Influenza in Neonates and Children - Guidelines for Clinical Management of Confirmed or Suspected

Publication: 30/12/2011  
Last review: 21/11/2017  
Next review: 01/11/2020  
Clinical Guideline
CURRENT 
ID: 2821 
Approved By: Improving Antimicrobial Prescribing Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2017  

 

This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Guidelines for clinical management of neonates and children with confirmed or suspected Influenza

  • Treatment Algorithm
  • Summary
    Influenza in Neonates and Children

    Influenza virus infection can present in a variety of ways and may therefore be managed according to several existing LTHT children’s infection pathways/guidelines:

    Define complicated/uncomplicated

    1. Uncomplicated influenza: Influenza presenting with fever, coryza, generalised symptoms (headache, malaise, myalgia, arthralgia) and sometimes gastrointestinal symptoms, but without any features of complicated influenza.
    2. Complicated influenza: Influenza requiring hospital admission and/or with symptoms and signs of lower respiratory tract infection (hypoxaemia, dyspnoea, lung infiltrate), central nervous system involvement and/or a significant exacerbation of an underlying medical condition.

    Investigations
    Nose and throat swab or nasopharyngeal aspirate for respiratory virus PCR (LTHT Internal Only)

    Non-antimicrobial treatment
    See condition-specific guidelines

    Antimicrobial treatment
    See algorithm and Influenza treatments
    Risk factors for complications (LTHT Internal Only)

    Duration of therapy
    Usually 5 days (May be extended in severe disease on in immunocompromised)

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    Background

    Influenza viruses are enveloped single-stranded RNA viruses with a segmented genome (8 segments). There are 3 types, A, B and C, determined by surface antigens. Type A infects humans and animals, whereas types B and C usually infect humans only. Influenza C usually causes mild disease, whereas A can cause severe illness and has a significant mortality.

    The envelope contains two glycoproteins in its lipid bilayer: haemagglutinin (HA), which attaches the virus to cellular receptors and neuraminidase (NA), which is involved in the release of newly formed viruses from infected cells. Variations in HA and NA structure, brought about by spontaneous mutations, determine subtypes (in humans: H1, H2, H3, N1, N2). NA is the target of the antiviral drugs oseltamivir and zanamivir, which are most commonly used to treat influenza.

    Epidemiology

    All age groups are affected but infection is most common in children. There is seasonal variation in incidence with most cases occurring during the winter months (usually December to March). Pandemics, resulting from the introduction of a new subtype into the population, can occur at any time.

    Incubation and infective period

    The incubation period prior to the onset of symptoms is usually 1 – 4 days, while the period of infectivity is from a day before onset of symptoms to 7 days after.

    Complications of influenza in children
    Influenza viruses produce a range of illness from mild upper respiratory tract infection to severe life-threatening illness. Complications are shown in Table 1.

    Table 1. Complications of influenza in Children

    Complication

    Incidence

    Comments

    Respiratory

    Acute bronchitis

    Common

    More common in those with chronic medical conditions.

    Primary viral pneumonia

    Uncommon

    Onset within 48 hours of start of fever.

    Secondary bacterial pneumonia

    Common

    Typically occurs 4 – 5 days after onset of illness.

    Bronchiolitis

    Common

    In young children

    Croup

    Uncommon

    Children, can be severe

    Cardiovascular

    ECG abnormalities

    Common

    Non-specific T wave and rhythm changes, ST segment deviation. Mostly not associated with cardiac symptoms.

    Myocarditis

    Rare

     

    Pericarditis

    Rare

     

    Muscle

    Myositis

    Uncommon

    Occurs during early convalescence

    Myoglobinuria and renal failure

    Rare

     

    Central Nervous System

    Encephalitis/ encephalopathy

    Rare

    Occurs within first week of illness. More common in children.

    Transverse myelitis

    Very rare

     

    Guillian-Barre syndrome

    Very rare

     

    Others

    Otitis media

    Very common in children

     

    Toxic shock syndrome

    Rare

     

    Parotitis

    Very rare

     

    Risk factors for complications (LTHT Internal Only)

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    Clinical Diagnosis

    NB. The spectrum of clinical disease associated with a new influenza A subtype (i.e. a pandemic strain) may differ from that described below for interpandemic influenza.

    Neonates may present with non-specific signs such as:

    • Fever (sometimes the only presenting feature).
    • Pallor.
    • Floppiness (poor peripheral circulation, poor tone).
    • Lethargy.
    • Rhinitis.
    • Poor feeding.
    • Cough.
    • Episodes of apnoea or other signs of respiratory distress.

    Infants and very young children (under 2 years) can present with:

    • Fever (may be the only presenting feature in this age group too).
    • They may be irritable or listless
    • Gastrointestinal symptoms such as diarrhoea and vomiting (More common than older children).
    • Febrile convulsions, particularly repeated convulsions, are positively associated with influenza A.
    • Otitis media is also a common complication in children.
    • Rhinitis.
    • Sore throat (off food).
    • Dry cough.
    • Respiratory distress.
    • Painful joints/muscles

    Older children - the presentation does not differ significantly from adults. (See adult guideline)

    Definitions2

    1. Uncomplicated influenza: Influenza presenting with fever, coryza, generalised symptoms (headache, malaise, myalgia, arthralgia) and sometimes gastrointestinal symptoms, but without any features of complicated influenza.
    2. Complicated influenza: Influenza requiring hospital admission and/or with symptoms and signs of lower respiratory tract infection (hypoxaemia, dyspnoea, lung infiltrate), central nervous system involvement and/or a significant exacerbation of an underlying medical condition.

    Severity Assessment

    Severity indicators in influenza are:

    • Signs of respiratory distress.
      Markedly raised respiratory rate, grunting, intercostal recession, breathlessness with chest signs
    • Cyanosis
    • Severe dehydration
    • Altered conscious level
    • Complicated or prolonged seizure
    • Signs of septicaemia – extreme pallor, hypotension, floppy infant

    Indications for transfer to High Dependency or Intensive Care

    • failing to maintain a SaO2 of >92% in FiO2 of >60%
    • shock
    • severe respiratory distress and a raised PaCO2 ( > 6.5 Kpa)
    • a rising respiratory rate and pulse rate with clinical evidence of severe respiratory distress with or without a raised PaCO2
    • recurrent apnoea or slow irregular breathing
    • evidence of encephalopathy

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    Investigation

    Recommendation: A nose and throat swab or nasopharyngeal aspirate should be sent for respiratory viral PCR when influenza is suspected.

    Method and details (LTHT Internal Only)

    [Evidence level B]

    Other investigations will be determined by clinical presentation – see relevant guidelines

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    Treatment
    Non-Antimicrobial Treatment
    See relevant condition-based guidelines.

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    Empirical Antimicrobial Treatment

    Recommendation: When clinical presentation and/or risk factor assessment indicated antiviral therapy should be given, commence antiviral therapy before the results of viral studies are available.
    [Evidence level C]

    Recommendation: Previously healthy children seen in A&E/CAT unit with uncomplicated influenza who do not require hospitalization, do not require antiviral therapy.
    [Evidence level C]

    Recommendation: Immunocompromised children seen in A&E/CAT unit with uncomplicated influenza should be treated with antivirals. See algorithm and influenza treatments
    [Evidence level C]

    Recommendation: Children who are hospitalized with influenza or who have complicated infection should be started on antiviral therapy. See algorithm and influenza treatments.
    [Evidence level C]

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    Directed Antimicrobial Treatment (when microbiology results are known)

    Recommendation: If influenza virus is identified in diagnostic samples but antiviral therapy has not been commenced, reassess using algorithm and see influenza treatments.
    [Evidence level C]

    Recommendation: If influenza virus is not identified in diagnostic samples consider stopping empirical antiviral therapy.
    [Evidence level C]

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    Duration of Treatment

    Recommendation: Antiviral therapy should be given for five days and stopped.
    [Evidence level C]

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    Treatment Algorithm

    IN CASE OF IN PATIENT WITH UNEXPECTEDLY POSITIVE INFLUENZA PCR, REASSESS BEFORE COMMENCING TREATMENT. IF IMPROVING SIGNIFICANTLY, AND NOT IMMUNOCOMPROMISED, SHOULD NOT NEED TREATMENT.

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    Provenance

    Record: 2821
    Objective:
    Clinical condition:

    Influenza in children

    Target patient group: Children with suspected influenza
    Target professional group(s): Secondary Care Doctors
    Pharmacists
    Adapted from:

    Evidence base

    1. British Thoracic Society Pandemic Influenza Guidelines (2009).
    2. PHE guidance on use of antiviral agents for the treatment and prophylaxis of influenza, 2017-18.

    A. Meta-analyses, randomised controlled trials/systematic reviews of RCTs
    B. Robust experimental or observational studies
    C. Expert consensus.
    D. Leeds consensus. (where no national guidance exists or there is wide disagreement with a level C recommendation or where national guidance documents contradict each other)

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    Approved By

    Improving Antimicrobial Prescribing Group

    Document history

    LHP version 1.0

    Related information

    Not supplied

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