Aetiology and Organ Involvement (acute onset)

Acute/ Sudden Onset
1. Pulmonary – Pneumothorax, Acute Ashma Attack, Pulmonary Embolism, Anaphylactic shock, Acute Pulmonary Oedema
2. Cardiovascular – Ishaemic Heart Disease
3. Psychogenic- Anxiety/ Panic attack
4. Miscellaneous- Foreign objects (choking), inhalation injury (chemical substance)

Tension Pneumothorax/ Secondary Spontaneous Pneumothorax.
-occurs when there is communication between the lung and the pleural space, with a flap tissue acting as a valve, allowing air to enter the pleural space during inspiration and preventing it frolom leaving during expiration.
-Air accumulates under increasing pressure in the pleural space, deflating the lungs and displacement of the mediastinum with obstruction of the great vessels.
-Sudden acute breathlessness, chest pain, tachypnoea and cynosis. May be hypotensive

Acute Astma Attack
-especially in acute exacerbation bronchial asthma attack, presenting with sudden onset of respiratory distress
- associated symptoms include wheezing, chest tightness and coughing.

Small/ Medium Pulmonary Embolism
- thrombus from systemic veins (usually pelvic and abdominal veins) dislodged and embolised into pulmonary arterial system.
-lung tissue is ventilated but not perfused producing an intrapulmonary dead space resulting in impaired gas exchangealveolar collapse and exacerbates hypoxaemia elevation of pulmonary arterial pressure and reduction in cardiac output.
- Area of lungs which are not perfused by pulmonary artery may infarct but often does not because O2 continues to be supplied by bronchial circulation.
-sudden onset of dyspnoea, may have chest pain (pleuritic or non-pleuritic), haemoptysis, pleural rub, hypoxemia or fever if infaction occurs.

Acute Pulmonary Oedema.
-when pressure in the lungs is above 20mmHg causes increased filtration of fluid out of capillaries into the interstitial space. When capillary pressure exceeds 25 mmHg, alveolar oedema occurs.
- Acute breathlessness, wheezing, anxious and perspiring profusely.
- other associated symptoms include productive cough, frothy, with blood-tinged sputum.

IHD (Acute Coronary Syndrome)
- Limited or occlusion of blood flow into coronary arteries due to Coronary Artery Disease
- Sudden onset chest pain with dyspnoea, sweating and palpitation.

Panic Disorders (hyperventilation syndrome)
- panic attack- overbreathing leading to a decrease in PCO2 and an increase of pH in arterial.
- Sudden onset of dyspnoea, palpitations, chest pain, choking sensation and sweating

Inhalation of foreign bodies
- usually in children inhaling peanuts or small toys.
- In adult, inhalation often occurs after an excess of alcohol or under GA
- Choking (sudden onset of dyspnoea), can become cyanosed.

aLVIN