Recently we discussed Urinary Retention in Kids and highlighted how this is not a condition that only affects adults and the elderly. Obviously, there are numerous examples of conditions typically segregated in our medical school texts as affecting only adults that, in fact, are important for us to consider in children as well (ex, PID, Pancreatitis, Cholelithiasis – interesting aside, one of my PEM fellows, Dr. Mary Grady, actually diagnosed Choledocholithasis in kid 2 weeks ago). When someone says “Legionella,” I’ll be honest, I typically imagine an elderly person developing pneumonia after swimming at the local American Legion… but, I am now adjusting my perception. Let’s review Legionellosis in Children:

Legionellosis

• Legionellosis incidence has been increasing steadily since 2000. [cdc.gov]
  • Likely underestimated in children. [Yu, 2010]

• Legionellosis = multi-system illness caused by Legionella pneumophila
  • Legionella pneumophila – named after outbreak in 1976 at an American Legion convention.
  • Infection occurs after inhalation of aerosolized water or from aspiration of water.
  • Outbreaks associated with contaminated water often found in:
    • Natural water sources
    • Cooling towers
    • Hot tubs and other human-made water systems
    • Medical equipment (yup… nosocomial transmission is important) [Campins, 2000]

• Legionellosis can present as two distinct illnesses:
  • Pontiac Fever (www.cdc.gov)
    • Mild febrile, influenza-like illness
    • No pneumonia.
  • Legionnaires’ Disease (www.cdc.gov)
    • More severe than Pontiac Fever
    • Fever, cough, respiratory distress
    • Gastrointestinal symptoms
    • Neurologic symptoms
      • Can cause tremor, seizures, Guillain-Barre, and chorea.
      • Has been linked to cases of Acute Cerebellar Ataxia. [Nigro, 1983]
    • Respiratory failure occurs in ~10% of all cases.

Legionellosis in Children

• Legionellosis in children is rare, but likely under-reported. [Yu, 2010]
• Features typically are of non-specific respiratory illness
  • Fever, cough, tachypnea [Greenberg, 2006]
  • There is no exam finding that clearly distinguishes Legionella infection from other causes of pneumonia [Greenberg, 2006]
• 46% of cases were community-acquired…
  • Which means most were hospital acquired. [Yu, 2010; Greenberg, 2006]
  • Legionella pneumophila can survive in plumbing for a long time.
• Immunocompromised children were the most commonly affected. [Greenberg, 2006; Campins, 2000]
  • Mortality was 33% higher in immunocompromised patients.
  • Children < 1 year of age were also at high risk of mortality.
  • Neonates who have been exposed are at high risk. [Shachor-Meyouhas, 2010]

Legionellosis: Management

• Should maintain a high clinical suspicion in:[Yu, 2010; cdc.gov]
  • Patients with history of exposure or travel
    • Some electronic medical records have “pop-up” alerts to indicate whether a patient may have previously been exposed to hazardous water sources.
  • Patients who develop pneumonia after admission to the hospital (>47 hrs from admission) are at risk for possible nosocomial legionellosis.
  • Immunocompromised patients (and neonates) with pneumonia.
  • Not improving when on 1st line therapies for pneumonia.
  • Patients with severe pneumonia requiring intensive care.
    • Patients with lung abscesses [Leruste, 2017]

• Make the diagnosis by: [cdc.gov]
  • Sending sputum sample (lower respiratory tract sample) on buffered charcoal yeast extract media for culture AND
  • Sending urine for Legionella antigen.
  • Serology is not helpful.

• Treat with: [cdc.gov]
  • Macrolides or respiratory fluoroquinolones
  • Azithromycin is 1st line therapy in children.
  • Levofloxacin may be required for immunosuppressed patients.
  • Doxycylcine, and Trimethoprom-Sulfamethoxazole are alternatives.

• Report it:
  • Legionellosis is a reportable disease.
  • Reporting to the local or state health departments can help with identification of source and prevention of large outbreaks.
  • Click HERE for the CDC’s Case Report Form

Moral of the Morsel:

• Bacteria don’t ask to see your ID. It might be more common for adults to encounter the legionella bacterium, but it can affect kids too.
• Being rare makes it more dangerous! Stay Vigilant!
• Don’t ignore the Pop-up! (even though you want to) If the patient has pneumonia and the electronic medical record has an alert that the patient may have encountered a potential infected source, pay attention and cover that base.
• Don’t give everyone Azithromycin! Ok, let’s be reasonable, Legionellosis is rare in children, so don’t start using Azithromycin on every child with pneumonia. Penicillin is still the correct answer for the vast majority of them.

References