Bronchiectasis and Chronic Infection Flashcards
What are the risk factors for developing chronic pulmonary infection?
Abnormal host response (immunodeficiency, immunosuppression), abnormal innate host defence (damaged bronchial mucosa, abnormal cilia, abnormal secretions), repeated insult (aspiration, indwelling material).
What type of immunoglobulin deficiencies cause respiratory infection?
IgA (increased acute, rarely chronic), hypogammaglobulinaemia (increased acute and chronic), CVID (common variable immune deficiency, recurrent infections), specific polysaccharide antibody deficiency (SPAD).
What other immunodeficiencies can cause respiratory infections?
Hyposplenism, immune paresis (myeloma, lymphoma, metastatic malignancy), HIV.
Give examples of immunosuppressive treatments.
Steroids, asathioprine, methotrexate, cyclophophamide, monoclonal antibodies (inflximab and etanercept - anti-TNFa, tiruximab - anti CD20, leflunamide), chemotherapy.
What can damage bronchial mucosa?
Smoking, recent pneumonia or viral infection, malignancy.
What syndrome causes abnormal cilia?
Kartenager’s syndrome, Young’s syndrome.
What causes abnormal secretions?
Cystic fibrosis, channelopathies.
What can lead to recurrent aspiration and indwelling material?
Recurrent aspiration - NG feeding regurgitated into trachea, poor swallow, pharyngeal pouch. Indwelling material - NG tube in wrong place, chest drain, inhaled foreign body.
What are some forms of chronic infection?
Intrapulmonary abscess, empyema, chronic bronchial sepsis, bronchiectasis, CF.
What is the clinical presentation of intrapulmonary abscess?
Indolent presentation (little or no pain), weight loss, lethargy, tiredness, weakness, cough, high mortality, usually preceding infection (pneumonia, post viral, foreign body).
What are the possible preceding illnesses of intrapulmonary abscess?
Pneumonia (flu -> staph pneumonia -> cavitating pneumonia -> abscess), aspiration pneumonia (vomiting, lowered conscious level, pharyngeal pouch).
What about the host immune response can cause intrapulmonary abscesses?
Hypogammaglobulinaemia, abscesses usually commonly failure of macrophages that need Ig to activate them.
What are the pathogens in intrapulmonary abscess?
Bacteria: strep, staph (particularly post flu), e.coli, Gm-ves. Fungi: aspergillus.
What are the bacteria that cause empyema?
Frequently aerobic organisms. Gm+ve: strep milleri, staph aureus (post op or hospital acquired [nosocomial], immunocompromised). Gm-ve: e.coli, pseudomonas, haemophilus influenzae, klebsiellae.
How would you diagnose empyema?
Clinical suspicion (slow to resolve pneumoia, lateral chest film), CXR (persisting effusion, particularly if loculations visible), USS (preferred investigation, used in targeted sampling).
In a PA CXR, what should you look for?
D sign.
What are lateral CXRs useful in?
Small retro-diaphragmatic collections.
What is the treatment for empyema?
IV antibiotics (broad spectrum, amoxicillin and metronidazole initially) then oral antibiotics (directed towards cultured bacteria, at least 14 days).
What type of drains are preferred initially in empyema?
Small bore seldinger type drains.
What is bronchiectasis?
Localised, irreversible dilation of the bronchial tree.
Describe what happens to the bronchi involved in bronchiectasis?
The become dilated, inflamed and easily collapsible.
What does bronchiectasis cause?
Airflow obstruction and impaired clearance of secretions.
What is the clinical presentation of bronchiectasis?
Recurrent chest infections, recurrent antibiotic prescriptions, no response to antibiotics or short-lived response to antibiotics, persistent sputum production.
How would you diagnose bronchiectasis?
Clinical: cough productive of sputum, chest pain, recurrent LRTIs. Radiological: HRCT (high resolution CT). Bronchiectasis looks like signet ring.
