Bulbar Onset ALS: An overview
Bulbar Onset Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, is a subtype and the most severe variant of ALS. ALS is a neurodegenerative disease affecting motor control. Unlike Parkinson's disease or Huntington's disease which also result in the decline of motor control, ALS directly affects motor neurons causing motor control to fail. ALS is a progressive disease, which leads to muscle atrophy and paralysis [1]. Since ALS is a progressive disease, it can be separated to different stages. We covered this in more detail in our blog about the 7 stages of ALS.
In general, 90% of all ALS cases are sporadic ALS, and the remaining 10% are familial ALS, meaning that they were passed by another family member as a consequence of a gene mutation[2].
Bulbar Onset ALS accounts for about 25% of all ALS cases, some of which have reported a specific genetic mutation causing the disease. For example, a familial mutation on the GSN gene was found in 5 family members with bulbar ALS [3].
Interestingly, the Bulbar Onset ALS are more prevalent among female, people living with cognitive impairment and seniors [2].
In Bulbar ALS, the motor neurons which are primarily affected originate in the corticobulbar area of the brain stem. This brain area controls the facial, head and neck muscles. Therefore, the bulbar symptoms include weakening of the facial muscles [2]. Not only that, Bulbar Onset ALS is associated with cognitive decline and shorter survival expectancy.
Symptoms of Bulbar Onset ALS
Bulbar onset ALS presents a variety of symptoms, however it starts with affecting the facial muscles.
Difficulty with swallowing and speaking
One of the earliest signs of bulbar onset ALS. This is due to the malfunction of the face muscles and pharynx sphincters, which can lead to problems with saliva management and aspiration of secretion to the airways [4].
Muscle weakness
Muscle weakness is another common early symptom of bulbar onset ALS. As the muscles weaken, the patient has difficulty with speaking, and swallowing but also experiences muscle twitching [5].
Changes in speech
Changes in speech are also common, with patients often experiencing slurred speech, pitch changes, and voice harshness. In some cases, hoarseness due to bilateral vocal cord paralysis can be the first manifestation of ALS [4, 6].
Facial muscle weakness
Another early-stage symptom of bulbar onset ALS is facial muscle weakness. As the disease progresses and the muscles are progressively weakening patients may experience posture challenges and difficulty holding up their head [2].
Uncontrollable episodes of laughing or crying,
This is a bulbar-specific symptom known as pseudobulbar affect [2].
Progressive muscle weakness in the limbs
Although Bulbar Onset ALS starts with weakening the facial muscles, as the disease progresses the muscle weakness spreads along the whole body [7].
Stages of Bulbar Onset ALS
Bulbar onset ALS progresses rapidly and the life expectancy is low. Typically, the lifespan of a patient with bulbar onset ALS is 2 years [2].
In the early stage of Bulbar Onset ALS, symptoms can be subtle and may include muscle weakness of the facial area, laboured breathing, difficulty speaking, and trouble swallowing [5].
As the disease progresses to the middle stage, early-stage symptoms worsen and more areas of the body are affected. In addition to the early-stage symptoms, patients may experience muscle cramps, neuropathy, weight loss and even anxiety or depression [5].
In the late stage or advanced ALS, patients experience muscle paralysis, and are bed-bound. In addition, the patient needs 24-hour care [5]. Usually, the patient might need additional life-supporting procedures like noninvasive ventilation or feeding tube to help them with breathing and food intake respectively [5].
Causes of Bulbar Onset ALS
Although the exact cause of Bulbar Onset ALS is still unknown, several risk factors contributing to the disease development have been identified.
For instance, an altered glucose metabolism and other conditions such as squamous cell carcinoma of the tongue or Chiari I malformation have also been suggested to play a role in the development of bulbar onset ALS [2, 8, 9].
Further, a small study found that bulbar onset ALS shows more excessive white and grey matter loss in the brain than the limb onset ALS (another subtype of ALS), suggesting a possible difference in the neuropathology of these two [2].
However, it's important to note that these are associations and not definitive causes. More research is needed to fully understand the causes of bulbar onset ALS.
Treatment for Bulbar Onset ALS
Although there are no cures for ALS, there are several options which can be used to improve the quality of life as well as manage the symptoms [2].
Medications such as amitriptyline (Endep) can be prescribed for drooling, while dextromethorphan/quinidine (Nuedexta) is used for the pseudobulbar effect. Analgesics are used for pain management, and antidepressants and anti-anxiety medications can help manage mood symptoms. Riluzole (Rilutek) is a medication that may potentially slow disease progression [2].
Dietary changes are often recommended in the early stages of bulbar onset ALS as well as the later stages. Because of the facial muscles weakening, and the occurrence of the swallowing and chewing difficulties it is recommended to adjust the diet accordingly. Cutting food into smaller pieces or a liquifying diet is preferred. In the later stages of ALS, the patient might need to switch to meal-replacement beverages and nutrient-dense liquids [2]
Speech therapy can also be beneficial. Having problems with speaking is a common symptom of ALS and Bulbar onset ALS specifically. Therefore, speech therapy helps the affected individual develop new ways of communicating, learning how to use gesture-based language and technology to help them continue to communicate [2]
Palliative care is another important aspect of treatment, focusing on improving quality of life and managing pain. This can involve supporting breathing, improving communication, and managing pain [2].
Emerging treatments for ALS include the hard work of researchers trying to find a possible way of curing ALS. One of the emerging treatments is GEMALS (ALS-Endotherapia) which has shown promising results in slowing disease progression as well as increasing life expectancy. However, more research needs to be done in order to fully understand the benefits and risks of this treatment [10].
Surgical interventions such as total laryngectomy may be considered in some cases to manage complications of bulbar weakness [11].
It's important to note that treatment plans should be individualized, taking into account the patient's specific symptoms, overall health, and personal preferences.