An Unusual Presentation of Respiratory Dysfunction in Parkinson's Disease: A Case Study

Abstract

Parkinson's disease (PD) is a progressive neurodegenerative disorder affecting around 10 million people worldwide. It is primarily associated with the loss of dopaminergic neurons in the substantia nigra pars compacta, though the exact mechanism is unclear. PD is characterized by resting tremor, muscular rigidity, bradykinesia, and postural instability. These motor symptoms, resulting from impaired muscle function, can lead to dysphagia and respiratory dysfunction. It is suggested that the muscular rigidity and bradykinesia in PD may impair repetitive motor actions, negatively impacting respiration. While less studied, PD-related respiratory dysfunction could stem from obstructive, restrictive, or CNS disturbances. This case report discusses a 69-year-old male with PD and dementia presented at an assisted living facility in Palmar Sur, Costa Rica, with difficulty exhaling after deep inhalation. Physical examination revealed typical PD symptoms (resting tremor, muscular rigidity, bradykinesia, postural instability) along with hypotension, bradycardia, and bradypnea. Respiratory assessment showed he could inhale but had difficulty exhaling, suggesting a myotonic-like pathology. The cogwheel-like rigidity during exhalation is unique and points to a myotonic-like respiratory dysfunction related to his PD, a presentation not commonly observed in PD patients. Research suggests respiratory impairments in PD may result from issues with central ventilatory control, restrictive lung disease (reduced lung capacity), or obstructive lung disease (blocked airflow). Restrictive mechanisms might stem from thoracic rigidity and posture changes, while obstructive factors could be exacerbated by the patient's smoking history. Respiratory muscle fatigue may arise from the demands of repetitive ventilation. Additionally, degeneration in the brain's respiratory center, possibly linked to α-synuclein deposits, could affect respiratory regulation. Osteopathic Manipulation Treatment (OMT) may help alleviate these symptoms by improving thoracic flexibility and respiratory function. Overall, this case highlights the varied presentations of PD, focusing on the lens respiratory dysfunction, possibly due to respiratory muscle rigidity or central nervous system involvement. Recognizing these symptoms is crucial for early intervention and preventing complications like aspiration pneumonia, a major cause of morbidity and mortality in PD. Further research is needed to better understand the relationship between PD and respiratory dysfunction.

Keywords: exhalation; parkinson' s disease; respiratory center; respiratory dysfunction; respiratory rigidity.

Figure 1. Depiction of potential mechanisms for respiratory impairment in PD