What Is Bulbar Muscle Weakness

There are differences between bulbar palsy and pseudobulbar palsy.

What is bulbar muscle weakness.

Bulbar relates to the medulla. Amyotrophic lateral sclerosis myasthenia gravis. Muscles of the mouth and throat responsible for speech and swallowing. The causes of this are broadly divided into.

Bulbar weakness or bulbar palsy refers to bilateral impairment of function of the lower cranial nerves ix x xi and xii which occurs due to lower motor neuron lesion either at nuclear or fascicular level in the medulla or from bilateral lesions of the lower cranial nerves outside the brain stem. The condition is associated with mutation of the androgen receptor ar gene and is inherited in an x linked recessive manner. The classic presentation is of slow progression of proximal weakness bulbar weakness including asymmetric or symmetric facial weakness and gynecomastia. Bulbar weakness is often associated with difficulty in chewing weakness of the facial muscles.

This bulbar weakness named for the nerves that originate from the bulblike part of the brainstem can cause difficulty with talking dysarthria chewing swallowing dysphagia and holding up the head. Early symptoms of als usually include muscle weakness or stiffness in a limb or muscles of the mouth or throat so called bulbar muscles. The former is a lower motor neuron lesion of the cranial nerves ix x xi and xii while the latter is an upper motor neuron lesion affecting ix x xi and xii cranial nerves. A speech deficit occurs due to paralysis or weakness of the muscles of articulation which are supplied by these cranial nerves.

Weakness and fatigue in the neck and jaw also can occur early in mg. Bulbar als symptoms are seen in 75 to 80 of the patients with classic als symptoms. Spinal and bulbar muscular atrophy sbma or kennedy s disease is an x linked motor neuron disease typically presenting in adult men in the 3rd to 5th decades. Gradually almost all the muscles under voluntary control are affected and individuals lose their strength and the ability to speak eat move and even breathe.

In contrast pseudobulbar palsy is a clinical syndrome similar to bulbar palsy but in which the damage is located in upper motor neurons of the corticobulbar tracts in the mid pons i e in the cranial nerves ix xii that is the nerve cells coming down from the cerebral cortex innervating the motor nuclei in the medulla. About 15 of patients present with bulbar symptoms. This is because the motor neuron cells in the spinal cord degenerate leading to their death due to als. Bulbar palsy is the result of diseases affecting the lower cranial nerves vii xii.

Spinal and bulbar muscular atrophy sbma popularly known as kennedy s disease is a progressive debilitating neurodegenerative disorder resulting in muscle cramps and progressive weakness due to degeneration of motor neurons in the brainstem and spinal cord.