pathology of respiratory tract infections Flashcards
what are different types of upper respiratory tract infections?
Coryza - common cold Sore throat syndrome Acute Laryngotracheobronchitis (Croup) Laryngitis Sinusitis Acute Epiglottitis
acute epiglottitis
group A beta- haemolytic streptococci
Haemophilus influenzae (type b - Hib)
what are charecteristics of lower respiratory tract infections?
Bronchitis Bronchiolitis Pneumonia Consequences Possible Complications
what are defence mechanisms for resp tract?
macrophage-mucociliary escalator system
general immune system
resp tract secretions
upper resp tract act as a filter
what is the macrophage-mucociliary system?
alveolar macrophages
mucociliary escalator
cough reflex
where is there deposition?
on the conducting airways
on the terminal bronchioles/proximal alveoli
what are patterns of pneumonia?
Bronchopneumonia
Segmental
Lobar
Hypostatic
Aspiration
Obstructive, Retention, Endogenous Lipid
what is bronchopneumonia?
inflammation of the lungs, arising in the bronchi or bronchioles
what is lobar pneumonia?
a form of pneumonia characterized by inflammatory exudate within the intra-alveolar space resulting in consolidation that affects a large and continuous area of the lobe of a lung
what are complications of pneumonia
Organisation
mass lesion
COP(cryptogenic organising pneumonia (BOOP))
Constrictive bronchiolitis
Lung Abscess
Bronchiectasis
Pneumonia is still a potentially fatal disease
what is nroncheictasis?
Bronchiectasis is a long-term condition where the airways of the lungs become abnormally widened, leading to a build-up of excess mucus that can make the lungs more vulnerable to infection
the pathological dilation of bronchi is due to?
Severe Infective Episode
Recurrent Infections - many causes
Proximal Bronchial Obstruction
Lung Parenchymal Destruction
what percentage of bronchiectasis start at childhood?
75%
what are the symptoms of bronchiectasis?
cough, ABUNDANT PURULENT FOUL SPUTUM, haemoptysis, signs of chronic infection
Coarse crackles, clubbing
how would you test for bronchiectasis?
thin section CT (previously bronchography)
how do you manage bronchiectasis?
Postural Drainage, Antibiotics, Surgery
in a recurrent lung infection, what make the defences fail?
Local Bronchial Obstruction - Tumour, Foreign body?
Local Pulmonary Damage - Bronchiectasis?
Generalised Lung Disease - Cystic Fibrosis?, COPD?
Non-Respiratory Disease - Immunocompromised (HIV, other)?, Aspiration?
what is aspiration pneumonia?
Aspiration pneumonia is a complication of pulmonary aspiration. Pulmonary aspiration is when you inhale food, stomach acid, or saliva into your lungs.
what are the symptoms of aspiration pneumonia?
Vomiting Oesophageal Lesion Obstetric Anaesthesia Neuromuscular Disorders Sedation
what are 4 abnormal states associated with hypoxaemia?
Ventilation / Perfusion imbalance - V/Q
Diffusion impairment
Alveolar Hypoventilation
Shunt
Pulmonary vascular changes in Hypoxia
Physiological pulmonary arteriolar vasoconstriction
When alveolar oxygen tension falls
Can be localised effect
All vessels constrict if there is arterial hypoxaemia
A protective mechanism
Do not send blood to alveoli short of oxygen!
why does pneumonia lead to hypoxaemia?
Ventilation / Perfusion abnormality (mismatch)
Bronchitis / Bronchopneumonia
Shunt
Severe bronchopneumonia
Lobar pattern with large areas of consolidation
does a large shunt respond to increase in FI O2?
responds poorly
why does copd lead to hypoxaemia?
Airway Obstruction Alveolar Hypoventilation Reduced Respiratory Drive Diffusion Impairment Loss of Alveolar Surface Area Shunt Only during acute exacerbation
what is Alveolar Hypoventilation
Insufficient amount of air moved in and out of lungs
what is FIO2
the Fraction of Inspired air which is Oxygen
does hypoventilation increase or decrease PACO2
increase
what does an increase in PACO2 do to, Paco2, PAO2 and paO2
increase in PaCO2
decrease in PAO2 which causes PaO2 to fall
what is Hypoxic Cor Pulmonale
Cor pulmonale is a maladaptive response to pulmonary hypertension
what does Hypoxic Cor Pulmonale cause?
Pulmonary vasoconstriction
Pulmonary arterioles
muscle hypertrophy and intimal fibrosis
Loss of capillary bed
Secondary polycythaemia
Bronchopulmonary arterial anastamoses
what is Chronic (Hypoxic) Cor Pulmonale
Hypertrophy of the Right Ventricle resulting from disease affecting the function and/or the structure of the lung, except where pulmonary alterations are the result of diseases primarily affecting the left side of the heart or congenital heart disease
