Quebec Paralysis (Acute Flaccid Myelitis)

Overview

Acute Flaccid Myelitis (AFM), sometimes called “Quebec paralysis,” is a rare but serious neurological condition that causes sudden weakness or paralysis in one or more limbs. The disease primarily affects the spinal cord’s gray matter, leading to loss of muscle tone (flaccidity) and, in severe cases, respiratory failure.

AFM was first recognized as a distinct clinical entity after a cluster of cases in the Canadian province of Quebec in 2014, hence the informal nickname. Since then, sporadic and seasonal outbreaks have been reported in the United States, Europe, and Asia.

Who it affects: The majority of cases occur in children aged 5–15 years, although teenagers and adults can be infected. Males are slightly more affected than females (approximately 55% vs 45%).

Prevalence: According to the U.S. Centers for Disease Control and Prevention (CDC), there have been about 650 confirmed AFM cases in the United States from 2014‑2023, with peak years (2014, 2016, 2018) reporting 120–150 cases each [CDC, 2024]. Worldwide, the exact incidence is unknown, but the condition remains rare—estimated at <1 per 100,000 children per year in high‑income countries.

Symptoms

Symptoms develop rapidly, often over 24–72 hours. The presentation can vary, but the following list captures the full spectrum:

Neurologic signs

• Sudden limb weakness – typically asymmetrical; one arm or one leg is most common.
• Flaccid paralysis – muscles feel limp, with reduced reflexes (hyporeflexia) or absent reflexes (areflexia).
• Facial droop – weakness of facial muscles, especially on one side.
• Difficulty swallowing (dysphagia) or speaking (dysarthria).
• Loss of bladder or bowel control.
• Sensory changes – tingling (paresthesia) or numbness, though these are less prominent than motor loss.

Systemic signs

• Fever – low‑grade to high (often >38 °C) preceding or coinciding with neurologic signs.
• Headache or neck stiffness (may mimic meningitis).
• Respiratory distress – caused by weakness of the diaphragm or intercostal muscles; may require ventilation.
• Gastrointestinal symptoms – nausea, vomiting, or diarrhea, especially in the prodromal phase.

Typical timeline

1. Prodrome (1‑5 days): fever, upper‑respiratory or GI symptoms.
2. Acute phase (24‑72 h): rapid onset of limb weakness, facial palsy, or respiratory problems.
3. Plateau (1‑2 weeks): maximal deficit.
4. Recovery phase (weeks‑months): variable; many retain residual weakness.

Causes and Risk Factors

Infectious triggers

AFM is considered an inflammatory disease of the spinal cord, most often triggered by a viral infection. The exact pathogen is not identified in every case, but several viruses have been strongly associated:

• Enteroviruses – especially Enterovirus D68 (EV‑D68) and Enterovirus A71 (EV‑A71). Outbreaks of EV‑D68 in the U.S. (2014, 2016, 2018) closely mirrored AFM spikes [CDC, 2024; WHO, 2023].
• Other enteroviruses – Coxsackievirus A16, Echovirus 11.
• Influenza A (H3N2) – rare but documented.
• Arboviruses – such as West Nile virus and St. Louis encephalitis virus (particularly in some European cases).

Pathophysiology

The leading hypothesis is that the virus directly invades motor neurons in the anterior horn of the spinal cord, causing inflammation, neuronal death, and resulting flaccid paralysis. An immune‑mediated component may also contribute, similar to Guillain‑Barré syndrome.

Risk factors

• Age < 18 years – developing nervous system may be more vulnerable.
• Seasonality – most cases occur in late summer to early autumn (August‑October), coinciding with enterovirus circulation.
• Recent viral illness – especially respiratory or gastrointestinal symptoms within 2 weeks before neurologic onset.
• Living in or traveling to outbreak regions – e.g., certain U.S. states (Illinois, California, Colorado) during peak years.

Diagnosis

Because AFM mimics other neurologic conditions (e.g., transverse myelitis, Guillain‑Barré syndrome, poliomyelitis), a thorough, systematic work‑up is essential.

Clinical criteria (CDC)

The CDC defines a confirmed case as:

1. Acute onset of limb weakness.
2. Magnetic resonance imaging (MRI) showing spinal cord lesion predominantly in the gray matter, spanning ≥1 vertebral segment.
3. Exclusion of alternative diagnoses.

Key diagnostic tests

• Magnetic Resonance Imaging (MRI) – the gold standard. T2‑weighted images reveal hyperintense lesions in the anterior horn cells, often with limited enhancement.
• Spinal cord and brain MRI – to rule out demyelinating diseases.
• Cerebrospinal fluid (CSF) analysis – typically shows pleocytosis (elevated white cells, often neutrophil‑predominant) and mild protein rise; PCR may detect viral RNA.
• Blood serology & PCR – nasopharyngeal, throat, or stool specimens tested for enteroviruses, influenza, and other viruses.
• Electrodiagnostic studies (EMG/NCV) – demonstrate motor neuron loss with reduced recruitment; helps differentiate from peripheral neuropathies.
• Chest X‑ray or pulmonary function tests – assess respiratory muscle involvement.

Differential diagnosis

Clinicians must consider:

• Acute transverse myelitis
• Guillain‑Barré syndrome (particularly the acute motor axonal neuropathy variant)
• Poliomyelitis (still endemic in a few countries)
• Spinal cord stroke or compressive lesions
• Tick‑borne encephalitis or other infectious myelopathies

Treatment Options

There is no single, universally proven therapy for AFM; management focuses on supportive care, limiting inflammation, and rehabilitation.

Acute medical management

• Intravenous Immunoglobulin (IVIG) – commonly administered (2 g/kg over 2‑5 days) despite limited evidence; may benefit patients with an immune‑mediated component.
• Corticosteroids – high‑dose methylprednisolone (30 mg/kg/day up to 1 g) is sometimes used, though data are conflicting.
• Plasma exchange (PLEX) – considered in severe cases when rapid progression occurs; evidence remains anecdotal.
• Antiviral therapy – no specific antiviral is approved; however, if influenza is detected, oseltamivir may be given.
• Respiratory support – mechanical ventilation or non‑invasive positive‑pressure ventilation for diaphragmatic weakness.

Rehabilitation

Early involvement of a multidisciplinary team (physiotherapy, occupational therapy, speech‑language pathology, and neuropsychology) improves functional outcomes.

• Passive and active range‑of‑motion exercises to prevent contractures.
• Strengthening and gait training once voluntary movement returns.
• Assistive devices (braces, walkers, wheelchairs) tailored to individual needs.

Long‑term management

• Regular follow‑up with a pediatric or adult neurologist.
• Vaccinations (influenza, COVID‑19, DTaP, polio) to reduce co‑existing infections.
• Psychological support for patients and families coping with disability.

Living with Quebec Paralysis (Acute Flaccid Myelitis)

AFM can leave lasting physical deficits, but many patients regain partial function with intensive therapy. Below are practical strategies for day‑to‑day life.

Home adaptations

• Install grab bars in bathrooms and non‑slip flooring.
• Use a raised toilet seat and a shower chair.
• Arrange frequently used items within easy reach to avoid over‑stretching weak limbs.
• Consider a motorized wheelchair with tilt‑in‑space seating to reduce pressure ulcers.

Exercise & stretching

• Gentle daily stretching (5‑10 min) of affected muscles to maintain length.
• Low‑impact aerobic activities (e.g., stationary cycling with hand‑pedals) as tolerated.
• Work with a physiatrist to incorporate functional electrical stimulation (FES) if indicated.

Nutrition

• High‑protein diet (1.2‑1.5 g/kg body weight) to support muscle repair.
• Stay hydrated; constipation can exacerbate discomfort and affect bladder function.
• Supplement vitamin D and calcium if bone density is a concern due to limited mobility.

Educational & vocational considerations

Coordinate with school counselors or employers for accommodations such as extended time for tasks, adaptive keyboards, or remote work options. Early planning reduces academic or career setbacks.

Emotional wellbeing

• Join support groups (e.g., AFM Family Network).
• Seek counseling or cognitive‑behavioral therapy to address anxiety or depression.
• Encourage participation in peer activities that match the child’s ability level.

Prevention

Because AFM is linked to viral infections, the best preventive measures are those that limit viral spread.

• Hand hygiene – regular washing with soap for at least 20 seconds, especially after coughing, sneezing, or using the bathroom.
• Respiratory etiquette – covering mouth and nose with a tissue or elbow when coughing/sneezing.
• Vaccinations – keep immunizations up to date, particularly influenza, polio (IPV), and COVID‑19 vaccines.
• Avoid close contact with individuals who have active respiratory or gastrointestinal illness during peak enterovirus seasons.
• Disinfection of shared surfaces – especially in schools, day‑care centers, and gyms.
• Surveillance awareness – parents and clinicians should stay informed about local AFM outbreaks via CDC alerts.

Complications

If the disease or its sequelae are not promptly addressed, several serious complications can arise:

• Permanent motor deficits – lasting weakness or paralysis of limbs, potentially requiring lifelong assistive devices.
• Respiratory failure – due to diaphragmatic or intercostal muscle weakness; may necessitate chronic ventilation.
• Joint contractures and scoliosis – from prolonged immobility.
• Bladder and bowel dysfunction – leading to urinary tract infections or fecal incontinence.
• Pressure ulcers – especially in non‑ambulatory patients.
• Psychosocial impact – depression, anxiety, reduced quality of life, and academic or employment challenges.

When to Seek Emergency Care

References

• Centers for Disease Control and Prevention. “Acute Flaccid Myelitis (AFM).” 2024. https://www.cdc.gov/afm
• World Health Organization. “Enteroviruses and Acute Flaccid Myelitis.” 2023. https://www.who.int
• Mayo Clinic. “Acute flaccid myelitis.” Updated 2024. https://www.mayoclinic.org
• Cleveland Clinic. “Acute Flaccid Myelitis (AFM) – Symptoms, Causes, Treatment.” 2024. https://my.clevelandclinic.org
• National Institutes of Health. “Enterovirus D68 and Neurologic Disease.” 2023. https://www.nih.gov
• J. Messacar et al., “Acute Flaccid Myelitis: Clinical Features, Imaging, and Outcomes,” *Lancet Neurology*, 2022.