A total of 777 patients with thrombocytosis, defined as a platelet count of greater than 500 x 10(9)l-1, seen in a University hospital over a 1-year period, were studied prospectively for aetiology. The most frequent causes of thrombocytosis were infection (21.9%), rebound thrombocytosis (19.4%), tissue damage (17.9%), chronic inflammatory disorders (13.1%) and malignancy (5.9%). Thrombocytosis associated with multiple causative factors, occurring simultaneously, was seen in 6.1% of cases. Thrombocytosis of greater than or equal to 1 million x 10(9)l-1 was found most frequently in patients with multiple aetiological factors occurring at the same time, in myeloproliferative disorders, or in postsplenectomy patients.

High humidity high flow nasal cannula has become a widely used alternative for nasal continuous positive airway pressure for the treatment of apnea of prematurity. We describe our experience of one incident of subcutaneous scalp emphysema, pneumo-orbitis and pneumocephalus with concomitant use of the high-flow nasal cannula. Journal of Perinatology (2008) 28, 779-781; doi:10.1038/jp.2008 Case Baby W was a 26 weeks gestation male with a birth weight of 901 g. He was born to a 20-year-old gravida 1 para 1 mother through a spontaneous vaginal delivery. Pregnancy was complicated by premature labor. His mother received steroids and was treated with magnesium sulfate prior to delivery. Her Group b-streptococcus status was unknown, serology non-reactive, hepatitis B surface antigen negative and Rubella immune. Baby W received continuous positive airway pressure (CPAP) at delivery and was intubated at 15 min of life. One dose of surfactant was given at the time of initial intubation. Baby W remained ventilated until 20 days of life. At that time he was extubated to 4 l min À1 high humidity high flow nasal cannula. Baby W had a large patent ductus arteriosis (PDA) that was treated medically with two courses of Neoprofen. The PDA decreased in size to small-moderate with no clinically significant shunting and did not require surgical ligation. Baby W was weaned to 2 l min À1 high humidity high flow nasal cannula by 36 days of life. At that time, Baby W was noted to have scalp crepitis.Scalp crepitis was noted in the frontal, parietal and occipital regions of the scalp, extending to the temporal regions with swelling noted on the right greater than left. Baby W's right eye was swollen, no proptosis was noted and there was no discharge from either eye. Skull X-rays showed subcutaneous edema and swelling, with no fracture of the skull. A chest X-ray showed no pneumothorax or pneumomediastinum. Baby W's high flow nasal cannula was discontinued and he was placed under an oxygen hood. A computerized tomography scan of the head revealed free air in the orbits bilaterally, and under the scalp. An ophthalmologist evaluated Baby W and his exam revealed no compromise of the blood supply or the optic nerves. The ophthalmologist recommended continued treatment with the oxygen hood as needed for oxygenation and discontinuation of the nasal cannula. Baby W continued under the oxyhood for 22 days and was then weaned to room air.Baby W was clinically evaluated frequently over the next 48 h. The scalp crepitis resolved over that time, as did the scalp swelling and eye swelling. Because the clinical symptoms resolved with use of the oxyhood there were no further studies performed. Baby W was discharged at a weight of 2266 g and at 75 days of life. He was not on oxygen at the time of discharge and had no further recurrence of scalp crepitis or orbital swelling.

Six hundred sixty-three children aged 1 to 16 years with thrombocytosis (defined as a platelet count of more than 500 x 10(9)/L) seen in a university hospital over a 1-year period were studied prospectively for etiology. The causes of thrombocytosis were infection (30.6%), hemolytic anemia (19.3%), tissue damage (15.2%), rebound thrombocytosis (14.8%), chronic inflammation (4.1%), renal disorders (4.1%), and malignancy (2%). Thrombocytosis associated with multiple, simultaneous causative factors was seen in 3.3% of cases. Among all patients with infections, osteomyelitis and septic arthritis were associated with higher platelet counts than other infections (P < .0001). Thrombocytosis secondary to infections was significantly more common in children under 5 years of age, whereas chronic inflammation, malignancy, and renal disorders were more common causes of thrombocytosis in children over 5 years of age. Thrombocytosis of 1 million or more platelets was seen in 13 (2%) children. No thrombocytosis-related complications were seen in any children, and none required any specific treatment. Thrombocytosis is a frequent finding in children. It is due to a variety of etiologic factors and is of little clinical discriminatory value. It is often due to an acute-phase phenomenon in response to infection, tissue damage, blood loss, or anemia, and is rarely due to malignancy.

CT scan imaging of the brain was done in eight children with Werdnig-Hoffmann Disease. Seven of them showed generalized cerebral cortical atrophy and one had low attenuated, non-enhancing areas in the white matter involving both frontal lobes. These changes could be due to repeated episodes of hypoxic injury.