RESP Flashcards
What is pneumonia?
Inflammation of lung parenchyma
Who is most at risk of developing pneumonia?
- Infants and the elderly
- COPD and certain other chronic lung diseases
- Immunocompromised
- Nursing home residents
- Impaired swallow (neurological conditions etc.)
- Diabetes
- Congestive heart disease
- Alcoholics and intravenous drug users
What viruses can cause pneumonia?
Adenoviruses, influenza A and B, measles, VZV.
Describe in 3 steps the pathogenesis of pneumonia.
- Bacteria translocate to normally sterile distal airway.
- Resident host defence is overwhelmed.
- Macrophages, chemokines and neutrophils produce an inflammatory response.
Describe the process of pneumonia resolution?
Bacteria are cleared and inflammatory cells are removed by apoptosis.
What can cause pneumonia to be severe?
- Excessive inflammation.
- Lung injury.
- Resolution failure.
What protective features does the respiratory tract have against pathogens?
Teeth, commensal bacteria, swallowing reflex - epiglottis closes respiratory tract, mucociliary escalator, coughing and sneezing etc.
What symptoms might you see in someone with pneumonia?
- Fever/sweats/rigors (infecion)
- Cough w/ rusty sputum (s. pneumoniae)
- SOB and pleuritic chest pain
- weakness/malaise
What signs might you see in someone with pneumonia?
- Signs of infection
- raised heart rate,
- raised respiratory rate,
- low blood pressure
- fever
- dehydration - Signs of lung consolidation on percussion and auscultation
- Dull to percussion
- Decreased air entry
- Bronchial breath sounds
- Crackles ± wheeze
- Increased vocal resonance
± Hypoxia and signs of respiratory failure especially if chronic lung disease or severe pneumonia
What investigations would you perform on someone with suspected pneumonia?
- CXR - look for air bronchogram in consolidated area.
- FBC (look at WBC’s).
- U+E.
- Liver function tests.
- CRP (marker of inflammation).
- Pulse oximetry
- Microbiology: sputum culture, blood culture, serology etc.
What is CURB65 used for?
It is a way of assessing the severity of community acquired pneumonia. It predicts mortality.
What does CURB65 stand for?
Confusion. Urea >7mmol/L. RR >30/min. BP reduced - systolic <90mmHg, diastolic <60mmHg. Age >65.
Why is CRB65 often used in the community?
Because facilities to measure urea are often not available.
Name 2 bacteria that are common causes of pneumonia?
- Streptococcus pneumoniae.
- Haemophilus influenzae.
(Legionella’s - back from spain with CI)
Describe s.pneumoniae.
Gram positive cocci chain. Alpha haemolytic and optochin sensitive.
Describe haemophilus influenzae.
Gram negative bacilli.
What antibiotic would you give to someone with haemophilus influenzae?
Co-amoxiclav or doxycycline.
What groups of people may develop pneumonia caused by klebsiella pneumoniae?
- Homeless people.
- Alcoholics.
- People in hospital.
What kind of bacteria is klebsiella pneumoniae?
Gram negative bacilli.
Name 3 groups of people who might be at risk of hospital acquired pneumonia.
- Elderly.
- Ventilator associated.
- Post operative patients.
What is the treatment for someone with mild pneumonia (a CURB65 score of 0-1)?
PO amoxicillin.
Where should someone with mild pneumonia (a CURB65 score of 0-1) be treated?
In the community.
What is the treatment for someone with moderate pneumonia (a CURB65 score of 2)?
PO amoxicillin and clarithromyocin.
Where should someone with moderate pneumonia (a CURB65 score of 2) be treated?
In hospital.
What is the treatment for someone with severe pneumonia (a CURB65 score of >3)?
IV co-amoxiclav and clarithromyocin.
A 66 y/o patient presents to you with fever and a productive cough. On examination you notice they are their confused. Their vital signs are: RR - 35; BP - 80/55 and HR: 130. You measure their urea and it comes back at 8mmol/L.
a) What is this patients CURB65 score?
b) Where should they be treated?
c) Describe the treatment for this patient.
a) Their CURB65 score is 5.
b) This patient should be treated in hospital and admitted to critical care.
c) The patient should be given IV clarithromyocin and co-amoxiclav.
Give 2 potential complications of pneumonia.
- Empyema.
2. Lung abscess.
Who would be eligible for having the vaccine for pneumonia? What is the vaccine?
Polysaccharide Pneumococcal Vaccine
- > 65 years
- splenic dysfunction,
- immunocompromised
- chronic medical condition
How do you differntiate between HAP and CAP?
Acquired at least 48 hours after hosp. admission
How is Hospital Aqcuired Pneumonia diagnosed?
- new fever
- purulent secretions
- New radiological infiltrates
- New leukocytosis / CRP increase
- plus increasing O2 requirements
A lady who has recently had pneumonia presents to you with SOB and chronic cough. She is producing copious amounts of purulent sputum. What is the likely diagnosis?
Bronchiectasis.
What antibiotic might be used against less common ‘atypical’ pathogens responsible for causing pneumonia?
Macrolides like clarithromyocin as they are often resistant to beta lactams.
How can less common ‘atypical’ pathogens responsible for causing pneumonia be identified?
They are hard to grow in culture and so serology and antigen tests are often used.
Name 3 less common ‘atypical’ pathogens that can be responsible for causing pneumonia.
- Mycoplasma pneumoniae.
- Chlamydia psittaci/pneumoniae.
- Coxiella burnetti.
- Legionella pneumophilia.
Aside from antibiotics, what else would you prescribe to patients admitted to the hospital with pneumonia?
ANALGESICS
LMWH if inpatient >12hrs
A patient comes in with bilateral lymphadenopathy. Give 3 conditions that you would include in your differential diagnosis?
- Local infection e.g. tonsilitis/TB.
- Lymphoma.
- Sarcoidosis.
Where are a high proportion of cases of TB found?
The indian sub continent e.g. India, Bangladesh, Pakistan etc.
Give 5 risk factors for TB.
- If you live in a high prevalence area.
- IVDU.
- Homeless.
- Alcoholic.
- HIV+.
How is TB transmitted?
Aerosol transmission - mycobacterium TB bacilli are inhaled and enter the lung.
Describe pulmonary infection of TB.
Bacilli settle in lung apex. Macrophages and lymphocytes mount an effective immune response that encapsulates and contains the organism forever. (granuloma formation)
Why are mycobacteria resistant to gram staining?
High lipid content with mycolic acids in cell wall
Describe the microorganism that causes TB?
MYCObacteria, gram negative acid fast bacilli
Describe the pathogenesis of pulmonary TB disease.
- Bacilli and macrophages form primary focus (ghon focus).
- Mediastinal lymph nodes enlarge.
- Primary focus and enlarged lymph nodes = primary complex. (ghon complex)
- Granuloma develops into a cavity.
- The cavity is filled with TB bacilli - these are expelled when the patient coughs.
TB disease: Where in the lung is a granuloma cavity most likely to develop?
Most likely to develop in the apex of the lung as there is more air and less blood supply/immune cells.
Presentation of TB: what systemic symptoms might you see?
- Weight loss.
- Night sweats.
- Anorexia.
- Malaise.
Presentation of TB: what pulmonary TB symptoms might you see?
- Cough.
- Chest pain.
- Breathlessness.
- Haemoptysis.
What might you see on a CXR taken from someone with TB?
- Consolidation.
- Collapse.
- Pleural effusion.
Name 6 places where TB might spread to?
- Bone and joints - pain and swelling.
- Lymph nodes - swelling and discharge.
- CNS - TB meningitis.
- Miliary TB - disseminated.
- Abdominal TB - ascites, malabsorption.
- GU TB - sterile pyuria, WBC in GU tract.
What test might you do to diagnose latent TB?
Mantoux test - stimulates type 4 hypersensitivity reaction.
How can TB be prevented?
- Active case finding - reduce infectivity.
- Detect and treat latent TB.
- Vaccination - BCG.
What is the gold standard for diagnosing TB?
SPUTUM TEST
(has to be repeated 3 times)
- would also see gohn complex on x ray
What are the different stages of TB?
Initially ACTIVE phase: bacterium are multiplying, not everyone has symptoms but can be fever, night sweats, weight loss, bloody sputum
LATENT phase: bacterium are no longer multiplying - 90% of people will remain asympotmatic
What is a gohn complex?
Combination of gohn focus (bacteria and macrophages forming a granuloma) and mediastinal enlarged lymph nodes
What happens if the bacteria do not stay contained within the gohn focus?
bacteria disseminate throughout the body causing MILIARY TB
What is the treatment for TB? How long do you need to take the medication for?
RIPE R- rifampicin (6 months) I - isoniazid (6 m) P -pyrazinamide (2 m) E -ethambutol (2 m)
What are the problems associated with drug resistance in TB treatment?
- TB becomes more difficult to treat.
- Medication course > 20 months.
- Increased risk of side effects.
- Increased relapse rate.
Why does TB treatment need to last for 6 months?
TB treatment lasts for at least 6 months to ensure all the dormant bacteria have ‘woken up’ and been killed.
Compliance in taking TB medication is critical. Why?
Resistance and relapse may be likely if the patient is non-compliant
Give side effects for each of the TB medications
Rifampicin - red urine/sweat/tears
Isoniazid - peripheral neuropathy
Pyrazinamide - hepatitis
Ethambutamol - optic neuritis
Name 2 upper respiratory tract infections.
- Common cold: caused by rhinovirus.
2. Sore throat: caused by adenoviruses, EBV.
What is the centor criteria?
The likelihood of a sore throat being due to bacterial infection. If 3 or 4 of Centor criteria are met, the positive predictive value is 40% to 60%
- Tonsillar exudate
- Tender anterior cervical adenopathy
- Fever over 38°C (100.5°F) by history
- Absence of cough.
Are URTI more likely to be bacterial or viral?
Viral
What is cystic fibrosis?
An autosomal recessive disorder in which CFTR channels are faulty leading to thick mucus clogging ducts.
State why cystic fibrosis increases the viscosity and tenacity of the bronchial mucus?
Failure to excrete Cl- leads to Na+ retention. This then leads to H2O retention.
Describe the pathogenesis of cystic fibrosis.
There is a defect in chromosome 7 coding CFTR protein. Cl- transport is affected and there is production of thickened mucus secretions.
When does CF present?
In childhood
What are the signs and symptoms of CF?
Signs: steatorrhea, children with a failure to thrive, finger clubbing, rectal prolapse
Symptoms: heavy mucus production, cough
How would you test for CF?
- FAECAL ELASTASE in newborns (marker of pancreatic damage caused by CF).
- Sweat test: measure the amount of salt collected from the skin.
Genetics testing
Give 4 potential complications of CF
- Infertility
- Pancreatitis
- RTI
- Bronchiectasis
- Malnutrition
- DM
How do you manage CF?
- Prevention of infection e.g. vaccination.
- Segregation to prevent spread.
- Surveillance - monitor FEV1.
- Enzyme supplements for pancreatic insufficiency.
- Anti-pseudomonal antibiotic therapy.
- Physical therapies e.g. airway clearance and exercise.
- Supporting therapies e.g. ensure a good diet.
Define inspiratory reserve volume (IRV).
The additional volume of air that can be forcibly inhaled after a tidal volume inspiration.
Define expiratory reserve volume (ERV).
The additional volume of air that can be forcibly exhaled after a tidal volume expiration.
Define forced vital capacity (FVC).
The maximum volume of air that can be forcibly exhaled after maximal inhalation.
Define total lung capacity.
The vital capacity plus the residual volume. It is the maximum amount the lungs can hold.
Define residual volume (RV).
The volume of air remaining in the lungs after a maximal exhalation.
Define functional residual capacity (FRC).
The volume of air remaining in the lungs after a tidal volume exhalation.
Define tidal volume (TV).
The volume of air moved in and out of the lungs during a normal breath.
Define FEV1.
The volume of air that can be forcibly exhaled in 1 second.
What 2 equations can be used to work out TLC?
- TLC = VC + RV.
2. TLC = TV + FRC + IRV.
What is a normal tidal volume?
500ml.
What equation can be used to work out FRC?
FRC = ERV + RV.
Define peak expiratory flow (PEF).
The greatest rate of airflow that can be obtained during forced expiration. Age, sex and height can all affect PEF.
What is the transfer coefficient?
The ability of O2 to diffuse across the alveolar membrane
How can you find the transfer coefficient?
Low dose CO is inspired, the patient is asked to hold their breath for 10s at TLC, the amount of gas transferred is measured.
Name 3 diseases that might have a low transfer coefficient.
- Emphysema.
- Anaemia.
- Fibrosing alveolitis.
Name a disease that might have a high transfer coefficient.
- Pulmonary haemorrhage.
How is airway obstruction defined by spirometry?
- FEV1 < 80% predicted.
- FEV1/FVC < 0.7.
What happens to the FVC and FEV1/FVC ratio in a restrictive lung disease?
- FVC reduced.
- FEV1/FVC ratio normal.
How would you describe the PEF for asthma.
variable
What factors can commonly exacerbate asthma?
- Allergens.
- Viral infections.
- Cold air.
- Exercise.
- Stress.
- Cigarette smoke.
- Drugs e.g. aspirin.
How would you describe the airways in asthma?
Hyper-reactive. This leads to inflammation.
What is allergic asthma?
When an innocuous allergen triggers an IgE mediated response. The immune recognition processes are faulty and so there is increased IgE, IL-3,4 and 5 production.
What is non-allergic asthma?
Airway obstruction induced by exercise, cold air and stress.
Describe the process of IgE binding to and activating mast cells.
IgE binds to the high affinity receptor on the mast cell surface. There is cross-linking and biochemical cascades. The mast cells are sensitised and there is degranulation.
What might be released on mast cell degranulation?
- Pre-formed histamine.
- Newly synthesised eicosanoids e.g. cysteinyl leukotrienes (cys LTs) and prostaglandin D2.
- Cytokines e.g. IL-3,4,5.
Give 3 reasons why the airways hyper-reactive in asthmatics?
- Inflammatory infiltrate.
- Eosinophils.
- Epithelium destruction gives easier access to bronchoconstrictors.
What are the 2 principles of asthma treatment?
- Alleviate symptoms.
2. Target inflammation.
What are the main cells responsible for inflammation in asthma?
Mast cells and eosinophils.
What is the advantage of having inhaled medications in the management of asthma?
Inhaled medications are more likely to reach the target sites and there is reduced chance of side effects.
A young person presents to you with breathlessness, wheeze and cough. There appears to be inflammation of the airways. When you do a spirometry test the results are variable. You ask the patient to do a peak flow diary and the results of this show diurnal variation. Is the patient likely to have asthma or COPD?
They are likely to have asthma!
Although breathlessness, wheeze and cough are symptoms of both asthma and COPD the fact that the spirometry results are variable is a large indication that this person has asthma!
The patient is also young and COPD tends to be more common in older people.