Concepts of Pulmonology

• Interstitial Lung Diseases (ILD) affect the space between the alveoli and the capillaries of the lung
• ILD cause a restrictive pulmonary defect, leading to a reduction of the Vital Capacity (VC) with reduced lung volume but normal air flow through the airways
• Alveolar Diseases can fill the alveoli with different substances:

  • Pus and inflammatory cells (Pneumonia)
  • Fluid:
  • Cardiac failure with pulmonary edema
  • Non-cardiac pulmonary edema (ARDS)
  • Protein (alveolar proteinosis)
  • Inflammatory cells: Interstitial lung disease, Organizing pneumonia
  • Malignant cells (Broncho-alveolar carcinoma)
• Crackles (Crepitations) are a common physical sign in alveolar diseases
• Pulmonary Embolus (PE) occludes a pulmonary artery, commonly originating from the deep venous system of the leg and pelvis

  • Effects of PE:
  • Right Heart: Causes pulmonary hypertension and even Right heart failure
  • Lung: Hypoxemia
  • Left Heart: Hypotension and even shock
  • Clinical presentation: Dyspnea with reduced Oxygen in the blood
  • Screening test: D-dimer
  • Confirmatory test: CT-angiogram or VQ lung scan
  • Treatment: Oxygen therapy, Anti-coagulation, Thrombolytic therapy if shocked
• Risk factors for DVT and PE (Virchow's Triad):

  • Stasis: Bedridden in hospital, Surgery, Heart failure
  • Hypercoagulability: Cancer, Factor 5 Leiden, Connective tissue diseases
  • Blood vessel diseases or abnormalities
• Shunt occurs when alveoli collapse, allowing blood to pass through the lungs without oxygen uptake, leading to hypoxemia

  • Hypoxemia is not relieved by giving oxygen but can be improved with Positive end expiratory pressure (PEEP) or CPAP
• Pulmonary Hypertension (PHT) is measured by pressure in the pulmonary artery, with causes including lung disease, left heart disease, systemic diseases, and pulmonary embolic disease
• ARDS (Adult Respiratory Distress Syndrome) is respiratory failure from acute lung injury

  • Common causes: Severe trauma, Drug overdose, Medical diseases, COVID-19
  • Clinical presentation: Dyspnea, crackles, bilateral lung infiltrates
  • ARDS causes Non-cardiac pulmonary edema
  • Respiratory Distress: Upright position, Monosyllabic speech, Tachypnea
  • Respiratory Failure types: Type 1 (hypoxemic) and Type 2 (ventilatory)
  • Respiratory failure can develop in normal or diseased lungs, triggering right heart failure
• Bronchial Diseases include Asthma, COPD, Bronchiectasis, associated with narrowed lower airways

  • Lower airway obstruction worsens on expiration
  • Reduced airflow with wheezes audible
  • Important lung volumes and functions:
  • FEV1: Measures airflow, decreases in obstructive diseases
  • FEV1/FVC ratio: Confirms COPD diagnosis
  • FVC: Forced vital capacity
  • RV: Residual volume, increases with hyperinflation and decreases with lung fibrosis