Introduction Despite its rare ocurrence, thromboembolic events are more frequent in newborns than in any other paediatric age group, and can results of diverse congenital or acquired prothrombotic factors. We report a case of deep venous thrombosis (DVT) in a previously healthy newborn admitted with Streptococcus pyogenes infection.

Case Report 7-day old term female infant, born by vacuum delivery (birth weight 3780 g, Apgar 9/10), referred to our NICU with a 24 h history of grunting, anorexia and painful, swollen and purple discoloration of left lower limb. Laboratory findings showed leucopenia (1750/uL), neutrophilia (88%), C Reactive Protein 4.5 mg/dL, normal haematocrit and platelet count. Remaining lab values, including electrolytes and coagulation tests were normal. Soft tissue infection was suspected and antibiotics started. Lower limb ultrasound and Doppler showed extensive DVT in the left side. Subcutaneous enoxaparin was started and dosage was adjusted according with anti-Xa factor levels. Homocisteyne, protein S, protein C and antithrombin levels were normal. Factor V Leiden, G2021A prothrombin and antiphospholipid antibodies were absent. Streptococcus pyogenes was isolated in blood and cerebrospinal fluid cultures confirming the diagnosis of sepsis and meningitis.

Discussion Thrombosis in neonatal period can cause significant morbidity and be life threatening. Early diagnosis and optimal treatment strategies are important to avoid complications. Streptococcus pyogenes has been associated with thromboembolic events in adults and older children. Despite being an uncommon cause of infection in neonates, this agent should be considered as the possible aetiology of DVT in previously healthy newborns.