Infections Flashcards
What are upper respiratory tract infections?
Common cold (coryza), sore throat (pharyngitis), sinusitis, epiglottitis, tonsillitis and quinzy, diphtheria
What are complications of the common cold?
Acute bronchitis and sinusitis
What are some organisms causing the common cold?
Adenovirus, respiratory syncytial virus, rhinovirus
What is the severe type of sinusitis?
Erythroid
What is a sign of epiglottitis and what should you never do?
Drooling- never open mouth as they will choke
What is quinzy?
Tonsil abscess
What makes diphtheria life threatening?
Toxin production
What are lower respiratory tract infections?
Acute bronchitis, COPD exacerbations, influenza, pneumonia
What are signs of acute bronchitis?
Cough, fever, possible wheeze
What is the treatment for acute bronchitis?
No antibiotics generally, maybe in those with a chronic lung disease
What happens in a COPD exacerbation?
Increased sputum, wheeze and dyspnoea
What are signs of a COPD exacerbation?
Respiratory distress, wheeze, coarse crackles, cya nosed, ankle oedema
What is the treatment for an acute exacerbation of COPD?
Amoxicillin (or doxycycline), steroids and bronchodilators
What additional things would be added to the treatment of a COPD exacerbation in secondary care?
CXR, ABG, oxygen if there is respiratory failure
What are symptoms of influenza?
Fever, malaise, myalgia, headache, cough, prostration
What are 8 signs of pneumonia?
Fevers, rigorous, herpes labialis, tachypnoea, crackles, rub, cyanosis, hypertension
What symptoms are particularly common in legionella?
GI disturbance and confusion
Besides CURB65, what are other severity markers of pneumonia?
Severe high or low temperature, WBC count <4 or >30, cyanosis and multi-lobar involvement
What investigations do you do to diagnose pneumonia?
Blood culture, serology, CXR, ABG, FBC, urea, liver function
How do you manage CA pneumonia?
Antibiotics, bed rest, fluids, oxygen, no smoking
What are complications of pneumonia?
Respiratory failure, pleural effusion, empyema, fibrous scarring, abscess, bronchiectasis, death
What is the further management needed for HA pneumonia?
Further gram negative cover
What is the further management needed for aspiration pneumonia?
Further anaerobic cover
What type of organisms tend to colonise the upper respiratory tract?
Gram + alpha haemolytic strep, beta haemolytic strep, gram negatives
What is an example of a gram positive alpha haemolytic strep?
Streptococcus pneumoniae
What is an example of a beta-haemolytic strep?
Streptococcus pyogenes
What are examples of gram - bacteria colonising the upper respiratory tract?
Haemophilus influenzae, moraxella catharalis
What bacteria causes TB?
Mycobacterium tuberculosis
What type of bacteria is m. tuberculosis?
Acid alcohol fast bacilli
How do you treat TB?
2 months rifampicin, isoniazid, pyrazinamide and ethambutol (RIPE), 4 months RI
What are the 3 ‘influenza’ viruses?
Influenza A/B (classical), parainfluenza virus (flu-like illness), haemophilus influenzae (a bacterium and not a direct cause of flu)
How do you treat influenza?
Bed rest, fluids, paracetamol, possibly antivirals e.g. olselamivir
What type of influenza is involved in pandemics?
Type A
What is the main cause of bronchiolitis?
Respiratory syncytial virus
How do you treat bronchiolitis?
Supportive therapy
What organism is known to cause infantile pneumonia?
Chlamydia trachomatis
What is chlamydia pneumoniae?
A mild respiratory tract infection
What causes epiglottitis?
Haemophilus influenzae type B
How do you treat epiglottitis?
Ceftriaxone
Who is epiglottitis more common in?
Immune compromised/suppressed
What are some bacteria causing a COPD exacerbation?
Haemophilus influenzae, moraxella catarrhalis, streptococcus pneumoniae (also some gram -‘s)
When do you treat a COPD exacerbation?
Whenever there is increased sputum purulence, new changes on CXR or pneumonia
What are some organisms involved in CF?
strep pneumoniae, haemophilus influenzae, staph aureus, burkholderia Cepacia, pseudomonas auriginosa
What are symptoms of whooping cough?
Cold like symptoms for 2 weeks, paroxysmal coughing, vomiting
What causes whooping cough and what kind of bacteria is this?
Bartedella pertussis- gram - cocco bacillus
When should you give antibiotics for a whooping cough?
If the cough has lasted <21 days
How is whooping cough diagnosed?
Culture from swab or PCR, serology, history and exam
What are the top 5 organisms causing CAP?
1) Strep. pneumoniae
2) Haemophilus. influenzae
3) Mycoplasma. pneumoniae
4) Staphylococcus. aureus
5) Gram -‘s e.g. Coxiella. burnetti
What are some atypical organisms causing CAP?
Legionella, moraxella. catarrhalis, chlamydia
What CAP causing organism is most common in children and young people?
Mycoplasma pneumoniae
What does mycoplasma pneumoniae show on a CXR?
Reticulo-nodular shadowing/patchy consolidation of 1 lobe
What does staph. aureus show on a CXR?
Bilateral cavitation bronchopneumonia
Where does legionella commonly come from?
Colonised hot water tanks
What does legionella show on a CXR?
Bi-basal consolidation
What are some examples of aspiration pneumonia as well as the common ones?
Klebsiella pneumoniae, E.coli, pseudomonas auriginosa
Who is Klebsiella pneumoniae common in and where is it commonly found?
Alcohol abuse- often in the upper lobes
What is the common bacteria in the immunocompromised?
Pneumocystis Jirovecii (PCP)
How do you treat PCP?
Co-trimoxazole
What else is common in immunocompromised?
Aspergillis
What are the 2 most common causes of HAP?
Staph aureus and gram - enterobacteria
What are other causes of HAP?
Pseudonomas, Klebsiella, Bacteroides, Clostridia
What is common in bronchiectasis?
Pseudonomas
What is TB infection?
The immune system has not completely cleared the disease
What is TB disease?
Showing symptoms of TB
How do diseases of lower lung lobes usually come about?
Through the bloodstream
How do diseases of upper lung lobes usually come about?
Through inhaled pathogens
What are 11 features of TB?
Weight loss, fevers, night sweats, malaise, pain, bowel obstruction, headache, fits, drowsy, cough
What confirms a diagnosis of TB?
Staining characteristics, culture
What will the radiology for TB show?
Upper lobe predominance with cavity formation?
What can happen when taking rifampicin?
It can cause other current medication not to work very well
Where does TB live in the body?
In macrophages
How long does it take to be non-infectious from TB?
1-2 weeks
What does single agent resistance usually target in TB and how is treatment changed?
Usually just affects isoniazid- treatment is prolonged
Was is commonly affected by MDR in TB?
Rifampicin and isoniazid
What are signs of latent TB?
No evidence of active TB, evidence of previous TB infection, calcification on x-ray
What tests can be used to test for previous TB exposure?
Interferon gamma release assay, mantoux test
What are TB drugs associated with and who is this more common in?
Disturbance of liver function- more common in women
What people have the highest rates of TB?
HIV
What are some viruses which can cause pneumonia?
Influenza, parainfluenza, measles, varicella-zoster, respiratory syncytial virus
What is lobar pneumonia?
Consolidation involving a whole lung lobe?
What organism most commonly causes lobar pneumonia?
Strep. pneumoniae
Who is lobar pneumonia more commonly found in?
Otherwise healthy young adults
What is the basic pathology behind lobar pneumonia?
Fibrin rich fluid, neutrophil infiltration, macrophage infiltration, resolution
What is bronchopneumonia?
Starts in the airways and spreads to adjacent alveolar lung
What context is bronchopneumonia most commonly seen in?
People with pre-existing disease
What is important to remember about the organisms causing bronchopneumonia?
They can be more varied
What type of pneumonia can commonly lead to abscess?
Aspiration pneumonia
What is bronchiectasis?
Abnormally fixed dilation of the bronchi usually due to fibrous scarring followed by infection
What accumulates in bronchiectasis?
Purulent secretions
What type of reaction is TB?
Delayed type IV hypersensitivity reaction- granulomas with necrosis
How does TB exert pathogenicity?
Avoids phagocytosis and stimulates a host T cell response
What happens in primary TB?
The inhaled organism is phagocytosed and carried to hilar lymph nodes
What happens in secondary TB?
Reinfection or reactivation of the disease in a person with some immunity.
Where does the disease tend to be in secondary TB?
Usually localised at the apices but can spread to the airways and bloodstream
Where does primary TB tend to be?
There is a small focus in the periphery of the midzone and large hilar lymph nodes
What is an important differential diagnosis in secondary TB?
Cancer
What makes TB reactivate?
Decreased T cell function or immunosuppressive therapy
What virus is common in the immunosuppressed?
Cytomegalovirus
What fungi is common in the immunosuppressed?
Aspergillus, candida, pneumocystis
What medication counts as being immunosuppressed?
Steroids and cancer treatment
What are differentials for a pulmonary infection?
Lung cancer, abscess, empyema, bronchiectasis, CF
What are risk factors for developing chronic lung infections?
Immunosuppressed/immunodeficiency, abnormal host defence, repeated insult, immunoglobulin deficiency
What does IgA deficiency predispose to?
Recurrent acute infections, not chronic
What does an intrapulmonary abscess present with?
Weight loss, lethargy, weakness, cough
What is common in people with an intrapulmonary abscess?
A preceding illness
What are some pathogens causing intrapulmonary abscess?
Bacterial (strep, staph, e-coli, gram -‘s) or fungi (aspergillus)
What can be causes of septic emboli and who is this common in?
Right sided endocarditis, infected DVT, septicaemia, common in PWID
What is empyema?
Pus in the pleural space
What are empyemas common following?
Pneumonia, and there is often a progression from effusion to empyema
What type of organisms cause empyema? What is the exception to this?
Usually aerobic organisms, anaerobic in severe pneumonia or poor dental hygiene
What tests are done for empyema?
CXR- will show white out ‘D sign’, CT and ultrasound
How do you treat empyema?
Broad spectrum IV antibiotics (amoxicillin, metronidazole) initially followed by oral antibiotics directed towards the specific organism for at least 14 days
How would you describe the bronchi in bronchiectasis?
Inflamed and easily collapsible
What does bronchiectasis present as?
Recurrent ‘chest infections’ and antibiotic prescriptions with no or little response . There is also persistent sputum production and a cough
How do you test for bronchiectasis?
High resolution CT
What is the presentation of bronchial sepsis?
Similar to bronchiectasis but with no evidence of that following tests
Who is bronchial sepsis common in?
Young people or adults in healthcare or older people with COPD or other airway diseases
What should the diagnosis of a chronic infection always lead to?
A check for underlying immunodeficiency
What is the main cause of the problem in CF?
A defect in the cystic fibrosis transmembrane conductance regulator- a chloride channel found in lumen cells
What does the CFTR channel do in normal people?
Transport of chlorine into the lumen of the lungs- it is ATP regulated and inhibits sodium and some other channels
What happens when the CFTR channel fails?
Sodium and water leaks into other cells which causes dehydration of the lumen.
What are the consequences of dehydration of the lumen in CF?
Salty sweat, intestinal blockage, fibrotic pancreas, failure to thrive, recurrent bacterial lung infections, absence of vas deferens
How many different classes of CFTR mutations are there and which is the worst?
5 different classes- Class I is the worst as there is no CFTR synthesis
What are some signs of CF in adulthood?
Upper lobe bronchiectasis, colonisation with staph, infertility and low weight
What treatment do you give if a CF patient is colonised with staph aureus?
Flucloxacillin oral or septrin oral
What treatment do you give if pseudomonas colonises a CF patient?
Oral azithromysin, nebulised colomycin, tobramycin and aztreonam and inhaled tobramycin
What can exacerbations of CF be managed by?
Antibiotics, physiotherapy, adequate hydration and increased dietary input
How many antibiotics should be given to CF patients and why?
Always 2 to reduce resistance
What antibiotics do you give to a CF patient with cepacia?
Temocillin
What is the G551D mutation in CF?
A class III mutation; there is a normal CFTR but a non-functioning channel
What drug can help in G551D mutations and why is it rarely used?
Ivacaftor- it is extremely expensive
