Acute flaccid myelitis: Difference between revisions

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{{CMG}}; {{AE}} {{HK}}
{{CMG}}; {{AE}} {{HK}}
{{SK}}; Acute flaccid paralysis, acute flaccid paralysis with anterior myelitis, paralysis with anterior myelitis, AFM
{{SK}}; Acute flaccid paralysis, acute flaccid paralysis with anterior myelitis, paralysis with anterior myelitis, AFM



Revision as of 12:32, 7 November 2018


Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Syed Hassan A. Kazmi BSc, MD [2]

Synonyms and keywords:; Acute flaccid paralysis, acute flaccid paralysis with anterior myelitis, paralysis with anterior myelitis, AFM

Overview

Historical Perspective

  • In 2014, physicians in California and Colorado (USA) noted an increase in the number of patients presenting with the acute onset of flaccid paralysis and MRI findings consistent with lesions in the gray matter of the spinal cord.
  • In 2014, a total of 120 cases were identified in the US and 22 were identified in 2015
  • In 2016, 145 cases of AFM were diagnosed across the USA.

Causes

Acute flaccid myelitis (AFM) may be caused by viral infections or environmental toxins. The following viruses are known to be associated with AFM:

  • West Nile Virus
  • Coxsackievirus
  • Adenovirus
  • Poliovirus
  • Enterovirus 71 (EV 71) and Entervirus D68 (EV 68)

Differentiating Acute Flaccid Myelitis From Other Diseases

The following table differentiates acute flaccid myelitis from other diseases that cause muscle weakness, hypotonia, and flaccid paralysis:

Diseases History and Physical Diagnostic tests Other Findings
Motor Deficit Sensory deficit Cranial nerve Involvement Autonomic dysfunction Proximal/Distal/Generalized Ascending/Descending/Systemic Unilateral (UL)

or Bilateral (BL)

or

No Lateralization (NL)

Onset Lab or Imaging Findings Specific test
Adult Botulism + - + + Generalized Descending BL Sudden Toxin test Blood, Wound, or Stool culture Diplopia, Hyporeflexia, Hypotonia, possible respiratory paralysis
Infant Botulism + - + + Generalized Descending BL Sudden Toxin test Blood, Wound, or Stool culture Flaccid paralysis (Floppy baby syndrome), possible respiratory paralysis
Guillian-Barre syndrome + - - - Generalized Ascending BL Insidious CSF: ↑Protein

↓Cells

Clinical & Lumbar Puncture Progressive ascending paralysis following infection, possible respiratory paralysis
Eaton Lambert syndrome + - + + Generalized Systemic BL Intermittent EMG, repetitive nerve stimulation test (RNS) Voltage gated calcium channel (VGCC) antibody Diplopia, ptosis, improves with movement (as the day progresses)
Myasthenia gravis + - + + Generalized Systemic BL Intermittent EMG, Edrophonium test Ach receptor antibody Diplopia, ptosis, worsening with movement (as the day progresses)
Electrolyte disturbance + + - - Generalized Systemic BL Insidious Electrolyte panel ↓Ca++, ↓Mg++, ↓K+ Possible arrhythmia
Organophosphate toxicity + + - + Generalized Ascending BL Sudden Clinical diagnosis: physical exam & history Clinical suspicion confirmed with RBC AchE activity History of exposure to insecticide or living in farming environment. with : Diarrhea, Urination, Miosis, Bradycardia, Lacrimation, Emesis, Salivation, Sweating
Tick paralysis (Dermacentor tick) + - - - Generalized Ascending BL Insidious Clinical diagnosis: physical exam & history - History of outdoor activity in Northeastern United States. The tick is often still latched to the patient at presentation (often in head and neck area)
Tetrodotoxin poisoning + - + + Generalized Systemic BL Sudden Clinical diagnosis: physical exam & dietary history - History of consumption of puffer fish species.
Stroke +/- +/- +/- +/- Generalized Systemic UL Sudden MRI +ve for ischemia or hemorrhage MRI Sudden unilateral motor and sensory deficit in a patient with a history of atherosclerotic risk factors (diabetes, hypertension, smoking) or atrial fibrillation.
Poliomyelitis + + + +/- Proximal > Distal Systemic BL or UL Sudden PCR of CSF Asymmetric paralysis following a flu-like syndrome.
Transverse myelitis + + + + Proximal > Distal Systemic BL or UL Sudden MRI & Lumbar puncture MRI History of chronic viral or autoimmune disease (e.g. HIV)
Neurosyphilis + + - +/- Generalized Systemic BL Insidious MRI & Lumbar puncture CSF VDRL-specifc

CSF FTA-Ab -sensitive

History of unprotected sex or multiple sexual partners.

History of genital ulcer (chancre), diffuse maculopapular rash.

Muscular dystrophy + - - - Proximal > Distal Systemic BL Insidious Genetic testing Muscle biopsy Progressive proximal lower limb weakness with calf pseudohypertrophy in early childhood. Gower sign positive.
Multiple sclerosis exacerbation + + + + Generalized Systemic NL Sudden CSF IgG levels

(monoclonal)

Clinical assessment and MRI Blurry vision, urinary incontinence, fatigue
Amyotrophic lateral sclerosis + - - - Generalized Systemic BL Insidious Normal LP (to rule out DDx) MRI & LP Patient initially presents with upper motor neuron deficit (spasticity) followed by lower motor neuron deficit (flaccidity).
Inflammatory myopathy + - - - Proximal > Distal Systemic UL or BL Insidious Elevated CK & Aldolase Muscle biopsy Progressive proximal muscle weakness in 3rd to 5th decade of life. With or without skin manifestations.

Epidemiology and Demographics

Incidence and Prevalence

USA

  • From June 1, 2012 to July 31, 2015, 59 reported cases met the California Department of Public Health (CDPH) case definition of acute flaccid myelitis (AFM), which defines AFM as acute onset of flaccid limb paralysis along with a lesion in the gray matter of the spinal cord.
  • Between August and December of 2014, 120 children from 34 US states met the criteria of AFM as outlined by the CDC.
  • From August 2014 through October 2018, CDC has received information on a total of 396 confirmed cases of acute flaccid myelitis (AFM) from EV-D68 across the US; most of the cases have occurred in children
  • In October 2018, the New York State Department of Health (NYSDOH) confirmed 39 cases of the enterovirus EV-D68 in children across the state which was associated with an increase in number of cases of AFM.
Acute Flaccid Myelitis number of confirmed cases from August 2014 to October 2018 based on AFM case definition: Onset of acute limb weakness and an MRI showing a spinal cord lesion largely restricted to gray matter


Risk Factors

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Criteria

Diagnosis Criteria
Confirmed
  • Acute onset of flaccid limb weakness

AND

  • An MRI showing a spinal cord lesion largely restricted to gray matter and spanning one or more spinal segments
Probable
  • Acute onset of flaccid limb weakness

AND

  • Cerebrospinal fluid (CSF) with pleocytosis (white blood cell count 9 5 cells/mm3

Symptoms

The following are the symptoms of acute flaccid myelitis:

  • Acute onset of flaccid limb paralysis (asymmetric)
  • Fever
  • Pain in the paralytic limb
  • Eyelid drooping
  • Difficulty with swallowing or slurred speech
  • Cranial nerve abnormalities
  • Headache
  • Neck pain
  • Bowel/bladder changes

Physical Examination

Laboratory Findings

Imaging Findings

Treatment

Medical Therapy

Surgical Therapy

Prevention