Transcript Cardinal Manifestations of Disease: DYSPNEA

Cardinal Manifestations of Disease:
DYSPNEA
Dr. Meg-angela Christi Amores
Dyspnea
• a "subjective experience of breathing
discomfort that consists of qualitatively
distinct sensations that vary in intensity. The
experience derives from interactions among
multiple physiological, psychological, social,
and environmental factors, and may induce
secondary physiological and behavioral
responses."
-American Thoracic Society
Mechanisms of Dyspnea
• Motor efferents
– Disorders of the ventilatory pump, muscles are
weak or fatigued, greater effort is required
• Sensory afferents
– Chemoreceptors in the carotid bodies and
medulla are activated by hypoxemia, acute
hypercapnia, and acidemia – air hunger
– Mechanoreceptors in the lungs, when stimulated
by bronchospasm, lead to a sensation of chest
tightness
Mechanisms of Dyspnea
• Integration: Efferent – Reafferent Mismatch
– discrepancy or mismatch between the feed-forward
message to the ventilatory muscles and the feedback
from receptors that monitor the response of the
ventilatory pump increases the intensity of dyspnea
– Asthma and COPD
• Anxiety
– altering the interpretation of sensory data or by
leading to patterns of breathing that heighten
physiologic abnormalities in the respiratory system
Differential Diagnoses
• Dyspnea is the consequence of deviations from normal
function in the cardiopulmonary systems
• Respi: 3 categories:
• Controller
• Ventilatory pump
• Gas exhanger
• Cardiovas: 3 categories
• Low
• Nomal
• High Cardiac output
Respiratory System Dyspnea
• Controller:
• Stimulation of pulmonary receptors, as occurs in acute
bronchospasm, interstitial edema, and pulmonary embolism
= air hunger
• High altitude, high progesterone states such as pregnancy,
and drugs such as aspirin
• Ventilatory pump
• Disorders of the airways – inc resistance
• stiffen the chest wall, such as kyphoscoliosis
• Gas Exchanger
• Pneumonia, pulmonary edema, and aspiration all interfere
with gas exchange
• Pulmonary vascular and interstitial lung disease
Cardiovascular System Dyspnea
• High Cardiac Output
• Mild to moderate anemia is associated with breathing
discomfort during exercise
• Left to right cardiac shunts
• Normal
• Cardiovascular deconditioning
• Diastolic dysfunction (hypertension, aortic stenosis, or
hypertrophic cardiomyopathy)
• Low
• Diseases of the myocardium resulting from coronary artery
disease
Approach to patient
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Let patient describe in his/her words
Ask for orthopnea, nocturnal dyspnea
Onset, persistence
Risk factors for certain diseases
Platypnea – dyspnea in the upright position,
relieved in the supine
Respiratory vs. CV system
• a cardiopulmonary exercise test should be
carried out to determine which system is
responsible for the exercise limitation
• At peak exercise, max ventilation reached, O2
sat below 90%, develops bronchospasm =
Respiratory
• If HR >85% of predicted max, anaerobic
threshold occurs early, BP high or drops,
ischemic changes in ECG = Cardiovascular
Treatment
• Correct underlying problem
• Supplemental Oxygen if sO2 is <90%
• In COPD: pulmo rehab
• For the next meeting, read on Cardinal
Manifestations of Disease : EDEMA
• Harrison’s Principles of Internal Medicine 17th
edition