases 1
• Thrombocytopenia is observed in 3.9% of patients 1

Hepatic Involvement

• Organomegaly (hepatomegaly and/or splenomegaly) is present in 13.9% of cases, associated with significantly higher Brucella CT titers and CRP levels 1
• Elevated liver function tests occur in 31.7% of pediatric patients 1
• Mild transaminitis is commonly observed 5

Neurological Complications

• Meningoencephalitis can occur as a presenting feature, with symptoms including irritability, sleepiness, and altered consciousness 4
• Neurobrucellosis may present with fever and neurological signs in endemic areas 6
• Lumbar puncture may initially show normal CSF protein and cell counts despite active infection 4

Cutaneous Manifestations

• Rash can occur, particularly on the lower extremities 3
• Cutaneous involvement is less common, occurring in approximately 4.5% of cases 2

Unusual Presentations

• Ocular involvement including keratitis and red eye phenomenon has been reported 4
• Coronary artery aneurysms can occur, potentially mimicking Kawasaki disease 4

Diagnostic Challenges and Pitfalls

Common Misdiagnoses

• Mycoplasma pneumonia is frequently considered initially, leading to inappropriate antibiotic therapy 3
• Incomplete Kawasaki disease may be suspected when coronary involvement is present 4
• The nonspecific nature of symptoms leads to diagnostic delays averaging 10 days or more before correct diagnosis 3

Critical Epidemiological Clues

• History of unpasteurized dairy consumption is a key risk factor 5, 6
• Occupational or household exposure to livestock, particularly sheep, should be actively sought 5, 6, 3
• Residence in or travel to endemic areas significantly increases pretest probability 5

Laboratory and Inflammatory Markers

Acute Phase Reactants

• Elevated ESR is significantly associated with bone-joint involvement 1
• Elevated CRP is substantially higher in patients with organomegaly 1
• High Brucella Coombs gel test titers (≥1/640) correlate with complicated disease including bone-joint involvement and organomegaly 1

Baseline Abnormalities

• Mild pancytopenia is commonly observed 5
• Elevated inflammatory markers (ESR and CRP) should be obtained at baseline 5

Special Populations

Congenital Brucellosis

• Vertical transmission can occur through placental infection 7
• Neonates may present with fever, meningitis, hyperbilirubinemia, and liver dysfunction 7
• Maternal symptoms including fatigue, arthralgia, fever, and premature membrane rupture may precede neonatal presentation 7
• This presentation poses significant treatment challenges with high relapse rates in infancy 7

Clinical Pearls

High acute-phase reactants (ESR, CRP) and elevated Brucella CT titers should prompt consideration of complicated brucellosis with organ involvement. 1 The combination of fever with rheumatological complaints in a child from an endemic area or with appropriate exposure history should always trigger evaluation for brucellosis, even when initial presentations suggest other diagnoses. 2 Early recognition through appropriate serological testing (SAT or colloidal gold immunochromatographic assay) can prevent diagnostic delays and reduce complications. 3