problems with respiratory system

• RESPIRATORY DISEASE

  • Obstruction (conditions which impede the rate of flow into/ out of the lungs)

  1. airway resistance increased
  2. outflow pressure reduced (elastic recoil of lungs lost)

  • restriction (conditions which cause reduced lung volume)

  1. reduced compliance (decreased vital capacity)

  • infection + inflammation
• to MEASURE AIRWAY RESISTANCE:

  forced expiratory volume in 1 second (FEV1) by spirometry, FEV1 is normally 80% of vital capacity
• CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)

  • decreased FEV1
  • narrowing of airways leads to increased airway resistance
  • elastic recoil of lungs lost leads to increased outflow pressure
  • increased residual volume leads to appearance of chest over-infection
  • main diseases:

  1. chronic bronchitis (narrowing)
  2. emphysema (recoil)
• CHRONIC BRONCHITIS

  • inflammation of the bronchi (mucus hyper-secretion)
  • ACUTE BRONCHITUS= due to bacteria/ virus- lasts days/ weeks
  • CHRONIC BRONCHITUS= due to smoking(80%), environmental irritants- lasts at least3 consecutive months in 2 consecutive years

  1. irritants case inflammation in bronchi
  2. abnormal mucus secretion
  3. plugs airways
  4. prone to infection
  5. further inflammation

  • TREATMENT= stop smoking, bronchodilators, antibodies
• EMPHYSEMA

  • smoking --> neutrophils + macrophages release elastic --> elastase destroys alveolar walls --> emphysema
  • OR... elastase is normally inactivated by alpha1 antitrypsin therefore a deficiency in this enzyme causes emphysema
  • compliance significantly above normal
  • increased RV --> increased FRC
  • Symptoms:

  1. shortness of breath on exertion
  2. hyperventilation
  3. expanded chest
  4. loss of alveoli (permanent)
  5. a1 antitrypsin deficiency

  • TREATMENT: supplement O2, lung transplant
• ASTHMA

  • mast cell activation --> histamine + cytokine release --> oedema, mucous, smooth muscle constriction (bronchoconstriction)
  • SYMPTOMS: bronco constriction, oedema of airway mucosa, mucus secretion
  • CAUSES: hypersensitivity reaction to allergens, air pollution, exercise and cold air, emotional stress
  • TREATMENT = bronchodilators, anti-inflammatories
• RESTRICTIVE LUNG DISEASE - alveolar walls become rigid

  • FIBROSIS= development of excessive connective tissue (stiffer lungs)
  • ACUTE DISEASE: sepsis severe trauma --> protein exhaustion --> oedema
  • CHRONIC DISEASE: industrial dust, drugs, rheumatism --> inflammation --> fibrosis
  • alveoli is replaced by fibrosis tissue --> decreased lung compliance
  • CAUSES: inhaled environmental and occupational pollutants, cigarette smoke, autoimmune disease
  • TREATMENT: no effective treatment
• RESPIRATORY TRACT INFECTIONS

  • upper respiratory tract infections are common but minor (average adult ~ 2.4 year)
  • lower respiratory tract infections are less common but more serious (e.g. bronchitis, pneumonia, tuberculosis)
• PNEUMONIA

  • caused by infection of bacteria: streptococcus, pneumoniae, straphyloccus aureus or klebsiella pneumoniae
  • affects bronchi and alveoli
  • inflammatory exudate fills alveoli
  • ledas to consolidation
  • lung tissue becomes firm and airless
• TUBERCULOSIS

  • CAUSED BY: inhalation of mycobacterium tuberculosis (highly contagious)
  • two phases: latent versus active disease

  1. latent (asymptomatic, non-infectious, granuloma in lung tissue)
  2. active (~10%)- spreads to bronchioles and circulation

  • initial infection leads to an ineffective immune response
  • bacteria moved to lymph nodes
  • collagen deposited around bacteria
  • lymph node erodes, releasing bacteria
  • TREATMENT: difficult due to antibiotic resistance