Chronic Dyspnea

Overview

Dyspnea (Greek dys, meaning “painful,” “difficult,” and pneuma, meaning “breath. Dyspnea is the medical term for subjective experience of breathlessness or shortness of breath. Dyspnea can be acute when it develops over hours to days and chronic when it has been for more than four to eight weeks.

Remember As a rule, chronic dyspnea begins with breathlessness on exertion—which, in time, progresses to dyspnea at rest.

Dyspnea may be due to diseases in virtually any organ system, whether caused by interference with breathing, increased demand for breathing, or weakening of the respiratory pump. In most cases, however, patients with dyspnea can be categorized into one of two groups: respiratory related dyspnea or cardiovascular related dyspnea.

COMMON CAUSES OF CHRONIC DYSPNOEA
Respiratory Disease	Cardiovascular Disease
COPD	Myocardial Dysfunction (Heart Failure)
Asthma	Obesity/de-conditioning
Interstitial lung disease

CAUSES OF DYSPNOEA
Acute	Chronic
Pulmonary edema	COPD
Asthma	Left-Sided Heart Failure
Injury to chest wall and intrathoracic structures	Asthma
Spontaneous pneumothorax	Pulmonary vascular disease
Pulmonary embolism	Psychogenic dyspnea
Pneumonia	Anemia (severe)
ARDS	Hypersensitivity disorders
Pleural effusion	Pleural effusion
Pulmonary Haemorrhage
Foreign body aspiration
Anxiety

NYHA classification of dyspnea (For Heart Failure)
I	nil at rest, some on vigorous activity
II	nil at rest, dyspnea on moderate exertion
III	mild dyspnea at rest, worse on mild exertion
IV	significant dyspnea at rest and worse on slight exertion

Investigation

Pulse oximetry
Full blood count (to exclude anaemia): The degree of dyspnea associated with anaemia may depend on the rapidity of blood loss and the degree of exertion that the patient undertakes.
Glucose
EUC
Thyroid stimulating hormone (TSH).
Spirometry pre and post inhaled bronchodilator OR full pulmonary function tests (PFTs) if the clinical evaluation does not suggest asthma or COPD.
Pulse oximetry during ambulation at a normal pace over approximately 200 meters and/or up two to three flights of stairs.
Chest X-ray
ECG
Brain Natriuretic Peptide (BNP)
Echocardiography is useful for evaluating suspected left ventricular dysfunction, pulmonary hypertension, and diastolic dysfunction.

Management

Oxygen
Fluids
Analgesis
Chest X-ray
ECG

Specific types of Dyspnea

Orthopnea – dyspnea when lying flat. patient usually sleeps with multiple pillows
Paroxysmal nocturnal dyspnea – episodes of breathlessness at night. It is associated with pulmonary oedema
Cheyne–Stokes breathing is characterized by alternating periods of hypoventilation and hyperventilation
Kussmaul breathing – Diabetic ketoacidosis who manifests with “air hunger”: rapid breathing.