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Lymphocytosis in a baby with pertussis
Clinical Picture
Lymphocytosis in a baby with pertussis Takanori Funaki, Isao Miyairi Lancet Infect Dis 2015; 15: 130 Division of Infectious Diseases, Department of Medical Specialties, National Center for Child Health and Development, Tokyo, Japan (T Funaki MD, I Miyairi MD); and Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, USA (I Miyairi) Correspondence to: Dr Isao Miyairi, Division of Infectious Diseases, Department of Medical Specialties, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan [email protected]
A 4-month-old girl presented to the emergency department after 10 days of persistent cough, 2 days of vomiting, and respiratory distress. Her parents had had a persistent cough for over a month, and she had not received any vaccination against pertussis. Her peripheral white blood cell count was 24 640 cells per μL and 78% of cells were lymphocytes. A Giemsa stain of the peripheral blood smear showed atypical lymphocytes (figure) with cleaved or lobulated nuclei. A PCR assay of the nasopharyngeal aspirates for Bordetella pertussis DNA was positive, which confirmed the diagnosis of pertussis. The girl completed oral therapy with azithromycin and her respiratory distress gradually improved, but her cough persisted for another month before complete resolution. The incidence of pertussis is increasing in young adults in Japan. This is possibly a result of waning immunity, in view of the fact that the pertussis immunisation
programme is limited to the initial three doses administered starting at 3 months of age followed by a booster dose at 12–18 months. Infections in young parents result in infections in young infants, as in the case presented, who are at the highest risk of complications. Lymphocytosis is a common systemic laboratory feature in infants with pertussis and is caused by the pertussis toxin. Increased lymphocytosis is associated with pulmonary hypertension, pneumonia, and death. Small mature lymphocytes with deep nuclear clefts can occasionally be observed in a peripheral smear as shown, and might serve as a diagnostic clue. Contributors FT took the photographs and produced the initial draft of the paper. IM reviewed the paper. Both authors wrote the final version. Declaration of interests We declare no competing interests.
Figure: Giesma stain of peripheral blood smear
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Lymphocytosis in a baby with pertussis Takanori Funaki, Isao Miyairi Lancet Infect Dis 2015; 15: 130 Division of Infectious Diseases, Department of Medical Specialties, National Center for Child Health and Development, Tokyo, Japan (T Funaki MD, I Miyairi MD); and Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, USA (I Miyairi) Correspondence to: Dr Isao Miyairi, Division of Infectious Diseases, Department of Medical Specialties, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan [email protected]
A 4-month-old girl presented to the emergency department after 10 days of persistent cough, 2 days of vomiting, and respiratory distress. Her parents had had a persistent cough for over a month, and she had not received any vaccination against pertussis. Her peripheral white blood cell count was 24 640 cells per μL and 78% of cells were lymphocytes. A Giemsa stain of the peripheral blood smear showed atypical lymphocytes (figure) with cleaved or lobulated nuclei. A PCR assay of the nasopharyngeal aspirates for Bordetella pertussis DNA was positive, which confirmed the diagnosis of pertussis. The girl completed oral therapy with azithromycin and her respiratory distress gradually improved, but her cough persisted for another month before complete resolution. The incidence of pertussis is increasing in young adults in Japan. This is possibly a result of waning immunity, in view of the fact that the pertussis immunisation
programme is limited to the initial three doses administered starting at 3 months of age followed by a booster dose at 12–18 months. Infections in young parents result in infections in young infants, as in the case presented, who are at the highest risk of complications. Lymphocytosis is a common systemic laboratory feature in infants with pertussis and is caused by the pertussis toxin. Increased lymphocytosis is associated with pulmonary hypertension, pneumonia, and death. Small mature lymphocytes with deep nuclear clefts can occasionally be observed in a peripheral smear as shown, and might serve as a diagnostic clue. Contributors FT took the photographs and produced the initial draft of the paper. IM reviewed the paper. Both authors wrote the final version. Declaration of interests We declare no competing interests.
Figure: Giesma stain of peripheral blood smear
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www.thelancet.com/infection Vol 15 January 2015