Question

A 57 year old man undergoes total knee replacement for severe degenerative joint disease. four days after surgery, he develops an acute onset of shortness off breath and right-sided pleuritic chest pain. He is now in moderate respiratory distress with a respiratory rate of 28 breaths per minute, heart rate of 120 bpm, blood pressure of 110/70 mm Hg. Oxygen saturation is 90%. Lung examination is normal. Cardiac examination reveals tachycardia but is otherwise unremarkable. The right lower extremity is post surgical, healing well and 2+ pitting edema, calf tenderness, erythema, an warmth; the left leg is normal. He has a positive Homan sign on the right (calf pain on dorsiflexion).

1. What is the patient's diagnosis?
2. What is the risk factors for the diagnosis?
3. What are the pathophysiological changes associated with this disorder?
4. What changes might you expect in ventilation/perfusion?
5. Would you expect to see changes in the spirometry readings (tidal volume and FEV1)?

Answer 1

SOLUTION

1. The person is diagnosed with large right sided spontaneous pneumothorax with posssible background of emphysematous disease.

2. The main risk factors are

• AGE;Pulmonary emphysema usually occurs at the age of 40-60.Here the person is having the age of 57.
• SMOKING;The disease mainly develops in smokers.
• occupational or chemical exposure
• expoure to second hand smoke also cause the disease.

3.PATHOLOGICAL CHANGES;Smokers have increased no.of neutrophills and macrophages in their alveoli and the smoking stimulates release of elastase and enhances elastase activity in macrophages.Smoking inhibits alpha antitrypsin.Tobacco smoke contains reactive oxygen species with inactivation of anti protease.alpha anti trypsin deficiency leads to tissue damage and emphysema.

4.Increased V/Q ratio:

As a result of emphysema V/Q increase because of the ventilation (V) stays the sameand perfusion (Q) GOES DOWN.Due to damaged alveoli in lungs in the emphysema also cause increase V/Q ratio.

5.Tidal volume decrease because the patient can't inhale and exhale normally. FEV1 (forced expiratory volume) it also low because of the damaged alveolar spaces.