Difference between revisions of "Weakness"

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Determine if pt has actual neuromuscular weakness (suggesting CNS dysfuction) or non-neuromuscular weakness.
 
Determine if pt has actual neuromuscular weakness (suggesting CNS dysfuction) or non-neuromuscular weakness.
  
==Diagnosis==
+
==Clincial Features==
 
=== History  ===
 
=== History  ===
 
*'''True motor weakness (neuromuscular weakness)? Bilateral or unilateral (distribution of weakness)?'''  
 
*'''True motor weakness (neuromuscular weakness)? Bilateral or unilateral (distribution of weakness)?'''  
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==== Upper Motor Neuron  ====
 
==== Upper Motor Neuron  ====
 
 
*BRAIN  
 
*BRAIN  
 
**Weakness - variable  
 
**Weakness - variable  
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==== Lower Motor Neuron  ====
 
==== Lower Motor Neuron  ====
 
 
*NERVE  
 
*NERVE  
 
**Weakness - distal > proximal and ascends  
 
**Weakness - distal > proximal and ascends  
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==== End-Plate/Muscle  ====
 
==== End-Plate/Muscle  ====
 
 
*MOTOR END PLATE  
 
*MOTOR END PLATE  
 
**Weakness - occular,bulbar and descends, fatigable  
 
**Weakness - occular,bulbar and descends, fatigable  
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**Pain - +/-
 
**Pain - +/-
  
== Workup  ==
+
==Differential Diagnosis==
 +
{{Weakness DDX}}
 +
 
 +
==Diagnosis==
 +
=== Workup  ===
 
'''On all pts:'''
 
'''On all pts:'''
 
*CBC (anemia)
 
*CBC (anemia)
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*LP (CNS infection, GBS)
 
*LP (CNS infection, GBS)
  
==Differential Diagnosis==
 
{{Weakness DDX}}
 
  
 
==Treatment==
 
==Treatment==
 
 
=== Intubation Indications  ===
 
=== Intubation Indications  ===
 
 
*Severe fatigue  
 
*Severe fatigue  
 
*Inability protect airway  
 
*Inability protect airway  

Revision as of 13:28, 20 July 2015

Background

Determine if pt has actual neuromuscular weakness (suggesting CNS dysfuction) or non-neuromuscular weakness.

Clincial Features

History

  • True motor weakness (neuromuscular weakness)? Bilateral or unilateral (distribution of weakness)?
    • Bilateral weakness:
      • W/symmetric ascending paralysis? Guillain-Barre Syndrome
      • W/weakness involving both CN + PNS? Inflammatory/Autoimmune or toxic/metabolic
      • W/discrete sensory level and/or bladder dysfxn? Spinal Cord Lesion
      • W/involvement of proximal > distal musculature? Myopathy
    • Unilateral weakness: CVA, TIA
  • If non-neuromuscular weakness then BROAD Ddx obtain:
    • ECG, CBC, Chem10, LFTs, blood cx, UA/UCx, drug levels, CXR, Consider Head CT (focal deficit, AMS, h/o CA, anticoagulation w/minor trauma)
  • Onset of weakness sudden or gradual?
    • Sudden suggests vaso-occlusive etiology CVA/TIA
    • Gradual onset likely non-vascular
  • Significant event surrounding onset of weakness?
    • SZ prior to weakness? Todd’s paralysis
    • Migraine HA? Complicated migraine
    • Sudden onset of severe HA? SAH
    • Trauma? Epidural or Subdural Hematoma
    • Severe migratory neck or chest pain? Arterial dissection syndromes
  • Temporal pattern to weakness? Fluctuating or fixed weakness?
  • Associated Sx?
    • HA: SAH, epidural/SDH, complicated migraines (young females), not usually stroke/TIA (unless high ICP)
    • Vision changes: Posterior circulation stroke, Myasthenia Gravis
    • SOB: CV etiology
    • CP or neck pain: Acute arterial dissection, AMI
    • Abdominal or back pain:
    • N/V: sign of ↑ ICP, can lead to electrolyte imbalances
    • Rash: Dermatomyositis

Physical Exam

Focus on clarifying if pt has true loss of strength and determining distribution of deficits. Check for trauma, carotid bruits, thyroid enlargement, irregular rhythm, unequal pulses, rashes or ticks.

Upper Motor Neuron

  • BRAIN
    • Weakness - variable
    • Bowel/Bladder -
    • Reflexes - increased
    • Sens - diminished
    • Pain - no
    • Asymmetric/unilateral
  • BRAINSTEM
    • "crossed" findings - ipsilateral cranial nerve weakness and contralateral hemiparesis
  • CORD
    • Weakness - fixed level
    • Bowel/Bladder - YES
    • Reflexes - increased
    • Sens - diminished
    • Pain - +/-

Lower Motor Neuron

  • NERVE
    • Weakness - distal > proximal and ascends
    • Bowel/Bladder - NO
    • Reflexes - diminished
    • Sens - nl/paresthesias
    • Pain - no

End-Plate/Muscle

  • MOTOR END PLATE
    • Weakness - occular,bulbar and descends, fatigable
    • Bowel/Bladder - NO
    • Reflexes - nl/diminished
    • Sens - nl
    • Pain - no
  • MUSCLE
    • Weakness - proximal > distal
    • Bowel/Bladder - NO
    • Reflexes - nl/diminished
    • Sens - nl
    • Pain - +/-

Differential Diagnosis

Weakness

Diagnosis

Workup

On all pts:

  • CBC (anemia)
  • Chem 10 (electrolyte disturbance,hypoglycemia, uremia)
  • ECG (Ischemia,hypo/hyperkalemia)

Consider:

  • CK (mypoathies)
  • ESR
  • CXR and UA (pt w/infectious sx and elderly)
  • FVC (if e/o resp compromise, i.e. Myasthenia, GBS)
  • CT head (if focal findings, AMS, h/o cancer, h/o any trauma in pt on anticoagulation)
  • LP (CNS infection, GBS)


Treatment

Intubation Indications

  • Severe fatigue
  • Inability protect airway
  • Rapidly increasing PaCO2
  • Hypoxemia despite O2
  • FVC <12 mL/kg
  • Neg Insp Force <20 cm H2O

References