Lower Respiratory Tract Infections Flashcards
What is acute bronchitis?
Thickening of the bronchial walls due to infection
Often preceded by a common cold
What are the clinical features of acute bronchitis?
Productive cough Fever Normal chest examination Normal chest x ray Transient wheeze
How is acute bronchitis treated?
Usually viral and self limiting- paracetamol and fluids
Antibiotics are NOT needed in the majority of cases
When may antibiotics be needed to treat acute bronchitis
Patients with chronic lung disease- it can cause significant morbidity
What is the risk of fatal pneumonia?
5-10%
30% if bacteraemic
What are the symptoms of pneumonia?
Malaise, Annorexia, Sweats, Rigors, Myalgia, Arthralgia, Headache, Confusion, Cough, Pleurisy, Haemoptasis, Dysphonia, Abdominal pain, diarrhoea
What can preceed a pneumonia?
An upper RTI
A UTI
How can pneumonia cause abdominal pain?
Sitting on top of the diaphragm
What would you expect to find on examination in a pneumonia patient?
Fever, rigors, herpes labialis, tachypnoea, crackles, rub, bronchial breath sounds, cyanosis, hypotention
Why may you see cold sores in a pneumonia patient
Herpes labialis remains dormant in the body. With pneumonia the immune system will be diverted leading to a flare up of cold sores/ herpes simplex
What investigations are required if pneumonia is suspected?
Blood and sputum culture Viral throat swab CXR ABGs Serology and urine (legionella only) Full blood count Urea and liver function
What does CURB 65 score stand for?
C- new onset of CONFUSION U- UREA > 7 (kidney failure) R- RESP RATE >30 B- BLOOD PRESSURE <90 systolic of <61 diastolic 65- age 65 or older
What does a curb 65 score of 0-2 imply?
Moderate pneumonia
What does a curb 65 score of >2 imply?
Severe pneumonia- higher mortality risk
What are other markers of severity for pneumonia?
Temperature <35 or >40
Cyanosis PaO2 <8kPa
WBC <4 or >30
Multi lobar involvement
Which are the most resistant strains of baceria causing pneumonia?
Legionella nad Staph aureus
What is the most common cause of pneumonia
Strep pneumoniae
Pneumonia: young person.
Whats the cause?
Mycoplasma pneumonia- protracted paroxysmal cough
Pneumonia: CF patient.
Whats the cause?
Pseudomonas aeruginosa
Pneumonia: PWID.
Whats the cause?
Staph aureus
Pneumonia: returned from spain.
Whats the cause?
Legionella pneumophilia
Pneumonia: COPD.
Whats the cause?
Haemophilus influenzae
Pneumonia: alcoholic.
Whats the cause?
Klebsiella pneumoniae
Pneumonia: bird keeper.
Whats the cause?
Chlamydia psittaci
What is mycoplasma pneumoniae resistant to?
All beta lactam antibiotics as they do not have a cell wall
When would you use IV antibiotics to treat pneumonia?
Nil by mouth
Sensitivities- resistant to oral antibiotics
Deep seated infections- abscesses (bones, pelvis)
First dose IV to increase the plasma concentration
Generally oral antibiotics are very good
What are the complications of pneumonia?
Respiratory failure
Pleural effusion
Empyema- infection in the pleural space
Abcess
What is an empyema?
An infection in the pleural space
Who is entitled to the pneumococcal vaccine?
Over 65’s
Anyone with a chronic chest or cardiac disease
Anyone who is immunocomprimised- eg splenectomy
What type of antibiotics do hospital acquired pneumonias require?
Gram negative cover
What type of antibiotics are needed for aspiration pneumonia?
Anaerobic cover
What is the incubation times for: Rhinovirus? Strep group A? Influenza and parainfluenza? RSV? Pertussis? Diphtheria? Epsin Barr virus?
Rhinovirus = 1-5 days Strep group A = 1-5 days Influenza and parainfluenza = 1-4 days RSV = 7 days Pertussis = 7-10 days Diphtheria = 1-10 days Epsin Barr virus= 4-6 weeks
What does pertussis cause?
Whooping cough- 100 day cough
What does the Epsin Barr virus cause?
Glandular fever
What are the 3 main risk factors for chronic pulmonary infection?
1) Abnormal host response = immunodeficiency or immunosupression
2) Abnormal innate host defence = damaged bronchial mucosa, abnormal cilia, abnormal secretions
3) Repeated insult = Aspiration or indwelling material (NG tube)
Which drugs cause immunosupression?
Steroids Monoclonal antibodies Chemotherapy Cyclophosphamide Methotrexate Azathioprine
What are the common imunodeficiencies?
IgA deficiency- increased incidence of acute infections- not chronic
Hypogammaglobulinaemia- rare- increased risk of acute and chronic infections
CVID (common variable immunodeficiency)- common and recurrent infections
SPAD (specific polysaccharide antibody deficiency)
Hypospenism- no spleen, antibiotics for life
HIV
Immune paresis
What causes a damaged bronchial mucosa?
Smoking, recent infection, malignancy
What causes abnormal cilia?
Kartenager’s syndrome, Young’s syndrome
What causes abnormal secretions?
CF and channelopathies
What causes recurrent aspiration?
NG feeding, poor swallow, pharyngeal pouch
What are the forms of chronic respiratory infection?
Intrapulmonary abscess Bronchiectasis Empyema CF Chronic bronchial sepsis
What are the common organisms causing intra pulmonary abscesses?
Streptococcus pneumoniae, Staph aureus, E coli, gram negatives and aspergillus fungi
What is suggested by multiple abscesses?
Bacteraemia
What is an empyema and what is the treatment?
Infection within the pleural space = Pus
Chest drain, antibiotics IV initially, oral antibiotics for 14 days directed at causative organism
If a patient has pleural fluid build up due to pneumonia, do they have an empyema?
No- the fluid must be infected
What are the characteristics and treatment for a simple parapneumonic effusion?
Clear fluid, pH >7.2, LDH <1000, Glucose >2.2
Resolve on its own- monitor
What are the characteristics and treatment for a complicated parapneumonic effusion?
pH <7.2, LDH >1000, Glucose <2.2
Chest drain
What organisms cause empyemas?
Often aerobic because oxygen readily difuses into the pleual space
Strep Milleri, Staph aureus (gram positive)
E coli, pseudomonas, H. influenzae, Kelbsiellae (gram negatives)
How is an empyema diagnosed?
CXR (consider lateral) persistent effusion with loculations
Ultrasound- targeted sampling of pleural fluid
How do you distinguish between an empyema and an abscess?
CT scan
What is Bronchiectasis?
Localised, irreversile dilation of the bronchial tree
Involved bronchi are dilated, inflamed and easily collapsible
What does bronchiectasis cause?
Air flow obstruction as airways lose rigidity
Impaired clearance of secretions as cilia don’t work
What is the common presentation for bronchiectasis?
Recurrent chest infections with lots of antibiotic prescriptions but with no or a short response
persistent sputum production, especially in the morning
How is bronchiectasis diagnosed?
High resolution CT
Signet ring sings where the bronchiole is larger than the accompanying pulmonary artery
What is the cause of bronchiectasis?
50% idiopathic CF Kartanager's syndrome Young's syndrome immunodefficiency Rheumatoid arthritis ABPA- allergic broncho pulmonary aspergillosis Pulmonary fibrosis Yellow nail syndrome Mounier-Khun syndrome
What is chronic bronchial sepsis?
Clinical bronchiectasis but without the radiological signs
Who gets chronic bronchial sepsis?
Younger females involved in child care or older with COPD
How is chronic bronchial sepsis treated?
Reactive antibiotics- send for a sputum culture and give antibiotics appropriate to the most recent positive culture.
Influenza and pneumococcal vaccines
If colinised, give prophylactic antibiotics (nebulised gentamycin or colomysin) or pulsed or alternating antibiotics
Low dose macrolife antibiotics have been shown to reduce exacerbation rates in bronchiectasis. True or flase?
True. Give a very low dose of clarithromycin od or azithromycin 3 times a week.
How is prognosis determined in bronchiectasis?
Bronchiectasis severity index
When is lung abscess development more common?
Aspiration pneumonia
What is lobar pneumonia?
Consolidation involving one complete lung lobe
What is bronchopneumonia?
Infection starting in airways and spreading to adjacent alveolar lung.
Patchy consolidation
What are the opportunistic pathagens in the imunocompramised host?
All these infection involve an MDT
Virus = Cytomegalovirus- CMV Bacteria = Mycobacterium avian intracellulare Fungi = aspergillus, candida, pneumocystis protozoa = cryptsporidia and toxoplasma
What is the difference between colonisation and infection?
Colonisation means the bacteria live in a particular area but they do not cause an infection necessarily
What host defences are found in the nasopharynx?
Nasal hairs, cilliaed epithilium and IgA which is found on the epithilial surface
What host defecnces are found in the oroparynx?
Saliva, coughing
What is sinisitis?
Infection of the paranasal sinuses
What is pharyngitis?
Infection of the pharynx, tonsils and uvula
What are the common colonisers of the nose and mouth? Gram negative and gram positive.
Gram positive 1) strep pneumoniae- alpha haemolytic 2) Streppyogens- Beta haemolytic 3) Staph aureus Gram negative 1) H. influenzae 2) Naraxella catarrhalis
What are the host defecnces in the conducting airways?
Mucocillary escalator
Cough
AMPs- complex matrix of proteins and cytokines
Cellular and humoral immunity
Which organism causes whooping cough?
Bordetella pertussis- gram neg cocobacillus
How long are people with whooping cough contagious for?
3 weeks
How is whooping cough diagnosed?
Pernasal swab: Cultured on charcoal blood agar PCR Serology Test will only be positive while the patient is infectious- during this time antibiotics can be given
What is the definition of a droplet and what PPE is needed for a droplet infection?
Particles greater than 5 microns that fall to ground within 2m
PPE = Face mask, apron, gloves. Ideally single room
What is the definition of an airborne infection and what PPE is needed for a droplet infection?
Particles less than 5 microns that travel long distances
PPE = Filter face piece 3, apron, gloves. Side room
What are the host defences in the lower respiratory tract?
This is normally a sterile area.
Alveolar lining fluid containing surfactant, immunoglobulins, complement, FFA and AMPs
ALveolar macrophages and neutrophils
What is the treatment for legionella?
Clarythromycin, Erythromycin, Quinolones (levofloxacin)
Does legionella have a cell wall?
No. Beta lactam antibiotics are not effective
What are the antibiotics to aviod to prevent C Diff?
Clindamycin, cepthalosporins, Co ammoxiclav, Ciprofloxacin
What is Legionella?
Environmental gram negative bacteria
Obligate intracellular organism- resides in aomebas
No person to person spread
Associated with forty air con and saunas
What is the rash associated with mycoplasma pneumoniae?
Irethima multi formae
Target rash
What is Q fever and how is it spread?
Coxiella Burnetii pneumonia
Infected sheep and goats- occupationally acquired
What causes pyrexia of unknown origin?
Coxiella Burnetii pneumonia
Q Fever
What is bronchiolitis and who does it commonly effect?
Viral infection of the bronchioles
Children aged 0-2
What are the symptoms of bronchiolitis?
Fever, cough, clod and wheeze
Severe = grunting, sternal indrawing, low PaO2
What are the complications of bronchiolitis?
respiratory of cardiac failure (esp if baby was premature or has pre existing respiratory or cardiac disease
What causes bronchiolitis and how is it diagnosed?
RSV- Respiratory Syncytial Virus (80%) Metapneumovirus
Nasal swab and PCR
How are lots of babies with bronchiolitis cared for?
Cohort nursing
Give an example of an STI causing infantile pneumonia and how its diagnosed?
Chlamydia trachomatis
PCR in urine of mother or nasal/throat swab of baby
What is MERS CoV and where is it prevalent?
Middle East Respiratory Syndrome Coronovirus
Saudia Arabia
What does Chlamydophilia pneumoniae cause
Mild respiratory infections, may be picked up on a test for psittacosis.
What are the current PCR tests in Tayside?
Influenza A Influenza B Parainfluenza 1-4 Coronavirus (4 species) causes the common cold Enterovirus Metapneumovirus Adenovirus RSV Rhinovirus Mycoplasma pneumonia
What is C diff?
Gram positive spore forming bacteria
