key: cord-0042635-cvvmvdph authors: Hongjun, LI; Ning, LI title: Clinical Manifestations date: 2012-12-26 journal: Radiology of Influenza A (H1N1) DOI: 10.1007/978-94-007-6162-9_5 sha: 46e79c75ab3d36f3acc23b1e630f6cc5f6697da7 doc_id: 42635 cord_uid: cvvmvdph The incubation period after infection of Influenza A(H1N1) is usually 1–7 days, being longer than common influenza and bird flu. due to the rapid development of respiratory conditions. In Mexico, the period from the onset of disease to hospitalization was averagely 6 days (ranging from 1 to 20 days), but a mean of 4 days in the US. The clinical manifestations of the death cases were fever, tachypnea, myalgia, tachycardia, low oxygen saturation and occasional hypotension and cyanosis. The severe cases had cardiac arrest in a short period after hospitalization. In Mexico, chest X-ray of patients with severe pneumonia demonstrated multifocal in fi ltration. The condition might rapidly develop into acute respiratory distress syndrome (ARDS), renal or multiple-organ failure [3] [4] [5] [6] . The median period from the onset of the disease to death was about 10 days, ranging from 2 to 23 days. Among the hospitalized patients in California, 60 % (15/25) were radiologically diagnosed as having pneumonia. The hospitalized patients had both increase and decrease of white cell counts. In Mexico, many hospitalized patients were found to have decreased lymph cells, increased transaminase and lactate dehydrogenase levels. Some were found to have very high level of creatinine. Half of the hospitalized patients had renal dysfunction of different severity, which might be secondary to rhabdomyolysis and myoglobinuria. The early symptoms of In fl uenza A (H1N1) are similar to common human in fl uenza, including fever, cough, sore throat, somatic pain, headache, chills, and fatigue. Some patients may have diarrhea/vomiting, muscle pain/fatigue and redness of eyes. The symptoms may deteriorate rapidly, being sudden and severe. The severe symptoms include sudden high fever over 39 °C, even with secondary complications of severe pneumonia, ARDS, pneumorrhagia, pleural effusion, pancytopenia, renal failure, sepsis, shock and Reye syndrome, respiratory failure and multiple organs failure to cause death. The patients' background diseases may deteriorate [7] [8] [9] [10] [11] . The abnormal signs of lungs are not obvious. Some patients may be found moist rale or pulmonary parenchymal changes. The fatal clinical signs include dif fi culty breathing, ARDS and multiple organs failure. For most patients with In fl uenza A (H1N1), recovery usually can be achieved within a week after positive treatment by clinical physicians. And for some patients, the clinical course may be longer. Clinical data indicated that the mortality rate of patients with In fl uenza A (H1N1) is about 6 % and the cause of death is commonly severe secondary complications. The period from the onset of symptoms to death is averagely 9 days, but the mortality rate is lower than those of bird fl u and severe acute respiratory syndrome (SARS). The serious illness or death of the patients is primarily due to complications. These complications include primary viral pneumonia and secondary bacterial pneumonia (especially group A streptococcal pneumonia and staphylococcus aureus pneumonia). Clinical features of the initial cases of 2009 pandemic in fl uenza A (H1N1) virus infection in China Novel Swine-Origin In fl uenza A (H1N1) Virus Investigation Team. Emergence of a novel swine-origin in fl uenza A (H1N1) virus in humans A-H1N1 pneumonia: a case report Critical in fl uenza (H1N1) pneumonia: imaging manifestations and histopathological fi ndings Initial HRCT fi ndings of novel in fl uenza A (H1N1) infection. In fl uenza Other Respi Viruses Imaging fi ndings of severe and critical severe pulmonary infections with A H1N1 in fl uenza Emergence of a novel swine-origin in fl uenza A virus (S-OIV) H1N1 virus in humans H1N1 2009 in fl uenza virus infection during pregnancy in the USA Hospitalized patients with 2009 H1N1 in fl uenza in the United States Clinical and epidemiologic characteristics of 3 early cases of in fl uenza A pandemic (H1N1) virus 2009 infection, People's Republic of China Clinical features of pneumonia caused by 2009 in fl uenza A(H1N1) virus in Beijing