top of page

Acute Flaccid Myelitis (AFM)

from a critical care perspective

Demographics

​

  • Current literature: > 50 % of AFM patients are admitted to an ICU at some point in their disease process.

  • Acute mortality is rare

  • ICU need is primarily for respiratory support.

​​

Goals of care for the ICU:

​

  • Limit complications through rigorous monitoring and supportive care

  • Facilitate a rapid and accurate diagnosis

​

Symptomatology:

​

  • Weakness

  • Respiratory distress

  • Feeding dysfunction

  • Pain/parasthesias

  • Neurogenic bowel/bladder

  • Autonomic dysfunction

​

Progression of symptoms:

​

  • Onset to nadir typically evolves in hrs to days.  

    • Gordon‐Lipkin, Eliza, et al. "Comparative quantitative clinical, neuroimaging, and functional profiles in children with acute flaccid myelitis at acute and convalescent stages of disease." Dev Med & Child Neuro 61.3 (2019): 366-375

  • Usually no second phase of worsening in the acute period 

 

Risk Factors for Respiratory Failure

** Currently no good data

​

  • Weakness leading to hypoventilation

    • Weakness of the neck/trunk and/or bilateral UE

    • Cervical cord lesion à specific but not sensitive

​

  • Aspiration

    • Bulbar weakness        

    • Encephalopathy

​

  • Apnea

    • Brainstem lesion (central)

    • Bulbar weakness (obstructive)

    • Weakness of the neck/trunk (obstructive)

 

Incidence of Respiratory Failure

While respiratory support is the most common reason for ICU admission, it is unclear what percent require invasive mechanical ventilation (reports are highly variable).

​​​

References

AFM table2.jpg

CDC cohort from 2014 shows high % of cervical involvement but only a fifth of patients developed respiratory failure.  Thus there may be reassurance that cervical lesions are a risk factor but do not predict with certainty which patients will need ventilation. 

Weakness of 4 extremities and/or CN palsies may be a stronger predictor.

 

Monitoring for Respiratory Dysfunction

​

  • Hypoventilation

    • consider Q4 hr assessment for 1st 48 hours

    • NIF/forced vital capacity (age > 6yr,  cooperation dependent)

    • Counting or singing a song (pick a task the child repeat consistently to assess for changes over time)

    • Pulse oximetry   - note: hypoxia is a late sign or evidence of secondary process

​

  • Apnea

    • CR monitor 

    • +/- sleep study

​

  • Aspiration

    • Identify high risk patients

      • Bulbar weakness (hypophonic voice, drooling/copious secretions, dysarthria, fatigue with talking, coughing with drinking, pocketing food)

      • Encephalopathy

      • Make patient NPO and obtain speech consult for swallowing eval

    • Identify aspiration promptly

      • Symptoms of fever, hypoxia, and tachypnea/dyspnea

      • Modify PO status where applicable

      • Assess for infection

      • Increase respiratory support as needed

​​

AFM resp.jpg

General supportive care

​

  • Neurological assessments

    • Neuro checks

    • Any interval < Q4 hours leads to diminishing returns if prolonged

    • Sleep deprivation and delirium confuse the picture.

    • Ask the family to video the motor exam, speech and facial movements.

​

  • Hemodynamics          

    • CR monitor

    • Hypertension is common

      • Etiology is often multi factorial

    • Assess for pain, neurogenic bladder, autonomic dysfunction 

​

  • Pain management

    • Children may not report pain when asked directly. 

    • Irritability or poor cooperation may be indicators of poorly controlled pain

    • Good pain control can normalize vital signs and improve cooperation with assessments and therapies.

    • Encourage use of non-narcotic pain medications (e.g. gabapentin)

    • Consult psychology and/or Child Life early to assist with anxiety and behavioral challenges

    • Promote sleep and maintenance of day/night cycles

​

  • Sedation

    • Minimize sedation where possible

    • Avoid medications that may exacerbate weakness (e.g. paralytics, steroids)

​

  • Bowel/bladder dysfunction

    • Gut dysmotility

      • Constipation is common.

      • Initiate bowel regimen early

    • Neurogenic bladder

      • Ask and assess for bladder retention.

      • In a child who is continent, ask them to urinate then perform a bladder scan or post void residual.

      • For neurogenic bladder, in and out cath preferred over continuous Foley catheterization

​

  • Nutrition 

    • Avoid gaps in feeding

    • Modify diet and encourage enteral feeds when appropriate/safe

    • Place NG tube early if risk for aspiration

​

  • Mobility and rehabilitation in the ICU

    • Consult PT/OT and PM&R early for assessment

    • Plan for mobilization

    • establish when mobilization is safe

    • Set activity goals

​

  • Skin care (avoidance of pressure palsies)

​

  • DVT prophylaxis for immobile patients (post pubertal patients highest risk)

​

  • Infection risk

    • Aggressive screening for infection & treatment where appropriate

    • Central line care

    • Avoidance of prolonged use of Foley catheters  

 

 

​Diagnosis

​

  • Refer to AFM diagnostic criteria – labeling is important

  • Physical Exam

  • LP for CSF studies

  • MRI brain and spine

  • Laboratory studies

  • EMG – most useful at least 2 weeks after symptom onset

 

Outcome

​

  • Data is incomplete

  • Kane et al, 12 month follow up (27/28)

    • 11 % (3) with tracheostomy (2 placed acutely, 1 later) patients

    • 15 % (4) with G tube dependence.

    • Kane, Miranda S., et al. "Incidence, risk factors and outcomes among children with acute flaccid myelitis: a population-based cohort study in a California Health Network between 2011 and 2016." The Ped infect Ds J 38.7 (2019): 667-672

bottom of page