Continuing Education Activity

Pseudobulbar palsy is due to an upper motor lesion caused by bilateral disturbance of the corticobulbar tracts. Pseudobulbar palsy is characterized by dysarthria, dysphagia, facial and tongue weakness, and emotional lability. This activity outlines the evaluation and management of pseudobulbar palsy and highlights the role of the healthcare team in managing patients with pseudobulbar palsy.

Objectives:

• Review the etiology and epidemiology of pseudobulbar palsy.
• Outline the appropriate history, physical, and evaluation of pseudobulbar palsy.
• Explain the treatment and management options available for pseudobulbar palsy.
• Describe some interprofessional team strategies for improving care coordination and communication to advance the management of pseudobulbar palsy and improve outcomes.

Introduction

Magnus reported the first case of pseudobulbar palsy in 1837 in a patient having multiple infarcts. Lepine, in 1877 introduced the term pseudobulbar palsy for differentiation purposes. Pseudobulbar palsy is due to an upper motor lesion caused by bilateral disturbance of the corticobulbar tracts. The corticobulbar tracts exert supranuclear control over brainstem motor nuclei and are involved in the muscular movement of the head and neck. They originate from pyramidal cells in the cortex and terminate at cranial nerve nuclei. These nuclei control mastication, deglutition, and speech. Pseudobulbar palsy is characterized by dysarthria, dysphagia, facial and tongue weakness, and emotional lability.[1][2] Any condition which damages bilateral corticobulbar pathways can cause pseudobulbar palsy.

Etiology

Pseudobulbar palsy is not a disease but a clinical constellation. Clinical conditions that involve corticobulbar tracts bilaterally can cause pseudobulbar palsy.[3] Many pathological conditions can lead to pseudobulbar palsy. These include traumatic brain injury, neoplasm, vascular lesions, metabolic abnormality, or neurological disease. Pseudobulbar palsy is one of the severe complications of cerebrovascular diseases.[2][3]

Neurological disorders, such as amyotrophic lateral sclerosis, Parkinson's disease, and progressive supranuclear palsy are common causes of pseudobulbar palsy.[1] Other causes include post-stroke pseudobulbar palsy, demyelinating conditions such as multiple sclerosis, and congenital malformations of the opercular or insular cortex.[1][4][5] Consecutive lacunar strokes can involve both corticobulbar tracts and cause pseudobulbar palsy.[6]

Rare causes of pseudobulbar palsy are:

Central pontine myelinolysis: Common symptoms include pseudobulbar palsy.[7]

Bilateral thalamic infarction: Very rarely infarction of specific nuclei manifests as pseudobulbar palsy.[4][8]

Methotrexate induced neurotoxicity: It is uncommon, but acute or subacute neurological clinical signs and symptoms, including pseudobulbar palsy, have been reported in the literature.[9][10]

Progressive multifocal leukoencephalopathy: rarely causes pseudobulbar symptoms.[11]

Cerebral malaria: Pseudobulbar palsy in cerebral malaria may occur probably due to demyelination.[12]

Bacterial endocarditis: Cerebral disturbance may occur in bacterial endocarditis and can manifest as pseudobulbar palsy.[13]

Syphilis: Requires CSF examination.[13]

Large petroclival meningioma: It presents as bulbar motor dysfunction and emotional lability that characterizes pseudobulbar palsy.[1]

Neurocysticercosis: uncommon[3]

Autoimmune encephalitis and Hashimoto encephalopathy causing pseudobulbar palsy have been reported; this highlights the importance of early detection of anti-thyroperoxidase antibodies in a patient with pseudobulbar palsy.[5]

Epidemiology

Pseudobulbar palsy epidemiology depends on the cause that has lead to corticobulbar pathway damage. A study on the prevalence of motor neuron disease, including pseudobulbar palsy, reveals that prevalence increases, particularly after 50 years of age. Incidence is higher in males compared to females among all age groups.[14]

History and Physical

Pseudobulbar palsy is due to an upper motor lesion in the corticobulbar pathways in the pyramidal fibers. Pseudobulbar palsy presents as:  

• Dysarthria, or anarthria 
• Dysphagia, drooling
• Dysphonia, hypernasal voice, slurred speech
• Glossplegia: with paresis of the tongue. Bilateral supranuclear lesions of the hypoglossal nerve in pseudobulbar palsy can produce an inability of the tongue to function.
• Difficulty in chewing: Weakness of the mastication muscle, and paresis of facial muscles
• Emotional lability (pseudobulbar affect): One of the abnormal expressions of emotion sometimes described in patients with pseudobulbar palsy is pathological laughter and emotional outburst, which is characterized by involuntary, uncontrollable laughter, or crying. Pathological laughter has also been reported in association with many tumors of the posterior fossa, particularly those involving pons and midbrain.
• Trismus: Acute pseudobulbar palsy can present with trismus due to the bilateral infarction of the internal capsule.
• On physical examination, there is a brisk jaw jerk. Other facial reflexes also become exaggerated. There are retained or increased palatal reflexes. Unlike lower motor neuron bulbar palsy, in pseudobulbar palsy, there is no atrophy or fasciculations of the affected muscles. Moreover, in bulbar palsy, emotions are not affected.[1][3][15]

Evaluation

The diagnosis of pseudobulbar palsy is mainly clinical and based on clinical features. Evaluation of the condition includes identifying the underlying cause. Possible causes of acute pseudobulbar palsy (neoplastic, inflammatory, demyelinating, myasthenic)[4] should merit consideration.

Detailed history, including any previous history of stroke, is required. Complete neurological examination with the Mini-Mental State Examination (MMSE) score.[8]

Investigations focus on evaluating for stroke, neoplasia, multiple sclerosis, or other demyelination disorders.

Complete blood count, metabolic profile and serology

Electroencephalogram

CSF analysis (oligoclonal bands)

Imaging studies: Brain computed tomography (CT) and MRI of the brain

Diffusion-weighted MRI/T2-weighted MRI.

Motor- and sensory-evoked potential tests

Videofluoroscopic swallowing study (VFSS)

Speech assessment

Psychiatric consult[7] 

Treatment / Management

Treatment of pseudobulbar palsy is mainly supportive and includes management of the underlying etiology.

Dysphagia treatments: such as the oromotor exercises, pharyngeal tactile stimulation, tongue retraction exercises, effortful swallowing exercises, the Mendelsohn maneuver, and shaker exercises

Percutaneous endoscopic gastrostomy tube (PEG): for patients with severe dysphagia or recurrent aspiration pneumonia

Speech therapy, vocal cord adduction exercises, respiration-phonation training, and dysarthria treatment.[8]

Acupuncture by a prompt and deep insertion technique has shown satisfactory results. It may result in the restoration of the swallowing and phonetic functions [2].

Although it is not a mood disorder, clinicians frequently prescribe antidepressants to address emotional outbursts of excessive laughing or crying. The pseudobulbar effect affects approximately 20 to 50% of patients with amyotrophic lateral sclerosis in pseudobulbar palsy. A fixed-dose combination of dextromethorphan/quinidine for the treatment of pseudobulbar affect has shown to reduce the frequency and severity of laughing and crying behavior.[16]

Methotrexate-induced pseudobulbar palsy: intravenous immunoglobulins.[9]

Rehabilitation: Patients with pseudobulbar palsy require comprehensive interprofessional care involving a physician, physical therapist, occupational therapist, speech pathologist, social worker, respiratory therapist, and nurse caseworker.

Differential Diagnosis

• Alcohol withdrawal seizure and delirium tremens[8]
• Metabolic encephalopathy[7]

Pathological laughter also correlates with large compressive posterior fossa tumors, posterior fossa meningiomas, epidermoid tumors, trochlear nerve neurinomas. Other tumors associated with pathological laughter include hypothalamic glioblastomas multiforme, pontine glioblastomas multiforme, and metastatic melanomas, etc.[1]

Prognosis

Prognosis of the pseudobulbar palsy depends on the underlying etiology.

Complications

• Aspiration pneumonia
• Severe dysphagia
• Social withdrawal

Deterrence and Patient Education

Patients and their caregivers require education about the etiology associated with pseudobulbar palsy and its possible outcome. For example, patients with stroke or brain trauma have different treatment requirements. Slow recovery may happen over some time and neurological functions recover. On the other hand, clinical conditions such as multiple sclerosis, Parkinson's disease, and amyotrophic lateral sclerosis require prolonged and consistent interprofessional management because of their progressive and irreversible nature.

Enhancing Healthcare Team Outcomes

Pseudobulbar palsy requires interprofessional management involving physicians, social workers, physical therapists, speech pathologists, respiratory consultants, pharmacists, and nurses. Other healthcare professionals can be integrated depending upon the etiology of pseudobulbar palsy. Patients with pseudobulbar palsy who suffer from pathological laughter and emotional outburst may be more prone to depression. A psychiatric evaluation can be of help. Physiatrists are often involved. Neuroscience and rehabilitation nurses care for patients and coordinate care with the team. These patients and their caregivers need to have counsel to improve perceptions, and this will help reduce social withdrawal. Patients and caregivers should understand the available pharmacological management. Pharmacists should assist the interprofessional team with a review of medications, check for drug interactions, and educate patients about the importance of compliance and potential side effects.[Level 5]