What causes serious coughing and choking complications in Parkinson’s disease patients and what is their prognosis?

Causes and Prognosis of Coughing and Choking Complications in Parkinson's Disease

Dysphagia (swallowing dysfunction) is the primary cause of serious coughing and choking complications in Parkinson's disease patients, and it is associated with significantly increased mortality due to aspiration pneumonia, which is the most frequent cause of death in this population. 1

Causes of Coughing and Choking Complications

Oropharyngeal Dysphagia

• More than 80% of Parkinson's disease patients develop dysphagia during the course of their disease, sometimes even early in the disease progression 1, 2
• Dysphagia prevalence based on subjective outcomes is around 35% but increases to 82% when using objective measures, indicating many cases go unrecognized 1, 2
• Only 20-40% of PD patients are aware of their swallowing dysfunction, and less than 10% report dysphagia spontaneously 1, 2

Risk Factors for Dysphagia

• Hoehn and Yahr stage above III (more advanced disease) 1
• Weight loss and BMI below 20 kg/m² 1
• Drooling or sialorrhea 1
• Dementia 1
• Silent aspiration is very common in PD, contributing to complications without obvious symptoms 1

Pathophysiological Mechanisms

• Both dopaminergic and non-dopaminergic mechanisms are involved in the development of dysphagia 1, 3
• Neurodegeneration affecting the central swallowing network and related structures 2, 3
• Impaired coordination between breathing and swallowing 4
• Weakened voluntary and reflexive cough function, which is critical for airway clearance 4, 5

Prognosis for Patients with Coughing and Choking Complications

Mortality Risk

• Pneumonia is the most frequent cause of death in Parkinson's disease and is substantially related to dysphagia 1, 2
• Aspiration pneumonia accounts for approximately 25% of all Parkinson's deaths 6
• Patients with dysphagia have significantly higher mortality than non-dysphagic PD patients 1

Quality of Life Impact

• Fear of aspiration and choking significantly reduces quality of life 1, 2
• Food modification requirements and dependence on others for food intake alter social and psychological wellbeing 1
• Complications with medication intake can lead to suboptimal disease management 2, 3

Nutritional Consequences

• Dysphagia is associated with high risk for decreased food and fluid intake 1
• Contributes to malnutrition, which affects approximately 15% of community-dwelling PD patients 2
• Weight loss is associated with increased disease severity 2

Screening and Assessment

Recommended Screening Approach

• All PD patients with Hoehn & Yahr stage above II or with weight loss, low BMI, drooling, dementia, or signs of dysphagia should be screened during an ON-phase 1, 2
• Screening tools include PD-specific questionnaires (SDQ or MDT-PD) or water swallow tests measuring average volume per swallow 1
• Patients with a maximum swallowing volume below 20 ml are very likely to suffer from dysphagia 1

Diagnostic Assessment

• Instrumental assessment should be performed for patients who screen positive for dysphagia 1
• Fiberoptic endoscopic evaluation of swallowing (FEES) is preferred, with videofluoroscopic swallowing study (VFSS) as an alternative 1, 7
• Clinical assessment alone is often unreliable due to the high prevalence of silent aspiration in PD 1, 3

Management Considerations

Therapeutic Approaches

• Respiratory-swallow coordination training has shown promising results in improving swallowing safety 4
• Voluntary cough skill training may improve both reflex and voluntary cough effectiveness 4
• Expiratory flow acceleration techniques may help reduce respiratory complications 8
• Modified consistency foods and fluids should be used according to individual needs 1

Monitoring and Follow-up

• Regular monitoring of body weight and nutritional status is recommended 2
• Ongoing assessment of swallowing function as disease progresses 2, 3
• Vigilance for signs of respiratory infection, which may indicate silent aspiration 6

Clinical Pitfalls to Avoid

• Relying solely on patient self-reporting of dysphagia symptoms, as most cases are silent or unreported 1, 2
• Using standard water swallowing tests as used in stroke patients, which are non-predictive of severe dysphagia in PD 1
• Failing to assess swallowing function during medication "ON" phases, which may mask dysphagia severity 1
• Overlooking the need for instrumental assessment in patients with suspected dysphagia 1, 3