Acute Dyspnea

» Pulmonology

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.

CAUSES OF DYSPNOEA
Acute	Chronic
Pulmonary edema	COPD
Asthma	Left cardiac failure
Injury to chest wall and intrathoracic structures	Asthma
Spontaneous pneumothorax	Pulmonary vascular disease
Pulmonary embolism	Psychogenic dyspnea
Pneumonia	Anemia (severe)
Acute respiratory distress syndrome	Hypersensitivity disorders
Pleural effusion	Pleural effusion
Pulmonary Haemorrhage
Foreign body aspiration
Anxiety

The usual causes of acute dyspnea in children differ from those in adults. In children, upper airway infection (e.g., epiglottis, laryngitis, or acute laryngotracheobronchitis) is a common cause.

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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 ACUTE DYSPNOEA
Respiratory Disease	Cardiovascular Disease
Pulmonary Embolism	Acute left ventricular failure (heart failure)
Pulmonary Infection (Pneumonia, bronchitis)	Acute Coronary Syndrome
Pneumothorax
Upper airway obstruction (Aspiration, anaphylaxis)
COPD/Asthma exacerbation

LIFE-THREATENING DYSPNOEA
Acute onset Dyspnea	Associated signs/symptoms
Foreign object	Sign of choking, Inspiratory and expiratory stridor
Anaphylaxis	Angioedema, stridor, rash, pruritus
Pulmonary Haemorrhage
Pulmonary Embolism	Acute dyspnea, fever, haemopytsis, pleuritic chest pain, signs of DVT
Pneumothorax	Acute dyspnea, one sided-pleuritic chest pain
Cardiac Tamponade	Cardinal Quatrad: hypotension,↑JVP, tachycardia, pulsus paradoxus
Acute Coronary Syndrome	Retrosternal chest pain, radiates to jaw/neck, diaphoresis and feeling of impending doom
Gradual onset Dyspnea	Associated signs/symptoms
Asthma exacerbation	Pallor/Cyanosis, ↑resp rate, accessory muscle use, wheezing, silent chest, muscle exhaustion
COPD exacerbation
Anaemia	From Haemorrhage: Shock
Epiglottitis	"Barking cough"
Diabetic ketoacidosis	History of polyuria, polydipsia, polyphagia, and progressive weakness; signs of severe disease include hyperventilation, altered mental status, and abdominal pain

Approach

History
- Drugs history
  - Amiodarone
  - Methotrexate

Pharmacology Amiodarone is a K+ channel blocker (class III antiarrythmic). It acts on the myocardium to delay repolarization and increase duration of the action potential. It also decreases SA and AV conduction rate. Side effects (6Ps): Prolongs action potential duration, Photosensitivity, Pulmonary fibrosis and inflammation, Pigmentation of skin, Peripheral neuropathy, Peripheral conversion of T4 to T3 is inhibited (Hypothyroidism).

Examination
- Smoker signs
- BMI

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

MRC Dyspnea score
1	Not troubled by breathlessness except on strenuous exercise
2	Dyspnea when hurrying or walking up a slight hill
3	Walks slower than contemporaries on level ground due to dyspnea, or has to stop for breath when talking at own pace
4	Stops for breath after walking 100m or less on ground level
5	Too breathless to leave house, or when getting dressed

Investigation

Pulse oximetry
Full Blood Count
EUC
Electrolytes
Cardiac troponin
Brain natriuretic peptide (BNP) or N-terminal pro-BNP
D-dimer
Chest X-ray
Electrocardiogram (ECG)

Specific 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
Hyperventilation - dysfunctional breathing, breathing off CO2 causes ↓CO2 and so increases pH