Clinical diagnosis
Case 50
The patient was given both of antiinfluenza agent (Rapiakuta) and antibiotics (Pishiribakuta, Aselli). Three days later, his body temperature was getting lowered to 37.6 centigrade and his appetite was improved. Lavoratory test revealed CRP 8.74 mg/dl, procalcitonin 6.20 ng/ml, LDH 239 U/L, creatinin 0.86, neutophils of 65.4 % , monocytes 11.1 % and white blood cells of 5790 mm3.
【Discussion】
Influenza A (H1N1) is originated from swine and the incubation period is 24 to 48 hours. Influenza virus initially deposited onto the respiratory tract epithelium. The host usually defenses with mucociliary clearance and secretion of IgA antibodies. When dysfunction of mucociliary clearance and absent secretary anti-influenza IgA antibodies, influenza infiltrates to epithelial cells and the adjacent interstitial cells, and extends from trachea to the distal airway, inducing edema of tracheobronchitis, bronchiolitis and pneumonia with cellular infiltration with lymphocytes and histocytes and desquamation of the ciliated epithelium (1, 2). Pneumonia occurs adjacent to the terminal and respiratory bronchioli at the early phase and thereafter, it expands via the lobules with interstitial lymphocyte infiltration. Alveolar spaces are occupied with fluid from cellular exudates and/or hemorrhage via hyperemic alveolar capillaries. In severe case, bilateral hemorrhagic pneumonitis, a necrotizing bronchiolitis with diffuse alveolar damage are observed (1, 2). The progressive pneumonia might be susceptible to the elderly or immune-compromised patients. Our patient was eighty two-year-old male.
Radiographic images of influenza pneumonia features ground-glass attenuation is most common (3-6) with the incidence of nearly 85%, bronchial wall thickening 25%, mixed with ground glass opacity and consolidation 64 % which tends to occur in the lower lobes and air space nodules which represent interlobular inflammation 25% (3-6). The patients present with consolidation have more severe clinical course. Namely, although ground glass opacity is most common in influenza virus pneumonia, these findings can be also observed in bacterial pneumonia. In our case, chest CT showed ground glass attenuation plus consolidation in the left lower lobe and patchy ground glass opacity in bilateral lungs.
Procalcitonin is a peptide precursor of calcitonin and produced by thyroid, lung and intestine (neuroendocrine cells) (7, 8). Procalcitonin is currently used in the risk assessment for progression to severe sepsis and septic shock along with other laboratory test such as CRP, blood culture and WBC counts (7, 8). Procalcitonin test is known to be useful to detect or rule out sepsis, distinguish between viral and bacterial meningitis, or detect/rule out bacterial pneumonia. It is best used on the first day of admission for diagnostic purposes and monitoring therapeutic effect. From a point of views on influenza pneumonia, bacteria pneumonia and mixed pneumonia, Ingram et al. reported that low values of procalcitonin indicates unlikely bacterial infection and using a cutoff of > 0.8ng/ml, the sensitivity and specificity of procalcitonin for detection of patients with bacterial/mixed infection were 100 and 62%, respectively (8). In our case, although WBC count is within normal limits, a procalcitonin value measured at admission was 14.0ng/ml, indicating the mixed infection of influenza A with bacterial infection.
【Summary】
We present an eighty two-year-old male with influenza A virus infection whose chest CT showed ground glass attenuation in the left lower lobe accompanied with patchy attenuation in the bilateral lung, indicating the typical finding of influenza pneumonia. However, laboratory test revealed elevation of procalcitonin value, indicating bacterial infection. Based on CT findings and laboratory test, our patient was diagnosed the mixed infection of influenza A and bacteria. We should keep in mind that the CT findings of influenza are ground-glass attenuation which is most common, followed by bronchial wall thickening and mixed with ground glass attenuation and consolidation. Further, procalcitonin, CRP and WBC are useful to detect or rule out sepsis or distinguish between viral and bacterial infections such as pneumonia or meningitis.
【References】
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2.Lai CJ, Markoff LJ, Sveda MM, Lamb RA, Dhar R, Chanock RM. Genetic variation of influenza A viruses as studied by recombinant DNA techniques. Ann N Y Acad Sci. 1980;354:162–171. doi:10.1111/j.1749-6632.1980.tb27965.x.
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6.El-Badrawy A, Zeidan A, Ebrahim MA. 64 multidetector CT findings of influenza A (H1N1) virus in patients with hematologic malignancies. Acta Radiol. 2012;53 (6): 662-7. doi:10.1258/ar.2012.120038 - Pubmed citation
7.Magrini L, et al. Comparison between white blood cell count, procalcitonin and C reactive protein as diagnostic and prognostic biomarkers of infection or sepsis in patients presenting to emergency department. Clin Chem Lab Med. 2014 Oct;52(10):1465-72. doi: 10.1515/cclm-2014-0210.
8.Ingram PR, et al. Procalcitonin and C-reactive protein in severe 2009 H1N1 influenza infection. Intensive Care Med. 2010 Mar;36(3):528-32. doi: 10.1007/s00134-009-1746-3.
2017.4.12
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