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Weakness, Emergency Medicine

Basics

Description

- Defined as a decrease in physical strength or energy - Often multifactorial - Distinguish neuromuscular disorder vs. non-neuromuscular disorder - Categories of neuromuscular disorders: - Upper motor neuron (UMN) lesions: - Deep tendon reflexes (DTR) increased - Plantar reflexes upgoing - Increased muscle tone - Muscle atrophy absent

- Lower motor neuron (LMN) lesions: - DTRs decreased to absent - Plantar reflexes absent or normal - Decreased muscle tone - Muscle atrophy present - Fasciculations

- Neuromuscular disorders: - UMN lesions: - Multiple sclerosis - Amyotrophic lateral sclerosis (mixed) - Transverse myelitis - Poliomyelitis

- Endocrine abnormalities: - Hypothyroidism - Adrenal crisis - Periodic paralyses

- Rheumatologic disorders: - Systemic lupus erythematosus - Polymyalgia rheumatica

- Altered physical strength: - Assessment of strength: - 1: No contraction - 2: Active movement with gravity eliminated - 3: Active movement against gravity - 4: Active movement against gravity and resistance - 5: Normal power

- Change in muscle tone: - Flaccidity - Spasticity - Rigidity

- Abnormal DTRs - Abnormal plantar reflexes - Muscle atrophy: - Difference of >1 cm in the leg and thigh and >0.5 cm in the forearm and arm

- Physiologic causes of weakness: - Simple fatigue: - Excessive physical activity - Inadequate rest - Excessive or inadequate diet - Pregnancy

- Neurology consult if needed - When the diagnosis is determined, specific therapies can be applied: - TPA for CVAs meeting criteria - Plasma exchange and/or IV immunoglobulin (IVIG) for Guillain " “Barre syndrome - Hydrocortisone for adrenal insufficiency - Potassium supplementation for hypokalemia - Dextrose for hypoglycemia - Antibiotics for infectious etiologies - Specific antidotes for botulism and diphtheria - Digibind for digoxin toxicity

  • Defined as a decrease in physical strength or energy
  • Often multifactorial
  • Distinguish neuromuscular disorder vs. non-neuromuscular disorder
  • Categories of neuromuscular disorders:Upper motor neuron (UMN) lesions:Deep tendon reflexes (DTR) increasedPlantar reflexes upgoingIncreased muscle toneMuscle atrophy absentLower motor neuron (LMN) lesions:DTRs decreased to absentPlantar reflexes absent or normalDecreased muscle toneMuscle atrophy presentFasciculationsNeuromuscular junction (NMJ) lesions:DTRs normalPlantar reflexes normal or absentDecreased muscle tone
  • Categories of non-neuromuscular disorders:InfectiousEndocrineMetabolicCardiacRheumatologicToxicPsychiatric

Etiology

  • Neuromuscular disorders:UMN lesions:Multiple sclerosisAmyotrophic lateral sclerosis (mixed)Transverse myelitisPoliomyelitisLMN lesions:Guillain " “Barre syndromeToxic neuropathiesImpingement syndromesDiphtheriaPorphyriaSeafood toxinsNMJ lesions/others:Myasthenia gravisLambert " “Eaton syndromeBotulismPeriodic paralysisTick paralysis
  • Non-neuromuscular disorders:DehydrationAnemiaElectrolyte imbalancesMalignancyCerebrovascular accidentHead or neck traumaMyocardial ischemiaInfection/sepsis:UTIPneumoniaMeningitisMononucleosisHIVArborvirusesEndocrine abnormalities:HypothyroidismAdrenal crisisPeriodic paralysesRheumatologic disorders:Systemic lupus erythematosusPolymyalgia rheumaticaToxins:MedicationsEnvironmentalCarbon monoxide poisoningCocaineAlcohol

Diagnosis

Signs and Symptoms

  • Altered physical strength:Assessment of strength:1: No contraction2: Active movement with gravity eliminated3: Active movement against gravity4: Active movement against gravity and resistance5: Normal powerChange in muscle tone:FlacciditySpasticityRigidityAbnormal DTRsAbnormal plantar reflexesMuscle atrophy:Difference of >1 cm in the leg and thigh and >0.5 cm in the forearm and arm
  • Systemic findings:WeaknessFatigueDizzinessParesisParesthesiasHoarse voiceDysphagiaVisual changesConfusionAssociated symptoms:FeverChest painDyspneaCoughWeight lossRashDysuriaUpper respiratory infection symptoms

Essential Workup

  • Review of medications
  • Clinical suspicion gathered through history and physical exam guides further testing:Generalized vs. focalAcute vs. chronicProximal vs. distalAscending vs. descendingSymmetric vs. asymmetricImproved vs. worsened with activity

Diagnosis Tests & Interpretation

Diagnostic testing should be broad unless history and physical exam identify the cause of weakness. ‚

Lab

  • Serum glucose
  • CBC
  • Electrolytes
  • BUN/creatinine
  • Toxin screen
  • Urinalysis
  • Thyroid function tests (rule out hypothyroidism)
  • ESR (rule out rheumatologic cause)
  • Carboxyhemoglobin (rule out CO poisoning)
  • Troponin/CK-MB (rule out cardiac ischemia)
  • Digoxin level (rule out digoxin toxicity)

Imaging

  • EKG (rule out acute coronary syndrome [ACS]/arrhythmia)
  • CXR (rule out pneumonia)
  • CT/MRI head (rule out intracranial pathology)

Diagnostic Procedures/Surgery

  • Bedside spirometry:Forced vital capacity, negative inspiratory force, peak expiratory flow rateMay identify those with impending ventilatory failure
  • Lumbar puncture:In suspected Guillain " “Barre syndrome:Albumin-cytologic dissociation in CSF (protein >400, WBC <10) is virtually diagnostic.
  • Tensilon test:Distinguishes myasthenic crisis from cholinergic crisis in myasthenia gravis

Differential Diagnosis

  • Physiologic causes of weakness:Simple fatigue:Excessive physical activityInadequate restExcessive or inadequate dietPregnancy
  • Psychiatric causes of weakness:Anxiety/depressionDependent personalityHypochondriasisChronic fatigue syndromeFibromyalgiaMalingering

Treatment

Treatment is geared to the underlying cause of weakness. ‚

Pre-Hospital

  • Supplemental oxygen
  • IV access
  • Finger-stick glucose determination
  • Consider endotracheal intubation in patients with severe respiratory distress.

Initial Stabilization/Therapy

  • Supplemental oxygen
  • IV access
  • Endotracheal intubation for impending ventilatory failure

Ed Treatment/Procedures

  • Neurology consult if needed
  • When the diagnosis is determined, specific therapies can be applied:TPA for CVAs meeting criteriaPlasma exchange and/or IV immunoglobulin (IVIG) for Guillain " “Barre syndromeHydrocortisone for adrenal insufficiencyPotassium supplementation for hypokalemiaDextrose for hypoglycemiaAntibiotics for infectious etiologiesSpecific antidotes for botulism and diphtheriaDigibind for digoxin toxicity

Follow-Up

Disposition

Admission Criteria

  • All patients with new-onset neuromuscular disorders should be admitted for definitive diagnosis.
  • Any evidence of impending ventilatory or circulatory compromise warrants ICU admission.

Discharge Criteria

  • Resolution of symptoms
  • Stable vital signs
  • Definitive diagnosis and correction of abnormality

Follow-Up Recommendations

  • Discharged patients with non-neurologic etiologies should have follow-up with their PCP.
  • Discharged patients with neurologic etiologies should have urgent neurology follow-up.

Pearls and Pitfalls

  • Identify early and aggressively treat patients at risk for respiratory compromise due to Guillain " “Barre, botulism, myasthenia gravis.
  • Identify elderly patients with ACS or infection presenting as weakness.
  • Consider endocrine causes of weakness, including adrenal insufficiency and hypothyroidism.

Additional Reading

  • Anderson ‚ RS Jr, Hallen ‚ SA. Generalized weakness in the geriatric emergency department patient: An approach to initial management. Clin Geriatr Med. 2013;29(1):91 " “100.
  • Chew ‚ WM, Birnbaumer ‚ DM. Evaluation of the elderly patient with weakness: An evidence based approach. Emerg Med Clin North Am. 1999;17(1):265 " “278.
  • Losman ‚ E. Weakness. In: Marx ‚ J, ed. Rosens Emergency Medicine: Concepts and Clinical Practice. 7th ed. St. Louis, MO: Mosby; 2009:87 " “92.
  • LoVecchio ‚ F, Jacobson ‚ S. Approach to generalized weakness and peripheral neuromuscular disease. Emerg Med Clin North Am. 1997;15(3):605 " “623.

Codes

ICD9

  • 728.2 Muscular wasting and disuse atrophy, not elsewhere classified
  • 728.87 Muscle weakness (generalized)
  • 780.79 Other malaise and fatigue
  • 340 Multiple sclerosis
  • 335.20 Amyotrophic lateral sclerosis
  • 357.0 Acute infective polyneuritis

ICD10

  • M62.50 Muscle wasting and atrophy, NEC, unsp site
  • M62.81 Muscle weakness (generalized)
  • R53.1 Weakness
  • G35 Multiple sclerosis
  • G12.21 Amyotrophic lateral sclerosis
  • G61.0 Guillain-Barre syndrome

SNOMED

  • 13791008 Asthenia (finding)
  • 26544005 Muscle weakness (finding)
  • 88092000 Muscle atrophy (disorder)
  • 24700007 Multiple sclerosis (disorder)
  • 40956001 Guillain-Barre syndrome (disorder)
  • 86044005 Amyotrophic lateral sclerosis (disorder)