Natural Course and Treatment for Bulbar ALS
Bulbar-onset ALS has a shorter life expectancy than limb-onset disease, with median survival of approximately 25-28 months from symptom onset, and requires early multidisciplinary intervention focused on nutritional support, respiratory management, and palliative care from diagnosis. 1
Natural Course of Bulbar ALS
Disease Progression Pattern
Bulbar ALS follows a predictable but relentless progression through five distinct stages 2:
- Stage 1: Normal eating habits with subtle prolonged meal times and fatigue during eating 2
- Stage 2: Early eating problems become apparent with difficulty chewing certain textures 2
- Stage 3: Dietary consistency modifications become necessary 2
- Stage 4: Tube feeding requirement develops 2
- Stage 5: Nothing by mouth (NPO) status 2
Core Bulbar Symptoms
The bulbar syndrome encompasses multiple interconnected deficits 2:
- Dysphagia: Difficulty managing food in the mouth, impaired bolus formation, delayed swallowing initiation, and critically increased aspiration risk 2
- Dysarthria: Progressive speech deterioration requiring augmentative communication devices 3
- Sialorrhea: Drooling from inability to manage saliva due to impaired swallowing and poor lip seal 2
- Nasal regurgitation: Reduced soft-palate closure causing reflux of food and liquid into the nose 2
Major Complications
Aspiration pneumonia occurs in 11.4-13% of bulbar ALS cases and represents a leading cause of mortality 2. Weight loss and malnutrition develop in 0-21% of patients at diagnosis but worsen progressively, with both being detrimental to survival and quality of life 2.
Prognosis Differences
Bulbar-onset patients demonstrate significantly worse outcomes compared to spinal-onset 4. Among patients with dysphagia who accepted PEG, bulbar-onset patients showed median survival of 28 months versus 44 months for spinal-onset patients with dysphagia 4.
Treatment Approach
Disease-Modifying Therapy
Riluzole 50 mg twice daily (taken at least 1 hour before or 2 hours after meals) is the FDA-approved disease-modifying treatment for ALS 5. Monitor serum aminotransferases before and during treatment, and discontinue if elevations exceed 5 times upper limit of normal 5.
Palliative Care Integration
A palliative care approach must be adopted from the time of diagnosis, not reserved for end-stage disease 4, 1. Early referral to palliative services is essential because speech and communication become severely limited in later stages, preventing meaningful end-of-life discussions 4. Current practice falls far short—only 8% of UK palliative units are involved from diagnosis, and only 28% of Irish ALS patients successfully accessed palliative services 4.
Nutritional Management
Assessment and Monitoring
Conduct nutritional status assessment (BMI, weight loss) every 3 months to detect early malnutrition 1, 2. For patients with low BMI, recommend weight gain; for higher BMI, recommend weight stabilization 1.
Dietary Modifications
For patients with dysphagia 1:
- Adapt food texture to facilitate swallowing
- Implement postural maneuvers (particularly chin-tuck posture to protect airways) 2
- Use thicker liquids and semisolid foods with high water content instead of thin liquids
- Fractionate and enrich meals 2
- Provide oral nutritional supplementation 2
Gastrostomy Timing
PEG placement should occur before respiratory function significantly deteriorates, ideally when FVC remains >50% of predicted 4. However, recent evidence demonstrates that PEG can be performed safely in patients with FVC <50% when non-invasive ventilation support is provided during the procedure 4. The American Academy of Neurology recommends refusing gastrostomy when FVC falls below 30% 4.
PEG is the preferred gastrostomy approach 4. When available, radiologically inserted gastrostomy (RIG) by an expert team may be indicated in more frail patients, though RIG tubes have higher rates of obstruction and dislocation due to narrow diameter 4.
A critical caveat: Age at ALS diagnosis is the only independent prognostic factor for survival after gastrostomy, not the FVC at time of placement 4. First-month mortality is higher in patients with FVC <50%, but overall survival is not significantly different 4.
Respiratory Management
Monitoring Parameters
Assess pulmonary function tests at minimum every 6 months, including FVC, MIP/MEP, SNIP, and PCF 4. Adjust testing frequency based on individual disease progression rate 4.
Monitor for respiratory compromise by assessing 2:
- Vital capacity (risk if <20 ml/kg)
- Maximum inspiratory pressure (risk if <30 cmH₂O)
- Maximum expiratory pressure (risk if <40 cmH₂O)
Non-Invasive Ventilation
Initiate NIV for patients with 4:
- FVC <80% of normal with symptoms
- FVC <50% predicted
- Awake PaCO₂ >45 mmHg
- Evidence of sleep-disordered breathing or hypoventilation on polysomnography
A critical limitation: Patients with bulbar impairment may not tolerate NIV or achieve adequate ventilation 4, 2. Use bilevel positive airway pressure (BPAP) with backup respiratory rate for better patient-ventilator synchrony 4, 2.
Mouthpiece ventilation (MPV) can provide daytime ventilatory support as an adjunct to nocturnal mask NIV in patients with preserved bulbar function, but progressive bulbar symptoms limit its use 4, 2.
Invasive Mechanical Ventilation
For patients in whom NIV fails, who are intolerant of NIV, or who have worsening bulbar function with frequent aspiration, invasive home mechanical ventilation via tracheostomy is the alternative 4. Discussions regarding tracheostomy should start early in the illness and include goals of care, potential need for institutionalization, and caregiver burden 4.
Sialorrhea Management
First-line therapy: Trial an inexpensive oral anticholinergic medication, continuing only if benefits outweigh side effects 4. Consider anticholinergic patch medication as first- or second-line therapy for longer-acting effect 4.
Second-line therapy: For inadequate response or intolerance to anticholinergics, use botulinum toxin therapy to salivary glands 4.
Monitor for anticholinergic side effects including dry mouth, urinary retention, and constipation 2.
Swallowing Assessment
All patients with suspected bulbar dysfunction require swallow screening before initiating oral intake 2. If screening is abnormal, perform a complete bedside swallow examination by a speech-language pathologist 2.
Patients with positive bedside screening or high aspiration risk require videofluoroscopy swallowing study (VFSS)/modified barium swallow 2. Fiberoptic endoscopic evaluation of swallowing (FEES) serves as an alternative to VFSS 2.
Videofluoroscopy is recommended at diagnosis to detect early signs of dysphagia even in asymptomatic ALS patients 1.
Secretion Management
Regular use of lung volume recruitment (LVR/breath stacking) using a handheld resuscitation bag or mouthpiece is recommended for patients with reduced lung function or cough effectiveness 4. However, effectiveness is limited by bulbar function 2.
Consider mechanical insufflation-exsufflation (MI-E) for secretion management, though effectiveness is reduced in patients with significant bulbar impairment 2.
Communication Support
Progressive dysarthria necessitates early involvement of speech-language pathology for augmentative and alternative communication (AAC) device assessment 3, 6. Early intervention by speech-language pathologists helps maintain communication function longer and improves quality of life 2.
A significant barrier exists: Patients and caregivers report difficulties accessing and receiving SLP services at multidisciplinary ALS clinics, particularly those with severe cognitive disease 6. Engaging caregivers earlier in SLP appointments is vital for care planning and in-time caregiver education 6.
Multidisciplinary Care Model
Multidisciplinary care improves both survival and quality of life in ALS 4. The team should include neurology, pulmonology, gastroenterology, speech-language pathology, nutrition, physical therapy, occupational therapy, social work, and palliative care 4, 7.
Effective communication between the multidisciplinary ALS team, primary care physician, and palliative care team is essential, as patients with end-stage ALS frequently develop distressing symptoms over a short period 4.