What is bulbar palsy?
The bulb is the medulla, and the term bulbar palsy refers to a syndrome of lower motor neuron paralysis, affecting muscles innervated by cranial nerves (mainly IX to XII) that have their nuclei closely approximated in the lower brain stem.
Muscles of the face, palate, pharynx, larynx, sternocleidomastoid, upper trapezius, and tongue are usually affected.
Patients may present clinically with dysarthria, dysphagia, hoarseness, nasal voice, palatal deviation, diminished gag reflex, or weakness of the sternocleidomastoid, upper trapezius, or tongue.
Atrophy and fasciculations may be evident. Bulbar palsy may result from various conditions involving the motor nuclei of the lower brain stem or their intramedullary fibers, the corresponding peripheral nerves, the myoneural junction, or the musculature.
Causes of intra-axial lesions include: brain stem infarction, syringobulbia, glioma, poliomyelitis, encephalitis, and motor neuron disease (amyotrophic lateral sclerosis or progressive bulbar palsy).
Extra-axial causes are neoplasms (meningioma or neurofibroma), chronic meningitis, aneurysms, neck trauma, and congenital abnormalities (Chiari malformation or basilar impression). Myasthenia gravis, Guillain–Barré syndrome, myositis, and diphtheria also may present with similar signs and symptoms.