Introduction to Respiratory Medicine

• The function of the lungs is ventilation and perfusion.
• Ventilation = drawing air containing 21% oxygen into lungs
• Perfusion = carrying de-oxygenated blood to the lungs from venous system and oxygenated blood away to arterial system
• Taking a history for respiratory diseases:

  • Symptoms
  • Past medical history
  • Drug history; allergies
  • Social history
  • Family history
  • Systems review
• Symptoms of respiratory diseases:

  • Breathlessness
  • Wheeze - whistling expiry noise
  • Cough - can be dry or can produce sputum
  • Sputum
  • Haemoptysis (coughing up of blood)
  • Pain (pleuritic pain)
• Symptoms of respiratory diseases - breathlessness:

  • Important to know if it's persistent or not
  • Pts with COPD may become breathless on very mild exertion, such as only being able to walk 10-20 metres before stopping due to breathlessness (severe breathlessness)
  • Someone with asthma may have episodic/acute breathlessness
  • More breathless when lying flat
• Symptoms of respiratory diseases - wheeze (whistling expiry noise):

  • Characteristic feature of asthma
  • Specifically when pt is breathing out - if wheeze-like noise when breathing in, it's stridor, which is characteristic of a blocked central airway (trachea)
• Symptoms of respiratory diseases - sputum:

  • If sputum is produced it may be clear, or green (indicating infection/inflammation), or it could be blood-stained (haemoptysis)
• Symptoms of respiratory diseases - haemoptysis (coughing up of blood):

  • Sinister symptom that always requires investigation - refer to GP
  • Might indicate lung cancer or laryngeal cancer
• Symptoms of respiratory diseases - pain (pleuritic pain):

  • When pt breathes in, it hurts - different from pain of angina
  • Usually from inflammation of the pleura (lining of the lung), or the ribs and the chest wall
• Respiratory diseases:

  • Airways (trachea and bronchi)
  • Asthma
  • COPD (chronic obstructive pulmonary disease)
  • Parenchyma
  • Fibrosis
  • Pneumonia
  • Vasculature
  • Pulmonary embolism

  Control of respiration (controlled in the brainstem): sedative effects -> decrease respiration rate
• Signs of respiratory diseases:

  • Respiratory distress
  • Pt appears breathless or has an increased respiratory rate (>30 breathes per minute)
  • Respiratory rate
  • Pulse
  • Blood pressure
  • Cyanosis
  • Blue-ish discolouration of skin/mucous membranes - best seen on the lips/tip of the tongue
  • Indicates low oxygen levels - but by the time you can see cyanosis the oxygen saturation is usually v low, therefore late feature of low oxygen levels
  • Stridor/wheeze
• Tests for respiratory diseases:

  • Bed-side - peak flow, oximetry
  • General - haematology, biochemistry
  • Radiology - chest x-ray, CT
  • Lung function - peak flow, spirometry
  • Bronchoscopy - biopsies, histology/cytology
  • Microbiology - TB, infections
• Carcinoma of lung:

  • Lung cancer can grow silently for a long time before any symptoms develop
  • By the time the pt develops symptoms, and people start undertaking investigations, the cancer has often already spread and is therefore incurable
  • Commonest fatal cancer in males
  • Overtaking breast cancer in females
  • Causes = smoking and passive smoking

  
• Symptoms of lung cancer:

  • Cough (often one of the first symptoms)
  • Haemoptysis
  • Weight loss
  • Anorexia
  • Pain
  • Metastases
• Causes of haemoptysis:

  • Tumours
  • Bronchial carcinoma
  • Laryngeal carcinoma
  • Infections
  • Tuberculosis
  • Pneumonia
  • Bronchiectasis
  • Bronchitis
  • Infarction
  • Pulmonary embolism
  • Pulmonary oedema
  • Pulmonary vasculitis
• Causes of clubbing:

  • Respiratory (most common)
  • Carcinoma
  • Fibrotic lung disease
  • Bronchietasis
  • Cardiac (rare)
  • Endocarditis
  • Cyanotic congenital heart disease
  • Gastrointestinal (rare)
  • Hepatic cirrhosis
  • Crohn's disease
  • Coeliac disease
• Tests for lung cancer:

  • Chest x-ray
  • CT scan
  • Bronchoscopy
  • Biopsy
• • Pt coughed up a small amount of blood (haemoptysis) - went on to have a chest x-ray
  • Shows whiteness in left upper lobe of the lung
  • Air-filled lung appears black on an x-ray
  • Where the air has been resorbed, the lung appears white
  • This x-ray is strongly suggestive of a blockage to the bronchus going to the left upper lobe, such that air is not going into the left upper lobe
  • Suggests that there is a tumour blocking the left upper lobe bronchus

  
• Treatment of lung cancer:

  • Surgery - only suitable if the tumour is confined to one area of the lung and has not spread to the lymph nodes or the rest of the body
  • Radiotherapy
  • Chemotherapy
  • Palliation of symptoms (when tumour has spread and can no longer be treated)
• Systemic effects of chemotherapy:

  • Marrow suppression - because chemotherapy kills off cells in the body that are growing quickly, i.e., tumour cells, but also bone marrow cells
  • Low haemoglobin levels -> anaemia
  • Low white blood cell levels -> infection
  • Low platelet levels -> haemorrhage
  • Alopecia
  • Nausea, vomiting
  • Infertility, ototoxicity, renal toxicity, neuropathy
• Oral effects of chemotherapy:

  • Oral ulceration, mucositis
  • Gingival bleeding, mucosal petechiae
  • Xerostomia, caries
  • Vulnerability to oral infection, such as dental abscess
  • Oral candidiasis
  • Altered taste
  • Herpes simplex
• Precautions during oral surgery:

  • Liaise with medical team in planning procedure
  • Ensure blood counts checked recently
  • Oral surgery should be as atraumatic as possible
  • Ensure haemostasis, local haemostatic measures (packs)
  • Consider risk of infection
  • Monitor for period post-procedure, contact if problems