CC BY-NC-ND 4.0 · Indian Journal of Cardiovascular Disease in Women - WINCARS 2020; 5(02): 165-167
DOI: 10.1055/s-0040-1713344
Student's Corner

Student’s Corner–1

P. Krishnam Raju
1  Department of Cardiology, Care Hospital, Care Op Center, Hyderabad, Telangana, India
A. N. Patnaik
2  Department of Cardiology, Sun Shine Hospitals, Hyderabad, Telangana, India
› Author Affiliations

Q) What Are the Differences between Dyspnea and Easy Fatigability?

Response by Prof. Patnaik

Both “dyspnea” and “easy fatigability” are common cardiac symptoms which are confusing in nature, as they are often interchangeably used by clinicians and students. Each of them denotes a different mechanism, and have distinctive clinical implications in the evaluation of a cardiac patient.

Dyspnea (also called shortness of breath) is used to refer to uncomfortable awareness of one’s own breathing. The patient can also describe it as the inability to take deep breath or chest tightness. It should not be confused with tachypnoea (rapid rate of breathing), hyperpnoea (excess act of breathing), or hyperventilation. Dyspnea majorly occurs due to pulmonary or cardiac causes. The mechanism of this clinical symptom is not clearly understood. The major mechanism involves abnormal pulmonary mechanics and increase in the overall work of breathing. The peripheral receptors (respiratory muscle spindles, receptors in pulmonary parenchyma and central airways, and chemoreceptors in carotid bodies) have a complex relation with the central nervous system (cortex and medulla) through the vagi and afferent neurons in the spinal cord. Any excess and inappropriate respiratory output in response to the stimulation of the peripheral receptors can give rise to sensation of dyspnea. Left-sided cardiac lesions and left ventricular failure that increase the left atrial (LA) pressure and the resultant raised pulmonary venous hypertension affects the pulmonary mechanics. Orthopnea and paroxysmal nocturnal dyspnea are two important subtypes of dyspnea.

Fatigue is a more persistent subjective feeling of lack of energy and motivation, malaise, lethargy, weariness, and diminished mental functioning (difficulty in concentration and memory), which impairs the quality of life. Patient may use descriptions like feeling run down, worn out, listless, and tired. It may be confused with drowsiness and loss of vitality associated with aging in the elderly. It is more difficult to assess and quantify. Many medical conditions such as anemia, hypothyroidism, convalescence from infections like typhoid, tuberculosis, dengue, chikungunya, influenza, cancer, celiac disease, chronic fatigue syndrome, sleep apnea, use of chemotherapy, β-blockers or diuretics, and cardiac conditions like right heart failure can present with fatigue. The ultimate mechanism probably involves altered skeletal muscle metabolism and efficiency with or without reduced blood flow into the skeletal muscles.

In a patient afflicted with chronic heart failure, both dyspnea and fatigue may be present. Dyspnea is more to do with the respiration, and fatigue is about the whole body muscle function. A few additional questions may be needed to bring out which symptom the patient is trying to convey.

Response by Prof. Krishnam Raju

Dyspnea and easy fatigability are two different symptoms and are vague by their very nature.

Dyspnea could be caused by five different forms of pathophysiology:

  1. Pulmonary parenchymal and vascular disease including upper respiratory forms of pathology. There are problems of ventilation, perfusion, mixed physiology, and perfusion ventilation mismatch.

  2. Low-cardiac output due to any cardiac diverse pathologies.

  3. Decreased oxygen carrying capacity, for example, anemia, etc.

  4. Respiratory neuromuscular paralysis of diverse etiologies.

  5. Psychiatric disorders, for example, anxiety reaction, conversion reaction, and hyperventilation syndrome

Easy fatigability could be due to a wide range of etiologies but basically due to decreased nutrients and/or oxygen supply/muscular disorders or neuromuscular disorders.

The etiologies could be as follows:

  • Metabolic causes like anemia, iron deficiency, and hypovitaminosis.

  • Low-cardiac output.

  • Hypoxemia.

  • Neuromuscular disorders.

  • Myopathies.

  • Endocrinopathies, for example, diabetes mellitus, hypothyroidism, hypoadrenalism, etc.

  • Dyselectrolytemia, for example, hyponatremia, hypokalemia, hypomagnesemia, etc.

  • Chronic fatigue syndrome.

  • Drug-induced, for example, statins, opioids, cocaine, etc.

Key points—both symptoms could coexist; it is important to be familiar with local, regional, and colloquial language expressions used by the patients, as they often tend to not be well-versed with the language we converse in; frequently, the attendants of the patients talk and not the patient.

Dyspnea is generally associated with rest or exercise, hypoxia, myocardial dysfunction, and pulmonary arterial or venous hypertension (PAH). Investigations advised to be conducted in order to determine the cause of dyspnea are as follows:

  1. Check for rest/exercise Spo2/arterial blood gases.

  2. Check for myocardial dysfunction at rest and on exercise. In select cases, it is appropriate to carry out exercise echo diastology.

  3. Check for PAH at rest and on exercise.

  4. Six-minute walk test could be safe, cheap, and useful.

  5. Pulmonary function tests.

  6. Hemogram.

  7. Check metabolic, electrolyte, and endocrine parameters in appropriate patients.

  8. Cardiopulmonary exercise testing.

Key points—all the above tests are not needed in all subjects. Use them appropriately and also remember that both symptoms may coexist. The most important point to remember is to conduct a good clinical evaluation because it will lead us to do appropriate laboratory testing in order to answer our specific clinical questions. If you have no relevant targeted questions, you will not get useful answers, and it will be bad economics.

Publication History

Publication Date:
02 June 2020 (online)

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