Bulbar palsy is a motor neuron disease that targets the lower motor neurons in the brain stem. The nerves affected include the glossopharyngeal, vagus, accessory, and hypoglossal. This progressive neurological disorder disrupts the signal from the lower motor neurons to the muscles responsible for movement in the face, throat, tongue, arms, legs, and chest. This single disruption blocks normal movement in these areas, leading to a variety of symptoms. Bulbar palsy is considered a variant form of Amyotrophic Lateral Sclerosis, or ALS, and many people with the former eventually develop the latter.
The exact cause of bulbar palsy is unknown, but experts connect some conditions to the syndrome, including infarction of the medulla, degenerative diseases such as ALS, malignancies of the brain stem, and inflammation, as seen in Guillain-Barre. Other causes could be environmental factors, toxins, viral infections, and genetics.
One of the muscles affected by bulbar palsy is the pharyngeal muscle, which is primarily responsible for swallowing. Dysphagia, or difficulty swallowing, is a main symptom of bulbar palsy related to weakness in this muscle. Symptoms of dysphagia can include pain while swallowing, drooling, a hoarse voice, feeling as if food is stuck in the throat, frequent heartburn or regurgitation, unexpected weight loss, coughing or gagging, and eventually an inability to swallow.
Bulbar palsy affects the nerves at the base of the brain, interrupting the normal signal these nerves put out to the muscles in the face. Disruption of this signal leads to muscle weakness or paralysis and reduced muscle tone. In addition to muscle weakness, fasciculation -- small muscle contractions that cause twitching -- can also occur in the facial muscles.
Interruption of the signals to the tongue can lead to muscle atrophy or a breakdown of the muscles. Control of the tongue may be lost, making eating difficult or impossible. In addition to muscle atrophy, fasciculation and fibrillation may occur. These rapid muscle contractions and movements can affect eating, swallowing, and speech.
Dysarthria is a speech disorder caused by the muscle weakness and impaired signals from the motor neurons in bulbar palsy. It may be difficult to form words or talking may be nearly impossible. Working with a speech and language therapist may help, but bulbar palsy is progressive, and often speech issues continue to progress.
Damage to the brain from bulbar palsy can lead to emotional lability, a neurological condition that affects mood. It can lead to rapid changes in mood and intense feelings, cause outbursts of uncontrollable laughter or crying, and intensify irritability and temper. Because these reactions are due to damage in the brain, there is no direct treatment. People can learn to cope with the condition by becoming aware of emotional triggers, changing the environment, or seeking counseling.
Bulbar palsy is considered a variant form of Amyotrophic Lateral Sclerosis and many people with bulbar palsy often eventually develop ALS. As the condition progresses, individuals may find weakness develops in the arms and legs, making daily activity difficult. This weakness is usually not as prominent as the weakness of the facial muscles.
Not all patients with bulbar palsy develop ALS, but it is common. ALS is a progressive neurodegenerative disease with no cure. As bulbar palsy affects the lower motor neurons in the brain stem, ALS affects nerves in the brain and spinal cord. The disease progresses from muscle weakness in the facial muscles to muscle weakness throughout the body. As the motor neurons die, complete loss of speech, the ability to eat, voluntary movement, and even the ability to breathe without assistance become impossible.
Diagnosing bulbar palsy begins with first ruling out other possible causes of facial muscle weakness, such as stroke or myasthenia gravis. Tests like an EMG will look at nerves in the brain and how they are functioning. A blood test for acetylcholine receptor-binding antibodies will rule out myasthenia gravis. Once the doctor determines another condition is not the cause, she will look at brain function and the patients’ symptoms, before making a diagnosis.
Bulbar palsy has no cure and is a progressive disease. Treatments focus on symptoms and making it easier to live with the condition. When swallowing or eating become difficult, an individual may require feeding tubes. Medications can help reduce muscle spasms and weakness, address drooling issues, sleep problems, and pain. Speech therapists can work with patients to help maintain speech as much as possible. Therapists can help individuals deal with depression and other side effects of a degenerative disease.
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