Chronic Pulmonary Infection (DISEASE MECHANISMS) Flashcards
What are the risk factors for developing chronic pulmonary infections?
Abnormal host response / innate host defence
Repeated insult
In which ways can innate host defects be abnormal increasing risk for developing chronic pulmonary infections?
Damaged bronchial mucosa
Abnormal cilia
Abnormal secretions
What are the two types of immunodeficiency?
Congenital
Acquired
What are the origins of immunosuppression?
Drugs
Malignancy
What are examples of repeated insult that can increase risk for chronic pulmonary infections?
Aspiration
Indwelling material
What are the four types of immunodeficiency?
Antibody deficiencies
Hypo-Splenism
Immune paresis
HIV
What does a deficiency in IgA cause? Is it common/rare?
Common
Increased risk of acute (rarely chronic) infections
What does hypogammaglobulinaemia cause? Is it common?
Rare
Increase risk of acute & chronic infections
What does CVID cause? is it common?
Most common cause of immunodeficiency
Causes recurrent infections
What is specific polysaccharide deficiency?
Inability to make antibodies against polysaccharides
Without a spleen you can’t produce ____ so you need _______________
antibodies
lifelong prophylactic penicillin therapy
What is immune paresis?
Can only produce 1 type of antibody that is typically non-functional and stops secretions of other antibodies
Which therapies cause immunosuppression?
Steroids Azathioprine Methotrexate Cyclophosphamide Monoclonal antibodies Chemotherapy
What can damage the bronchial mucosa`
Smoking
Recent pneumonia
Viral infection
Malignancy
What cause cause abnormal cilia (congenital)?
Kartenager’s syndrome
Young’s Syndrome
What can cause abnormal secretions?
Cystic fibrosis
Channelopathies
What can cause recurrent aspiration?
NG feeding
Poor swallow
Pharyngeal pouch
What can cause indwelling material?
NG tube in the wrong place
Chest drain
Inhaled foreign body
What are the forms of chronic infection?
Intrapulmonary abscess Empyema Chronic bronchial sepsis Bronchiectasis CF Others
How does a patient with an intrapulmonary abscess present?
Indolent
Weight loss commonLethargy, tiredness, weakness
Cough +/- sputum
High mortality if untreated (death by sepsis)
Usually preceding illness
Which illnesses precede intrapulmonary abscesses?
Pneumonia
Aspiration pneumonia
Poor host immune response (Hypogammaglobulinaemia)
What is the course of treatment if an abscess is too large for antibiotics to reach it?
‘Pop’ the abscess then give antibiotics
Which pathogens cause intrapulmonary abscesses?
Bacteria (streptococcus / staphylococcus)
E-coli
Gram negs
Fungi (Aspergillus)
How are multiple abscesses formed?
Bacteria enter blood > lungs act as filter > filter out clots & bacteria -causes-> seeding of bacteria throughout lung
What is empyema?
Pus in the pleural space
Patients with empyema have a ___ mortality
high
How does a simple parapneumonic effusion progress to empyema?
pH and glucose decrease below 2.2 and LDH rises above LDH to form complicated parapneumonic effusion and then empyema
Most of the bacteria that cause empyema are _____
aerobes
Which aerobic gram positive bacteria cause empyema?
Staph Milleri
Staph Aureus
Which aerobic gram negative bacteria cause empyema?
E-coli
Pseudomonas
Haemophilus Influenza
Kelbsiellae
Anaerobic bacteria caused empyema is usually only seen in ____ _______ or _____ _____ ______
severe pneumonia
poor dental hygiene
How is an empyema diagnosed?
Clinical suspicion (slow-resolving pneumonia / lateral chest film)
CXR - persisting effusion, loculations?
USS - targeted sampling
CT - differentiate empyema & abscess
How is an empyema treated?
USS or CT guided drain
IV (amoxicillin or metronidazole initially) oral antibiotics
What is bronchiectasis?
Localised irreversible dilation of the bronchial tree
What happens in bronchiectasis?
Involved bronchi are dilated, inflamed and easily collapsible causing airflow obstruction and impaired clearance of secretions
How does bronchiectasis present?
Recurrent chest infections
No or short-lived response to antibiotics
Persistent sputum production
What is meant by a signet ring? (referring to radiology)
Large bronchiole with a small artery
How do you diagnose bronchiectasis?
Clinical - cough + sputum
Chest pain
Recurrent LRTs
Radiological - HRCT - bronchioles > 1 cm wide
What is the pathophysiology of bronchiectasis?
Bronchial obstruction Cystic fibrosis Young's syndrome kartaneger's syndrome ABPA Immunodeficiency RA Bronchopulmonary sequestration Mounier-Khun syndrome Yellow nail syndrome Traction bronchiectasis associated with pulmonary fibrosis Alpha-1 antitrypsin deficiency > 50% IDIOPATHIC
How does chronic bronchial sepsis present?
All bronchiectasis hallmarks / no bronchiectasis on HRCT / confirmed pos. sputum results / often young (mainly female) patients often involved in child care / others older usually with COPD or airways disease
How can chronic bronchial sepsis be treated ?
Stop smoking
Flu vaccine
Pneumococcal vaccine
Reactive antibiotic - most appropriate to most recent sputum sample
How can chronic bronchial sepsis be treated when colonised with persistent bacteria?
Prophylactic antibiotic
Nebuliser gentamicin/colomycin
Pulse iv abs
Alternating oral antibiotic
What anti-inflammatory treatment is there for chronic bronchial sepsis?
Low dose-macrolide reduce exacerbation rates in bronchiectasis
Clarithromycin
Erythromycin
