Neuromuscular Dyspnea Flashcards
What happens to the diaphragm’s workload when a person is supine?
The diaphragm shoulders a greater burden when supine.
What muscles provide force during active expiration?
Internal intercostals, rectus abdominis, transversus abdominis, external and internal oblique muscles.
What role do upper airway dilator muscles play in respiration?
Maintain patency and reduce resistance during respiration.
What is positional dyspnea?
Positional dyspnea includes orthopnea or trepopnea in supine or lateral recumbent positions respectively.
What central lesions can alter breathing patterns and cause dyspnea?
Brain or brainstem ischemia, demyelination, or malignancy.
The emergence of respiratory system weakness typically presents as?
Sleep-disordered breathing before diurnal dyspnea.
What can bulbar weakness impair in patients with NMDs?
Cough, airway patency, and secretion clearance.
What can reduced lung volumes in neuromuscular respiratory patients lead to in the lungs?
Alveolar collapse and atelectasis, particularly at the lung bases.
What is the consequence of non-ventilated alveoli (from NMDs) getting perfusion?
Non-ventilated alveoli receive perfusion without airflow, causing respiratory fatigue and hypercarbia.
What musculoskeletal change can reduce lung volumes in long-standing NMDs?
Scoliosis due to spinal rigidity.
How does scoliosis affect lung function in NMD patients?
Reduces lung volumes and compliance.
What does trepopnea indicate in patients with NMDs?
Asymmetric diaphragm involvement, preferring position with more affected diaphragm downwards.
What does orthopnea suggest in patients with NMDs?
Diaphragm weakness.
What syndrome can occur in patients with C4-C7 spinal cord lesions?
Platypnea-orthodeoxia syndrome. This is dyspnea and impaired O2 sat in seated position likely due to better abdominal support of respiration when supine.
Platypnea is a rare medical condition where an individual has worse dyspnea sitting or standing that improves when laying down. It’s often caused by an intracardiac shunt like PFO. It can also be caused by pulmonary embolus, and pulmonary AVM. Think Platypnea=PPP (Pfo, Pe, Pulmonay avm)
Symptoms of nocturnal hypoventilation
Nighttime awakenings, daytime sleepiness, and morning headaches.
What does weakness of neck flexion correlate with?
Reduced forced vital capacity (FVC).
What respiratory parameters does the single-count breath test assess/correlate with?
It correlates with forced vital capacity (FVC) and negative inspiratory force (NIF). Counts below 25 indicate abnormal respiratory function (count on exhalation 2 (unclear if 1 or 2) counts/second).
What FVC drop percentage in the supine position (compared to upright) indicates diaphragmatic weakness?
> 25% drop in FVC is 90% specific and 79% sensitive for diaphragmatic weakness.
What does MIP test?
Combined strength of inspiratory muscles.