Progressive bulbar palsy (PBP) is a medical condition. It belongs to a group of disorders known as motor neuron diseases. Lapiedra 2002 PBP is a disease that attacks the nerves supplying the bulbar muscles. These disorders are characterized by the degeneration of motor neurons in the cerebral cortex, spinal cord, brain stem, and pyramidal tracts. This specifically involves the glossopharyngeal nerve (IX), vagus nerve (X), and hypoglossal nerve (XII). Hughes 1998 This disorder should not be confused with pseudobulbar palsy or progressive spinal muscular atrophy. The term

infantile progressive bulbar palsy Infantile progressive bulbar palsy is a rare type of progressive bulbar palsy that occurs in children. The disease exists in both rapid and slow onsets, and involves inflammation of the gray matter of the bulb. Infantile PBP is a disease that ma ...

is used to describe progressive bulbar palsy in children. The ICD-11 lists progressive bulbar palsy as a variant of

amyotrophic lateral sclerosis Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...

(ALS).

Signs and symptoms

Prognosis for PBP patients is poor. Progressive bulbar palsy symptoms can include progressive difficulty with talking and swallowing. Merck 2005 Patients can also exhibit reduced gag reflexes, weak palatal movements, fasciculations, and weak movement of the facial muscles and tongue. In advanced cases of PBP, patients may be unable to protrude their tongue or manipulate food in their mouth. Patients with early cases of PBP have difficulty with pronunciations, particularly lateral consonants (linguals) and velars, and may show problems with drooling saliva. If the corticobulbar tract is affected a pseudobulbar affect with emotional changes may occur. Because PBP patients have such difficulty swallowing, food and saliva can be inhaled into the lungs. This can cause gagging and choking, and it increases the risk of pneumonia. Death, which is often from pneumonia, usually occurs 1 to 3 years after the start of the disorder. About twenty-five percent of patients with PBP eventually develop the widespread symptoms common to ALS. Swash 2000

Cause

The cause of PBP is unknown. One form of PBP is found to occur within patients that have a CuZn-superoxide dismutase (''SOD1'') mutation. Kadekawa 1997 Progressive bulbar palsy patients that have this mutation are classified with FALS patients, Familial ALS (FALS) accounts for about 5%-10% of all ALS cases and is caused by genetic factors. Within these, about 20–25% are linked to the ''SOD1'' mutation. It is not currently known if and how the decreased ''SOD1'' activity contributes to Progressive Bulbar Palsy or FALS, and studies are being done in patients and transgenic mice to help further understand the impact of this gene on the disease. A case study was done on a 42-year-old woman who complained of muscle weakness 10 months prior to admission in the hospital. Upon neurological examination, the patient showed

muscle atrophy Muscle atrophy is the loss of skeletal muscle mass. It can be caused by immobility, aging, malnutrition, medications, or a wide range of injuries or diseases that impact the musculoskeletal or nervous system. Muscle atrophy leads to muscle weakness ...

fasciculation A fasciculation, or muscle twitch, is a spontaneous, involuntary muscle contraction and relaxation, involving fine muscle fibers. They are common, with as many as 70% of people experiencing them. They can be benign, or associated with more serio ...

in all limbs and decreased deep tendon reflexes. The patient’s older brother, father, and paternal uncle had previously all died of ALS or an ALS type syndrome. The patient developed progressive bulbar palsy, became dependent on a respirator, and had two episodes of cardiac arrest. The patient died from pneumonia two years after the onset of the disease. After studying the patient, it was found that the patient had a two base pair deletion in the 126th

codon The genetic code is the set of rules used by living cells to translate information encoded within genetic material ( DNA or RNA sequences of nucleotide triplets, or codons) into proteins. Translation is accomplished by the ribosome, which links ...

exon An exon is any part of a gene that will form a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term ''exon'' refers to both the DNA sequence within a gene and to the corresponding sequen ...

5 of the ''SOD1'' gene. This mutation produced a

frameshift mutation A frameshift mutation (also called a framing error or a reading frame shift) is a genetic mutation caused by indels ( insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three. Due to the triplet nature ...

, which led to a stop codon at position 131. ''SOD1'' activity was decreased by about 30%. The patient’s histological examination showed severe reduction in lower motor neurons. Upon further study, this case proved to be important because it demonstrated that ''SOD1'' mutations might not effect steady neuropathological changes, and that environmental and genetic factors might affect the phenotype of the SOD1 mutations.

Treatment

PBP is aggressive and relentless, and there were no treatments for the disease as of 2005. However, early detection of PBP is the optimal scenario in which doctors can map out a plan for management of the disease. This typically involves symptomatic treatments that are frequently used in many lower motor disorders.

History

The disease was first recognized by the French neurologist Guillaume Duchenne in 1860 and termed, “labioglossolaryngeal paralysis”. Fawcett 2000 In 1859, Wachsmuth changed the name to progressive bulbar palsy. In 1869, Charcot studied the involvement of the corticospinal tracts and with Joffroy, who noted the loss of the bulbar motor nuclei, discovered the similarities to

(ALS). It was observed that a distinction from ALS was fatigue that predominated in muscles innervated by lower cranial nerve nuclei, rather than the

upper motor neurons Upper motor neurons (UMNs) is a term introduced by William Gowers in 1886. They are found in the cerebral cortex and brainstem and carry information down to activate interneurons and lower motor neurons, which in turn directly signal muscles t ...

References

Bibliography

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External links

* {{Diseases of the nervous system Systemic atrophies primarily affecting the central nervous system Motor neuron diseases