Pediatric Human Metapneumovirus Workup

Updated: May 02, 2018
  • Author: Joseph Domachowske, MD; Chief Editor: Russell W Steele, MD  more...
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Laboratory Studies

A general respiratory virus culture obtained by nasal wash or nasopharyngeal swab should be performed in patients with clinical symptoms of lower respiratory tract viral infections.

Human metapneumovirus (hMPV) has proven to be difficult to identify using common clinical virologic procedures. [12] Human metapneumovirus replicates slowly in primary cynomolgus monkey kidney cells and poorly in Vero cells and A549 cells (a human respiratory epithelial cell line). Other cell lines commonly used in viral diagnostic laboratories do not appear to support the replication of human metapneumovirus.

Commercial reagents to confirm the presence of human metapneumovirus infection are available. Detection techniques that have been developed include virus identification by reverse transcriptase-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and the rapid culture technique known as shell vial amplification. The clinical sample appropriate for submission to the laboratory may include nasal wash or aspirate fluid, nasopharyngeal flock swab culture, endotracheal tube aspirate, and/or bronchoalveolar lavage fluid. [13] To determine the optimal biologic sample, consult directly with the local clinical virology team because the best sample types vary according to the specific tests offered.

Multiplex PCR assays are more generally available than in recent years, often including the ability to diagnose hMPV and more than a dozen other respiratory viruses from a single panel. Since some of the respiratory viral pathogens do not grow well, or at all, in standard tissue culture, nucleic acid–based testing provides the ability to detect their presence, or co-presence with another virus. [14, 15] Co-infection with more than one respiratory virus in hospitalized children with acute respiratory illness is as high as 28% when all common respiratory viruses are taken into account.

Further diagnostic evaluation, including a CBC count and a blood culture, may be necessary to exclude invasive bacterial disease.


Imaging Studies

Chest radiography is appropriate in patients who present with symptoms of lower respiratory tract disease.

A systematic review that included 215 children with HMPV reported that parahilar opacities were the most common (87%) chest radiographic abnormality seen followed by hyperinflation (69%), atelectasis (40%) and consolidation (18%). [16]


Histologic Findings

Currently, histologic findings are unknown.