Acute Peripheral Neurologic Lesions

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Acute Peripheral Neurologic Lesions
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• Peripheral nervous system serves sensory, motor
  and autonomic functions.
• On PE the most important finding in a peripheral
  nerve process is reduction or absence of
  reflexes.
• Abnormalities of proprioception, vibratory
  sensation, andn pain and temp can also be seen.

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• It is important to determine which part of the
  peripheral nervous system is involved.
• A localized process strongly suggests a focal
  lesion.
• Most muscle related processes result in weakness
  of large proximal muscles. Difficult getting out
  of chairs.
• May see pain and tenderness of muscles with
  elevated CK.

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• Neuropathies frequently affect both the motor and
  sensory systems, effecting longer nerves and
  reducing distal muscle power.
• Pinpoint the time and course of illness, diurnal
  fluctuations, a review of meds, and any other
  illnesses.
• In the ED useful tests include serum chem,
  metabolic profile and CK.

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• Treatment depends on the specific diagnosis, but
  neurological consult should be obtained.
• Supportive care in the ED for severe,
  life-threatening neuromuscular diseases should
  begin in the ED.
• Admission for acute peripheral neurological
  conditions is warranted for respiratory or
  autonomic compromise.

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Myopathies

• Polymyositis is an inflammatory myopathy
  affecting people older than 30, MgtF.
• Usually presents with proximal symmetric
  weakness. May progress to dysphagia and resp.
  failure.
• On PE will see reduced proximal strength but no
  sensory loss, and reflexes should be intact.
• Labs may show elevated ESR, leukocytosis, CK

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• Dermatomyositis can affect kids and affects
  mostly women.
• Clinically similar to polymyositis except a
  violaceous rash over the hands and face.
• A large number of substances including
  environmental, occupational, and pharmacologic
  agents can cause myopathies.

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• Myopathies cause a predominantly proximal pattern
  of weakness with normal sensation and preserved
  tendon reflexes.
• Viral myositis causes an acute myopathy,
  occasionally involving the heart, assoc. with
  febrile illness, myalgia and elevated CK levels.

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Disorders of Neuromuscular Junction

• Clostridium botulism is an acute disease marked
  by weakness and GI slowing.
• Ingestion of home canned vegetables 1-2 days
  before symptoms is a hallmark of botulism.
• Ingestion of honey by infants can lead to
  botulism and symptoms present with poor sucking.
• Absence of pupillary light reflex distinguishes
  botulism from myasthenia gravis.

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• Proximal limb weakness, intact sensation, and
  normal reflexes are generally found.
• Treatment in infants include antibiotics and
  immune serum. Adults receive immune serum.

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• Guillain-Barre syndrome affects individuals of
  all ages with the most common form being acute
  generalized neuropathy.
• Pts report a preceding viral illness with
  numbness and tingling of the lower ext. being the
  first symptoms with progressive ascending
  weakness.
• Most cases are caused by autoimmune attack on
  myelinated motor nerves.

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• Hallmark of GBS is the lack of deep tendon
  reflexes.
• Respiratory failure and lethal autonomic
  disturbances can occur.
• In the acute phase, LP should be performed. CSF
  protein will be high after one week of symptoms
  with normal glucose and cell ct.

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• Lyme disease present similar to GBS but with CSF
  pleocytosis with a hx of tick bites or with CSF
  lyme antibodies.
• GBS should be admitted to the hospital for plasma
  exchange or IVIG.
• Acute intermittent porphyria is a rare autosomal
  dominant condition with weakness, psychosis and
  abd. pain.

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Focal Neuropathies

• Carpal tunnel syndrome- numbness of first three
  digits-worse at night.
• Reproduced by compression of the median nerve or
  by tapping on the nerve.
• Treat with splints at night and NSAIDS.
• Refer to hand surgeon

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• Ulnar nerve entrapment-occurs most commonly at
  elbow with numbness of 5th and half of the 4th
  finger. Wasting of hypothenar muscles occur.
• Deep peroneal nerve entrapment at the fibular
  head can cause footdrop and numbness between the
  1st and 2nd toes. Treat conservatively and
  improves without specific therapy.

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• Meralgia paresthetica-entrapment of the lateral
  cutaneous nerve of the thigh. Numbness of the
  lateral thigh. Occurs after weight loss, OB
  surgeries or wearing heavy belt (carpenter,
  police).
• Bells Palsy-diagnosis of exclusion. Sudden
  facial weakness (involves forehead), difficulty
  with articulation, problems keeping eye closed,
  inablity or keep one side of mouth closed.

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• Treatments for Bells palsy can include 50mg
  prednisone for 7 days and acyclovir 200mg po 5
  times daily for 10 days.
• Lyme disease- pathogen Borrelia burgdorferi.
  Neurologic signs such as 7th nerve palsy may
  present after fatigue and arthralgias.
• Affects the peripheral nerves and nerve roots.
  May see progression of weakness and sensory loss.
  There will be a patchy myotomal pattern.

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• Deep tendon reflexes will be diminshed and lab
  studies should show CSF lyme antibodies.
• 3 weeks of ceftriaxone or doxy IV is treatment
• Brachial neuritis-acute condition manifests as
  shoulder back or arm pain followed by weakness of
  the arm or shoulder girdle.
• Idiopathic
• Upper trunk is most affected
• Reflexes diminished
• Inability to form a pincer with the index finger
  and thumb

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• Lumbar plexopathy occurs in diabetic pts and
  presents with back pain followed by weakness.
• Acute onset of ipsilateral back pain, followed by
  progressive leg weakness. Sensory intact.
• Long term muscle wasting
• In ED lumbar X rays to screen for degenerative
  or neoplastic disease.

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• In late AIDS virus pt may have acute radiculitis
  caused by CMV infection.
• Pts become acutely weak with mainly lower ext
  involvement with weakness and hyporeflexia,
  decreased sensation and /- rectal tone loss.

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• Tintinalli