Lessons learned during the 2009 H1N1 outbreak in Mexico City: respiratory symptoms does not necessarily mean pandemic influenza in subjects with AIDS
A. Campos-Loza, L. Soto-Ramirez, J. Sierra-Madero, B. Crabtree-Ramirez, A. Galindo-Fraga, S. Moreno-Espinosa, M. Lourdes-Guerrero, G. Ruiz-Palacios
Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Infectious Diseases, México, Mexico
Background: During the 2009 H1N1 influenza outbreak in Mexico City, we expected an important increase of severe cases of pandemic influenza in people living with HIV (PLHIV), particularly in patients with severe immunosupression. We describe the definitive diagnoses in PLHIV with respiratory symptoms who seek for medical assistance during the outbreak.
Methods: All PLHIV with Acute Respiratory Illness (ARI) during the outbreak were evaluated exclusively at emergency room and a nasopharyngeal swab (NPS) was taken. For hospitalized patients, additional studies were made at the discretion of the physician. Subjects were categorized according to CD4+ levels.
Results: Twenty patients with ARI and a NPS were analyzed (18 male, 2 female, median age 40 years). 2009 H1N1 was the most common diagnosis in patients with CD4+ > 200cells/mm3 (9/12 [75%]). Other diagnoses in this group included: Rhinovirus, lobar pneumonia and ILI (last two without an identified cause).
Diagnoses other than influenza were more common in subjects with CD4 < 200 cells/mm3 (6/8 [67%]) and included: Non Hodgking Lymphoma(1), disseminated histoplasmosis(1), lymph node tuberculosis(1), rhinovirus(2) and a case of interstitial pneumonia without an identified agent. Only 2 cases of 2009 H1N1 were identified in this group. In addition, all three fatal cases had CD4 < 200 cells/mm3. Although no other differences were found regarding clinical picture at presentation, severity or outcome between influenza and non-influenza cases, dyspnea was more common in non-influenza (6/9[66%]) than influenza cases (1/11[9%]) p=0.02.
Conclusions: During the 2009 influenza outbreak in Mexico City, diagnoses other than influenza were more common in subjects with severe immunosupresion. Thus, even in face of a pandemic influenza outbreak, typical opportunistic diseases mustn´t been forgotten from the wide differential diagnosis in patients with AIDS.
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