Weakness

Weakness differs from fatigue, though the terms are often used interchangeably. True weakness involves decreased muscle strength, making it difficult to move a part of your body against resistance. Fatigue, on the other hand, is a feeling of tiredness or exhaustion that doesn't necessarily involve loss of muscle strength.

Weakness can be classified as subjective (you feel weak but muscle strength tests normal) or objective (measurable loss of muscle strength). It can also be acute (sudden onset) or chronic (developing over time), and either localized (affecting specific muscles) or generalized (affecting the whole body).

The nervous system controls muscle movement through a complex pathway from the brain to the muscles. Weakness can result from problems anywhere along this pathway - in the brain, spinal cord, peripheral nerves, neuromuscular junction, or the muscles themselves. Understanding the pattern and progression of weakness helps determine its cause.

Neurological Causes

• Stroke: Sudden weakness, often one-sided
• Multiple sclerosis: Weakness that comes and goes
• ALS (Lou Gehrig's disease): Progressive muscle weakness
• Myasthenia gravis: Weakness worsening with activity
• Guillain-Barré syndrome: Ascending paralysis
• Peripheral neuropathy: Nerve damage causing weakness
• Spinal cord compression: From disc, tumor, or injury
• Brain tumor: Gradual or sudden weakness
• Parkinson's disease: Weakness with tremor, stiffness
• Bell's palsy: Facial weakness

Muscular Causes

• Muscular dystrophy: Progressive muscle weakness
• Inflammatory myopathies: Muscle inflammation
• Rhabdomyolysis: Muscle breakdown
• Disuse atrophy: From prolonged inactivity
• Steroid myopathy: From corticosteroid use

Metabolic and Systemic Causes

• Anemia: Low red blood cells
• Electrolyte imbalances: Low potassium, sodium
• Thyroid disorders: Both hypo and hyperthyroidism
• Diabetes: Complications affecting nerves
• Kidney disease: Toxin buildup
• Liver disease: Metabolic disturbances
• Heart failure: Poor oxygen delivery
• Chronic fatigue syndrome: Persistent weakness
• Dehydration: Severe fluid loss
• Malnutrition: Vitamin deficiencies

Other Causes

• Medications: Statins, diuretics, sedatives
• Infections: Flu, COVID-19, sepsis
• Cancer: Direct effect or treatment side effects
• Depression: Psychomotor retardation
• Chronic pain: Deconditioning
• Sleep disorders: Poor rest quality
• Aging: Natural muscle loss (sarcopenia)

Weakness often occurs with other symptoms that help identify the underlying cause:

• Numbness or tingling: Nerve involvement
• Pain: Inflammation, injury, or nerve compression
• Muscle cramps: Electrolyte imbalance, dehydration
• Tremor: Parkinson's, essential tremor
• Vision changes: Multiple sclerosis, stroke
• Speech difficulties: Stroke, myasthenia gravis
• Difficulty swallowing: Neuromuscular disorders
• Breathing problems: Respiratory muscle weakness
• Dizziness: Cardiovascular or neurological causes
• Fatigue: Often accompanies weakness
• Weight loss: Cancer, chronic disease
• Fever: Infection, inflammation
• Joint pain: Inflammatory conditions
• Skin changes: Dermatomyositis

Signs of Stroke

• Sudden weakness on one side
• Facial droop
• Arm drift when raised
• Slurred speech
• Time is critical - act FAST

Signs of Spinal Cord Emergency

• Weakness in both legs
• Loss of bowel/bladder control
• Numbness in saddle area
• Back pain with weakness
• After trauma

Signs of Neuromuscular Crisis

• Difficulty breathing
• Trouble swallowing
• Rapidly worsening weakness
• Drooping eyelids
• Double vision

Medical History

• Onset and progression
• Pattern of weakness
• Associated symptoms
• Time of day variations
• Aggravating factors
• Family history
• Medications
• Recent infections
• Trauma history

Physical Examination

• Muscle strength testing (0-5 scale)
• Reflex testing
• Sensory examination
• Coordination tests
• Gait assessment
• Cranial nerve testing
• Muscle bulk and tone

Diagnostic Tests

• Blood tests: CBC, electrolytes, thyroid, CK
• EMG/Nerve conduction: Nerve and muscle function
• MRI brain/spine: Structural abnormalities
• CT scan: Emergency evaluation
• Lumbar puncture: If infection/inflammation suspected
• Muscle biopsy: For muscle diseases
• Antibody tests: Autoimmune conditions

Daily Management

• Pace activities to conserve energy
• Use assistive devices as needed
• Modify home for safety
• Plan rest periods
• Maintain good nutrition
• Stay hydrated
• Keep active within limits
• Monitor symptoms

Safety Precautions

• Remove trip hazards
• Install grab bars
• Use night lights
• Wear supportive shoes
• Avoid stairs if unsteady
• Keep phone accessible
• Medical alert systems
• Regular check-ins

Exercise and Activity

• Work with physical therapist
• Start slowly and progress
• Focus on maintaining function
• Include range of motion
• Water exercises helpful
• Avoid overexertion
• Listen to your body

• Regular exercise: Maintain muscle strength and mass
• Balanced nutrition: Adequate protein and vitamins
• Manage chronic conditions: Control diabetes, thyroid issues
• Medication review: Monitor for side effects
• Fall prevention: Reduce injury risk
• Adequate sleep: Allow muscle recovery
• Stress management: Prevent tension-related weakness
• Regular check-ups: Early detection of problems
• Vaccination: Prevent infections causing weakness
• Limit alcohol: Avoid toxic effects
• Workplace ergonomics: Prevent overuse
• Stay hydrated: Maintain electrolyte balance

Schedule an Appointment For:

• Gradually worsening weakness
• Weakness interfering with daily activities
• Weakness with weight loss
• Muscle weakness with pain
• Weakness after starting new medication
• Family history of muscle disease
• Weakness with skin changes
• Difficulty climbing stairs or rising from chair
• Frequent falls or near-falls

Seek Immediate Care For:

• Sudden onset weakness
• One-sided weakness
• Weakness with speech problems
• Difficulty breathing or swallowing
• Weakness after injury
• Loss of consciousness
• Chest pain with weakness
• High fever with weakness