Respiratory System and Diseases 1 Flashcards
What is a Common cold?
A catarrhal disorder of upper respiratory tract, very common
What type of virus is the common cold normally?
Mainly by rhinoviruses (picornavirus group, over 100 strains
- vaccination impracticable)
How is the common cold spread?
Spread by close personal contact, droplets
Common cold pathology
inflamed mucosal membrane of the nose
What virus is Influenza caused by?
Influenza virus (orthomyxovirus), main forms A, B−type A: cause for pandemics
Influenza antigens
- Haemagglutinin (H) – cell attachment
- Neuraminidase (N) – cell penetration
- H1-H3 and N1&N2 subtypes have established stable lineage in human population
Genetic variations of influenza virus - major and minor antigenic
−Major antigenic shift= pandemics
−Minor antigenic drift= less severe epidemics
Influenza spread
By droplets and fomites
Influenza incubation
1-3 days
Influenza Symptoms
Fever, shivering, generalised aching (limbs)−Severe headache, sore throat, persistent dry cough
Influenza Prophylaxis
Influenza vaccines; recent advance:M2-protein based multi- strain vaccine; universal vaccine targeting core proteins on trial
Pneumonia
Inflammation of alveoli, usually caused by bacteria
Pneumonia Classifications - Anatomica
Lobar pneumonia (whole of one lobe)
Pneumonia Classifications - Aetiological
Bacterial, Viral, Other
Pneumonia bacteria
Streptococcus pneumoniae
Bronchopneumonia
Lobar pneumonia
Pneumonia bacteria explained
- Streptococcus pneumoniae: Common cause of community -acquired acute pneumonia
- Bronchopneumonia:−Most commonly in old age, infancy and patients with debilitating diseases
- Lobar pneumonia:−Typically healthy adults between 20-50 yrs
Pneumonia Pathology
- Alveolar inflammation
- Protein-rich exudate
- Bronchopneumonia: - foca; inflammation along the airways (patchy consolidation); often bilateral of the lung
- Lobar pneumonia: –Diffuse inflammation affecting the entire lobe; pleural exudate common
Clinical features of pneumonia
Signs
- Consolidationof lung with disease
- Pleural friction rub
- Elderly patients often have fewer symptoms
Clinical features of pneumonia - respiratory and systemic symptoms
- Respiratory symptoms:Cough, Purulent or “rusty” sputum Dyspnoea
- Systemic symptom: Pyrexia (fever)
Pneumonia Investigations
- Chest X-ray
- Blood cell count:
−WBC count >15x109 /L - bacterial infection - Sputum:−Gram stain, culture & sensitivity tests
- Other specific tests−Myoplasma, legionella
Management of Pneumonia
- Community-acquired:
−Antibioticsimmediately without waiting for microbial results
- Hospital-acquired:−Often Gram-negative organisms; different antibiotics
- Treatment should be modified -culture and sensitivity results
Pneumonia specific measures
−Analgesia (pleuritic pain)
−O2therapy (hypoxaemia)
−Intensive care (severe pneumonia)
Pneumonia Complications
- lung abscess
- empyema - pus in the pleural cavity
Tuberculosis
- Major cause of death/morbidity in developing countries
- Prevalenceon the increasein developed countries
- Lung – the commonest site
Tuberculosis - Aetiology, transmission & risk factors
- Caused mainly by:−Mycobacterium tuberculosis
- Transmission:−Through the air, or from direct contact
- Predisposing factors:−Alcohol, diabetes, immunosuppression
Tuberculosis Pathology - Primary
Small granulomas in lobes (Ghon complex); often resolves
Miliary tuberculosis
Disseminated(spread) granulomas in many organs
Tuberculosis Pathology - Secondary
Reactivation
lesions in apices:
-caseous necrosis ingranulomas
- convert to fibrocalcific scars
Tuberculosis - clinical features- symptoms
Primary TB: usually asymptomatic Cough, chest pain, and fever Purulent sputum
Tuberculosis - Diagnosis
Chest X-ray: Upper zone shadows, fibrosis–Sputum samples: Stain & culture
Prevention & treatment of Tuberculosis
3 or 4 different kinds of antibiotics in combination over six to nine months
