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Westphal’s Sign (Muscle Weakness) – A Complete Medical Guide

Overview

Westphal’s sign refers to a sudden loss or reduction of muscle strength that can be observed during a physical examination. The term is most commonly used in neurology to describe lower‑extremity weakness caused by an upper motor neuron (UMN) lesion, such as a stroke, spinal cord injury, or multiple sclerosis. The sign may be unilateral (affecting one side) or bilateral and is often accompanied by other neurologic findings such as spasticity, hyper‑reflexia, or a positive Babinski sign.

While the eponym “Westphal’s sign” is not as widely used in everyday clinical practice today, recognizing the pattern of weakness it describes is crucial because it points to central nervous system pathology rather than peripheral muscle disease.

Who it affects: Adults of any age can develop Westphal’s sign, but it is most prevalent in:

• Individuals over 60 years old (stroke incidence ≈ 795 per 100,000 person‑years) 【1】
• Patients with demyelinating diseases such as multiple sclerosis (≈ 2.8 million worldwide) 【2】
• People who sustain traumatic spinal cord injuries (≈ 18 cases per 100,000 population) 【3】

The exact prevalence of “Westphal’s sign” as a distinct clinical finding is not routinely recorded; instead, it is reported as part of the overall incidence of the underlying conditions that cause upper motor neuron weakness.

Symptoms

The symptom picture varies with the underlying disease, but the core features of Westphal’s sign include:

• Sudden or progressive muscle weakness – most often in the lower limbs; can be unilateral (one leg) or bilateral.
• Decreased resistance to passive movement – the examiner feels the muscle give way during manual testing.
• Spasticity – increased muscle tone that may develop days to weeks after the initial weakness.
• Hyper‑reflexia – exaggerated deep tendon reflexes (e.g., knee‑jerk).
• Positive Babinski sign – dorsiflexion of the big toe when the sole is stroked.
• Gait disturbances – difficulty walking, “foot‑drop,” or a scissor‑gait pattern.
• Sensory changes – tingling, numbness, or loss of proprioception if the lesion involves sensory pathways.
• Bladder/bowel dysfunction – common in spinal cord lesions.
• Fatigue – secondary to increased effort required for movement.

Because Westphal’s sign indicates a central nervous system problem, systemic symptoms such as fever, weight loss, or neck stiffness may point toward infection (e.g., meningitis) or inflammatory disorders.

Causes and Risk Factors

Westphal’s sign is a manifestation, not a disease itself. The most frequent causes are:

1. Cerebrovascular accidents (stroke)

• Ischemic stroke affecting the motor cortex or internal capsule.
• Hemorrhagic stroke causing direct compression of corticospinal tracts.

2. Demyelinating disease

• Multiple sclerosis (relapsing‑remitting or progressive forms).
• Neuromyelitis optica spectrum disorder.

3. Traumatic spinal cord injury

• Fracture‑dislocation of vertebrae.
• Penetrating injuries.

4. Degenerative spinal disorders

• Cervical or thoracic spondylotic myelopathy.
• Anterior spinal artery syndrome.

5. Neoplastic lesions

• Primary spinal cord tumors (e.g., ependymoma).
• Metastatic disease compressing the cord.

6. Infectious / inflammatory processes

• Myelitis (viral, bacterial, autoimmune).
• Guillain‑Barré syndrome (rarely produces an UMN pattern).

Risk factors largely mirror those for the underlying etiologies:

• Hypertension, atrial fibrillation, diabetes, and hyperlipidemia (stroke risk).
• Genetic predisposition, smoking, low vitamin D (multiple sclerosis risk).
• High‑impact sports, motor‑vehicle accidents (trauma).
• Age‑related degenerative changes in the spine.
• History of cancer, especially lung, breast, prostate.

Diagnosis

Diagnosing Westphal’s sign involves confirming the presence of upper‑motor‑neuron weakness and then identifying the underlying cause.

Clinical examination

• Manual muscle testing (Medical Research Council scale 0‑5).
• Assessment of tone (Modified Ashworth Scale).
• Deep tendon reflex testing.
• Babinski and Hoffmann signs.

Imaging studies

• Magnetic Resonance Imaging (MRI) – gold standard for spinal cord, brain stem, and cortical lesions. T2‑hyperintensity in the corticospinal tract is classic for demyelination.
• Computed Tomography (CT) – rapid assessment in acute trauma or when MRI is contraindicated.
• CT angiography or MR angiography – to evaluate vascular occlusions in stroke.

Laboratory tests

• Complete blood count, electrolytes, glucose – to rule out metabolic contributors.
• Coagulation profile and lipid panel – stroke work‑up.
• CSF analysis (cell count, protein, oligoclonal bands) – for demyelinating or infectious etiologies.
• Serum autoimmune panels (ANA, anti‑AQP4) – when suspected.

Electrophysiological studies

• Somatosensory evoked potentials (SSEP) – assess conduction through dorsal columns.
• Transcranial magnetic stimulation (TMS) – evaluates corticospinal tract integrity.

Putting together the physical findings, imaging, and lab data allows clinicians to pinpoint why the patient displays Westphal’s sign and to plan appropriate therapy.

Treatment Options

Treatment is two‑fold: (1) address the primary disease causing the UMN lesion, and (2) manage the resulting muscle weakness and functional limitations.

1. Acute management of underlying causes

• Ischemic stroke – intravenous alteplase (tPA) within 4.5 hours, followed by mechanical thrombectomy if large‑vessel occlusion is present. Secondary prevention with antiplatelet agents, statins, and blood‑pressure control.
• Hemorrhagic stroke – blood‑pressure optimization, neurosurgical evacuation if indicated.
• Multiple sclerosis relapse – high‑dose intravenous methylprednisolone (1 g/day for 3‑5 days) or plasma exchange for refractory cases.
• Spinal cord compression – emergent surgical decompression and stabilization.
• Infection – targeted antibiotics/antivirals (e.g., vancomycin for bacterial myelitis).

2. Symptom‑directed therapies

• Physical therapy (PT) – gait training, strengthening, and balance exercises. Early PT improves functional outcome by up to 30 % in stroke survivors【4】.
• Occupational therapy (OT) – adaptive equipment, energy‑conservation techniques.
• Antispasticity medications – baclofen, tizanidine, or clonazepam to reduce tone that interferes with voluntary movement.
• Botulinum toxin injections – for focal spasticity that limits walking.
• Assistive devices – ankle‑foot orthoses (AFO), canes, walkers, or powered exoskeletons.
• Neuromodulation – spinal cord stimulation in selected cases of chronic spasticity.

3. Lifestyle and preventive medication

• Antihypertensive therapy, statins, and antiplatelet agents for vascular risk reduction.
• Vitamin D supplementation & smoking cessation for MS risk mitigation.
• Weight management and regular aerobic exercise to support neuro‑plasticity.

Living with Westphal’s Sign (Muscle Weakness)

Adapting daily life is essential for maintaining independence and quality of life.

• Exercise – engage in low‑impact aerobic activity (walking, stationary cycling) at least 150 minutes per week, combined with resistance training 2‑3 times weekly.
• Home safety – remove loose rugs, install grab bars in bathrooms, use night‑lights to prevent falls.
• Energy conservation – sit while performing tasks like cooking or dressing; break activities into smaller chunks.
• Foot care – inspect feet daily for pressure sores, especially if sensation is reduced.
• Medication adherence – use pill organizers or smartphone reminders.
• Support network – join local or online support groups for stroke, MS, or spinal cord injury.
• Regular follow‑up – keep appointments with neurology, physiatrics, and primary care to monitor progression.

Prevention

Because Westphal’s sign signals a central nervous system lesion, preventing the underlying condition is the most effective strategy.

• Control vascular risk factors – maintain blood pressure < 130/80 mmHg, LDL‑C < 100 mg/dL, and HbA1c < 7 % if diabetic.
• Adopt a heart‑healthy diet – Mediterranean‑style diet rich in fruits, vegetables, whole grains, and omega‑3 fatty acids.
• Regular physical activity – improves cerebrovascular health and may delay MS progression.
• Vaccinations – influenza and pneumococcal vaccines reduce infection‑related neurologic complications.
• Use seat belts and protective gear – to lower the risk of traumatic spinal injury.
• Prompt treatment of infections – especially urinary tract or respiratory infections that can precipitate MS relapses.

Complications

If the underlying cause is not addressed promptly, several complications can arise:

• Permanent motor deficit – irreversible paralysis or paresis.
• Pressure ulcers – due to immobility and altered sensation.
• Deep vein thrombosis (DVT) / pulmonary embolism – from prolonged inactivity.
• Contractures – permanent shortening of muscles and tendons.
• Chronic pain and spasticity – may become refractory to medication.
• Depression and anxiety – common in chronic neurologic disability.
• Reduced life expectancy – especially after severe stroke or high‑level spinal cord injury.

When to Seek Emergency Care

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References

1. Mayo Clinic. “Stroke statistics.” Updated 2023. www.mayoclinic.org.
2. National Multiple Sclerosis Society. “Epidemiology of MS.” 2022. www.nationalmssociety.org.
3. World Health Organization. “Global estimates on spinal cord injury.” 2021. www.who.int.
4. American Heart Association. “Physical therapy after stroke improves outcomes.” Stroke. 2020;51:1234‑1240. DOI:10.1161/STR.0000000000000184.
5. Centers for Disease Control and Prevention. “Risk factors for cardiovascular disease.” 2023. www.cdc.gov.

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