Persistent tachypnea in children: keep pulmonary embolism in mind.

PURPOSE: Tachypnea in children is associated with respiratory disorders and nonrespiratory disorders such as cardiac disease, metabolic acidosis, fever, pain, and anxiety. Pulmonary embolism is seldom considered by pediatricians as a cause of tachypnea. PATIENTS AND METHODS: Three children of various ages with persistent tachypnea are described: a girl after orthopedic surgery for kyphoscoliosis, a boy with nephrotic syndrome, and a neonate with Hirschsprung disease. Other causes of tachypnea were diagnosed and treated before pulmonary embolism was considered. RESULTS: Ventilation-perfusion scanning appeared to be highly probable for pulmonary embolism in these patients. Anticoagulant therapy was started. CONCLUSION: Pulmonary embolism should be kept in mind in children with tachypnea, especially when other risk factors for venous thromboembolism are present, to avoid delay in anticoagulant treatment and a fatal outcome.

Glanzmann's thrombasthenia caused by homozygosity for a splice defect that leads to deletion of the first coding exon of the glycoprotein IIIa mRNA.

Glanzmann's thrombasthenia (GT) is the result of the absence or of an altered and dysfunctional expression on the platelet membrane of the fibrinogen receptor (glycoprotein [GP] IIb/IIIa complex). Various molecular genetic mechanisms have been found to be responsible for this inherited disease. In a patient with a severe type of GT, we have found a splice variant in the GP IIIa gene that leads to premature chain termination. Immunoprecipitation experiments, using monoclonal antibodies specific for GP IIb/IIIa, showed that GP IIb/IIIa was not detectable on the platelet membrane. Amplification of reversely transcribed platelet GP IIIa mRNA by the polymerase chain reaction and subsequent sequence analysis showed a 86-bp deletion, which corresponds to exon i of the GP IIIa gene. This deletion results in a shift of the reading frame leading to eight altered amino acids followed by a premature termination codon. Analysis of the corresponding genomic DNA fragments showed three mutations in the exon i-intron i boundary region of the GP IIIa gene. One of these mutations is a G-->T transition that eliminates the GT splice donor site in the wild type. This base pair change creates a restriction site for the enzyme Mse I. Allele-specific restriction enzyme analysis (ASRA) with Mse I of amplified genomic DNA of the parents and the proposita showed that both parents (who are first cousins) are heterozygous, whereas the proposita is homozygous for the G-->T substitution.