Makindo Medical Notes

Aide Memoire: Remember that "P" stands for Pseudobulbar and it involves upper motor neurons.

Overview

Bulbar Palsy and Pseudobulbar Palsy are neurological conditions affecting the cranial nerves responsible for motor control of the face, throat, and tongue. Understanding the differences between these two types of palsy is crucial for accurate diagnosis and effective management.

Comparison: Bulbar vs Pseudobulbar Palsy

Aspect	Bulbar Palsy	Pseudobulbar Palsy
Type of Neuron Affected	Lower Motor Neuron (LMN)	Upper Motor Neuron (UMN)
Etiology	Polio Guillain-Barré Syndrome Motor Neuron Disease (MND) Syringobulbia Neurosyphilis	Bilateral Strokes Bilateral Multiple Sclerosis (MS) Plaques Bilateral Tumors Motor Neuron Disease (MND) Progressive Supranuclear Palsy
Clinical Features	Tongue wasting and fasciculations Dysphagia (difficulty swallowing) Dysarthria (difficulty speaking) Aspiration pneumonia Wet voice (dysphonia)	Increased/Brisk Jaw Jerk Weak and spastic tongue Dysphagia Donald Duck-like tight high-pitched nasal speech Emotional lability Dyspraxia (difficulty with coordinated movements)
Cognition	Unaffected	May be affected, including emotional lability and dyspraxia
Management	Protect airway to prevent aspiration Prevent aspiration pneumonia Support nutrition through feeding tubes if necessary Overall care depends on underlying cause	Protect airway to prevent aspiration Prevent aspiration pneumonia Support nutrition through feeding tubes if necessary Address emotional and cognitive symptoms Overall care depends on underlying cause

Pathophysiology

Both bulbar and pseudobulbar palsy affect the cranial nerves responsible for motor control of the face, throat, and tongue, but they differ in the location of the neuronal damage.

• Bulbar Palsy: Results from lesions in the lower motor neurons located in the brainstem's medulla oblongata. This leads to muscle atrophy, weakness, and fasciculations.
• Pseudobulbar Palsy: Caused by lesions in the upper motor neurons located in the cerebral cortex or corticobulbar tracts. This results in spasticity, hyperreflexia, and emotional lability.

Clinical Presentation Details

• Bulbar Palsy:
• Tongue wasting and fasciculations indicate LMN involvement.
• Dysphagia and dysarthria result from weakened or paralyzed muscles controlling swallowing and speech.
• Aspiration pneumonia occurs due to impaired swallowing, increasing the risk of inhaling food or liquids into the lungs.
• Wet voice (dysphonia) is due to incomplete closure of the vocal cords.
• Pseudobulbar Palsy:
• Increased jaw jerk reflex indicates UMN involvement.
• Weak and spastic tongue reflects spasticity of the muscles controlling tongue movement.
• Dysphagia arises from impaired coordination and control of swallowing muscles.
• Donald Duck-like speech is a high-pitched, strained voice resulting from involuntary contractions of facial muscles.
• Emotional lability includes uncontrollable laughing or crying, unrelated to the patient's actual emotional state.
• Dyspraxia involves difficulty in planning and executing coordinated movements, affecting speech and swallowing.

Investigations

Accurate diagnosis of bulbar vs pseudobulbar palsy involves clinical evaluation and targeted investigations to identify the underlying cause and the extent of neuronal damage.

• Neurological Examination:
  • Assess muscle strength, tone, and reflexes to differentiate between LMN and UMN lesions.
  • Evaluate speech and swallowing functions.
  • Check for signs of emotional lability or cognitive impairment.
• Electromyography (EMG):
  • Detects muscle atrophy and fasciculations indicative of LMN involvement in bulbar palsy.
• Imaging Studies:
  • Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) Scan to identify structural lesions affecting the cranial nerves or motor tracts.
• Blood Tests:
  • Evaluate for infectious or inflammatory causes (e.g., Lyme disease, Guillain-Barré syndrome).
• Genetic Testing:
  • For hereditary conditions like Multiple Sclerosis or Progressive Supranuclear Palsy.

Management

Management strategies for bulbar and pseudobulbar palsy focus on addressing the underlying cause, alleviating symptoms, and preventing complications.

• Protect Airway:
  • Ensure patency of the airway to prevent aspiration pneumonia, especially in bulbar palsy.
  • Use of feeding tubes or ventilatory support in severe cases.
• Prevent Aspiration:
  • Positioning strategies during and after feeding.
  • Swallowing therapy with a speech-language pathologist.
• Support Nutrition:
  • Use of modified diets or enteral feeding to ensure adequate nutrition.
• Speech and Swallowing Therapy:
  • Rehabilitation to improve speech clarity and swallowing safety.
• Pharmacological Treatments:
  • For pseudobulbar palsy, use of medications like selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants to manage emotional lability.
  • Botulinum toxin injections for spasticity in specific muscles.
• Address Underlying Cause:
  • Manage infections, autoimmune disorders, or structural lesions contributing to the palsy.
  • Surgical intervention if a tumor or other structural abnormality is identified.
• Regular Monitoring:
  • Frequent follow-up to assess progression, adjust treatments, and manage complications.

Prognosis

The prognosis for individuals with bulbar or pseudobulbar palsy depends largely on the underlying cause, the extent of neuronal damage, and the timeliness of intervention. Early diagnosis and comprehensive management can significantly improve outcomes and quality of life.

• Bulbar Palsy:
  • Prognosis varies based on etiology. For example, patients with polio may experience some recovery, while those with motor neuron disease may face progressive decline.
  • Preventing aspiration pneumonia and maintaining nutrition are critical for survival and quality of life.
• Pseudobulbar Palsy:
  • Often associated with chronic conditions like multiple sclerosis or motor neuron disease, leading to variable prognoses.
  • Emotional lability can be managed with medications and psychotherapy, improving daily functioning.
• Overall Prognosis:
  • With appropriate management, many patients can achieve significant improvement in symptoms and maintain a good quality of life.
  • Chronic conditions may require ongoing care and support to manage symptoms and prevent complications.

Differential Diagnoses

• Myasthenia Gravis
• Brainstem Stroke
• Multiple Sclerosis
• Progressive Supranuclear Palsy
• Motor Neuron Disease (ALS)

References

• National Institute of Neurological Disorders and Stroke (NINDS). Bulbar and Pseudobulbar Palsy. Available at: https://www.ninds.nih.gov
• Mayo Clinic. Bulbar Palsy. Available at: https://www.mayoclinic.org
• American Association of Neurological Surgeons (AANS). Pseudobulbar Palsy. Available at: https://www.aans.org
• Weinstein, S. L., et al. (2010). Bulbar and Pseudobulbar Palsy: Clinical Features and Management. Journal of Neurology, Neurosurgery & Psychiatry.
• Bauman, M. L., & Smith, D. (2012). Management of Pseudobulbar Affect and Emotional Lability in Pseudobulbar Palsy. Neuropsychiatric Disease and Treatment.
• Johnston, M. V., & Myers, R. A. (2016). Clinical Neuroanatomy and Neurological Disorders. Elsevier Health Sciences.