Acute flaccid myelitis: Difference between revisions
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==Background== | ==Background== | ||
*Polio-like illness, subset of [[transverse myelitis]] | *[[Polio]]-like illness, subset of [[transverse myelitis]] | ||
*More common in children | *More common in children | ||
*Likely caused by: | *Likely caused by: | ||
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*Acute onset, focal [[weakness]] of 1 or more extremity | *Acute onset, focal [[weakness]] of 1 or more extremity | ||
*Decreased muscular tone | *Decreased muscular tone | ||
*Absent or hypoactive reflexes | *Absent or hypoactive [[reflexes]] | ||
*Rarely have numbness, but may have some neuropathic pain | *Rarely have [[numbness]], but may have some [[neuropathic pain]] | ||
*[[Fever]] and other symptoms of infection by causative virus (e.g. [[URI]] symptoms, [[gastroenteritis]]) | *[[Fever]] and other symptoms of infection by causative virus (e.g. [[URI]] symptoms, [[gastroenteritis]]) | ||
*In severe cases: | *In severe cases: | ||
**Bulbar dysfunction (dysphagia, dysarthria, dysphonia, facial weakness, ptosis) | **Bulbar dysfunction ([[dysphagia]], [[dysarthria]], [[dysphonia]], [[facial weakness]], ptosis) | ||
**Respiratory muscle weakness | **[[respiratory failure|Respiratory muscle weakness]] | ||
**Autonomic instability, | **Autonomic instability, [[arrhythmias]] if cervical lesion present | ||
*Paralysis usually maximal at 3-5 days after onset | *Paralysis usually maximal at 3-5 days after onset | ||
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==Evaluation== | ==Evaluation== | ||
[[File:MRI Brain and Spinal Cord in a child with Acute Flaccid Myelitis.png|thumb| <ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5234096/</ref>]] | |||
*Evaluate for other causes of symptoms (e.g. [[HSV]], [[bacterial meningitis]], [[Guillain-Barre syndrome]]) | *Evaluate for other causes of symptoms (e.g. [[HSV]], [[bacterial meningitis]], [[Guillain-Barre syndrome]]) | ||
*CSF: Pleocytosis (WBC count >5 cells/mm<sup>3</sup>), +/- elevated protein | *[[LP|CSF]]: Pleocytosis (WBC count >5 cells/mm<sup>3</sup>), +/- elevated protein | ||
*MRI: spinal cord lesion, largely restricted to gray matter, spanning one or more spinal segments | *MRI: spinal cord lesion, largely restricted to gray matter, spanning one or more spinal segments | ||
**Spinal cord lesions may not be present on initial MRI if performed within the first 72 hours of onset of acute limb weakness. | |||
==Management<ref>http://www.cdc.gov/acute-flaccid-myelitis/downloads/acute-flaccid-myelitis.pdf</ref>== | ==Management<ref>http://www.cdc.gov/acute-flaccid-myelitis/downloads/acute-flaccid-myelitis.pdf</ref>== | ||
*Report suspected cases to CDC/department of health | *Report suspected cases to CDC/department of health | ||
*Respiratory: | *Respiratory: | ||
**Consider intubation for airway protection if evidence of bulbar dysfunction | **Consider [[intubation]] for airway protection if evidence of bulbar dysfunction | ||
**Consider NIPPV if evidence of respiratory muscle weakness (by clinical exam, hypoxia, hypercarbia, vital capacity <15 mL/kg, or NIF <30) | **Consider [[biPAP|NIPPV]] if evidence of respiratory muscle weakness (by clinical exam, hypoxia, hypercarbia, vital capacity <15 mL/kg, or NIF <30) | ||
*Treat neuropathic pain | *Treat [[neuropathic pain]] | ||
*Elevate head of bed >30 degrees | *Elevate head of bed >30 degrees | ||
*No evidence of benefit from [[corticosteroids]], [[IVIG]], plasmapheresis, or antivirals as of yet | *No evidence of benefit from [[corticosteroids]], [[IVIG]], plasmapheresis, or antivirals as of yet | ||
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==External Links== | ==External Links== | ||
*https://wwwn.cdc.gov/nndss/conditions/acute-flaccid-myelitis/case-definition/2018/ | |||
==References== | ==References== | ||
Latest revision as of 09:16, 24 October 2020
Background
- Polio-like illness, subset of transverse myelitis
- More common in children
- Likely caused by:
- Enterovirus, particularly Enterovirus D68, poliovirus
- West nile virus
- Adenovirus
Clinical Features[1]
- Acute onset, focal weakness of 1 or more extremity
- Decreased muscular tone
- Absent or hypoactive reflexes
- Rarely have numbness, but may have some neuropathic pain
- Fever and other symptoms of infection by causative virus (e.g. URI symptoms, gastroenteritis)
- In severe cases:
- Bulbar dysfunction (dysphagia, dysarthria, dysphonia, facial weakness, ptosis)
- Respiratory muscle weakness
- Autonomic instability, arrhythmias if cervical lesion present
- Paralysis usually maximal at 3-5 days after onset
Differential Diagnosis
Weakness
- Neuromuscular weakness
- Upper motor neuron:
- CVA
- Hemorrhagic stroke
- Multiple sclerosis
- Amyotrophic Lateral Sclerosis (ALS) (upper and lower motor neuron)
- Lower motor neuron:
- Spinal and bulbar muscular atrophy (Kennedy's syndrome)
- Spinal cord disease:
- Infection (Epidural abscess)
- Infarction/ischemia
- Trauma (Spinal Cord Syndromes)
- Inflammation (Transverse Myelitis)
- Degenerative (Spinal muscular atrophy)
- Tumor
- Peripheral nerve disease:
- Neuromuscular junction disease:
- Muscle disease:
- Rhabdomyolysis
- Dermatomyositis
- Polymyositis
- Alcoholic myopathy
- Upper motor neuron:
- Non-neuromuscular weakness
- Can't miss diagnoses:
- ACS
- Arrhythmia/Syncope
- Severe infection/Sepsis
- Hypoglycemia
- Periodic paralysis (electrolyte disturbance, K, Mg, Ca)
- Respiratory failure
- Emergent Diagnoses:
- Symptomatic Anemia
- Severe dehydration
- Hypothyroidism
- Polypharmacy
- Malignancy
- Aortic disease - occlusion, stenosis, dissection
- Other causes of weakness and paralysis
- Acute intermittent porphyria (ascending weakness)
- Can't miss diagnoses:
Evaluation
- Evaluate for other causes of symptoms (e.g. HSV, bacterial meningitis, Guillain-Barre syndrome)
- CSF: Pleocytosis (WBC count >5 cells/mm3), +/- elevated protein
- MRI: spinal cord lesion, largely restricted to gray matter, spanning one or more spinal segments
- Spinal cord lesions may not be present on initial MRI if performed within the first 72 hours of onset of acute limb weakness.
Management[3]
- Report suspected cases to CDC/department of health
- Respiratory:
- Consider intubation for airway protection if evidence of bulbar dysfunction
- Consider NIPPV if evidence of respiratory muscle weakness (by clinical exam, hypoxia, hypercarbia, vital capacity <15 mL/kg, or NIF <30)
- Treat neuropathic pain
- Elevate head of bed >30 degrees
- No evidence of benefit from corticosteroids, IVIG, plasmapheresis, or antivirals as of yet
Disposition
- Admit
- Consider ICU admission for:
- Respiratory muscle weakness
- Bulbar weakness causing impaired airway protection
- Altered mental status
- Autonomic instability
- Cervical lesion on MRI
- Rapidly progressive course