Microbiology Flashcards
What are the range of conditions associated with an upper respiratory tract infection?
Common cold - coryza
Sore throat - pharyngitis
Sinusitus
Epiglottis
What are the range of conditions associated with an lower respiratory tract infection?
Acute bronchitis Acute exacerbation of chronic bronchitis Penumonia Influenza Fungal infection
What viral diseases acn a throat swab test for?
Influenza A Influenza B RSV Metpneumovirus Rhinovirus Coronavirus Parainfleuza Adenovirus Enterovirus Parechovirus
What are some symptoms of coryza?
It is an acute viral infection of the nasal passages that is often accompanied bu a sore throat
It is sometimes accompanied by a mild fever and is spread by droplets and fomites. Complications can include sinusitus and acute bronchitis
What are symptoms of acute sinusitis?
Frontal headache
Retro-orbital pain
Maxillary sinus pain - build up of pus in the maxillary sinus before it can be drained
Tooth ache
Discharge
The lymphatic drainage in this area of the face is drained directly back to the brain
It is usually viral but can sometimes need antibiotics
What are the symptoms of strep throat?
Exudate
Pus
Dysphagia
Dysphonia
What are the symptoms of acute tonsilitis?
Erythematos - bright red palatine tonsils
Dysphagia
Dysphonia
Recurrent
What can be done to cure recurrent tonsilitis?
Tonsillectomy
What is a complication of tonsilitis?
Quinsy - tonsillar abscess which can be drained
What is diptheria?
A life threatening throat condition where the bacteria produce a toxic chemical that causes massive swelling in the back of the throat, asphyxiating the child/adult
What is acute epiglottis?
Life threatening condition that occurs due to obstruction
GOLDEN RULE - call for an anesthetist and give antibiotics - usually penicillin
What are some symptoms of acute bronchitis?
Productive cough Fever - minority of cases Normal chest examination Normal CXR May have a transient wheeze Not life threatening as the infection does not migrate but will cause thickening of the bronchi due to inflammation
What is the treatment on acute bronchitis?
Usually self-limiting and antibiotics are NOT indicated in normal people
Paracetamol and fluids
What are the incubation times of common upper respiratory tract infections?
Rhinovirus: 1-5 days Group A streptococci: 1-5 days Influenza and parainfluenza: 1-4 days RSV: 7 days Pertussis: 7-21 days Diptheria: 1-10 days Epstein-Barr virus: 4-6 week
What are the symptoms of an acute exacerbation of COPD?
Chronic sputum production, bronchoconstriction, inflammation of the airways Usually preceded by an URTI Increased sputum production Increased sputum purulence More wheezy Breathless Chest pains
What will be seen on examination of an acute exacerbation of COPD?
Respiratory distress Wheeze Coarse crackles Cyanosed In advanced disease- ankle oedema
How is an acute exacerbation of COPD managed in primary care?
Antibiotics - doxycyline or amoxicillin
Bronchodilator inhalors
Short course of steroids in some cases
When should you refer to secondary care?
If there is respiratory failure
They cannot cope at home with their disease
How is an acute exacerbation of COPD managed in secondary care?
Same as primary care with the addition of:
Arterial blood gases - to determine whether in type 2 resp failure
CXR to look for other diseases
Oxygen if in resp failure - but controlled if in type 2
What can the appearance of the lung tissue look like during pneumonia?
Can be cosolidated and look more red. This is called red hepatisation due to the resemblance to liver tissue rather than lung tissue
Histologically, what will the lung tissue look like?
The alveolar spaces are filled with inflammatory cells
What are the symptoms of pneumonia?
Malaise Anorexia Sweats Rigors Myalgia - muscle pain Arthralgia - joint pain Headache Confusion Cough Pleurisy Haemoptysis Dyspnoea Preceding URTI Abdo pain- this is due to the pneumonia sitting on top of the diaphragm irritating it Diarrhoea
What are the signs of pneumonia?
Fever Rigors Herpes labilais - cold sores Tachypnoea - high resp rate Crackles Rub Cyanosis Hypotension
How can penumonia be investiaged/diagnosed?
Blood culture Serology Arterial gases Full blood count Urea Liver function CXR
What is the CURB 65 severity score for community acquired pneumonia
C = new onset of confusion U = Urea >7 R = Respiratory rate >30/min B = Blood pressure systolic <90 or diastolic <61 65 = Aged 65 years or older Score 1 point for each above
What are other severity markers for pneumonia?
Temp <35 or >40
Cyanosis PaO2 <8 kPa
WBC <4 or >30
Multi-lobar involvement
What is the management of community acquired penumonia?
Antibiotics - amoxicillin or doxycycline Oxygen - maintain SaO2 94-98% or 88-92% Fluids Bed rest No smoking
What are special cases of pneumonia?
Hospital acquired - need extended gram negative cover
Aspiration pneumomnia - anaerboic cover
Legionella - chest symptoms minimal, GI disturbance common, confusion common
Why should you be cautious with the young?
They can compensate well for being unwell - the CURB can be fine but they are septic
C: Good cerebral vasculature - all the brain works
U: Good kidneys
R: Can increase Vt - increase tidal volume rather than resp rate
B: Inotropic, chronotropic, vascular responses - BP won’t fall
They will decompansate VERY quickly
How could you overtreat the old?
They could be at a CURB1 before they start:
C: Poor cerebral perfusion
U: Poor renal pefusion
R: Rely on resp rate rather than increasing tidal volume
B: Poor inotropic, chronotropic and vascular responses
When should you give IV a/b?
When the oral route is not available - NPO
Sensitivities - drug resistant organisms
Deep seated infections - abscesses, bone, endocarditis, meningitis
First dose - rapid increase in plasma conc
How can lifestyle affect the chance of contracting an URTI?
HIV PWID (people who inject drugs) - staph aureus Alcohol/homelessness - TB, klebsiella Frequently hospitalised - pseudomonas Returning traveller - leginoells, TB Indian sub-continent - TB Easten europre- MDR TB, XDRTB
What are complications of pneumonia?
Respiratory failure
Pleural effusion
Empyema
Death
How can pneumonia be prevented?
Influenza and penumococcal vacines in people:
Over 65, with chronic chest or cardiac disease, diabetes, immunocompromised - splenectomy
Infleunza virus - health care workers
What is empyema?
The collection of pus in a cavity in the body, especially in the pleural cavity
What are the upper respiratratory tract defecnces?
Nasopharynx: nasal hairs, ciliated epithelia, IgA
Oropharynx: Saliva, Sloughing, Cough
What are some common URT colonisers that are gram positive?
Alpha-haemolytic streptococci - strep pneumoniae
Beta-haemolytic streptococci - strep pyogenes
Staphylococcus aureus
What are some common URT colonisers that are gram negative?
Haemophilus influenzae
Moraxela cararrhalis
What are some conducting airway defences?
Mucociliary escalator Cough AMP's Cellular and humoral immunity Infections occur when there are changes: Trauma/intubation of airway Abnormalities of defence - ciliary escalator and others as occurs in CPD and CF Virulent pathogen/large inocolum
What are the clinical signs of acute bronchitis?
Infection and inflammation of the bronchi Productive cough \+/- wheeze \+/- fever Normal chest examination and CXR
What is the microbiology for acute bronchitis?
90% viral
Preceded by URT infection
Normal chest examination and CXR
Antibiotics not usually indicated
What are the clinical signs of a acute exacerbation of COPD?
Adults Productive cough or acute chest illness Breathlessness Wheezing Increased sputum purulence Often follow viral infection or fall in temp and increase in humidity
What is the microbiology of an acute exacerbation of COPD?
30% viral alone 50% bacterial Haemophilus influenzae Moraxella catarrhalis Streptococcus pneumoniae Gram-negative
What are the symptoms of whooping cough?
Acute trachea bronchitis
Cold like symptoms for 2 weeks
Repeated violent exhalations with severe inspiratory whoop, vomiting common
Residual cough for a month or more
What is the microbiology of petussis?
Bordetella pertussis
Gram negative coccobacillus
Exculsively human pathogen
Vaccine preventable
How is bordetella pertussis diagnosed?
Bacterial culture
Pernasal swab (<21 days)
Serology
Clinical signs and symptoms (low numbers of organisms by onset of paroxysmal cough)
Treatment with antibiotics <21 days cough
What are the 3 main routes of transmission?
Contact (touch)
Airbourne
Droplet
What are the characteristics of airbourne particles?
Small particles that are less than 5 microns in size
Airbourne
Limited indications - multi-drug resistant TB, some viruses, TRI undergoing aeresol
Require standard infection control precautions and a filtering face piece 3 (FFP3)
What are the characteristics of a droplet?
Larger particles, more than 5 microns in size and fall to the floor within 2m
Spread via direct contact of droplets with the mucous membranes
Droplet, then surface, then contact spread
Ideally in a single room, not in a ward
How is CF contracted?
It is an inherited disease that leads to abdonrmally viscous mucus, blocking many tubular structures including conducting airways and lungs
What are the clinical signs of CF?
Repeated chest infections and chronic colonisation
What is the microbiology of CF?
Inefficient clearance and build-up of mucus
Staph aureus, haemophilus influenzae, strep pneumoniae, pseudomonas aeruginosa, burkholderia cepacia and many others
What are the lung defences?
Normally sterile
No ciliary escalator, alveolar lining fluid which contains surfactant, Ig, complement, FFA, AMP
Alveolar macrophages and neutrophils
Phagocytosis leads to an inflammatory response
What are the signs of community acquired pneumonia?
Cough Increased sputum Chest pain Dyspnoea Fever CXR with infiltrates Acquired in the community
What is the pathology of community acquired pneumonia?
Organism reaches the lungs leads to immune activation and infiltration (systemic response) leads to fluid and cellular build up in alveoli which leads to impaired gas exchange
What is the microbiology of community acquired pneumonia?
Causative organisms: Streptococcus penumoniae 70% Atypicals/viruses 20% Hemophilus influenzae 5% Staphylococcus aureus 4% Other bacteria 1%
What are the risk factors to getting community acquired penumonia?
Increasing age
Immunocompromised
Smoking
How is community acquired pneumonia diagnosed?
Sputum culture - purulence
Viral PCR
What antibiotics is streptocococcus pneumoniae?
Amoxicillin, doxycycline and co-trimoxazole
What is a typical type of community acquired pneumonia?
Streptocococcus pneumoniae
What is a atypical type of community acquired pneumonia?
Mycoplasm pneumoniae, legionella pneumonia, chlamydophila pneumonia
What are the 4 types of pneumonia?
Typical vs atypical (community acquired)
Hospital associated pneumonia
Aspiration pneumonia
Pneumonia in the immunosupressed (Pneumocystis, TB)
What can be seen in the microbiology for legionella pneumonia?
Urinary antigen - pos Legioniella PCR - pos Culture - pos Routine culture - neg Viral PCR - neg
How is legionella pneumonia diagnosed?
Legionalle urinary antigen
Detects serogroup 1 only
Culture is slow on selective media
Paired serology rises in titres
What antibiotics are given to treat legionella pneumonia?
Clarythromycin, erythromycin, quinolones (levofloxacin)
What are the clinical signs on leginoella pneumonia?
Flu like illness which may progress to a severe pneumonia, with mental confusion, acute renal failure and GI symptoms
What is the epidemiology of legionella pneumonia?
No person-to -person spread
Transmitted by inhalation of contaminated water droplets
Exposure to contaminated aerosolised water and impaired immunity put you at risk for catching legionela pneumonia
What is staphylococcus pneumonia?
Post infleunza (strep pneumo still more common that staph post influenza Haematogenous spread of staphylococcus aureus (CV infections)
