Chronic pulmonary Infection Flashcards
What are the possible diagnoses for a patient with the following symptoms:
- Shadow on CXR
- Weight loss
- Persistent sputum production
- Chest pain
- Increasing shortness of breath
- Lung Cancer
- Intrapulmonary abscess
- Empyema
- Bronchiectasis
- Cystic Fibrosis
What are risk factors for developing chronic pulmonary infection?
Abnormal host response
- Immunodeficiency (congenital, acquired)
- Immunosuppression (drugs, malignancy)
- Abnormal innate host defence (damaged bronchial mucosa, abnormal cillia, abnormal secretions)
- Repeated insult (aspiration, indwelling material)
What can cause immunodeficiency?
- Immunoglobulin deficiency
- Hypo-splenism
- Immune paresis
- HIV
What are different types of immunoglobulin deficiency?
- IgA Deficiency: common, increased risk of acute infections, rarely chronic infections
- Hypogammaglobulinaemia: rarer, increased risk of acute, and chronic infections
- CVID: commonest cause of immunodeficiency, recurrent infections
- Specific Polysaccharide Antibody Deficiency
How can smoking cause immunosuppression?
Abnormal cilia beat
What can causes aspiration?
NG tube down trachea rather than oesophagus
What is Specific Polysaccharide Antibody Deficiency (SPAD)?
Inability to develop antibodies against polysaccharide, so cannot resist certain bacteria
Why is hypo-splenism dangerous?
If no spleen, cannot produce polysaccharide antibodies
What is immune paresis?
Immune system goes into paretic state due to things like myeloma, lymphoma and metazoic malignancies
Why is immunosuppression common?
Due to increased use of immunosuppressant drugs
What are examples of immunosuppressant drugs?
- Steroids
- Azathioprine
- Methotrexate
- Cyclophosphamide
- Monoclonal antibodies (Infliximab, etanercept: TNFa, Rituximab: CD20, Leflunamide)
- Chemotherapy
What factors can damage bronchial mucosa?
- Smoking
- Recent pneumonia, or viral infection (‘Flu)
- Malignancy
What conditions can lead to abnormal cillia?
- Kartenager’s Syndrome
* Youngs Syndrome
What conditions cause abnormal secretions?
- Cystic fibrosis
* Channelopathies
What are causes of recurrent aspiration?
- NG feeding
- Poor swallow
- Pharyngeal pouch (collects food, etc)
What are causes of indwelling material?
- NG tube in the wrong place
- Chest drain
- Inhaled foreign body (peanut, chicken bone, piece of coal, etc)
What are forms of chronic respiratory infection?
- Intrapulmonary abscess
- Empyema
- Chronic Bronchial Sepsis
- Bronchiectasis
- Cystic Fibrosis and other oddities
What are clinical features of intrapulmonary abscesses?
- Indolent presentation (no pain)
- Weight loss common
- Lethargy, tiredness, weakness
- Cough
- Possible sputum
Why is treatment for intrapulmonary abscesses vital?
High mortality if not treated
What are causes of intrapulmonary abscesses?
Usually a preceding illness of some sort
- Pneumonic infection
- Post viral
- Foreign body
What are preceding illnesses of intrapulmonary abscesses?
Pneumonia (Remember ‘Flu -> Staph Pneumonia -> Cavitating Pneumonia -> Abscess) Aspiration pneumonia * Vomiting * Lowered conscious level * Pharyngeal pouch Poor host immune response * Hypogammaglobulinaemia
What pathogens cause abscesses (stemming form pneumonia)?
Bacteria
- Streptococcus
- Staphylococcus (Particularly post ‘flu)
- E-Coli – normally in bowel but can present in chest to cause pneumonia
- Gram Negatives
Fungi
* Aspergillus
What can multiple abscesses on a CXR be indicative of?
Bacteraemia - bloot infection
What are causes of septic emboli?
- Right sided endocarditis
- Infected DVT – once infected travel to lungs
- Septicaemia
- Intravenous drug users
Why are intravenous drug users at risk of septic emboli and abscesses?
- Inject into groin – blood clot due to repeated trauma to the vien
- Leads to DVT
- Then Infection
- Then PE + Abscesses
Why are abscesses caused by PE’s so dangerous?
- Very high mortality - 75%
* Abscesses sit close to pulmonary vessels – if abscess erodes into pulmonary artery, loss of blood (exsanguination)
What is empyema?
Pus in the pleural space
What are causes of empyema?
- 57 % of all patients with pneumonia develop empyema (commonest cause)
- Remainder are “Primary Empyema”, often iatrogenic, many idiopathic
What is the mortality of empyema?
- High mortality
- As high as severe pneumonia
- > 20 % of all patients with empyema die
What is the appearance of an empyema on a CT?
Looks like a banana - dark with lighter areas
What are the features of simple parapneumonic effusion?
Simple Parapneumonic Effusion
- Clear fluid
- pH > 7.2
- LDH < 1000
- Glucose > 2.2
What are the features of complicated parapneumonic effusion?
- pH < 7.2
- LDH > 1000
- Glucose < 2.2
- Requires chest tube drainage
What are the features of empyema?
Presence of pus
What is the bacteriology of empyema?
Aerobic organisms most frequently
- Gram Positive (strep Milleri, Staph Aureus)
- Gram Negatives (E-Coli, Pseudomonas, Haemophilus Influenza, Kelbsiellae)
- Anaerobes in 13 % of cases (usually in severe pneumonia, or poor dental hygiene)
Why is it mostly aerobic organisms found in empyema?
Very high PO2 (anaerobes only found in severe pneumonia or poor dental hygiene)
How is empyema diagnosed?
CXR
- Loculations visible
- D-sign
USS (ultrasound scan)
- The preferred investigation
- Simple, bedside test
- Targetted sampling
CT
* Differentiation between Empyema and Abscess (empyema C-shaped)
How is the drain site positioned?
Using USS or CT
What are treatments (other than a chest drain) for empyema?
IV antibiotics Broad spectrum Amoxicillin and Metronidazole initially Oral antibiotics Directed towards cultured bacteria At least 14 days
What are treatments (other than a chest drain) for empyema?
IV antibiotics
- Broad spectrum
- Amoxicillin and Metronidazole initially
Oral antibiotics
- Directed towards cultured bacteria
- At least 14 days
What kind of pleural effusion is more likely to lead to empyema?
Complicated pleural effusion - requires sampling go the effusion
What is bronchiectasis?
Localised, irreversible dilation of the bronchial tree
What are the characteristics of the bronchi in bronchiectasis?
Involved bronchi are dilated, inflamed and easily collapsible
What are the effects of bronchiectasis?
- Airflow obstruction
* Impaired clearance of secretions
What are the clinical features of bronchiectasis?
- Recurrent “chest infections” (LRTIs)
- Recurrent antibiotic prescriptions
- No response to antibiotics or short lived response to antibiotics
- Persistent sputum production
- Possible chest pain
What are radiological signs of bronchiectasis?
High resolution CT
- Bronchus is larger in diameter than adjacent pulmonary artery
- signet ring
What is the pathophysiology of bronchiectasis?
- Bronchial obstruction
- Cystic Fibrosis
- Young’s Syndrome
- Kartanager’s Syndrome
- ABPA
- Immunodeficiency
- Rheumatoid Arthritis
- Bronchopulmonary sequestration
- Mounier-Khun Syndrome
- Yellow Nail Syndrome
- Traction bronchiectasis associated with pulmonary fibrosis
- Alpha1 Antitrypsin deficiency
What are over 50% of bronchiectasis cases caused by?
Idiopathic > 50 %
What is chronic bronchial sepsis?
All the hallmarks of bronchiectasis (including positive sputum result) but no bronchiectasis on HRCT scan
What individuals are infected with chronic bronchial sepsis?
- Often younger patients, mainly women, often involved in childcare
- Others are older, usually with COPD, or airways disease
What is a condition associated with chronic bronchial sepsis?
Chronic sinusitis - Infection with bacteria/viruses that are chronically in the sinuses
What are the treatment options for chronic bronchial sepsis/bronchiectasis?
- Stop smoking
- ‘Flu vaccine
- Pneumococcal vaccine
- Reactive antibiotics - send sputum sample and give antibiotics appropriate to most recent positive culture (e.g. amoxicillin resistant culture, don’t give amoxicillin)
What is the treatment for chronic bronchial sepsis/bronchiectasis when colonised with persistent bacteria?
- Prophylactic antibiotics
- Nebulised gentamicin, colomycin
- Pulsed IV abx
- Alternating oral antibiotics
What is anti-inflammatory treatment for bronchiectasis?
Low dose macrolide antibiotics have been shown to reduce exacerbation rates in bronchiectasis
- Clarithromycin 250 mg OD
- Azithromycin 250mg Three Times a Week (particularly effective in pseudomonas colonised individuals)
What is the prognosis for bronchiectasis?
- Recurrent infection
- Frequent Abscesses and empyema
- Colonisation (treatment is often aggressivetotry and prevent colonisation)
What is used to measure the severity of bronchiectasis?
Bronchiectasis severity index (BSI)
In general examination, what is a sign of bronchiectasis?
Finger clubbing
What is the incidence of cystic fibrosis?
- Carrier rate of 1 in 25
* Incidence of 1 in 2,500 live births
What are complications of cystic fibrosis?
- Bronchiectasis (cystic and saccular)
- Tenacious sputum
- Biliary obstruction, and obstructive hepatitis
- Pancreatic dysfunction (endocrine - CFRDM, exocrine - steatorrhoea)
- Infertility for males
- Psychology issues for all
What is the mortality for abscesses and empyema?
Abscess - 10%
Empyema - 20%
