Pathology Respiratory infection Flashcards
Lung infections are the outcome of which opposing factors?
microorganism pathogenicity; Primary, facultative, opportunistic
capacity to resist infection: state of host defence mechanisms, age of the patient
population at risk
NAme some Upper Respiratory Tract infections
coryza - common cold
sore throat syndrome
acute laryngotracheobronchitis (croup)
laryngitis
sinusitis
acute eppiglottitis
Explain acute epiglottitis
Haemophilus influenza (type b - hib)
Group a beta-haemolytic streptococci
(rarely caused by parainfluenza virus type 5 but other viruses also responsible)
signs of epiglottitis
red cherry like swollen epiglottis
child has breathing difficulties
List some lower respiratory tract infections
Bronchitis
Bronchiolitis
pneumonia - infection within parenchyma alveoli of the lung
What are the respiratory tract defence mechanisms
macrophage-mucociliary escalator system
general immune system - humoral and cellular immunity
- respiratory tract secretions (antimicrobial to an extent)
- upper respiratory tract acts as a filter (breathe through the nose for the larger matter) also uRT act humidifier to deliver warm humid air.
failure of any of these systems increases the risk of RTI
what does the macrophage-mucociliary escalator system involve
- alveolar macrophages
the mucociliary escalator itself
an intact and functioning cough reflex
What sort of environment is the normally lower respiratory tract
sterile
explain what alveolar macrophages do in the respiratory tract
travel around the large surface area eating (phagocytosis) foreign material and migrate the end product to the ciliated airways.
mucus conducts material out of the lung up ciliated areas on epithelium (like escalator) movement to back of throat
to top of the trachea and out
how is smaller material excreted out the respiratory system?
through the lymphatic system and out into the lymph nodes in the mediastinum.
What is required to keep the lower respiratory tract sterile?
intact ciliated respiratory epithelium
what is an important risk to note following a severe influenza infection
secondary bacterial infection
can cause morbidity and mortality during influenza pandemics
why is this secondary infection following influenza infection happening?
damage to the respiratory epithelium - failure of defence mechanisms = inhaled bacteria then cause secondary infection - very common scenario
explain bronchiolitis
cellular
lymphoid chronic inflammatory reaction
causes airway obstruction by inflammatory exudate - patient has small airways for short time while the cellular bronchitis is active
Explain the classifications of pneumonia
anatomical - radiology
aeitiological - (circumstance ) (useful)
microbiology (appropriate for treatment) what caused infection
list aetiological classifications for pneumonia
- community aquired pneumonia - hospital aquired (nosocomial) pneumonia - pneumonia in the immunocompromised -atypical pneumonia - aspiration pneumonia - recurrent pneumonia
What is an important thing to note for nosocmial pneumonia?
Hospital-acquired - this type of pneumonia are very often drug resistance
what is atypical pneumonia
pneumonia caused by rare organisms or viruses or sub bacterial particles e.g. mycoplasma
What is aspiration pneumonia
aspiration into the lungs of food material for a variety of reasons that has then caused the infection
patterns of pneumonia
- Bronchopneumonia - segmental - lobar
- hypostatic - aspiration - obstructive
- retention - endogenous - lipid
what is hypostatic pneumonia
the localisation of the infection or infectious process in the lower zones of both lung and relates to other diseases like cardiac failure or COPD where excess secretions or oedema accumulate in the lungs through gravity.
describe bronchopneumonia (with histology)
multifocal usually involves both lungs + more in lower zones
common in COPD - establish in small areas of bronchi + bronchioles and spills over into adjacent alveoli (see pus)
see neutrophils and polymorphs + inflammatory exudates relating to cause infection airspaces.
focal (cm-mm size areas of the lung)
spreads a little into centriacinar
confluent bronchopneumonia (severe)
spreads centriacinar focal patchy process - significant consolidation of lung - nut reaching the pleura
bronchopneumonia xray signs
patchy opaque nature of xray
xray signs lobar/segmental pneumonia
the infectious process involving the whole lobe or large chunk of one - or sometimes two lobes
pathological change when organism lands in the lung (completely solid section) white
outcome/complication of pneumonia
Outcome
- most resolve (if not why not?)
- *Complication**
- Pleurisy (pleural inflammation), Pleural effusion and empyema (pus in pleural space)
- Change of organisation -
A mass lesion, COP (cryptogenic organising pneumonia - BOOP) - Lung abscess - Bronchiectasis - Pneumonia is still potentially fatal
what is pleural effusion
Pleural effusion sometimes referred to as “water on the lungs,” is the build-up of excess fluid between the layers of the pleura outside the lungs. The pleura are thin membranes that line the lungs and the inside of the chest cavity and act to lubricate and facilitate breathing.
what is pleurisy
Pleurisy is a condition in which the pleura — two large, thin layers of tissue that separate your lungs from your chest wall — becomes inflamed. Also called pleuritis, pleurisy causes sharp chest pain (pleuritic pain) that worsens during breathing.
what is empyema?
Empyema / purulent pleuritis. It’s a condition in which pus gathers in the area between the lungs and the inner surface of the chest wall (pleural space)
what is bronchiectasis
pathological dilation of bronchi (inappropriate for position in bronchial tree) due to:
severe infective episode recurrent infections (many causes)
proximal bronchial obstruction
lung parenchymal destruction
What are the signs of bronchiacstatis
- 75% start in childhood
- Cough, abundant, purulent, fouls sputum
haemoptysis coughing of blood from lung (signs of chronic infection)
coarse crackles clubbing
investigating for bronchiactesis
thin section CT (previously bronchography)
treating bronchiectasis
postural drainage
antibiotics
surgery
what is a big risk of bronchiectasis poses
severe bronchial haemorrhage which can be fatal
Recurrent Lung infections - what can cause them?
- Localbronchial obstruction - Tumour/foreign body
- Local pulmonary damage -bronchiectasis
- Generalised lung disease - cystic fibrosis - COPD - Asthma
- Non-respiratory disease: Immunocompromised
HIV - other
Aspiration
what may cause aspiration pneumonia
- Vomiting - Oesophageal Lesion
- Obstetric Anaesthesia - Neuromuscular disorder
- Sedation
oesophageal disease (reflux)
opportunistic infections
increased chance of “ordinary” infections - sometimes ones not normally capable of causing infection: opportunistic pathogens
- usually in immunocompromised pm steroidal therapy, chemotherapy
- infection by organisms not normally capable of producing disease in patients with intact lung defences
- low-grade bacterial pathogens CMV
pneumocystis jirovecil
other fungi and yeasts
the upper respiratory tract and infections:
nose, larynx, pharynx, epiglottis,
nose - rhinitis
ear -otitis media
pharynx - pharyngitis
Larynx - laryngitix
epiglottis - eppiglotitis
respiratory
infections invasions?
virus - repelled?
bacteria 1 pneumococcus, Haemophilus, staph, Moraxella
bacteria 2 invasion pertussis, mycoplasma
what is the fine line between colonisation and infection
epithelium
what are the side effects of antibiotics (child URTI)
- diarrhoea
- oral thrush
- nappy thrush
- allergic reaction
- multi resistance
what percentage of admissions of all children to hospital are (child URTI AND LRTI)
roughly 1/3
(child URTI) facts
common
- fever; antibiotic or not? prodrome to serious illness?
(child URTI) hint for management
give it time.
look hydration and nutrition
antipyretic (paracetmol)
sugary fluids and time.
can review in future.
what is rhinitis
very common
winter months occurs often
self-limiting condition
prodrome to other illness: pneumonia, bronchiolitis, meningitis, septicaemia
review If not sure
normal duration symptoms 11-16 days
what is otitis
infection of ear
the bulging eardrum can pop and pus comes out
common - self-limiting - very red -a primary viral infection
- secondary infection with pneumococcus h’flu
spontaneous rupture of the ear drum
antibiotic treatment usually doesn’t help
3-7 days duration normal
treat otitis NICE
offer regular paracetamol or ibuprofen for pain
self-care
consider antibiotic
reassess if symptoms worsen or signs of more serious illness of condition
refer hospital if severe systemic infection or complication like mastoiditis
Mastoiditis is a serious infection in the mastoid process, (hard, the prominent bone just behind and under the ear). Ear infections that people fail to treat cause most cases of mastoiditis.
what is tonsilitis/pharyngitis (child URTI)
common infection
is it viral or bacterial?
take throat swab
treat with nothing or 10 pays penicillin Alternative first choices for penicillin allergy or intolerance are clarithromycin or erythromycin.
not amoxicillin - avoid if there is a possibility of glandular fever (Epstein Barr virus).
(CHILD URTI) - how to try differentiate bacterial or viral tonsillitis/pharyngitis
children who have strep throat often have scarlet fever - faint pink rash
classically pallor (an unhealthy pale appearance.) around the mouth and often not felt right/well for a week or two
(CHILD URTI) treat tonsilitis/pharyngitis
treat with nothing or 10 pays penicillin Alternative first choices for penicillin allergy or intolerance are clarithromycin or erythromycin.
not amoxicillin - avoid if there is a possibility of glandular fever (Epstein Barr virus).
normally lasts 2-3 days but can last over a week
(child URTI) croup/epiglottitis
croup (LTB) (larynx), windpipe (trachea) and bronchial tubes (bronchi). Human parainfluenza viruses
common
generally well
coryza (catarrhal inflammation of the mucous membrane in the nose, caused especially by a cold or by hay fever)
stridor, hoarse voice “bark” cough
treat oral dexamethasone
(child URTI) croup/epiglottitis
Haemophilus influenzae (H influenzae) type B
rare
toxic
symptoms: stridor, -drooling (partial obstruction oesophagus)
treatment - needs intubation and antibiotic.
usual duration 1 day.
(child LRTI) - conditions and what is LRT
trachea - bronchus -bronchioles - lungs - pleura
trachea - tracheitis; bronchus - bronchitis; bronchioles - bronchiolitis
lung - pneumonia; pleura - empyema
(child LRTI)
the typical definition of infection and when it is cleared
no infection in an otherwise sterile area
infection is the sterile area becomes occupied by an infective agent
infection is cleared when the agent is cleared and has left the area sterile again
two most common bacterial causes of infection (child URTI)
Haemophilus and pneumococcus
common bacterial causes of infection (child URTI)
bacterial; strep pneumonia, Haemophilus influenzae, Moraxella catarrhalis, mycoplasma pneumonia, chlamydia pneumonia
viral - RSV, parainfluenza 3, influenza A and B, adenovirus
principles of management (child LRTI)
- make a diagnsis
assess the patient
oxygenation, hydration, nutrition
treat or not treat?
what is tracheitis (child LRTI)
swollen tracheal wall narrowed tracheal lumen luminal debris
uncommon “croup which does not get better) LBT
fever, sick child staph or strep invasive infection
give augmentin Amoxicillin/clavulanic acid, also known as co-amoxiclav
(child LRTI) bronchitis signs
common ++ endobronchial infection loose rattly cough with URTI
post-tussive vomit (glut) chest free of crepitations or wheeze
Haemophilus / pneumococcus cause
mostly self-limiting
child very well + parent worried
(child LRTI) bronchitis mechanisms/causes
- disturbed mucociliary clearance (escalator cilia)
minor airway malacia (abnormal softening of biological tissue)
RSV/adenovirus
lack of social inhibition
- bacterial infection/ overgrowth is secondary
can last 7-10 days can be 25 days.
what is natural history/pattern of bacterial bronchitis (child LRTI)
follows from URTI (rhinovirus) can last up to 4 weeks
60=80% cases respond to antibiotics (sometimes significant side effects)
morbidity: 1st winter children at nursery high symptoms
2nd winter lapse and but better
3rd winter fine
** any winter it’s usually pneumococcus and Haemophilus cold**
what is the best approach with persistence with bacterial bronchitis (child LRTI)
make diagnosis
reassure parents/family
do not treat with antibiotic
nutrition +hydration
what is the bronchiolitis (child LRTI)
- LRTI of infants
affects 30-40% of all infants
- usually RSV virus, others include paraflu 3, HMPV
nasal stuffiness, tachypnoea, poor feeding
crackles +/- wheeze
what is should you consider with bronchiolitis symptoms regarding days inoculated?(child LRTI)
day 1-2 child is well day 3-5 child worsens day 5-7 child stabilising day 7> recovery
if a child on day 3 is not feeding and o2 low with poor hydration, you would admit to the hospital as you know they will get worse
if a child on day 5 you know the child is stabilising and likely to not get worse
normal duration about 12 days some more than 16 days
Respiratory syncytial virus (RSV)
what is the natural history/pattern of bronchiolitis (child LRTI)
under 12 months old (infants)
one-off infection (not recurrent)
treat with maximum observation + minimal intervention
typical investigation for a clinical diagnosis of w bronchiolitis (child LRTI)
nasopharyngeal aspirate NPA - to identify what the virus is (nurse in the same ward)
test spo2 (severity)
no routine need for a chest x-ray, blood or bacterial culture
what medications don’t benefit bronchiolitis (child LRTI)
- salbutamol
ipratropium bromide
adrenalin
steroid
antibiotic
nebulised hypertonic saline
(child LRTI) common symptoms
48 hour fever (>38.5); shortness of breath; cough; grunting
- wheeze makes bacterial cause unlikely
reduced or bronchial breath sounds
often caused by infective agents (virus + commensal bacteria/bacterium) (usually does no harm but if given opportunity then can)
Pneumonia (child LRTI) when to call it pneumonia
- word causes anxiety be careful
signs of pneumonia IF
-signs are focal i.e one whole area (left lower zone e.g)
you hear crepitations
they have a high fever
otherwise, call it a lower respiratory tract infection
(child LRTI) BTS guidelines for community-acquired pneumonia
investigate chest cray and inflammatory markers (not routine)
management
nothing if symptoms are mild (offer review if things get worse)
-Oral amoxicillin first line
oral macrolide second choice
only for Iv if vomiting
guideline for antibiotic prescribing in upper and lower RTI
bronchiolitis - not indicated (usually RSV, parainfluenza 1, adenovirus)
croup - not indicated (usually parainfluenza 3, also RSV, adenovirus)
acute lower respiratory tract infection - not often indicated - child <2 mild presentations rarely need and have pneumococcal vaccine however, first-line can be amoxicillin
otitis media - antibiotic not usually indicated - amoxicillin if under age 2 and signs of bilateral infection
pharyngitis/tonsillitis - not usually indicated - consider penicillin, not amoxicillin
what is pertussis
whooping cough
what helps avoid pertussis (child LRTI)
it’s common
vaccine reduces risk
vaccine reduces severity
symptoms - coughing fits - paroxysm of coughing convulsed
vomiting and colour change of skin
what is empyema (child LRTI)
- complication of pneumonia
extension of infection into pleural space
includes chest pain and feeling very unwell
- give antibiotics +/- drainage
- good prognosis in contract to adults
what part of the pleura causes pain in empyema (child LTRI)
The parietal pleura is sensitive to pressure, pain, and temperature. It produces a well localised pain, and is innervated by the phrenic and intercostal nerves.
treating (child LRTI) best treatment and what antibiotic
first sort out oxygenation, hydration and nutrition
antibiotic? which one?
tracheitis yes Augmentin
Bronchitis no
LRTI/pneumonia optional oral amoxicillin
bronchiolitis no
empyema yes iv antibiotics
(adult LRTI) conditions
- acute bronchitis - exacerbation of COPD -pneumonia
- empyema - Lung abscess - bronchiectasis
(adult LRTI) what is bronchitis
- inflammation of bronchi
- temporary <3 weeks
- cough and sputum
usually viral
requires supportive management
(adult LRTI)what is gp advice regarding acute bronchitis
- if cough severe or last longer than 3 weeks
high temp for more than 3 days (sign of flu or more serious e.g. pneumonia)
cough mucus with blood
have underlying heart or lung condition e.g. asthma, heart failure or emphysema
becoming more breathless
have repeated episodes of bronchitis
signs of COPD exacerbation (adult LRTI)
- change the colour of sputum -fevers - increased breathlessness - wheeze - cough
caused often by streptococcus pneumonia Haemophilus influenza Moraxella catarrhalis viral
treating COPD exacerbation (adult LRTI)
- steroids
antibiotics - amoxicillin doxycycline co-trimoxazole clarithromycin
+/- nebulisers
explain pneumonia (adult LRTI)
inflammation of lung parenchyma and consolidation - solidification due to cell exudate impairs gas exchange
1 in 20 bronchitis develop to pneumonia (due to damaged cilia unable to escalate products out of lung)
Risk factors: smoking; alcohol excess; extremes of age; pre-existing lung disease; chronic illness; immunocompromised; hospitalisation; IVDU; preceding viral illness
pneumonia signs and symptoms (adult LRTI)
symptoms: fever; rigours; myalgia muscle pain; cough + sputum; chest pain (pleuritic) increase inspiring; dyspnoea; haemoptysis
rusty brown sputum typical streptococcus pneumonia
signs: tachypnoea (>RR); tachycardia; reduced expansion chest; dull percussion; bronchial breathing; crepitations; a vocal resonance
community and hospital investigations for pneumonia (adult LRTI)
community - maybe none, chest x-ray if in doubt or not improving (rule out cancer)
Hospital - bloods (serum biochemistry, Full blood count, CRP, Blood cultures
Chest x-ray
sputum culture, viral throat swab legionella urinary antigen
what are differential diagnoses for pneumonia (adult LRTI)
- tuberculosis
- lung cancer
pulmonary embolism
pulmonary oedema
pulmonary vasculitis (Wegener’s granulomatosis)
pneumonia on chest-x-ray (adult LRTI)
right upper zone in pic - will see clear white exudate and consolidation
what viruses often cause pneumonia (adult LRTI)
streptococcus pneumonia
h. influenzae
viruses
less common - legionella, staph aureus, mozzarella catharsis, mycoplasma pneumonia, chlamydia pneumonia, chlamydia psittaci, Coxiella burnetti
clasiffication on pneumonia (adulte LRTI)
typical and atypical
- *Community-acquired**
- *typical** streptococcus pneumonia (gram neg) Haemophilus influenzae mycoplasma pneumonia
**atypical** (more systemic symptoms e.g. more dry cough less sputum) legionella pneumophilia (fresh water a/c), chlamydia pneumonia, chlamydia psittaci, Coxiella burnetti, Moraxella catarrhalis, viruses
clasiffication on pneumonia (adult LRTI)
nosociomial
nosocomial (>48 hours)
enterobacteria (aspiration); staphylcoccus aureus; pseudomonas aerigunosa; klebseilla pneumonia - chlostridia - anaerobes - TB
Which type of infecions can cause cavitation?
staphylcoccus aureus;
klebseilla pneumonia
TB
which type of infection shows a bright yellow foul smelling sputum? (adult LRTI)
pseudomonas aerigunosa;
pneumonia severity scoring what is it for?
to determine whether or not somebody can be treated in the community or needs to come into hospital
CURB65
What is the scoring for pneumonia severity scoring (adult LRTI)
c - confusion
u - blood urea >7mmol/l
R - respiratory rate >30 min
B - Systolic bp <90mmHg diastolic bp < 60mmHg
65 - age >65
A score of 0-1 low risk treat community: 2 - moderate risk - usually hospital treat: 3-5 high risk of death need for ITU
what should clinicians be wary of scoring pneumonia? (adult LRTI)
- young people they likely wont score on this but doesn’t mean they don’t have severe pneumonia. they tend to compensate physiologically until they get bad.
- hypoxic patients
- those with multilobular consolidation
treating pneumonia (adult LRTI)
severity antibiotic penicillin allergy duration
CURB 0-1 AMOXICILLIN Clarythromycin or doxycycline 5 days
CURB 2 amoxicillin
+clarythromycin Levofloaxin 5-7 days
(atypicals)
CURB 3-5 Co-amoxiclav Levofluoxacin or
+clarithromycin co-trimoxazole 7-10 days
(atypicals)
** consider route iv vs oral
apart from antibiotic, what other treatment should be considered for pneumonia (adult LRTI)
o2 therapy, fluids (iv or oral)
antipyretic (paracetamol), NSAIDS ibuprofen
intubation and ventilation
when Is Iv antibiotic more appropriate for patients with pneumonia (adult LRTI)
if they cannot swallow, if they are septic or have signs of sepsis (high temp, tachy)
if vomiting
circumstances of pneumonia (adult LRTI) influenza occurs from__
staphylococcus aureus secondary infection
circumstances of pneumonia (adult LRTI) aspiration pneumonia often happens due to __
treat with __
stroke, MS, myasthenia, sedation, oesophageal disease (struggling to swallow)
anaerobes are likey (anaerobes are organisms that do not require energy oxygen for metabolism)
treat with - Amoxicillin and metronidazole
circumstances of pneumonia (adult LRTI) pneumonia in immunocompromised
treat with __
haemoglobion malignancy, neutropenia, HIV
- fungis usually - aspargillus fumigatus, candida
viruses usually - CMV, HSV, VZV
pneumocystis jiroveci pneumonia treat cotrimoxazole
MRSA treat vancomycin
complications of pneumonia (adult LRTI)
- Sepsis - AKI (acute kidney injury) - Adults respiratory distress syndrome
- Parapneumonid effusion (fluid pleural space) - empyema - lung abscess
- disseminated infection (bacteremia which can cause sceptic emboli in other organs)
signs of these: swinging fever, sweats, persistently high WBC count/CRP, weight loss, failure to improve
- Parapneumonic effusion (fluid pleural space) how to diagnose (adult LRTI)
thoracic ultrasound +/- aspirate
- fluid parameter
simple ph >7.2
complicated <7.2
empyema pus/culture +ve
May need drain and prolonged antibiotic
surgery/intrapleural tPA + DNAse
Tissue plasminogen activator (tPA) is a protein involved in the breakdown of blood clots.
Diagnosing lung abscess (adult LRTI)
more likely with staph aureus pseudomonas, anaerobes
- purulent sputum, haemoptysis
- screen for TB
CT scan +/- bronchoscopy
prolonged antibiotic
what is normal recovery with pneumonia (adult LRTI)
recovery can take weeks
repeat chest x-ray 6 weeks if over 50 years old and smokers
recommend smoking cessation
recurrent pneumonia
? immunocompromised
underlying structural lung disease
?aspiration
Bronchiactases adult LRTI
would give recurrent LRTI
havin dilated distal bronchi - tend to produce sputum in thickened/inflames airways. = airway becomes narrow due to inflammation regardless of dilated airway
= obstructive change on spirometry.
chest x-ray of bronchiectasis (adult LRTI)
- wider bronchi than corresponding blood vessels
- signet ring sign - bronchi look like a ring
- tree bud change in the structure
causes of bronchiectasis (adult LRTI)
- idiopathic - Childhood infection - pertussis,/whooping cough - Ciliary dyskinesia - Hypogammaglobulinaemia - Cistic Fibrosis
- Allergic broncho-pulmonary aspergillosis (ABPA)
signs and symptoms of bronchiectasis (adult LRTI)
- Chronic productive cough - breathlessness - recurrent LRTI -Haemoptysis
- Finger clubbing -crepitations (coarse) - Wheeze - Obstructive spirometry
test and treatment for bronchiectasis (adult LRTI)
exacerbations: staph aureus ; h influenzae; pseudomonas aerigonsa
need: sputum, chest x-ray (including AAFB)
- seen by chest physio - mucolytics
- prolonged antibiotic course 10-14 days
vaccinations
consider prophylactic antibiotic
define endemic
a constant presence and/or prevalence of a disease/infectious agent in a population within a geographical area
e,g, chickenpox UK: malaria Malawi
define epidemic
increase, often sudden, in number of cases of a disease above what is normally expected in population in a certain area
outbreak definition
carries the same definition of. epidemic (sudden increase number of cases of a disease above normal ina population area(s)
but it often used for a more limited geographical area
Define pandemic
an epidemic that has spread over several countries or continents, usually effecting a large number of people
virology viruses alpha beta gamme and delta
alpha and beta (most common for infection humans) source mainly bats
gamma - mainly comes from birds
Delta - comes porcine so pigs
transmission factors for covid-19
Incubation period days - 1-14 days
median 5-55 days for symptoms
infectious peak 24 hours pre symptoms.
reproduction number - people acquiring infection from infected 2.2 - 3.3
1.4 Scotland
Pathophysiology of COVID-19
1 viral entry+early infection:
2 host immune response - immune cells early macrophages + dendritic - late phase cytotoxic cells
- hyperinflammatory phase infects t cells and macrophages = more cytokine release that is infected
4 multiple organ dysfunction - lungs reduce the capacity of airways alveoli reduced capacity spreads to other organs and poor o2 shut down need ventilation - death
common general symptoms of COVID-19
- rhinorrhoea (runny nose) -general malaise (unwell pale) - headache - sore throat - cough fever
respiratory symptoms of covid-19
covid can cause pneumonia and acute respiratory distress syndrome - lots of white patches
extra pulmonary symptoms of COVID-19
brain headache dizziness, confusion, epilepsy. ataxia,ansomia, ageusia: systemic inflammation _ cerebral edemam pulmonary hypoxia, matebolic acidosis
heart elevated cardiac troponin elevated nt-probnp, bnp: myocarditis - stress-induced cardiomyopathy
kidney elevated serum creatinine, increase urea, proteinuria: direct infection, systemic inflammation
blood - increased: prothrombin time, d-dimer, fibrinogen, aPTT: SARS COV 2 MEDIATED ENDOTHELIAL DYSFUNCTION systemic inflammation (e.g. cytokine, complement pathway)
body increased: ferritin, c reactive protein, esr + lymphopenia, fever: systemic inflammation
prevention for COVID-19
Handwashing
social distancing
mask wearing
isolation
vaccines
PPE
Isolation with COVID-19
if you are well to stay at home - 10 days
if unwell (e.g. admitted to hospital) 14 days
if very unwell and needed ITU or immunocompromised - 21 days
types of COVID-19 vaccines
pzifer/niontech moderna aztrazenca
vaccine type mRNA vaccine mRNA vaccine attenuated virus
efficacy 95% 94% 70%
Authorised dose doses 3 weeks 2 doses 4 weeks 2 doses 12 weeks
apart apart apart
treatment for COVID-19
anti-pyretic (paracetamol)
steroids
supportive therapy
clinical trials
02 therapy
6mg dexamethasone once a day for 10 days for anyone who needs o2 therapy.
o2 therapies for COVID-19
mild - nasal cannula 1-6L
moderate nasal cannula or simple facemask (sm) 5-10L
severe - simple facemask or reservoir mask 15L
very severe nasal high-flow o2 (up tp 70L) or Cpap (15L)
for airway maintenance - venturi mask suitable for resp type 2 failure 2-15L
non-invasive ventilation 0-15L
vulnerable groups for TB in UK
those from high prevalence countries
- 70% non-UK born most aged between 15 and 44
HIV positive or immunocompromised
elderly, neonates and diabetics
homeless, alcohol dependency, idvu, those with mental health problems and those in prisons approximately 1 in 10 cases
mycobacteria - what are they?
numerous species - ubiquitous in the soil and water
few species responsible for human disease
tuberculosis )m.tuberculosis, m africanum, m bovis (bovine tb is bcg strain)
non-tuberculosis - mycobacteria NTM infection/atypical mycobacteria
leprosy (m leprae)
non-motile bacillus, slow-growing (disease slow but treatment is long)
aerobic (predilection for apices or lungs)
uniquely thick fatty cell wall - resistant to acids, alkalis and detergents
resistant to neutrophil and macrophage destruction
not all AAFB are tb (aafb= alcohol and acid fast bacilli)
how does TB spread?
airborne (pulmonary and laryngeal tb)
someone with tb in lungs if they cough, sneeze, yell, sing
tb bacteria attaches to aerosol droplets
someone breathing these bacteria in through droplets - required prolonged close contact
outdoors - mycobacteria usually eliminated by UV radiation and dilution
not by shaking hands, sharing food, touching surfaces, sharing toothbrushes or kissing
exception to rule is mycobacterium bovis can be spread by consumption of unpasturised infected cows milk (uncommon in UK)
An endemic is a sudden increase in cases of a disease, above what would normally be expected in a given population.
Select one:
True
False
False – this describes an epidemic. An endemic disease is maintained at a consistent and predictable level in a given population, for example chickenpox in the UK.
Influenza can lead to secondary bacterial infection by impairing the body’s ability to make antibodies.
Select one:
True
False
False – secondary bacterial infection after flu is usually due to damage to the mucociliary escalator, which results in bacteria and mucus accumulating in the lower respiratory tract.
Diarrhoea and vomiting are a feature of atypical pneumonia.
Select one:
True
False
True – pneumonia caused by atypical organisms classically presents slightly differently to typical pneumonia. Features include diarrhoea and vomiting, headache, myalgia (muscle ache) and dry cough.
Lung consolidation results in a decrease in vocal resonance on examination.
Select one:
True
False
False – vocal resonance is used as part of clinical examination to detect areas of consolidation in the lung. Consolidated lung transmits sound more effectively than aerated lung, so the voice of the patient is heard more clearly over abnormal lung, i.e. vocal resonance is increased.
A patient with hypoxia due to pneumonia will have a CURB 65 score of at least 2.
Select one:
True
False
False – not necessarily. CURB 65 does not account for hypoxia, and young patients with a good capacity to compensate physiologically may not have a high respiratory rate or low blood pressure until they are very unwell. Hypoxia is an important feature indicating severe illness regardless of CURB 65 score
People with neuromuscular disorders are at higher risk of opportunistic infections.
Select one:
True
False
False – opportunistic infections generally occur in people with severely compromised immune systems, for example from untreated HIV. However, people with some neuromuscular disorders are at higher risk of aspiration pneumonia, through impaired swallowing mechanism.
Croup is treated with oral steroid.
Select one:
True
False
True – Croup – or laryngotracheobronchitis – is a common childhood illness, most commonly caused by the Parainfluenza I virus. It causes a barking cough and stridor (sound caused by upper airway obstruction). Treatment, when required, is with dexamethasone (a steroid) to reduce inflammation.
Recurrent lung infection is always concerning.
Select one:
True
False
True – if a person is recurrently developing lung infections, this indicates that one or more parts of their body’s defence mechanism are not working. Examples include diseases such as COPD, cystic fibrosis, or bronchiectasis; localized obstruction such as a tumour or a foreign body; or immunocompromise due to HIV or medications.
A 72 year old with pneumonia who is alert, has a respiratory rate of 26, a blood pressure of 100/80mmHg and a blood urea of 4.5mmol/L has a CURB 65 score of 3.
Select one:
True
False
False – this patient would have a CURB 65 score of 1, for their age. Remember:
C = confusion
U = blood urea >7mmol/L
R = respiratory rate over 30
B = systolic BP <90mmHg, diastolic BP <60
and 65 = age over 65.
Each component scores 1 point. Patients with a CURB 65 score over 3 have a significant risk of death and require critical care input.
Bacterial lower respiratory tract infections in children always requires antibiotics.
Select one:
True
False
False – if the child is eating and drinking well, and their oxygen levels are normal, it is reasonable to keep a close eye on them and do nothing.
Patients being treated for TB with ethambutol should have their vision monitored as it can cause optic neuritis.
Select one:
True
False
True – this is a recognized side effect of ethambutol, so patients will routinely have their vision monitored during treatment.
Amoxicillin will treat pneumonia caused by most typical and atypical organisms.
Select one:
True
False
False – Amoxicillin does not have much activity against atypical organisms. When pneumonia is severe or atypical infection is suspected, treatment should include a macrolide antibiotic like clarithromycin, or an alternative like doxycycline, levofloxacin or co-trimoxazole.
A positive AAFB smear is diagnostic of pulmonary TB.
Select one:
True
False
False – while pulmonary TB will often give a positive Acid Alcohol Fast Bacilli smear, not all positive AAFB smears are TB, and a negative AAFB smear does not rule out TB.
how TB bacteria ends up in alveoli
1 activates macrophages recognising TB - ingests bacteria - t helper cells activated and come from lymph nodes secreting cytokines - develop into epithelioid cells and Langhans giant cells
2 create granulomas for the immune system to fend off infection
3 causes ventral necrosis which may later calcify
history of TB primary infection stage
- no preceding exposure or immunity
- mycobacteria spread via lymphatics to draining hilar lymph nodes
usually, no symptoms can have fever malaise (generally unwell pale) erythema nodosum (Erythema nodosum is swollen fat under the skin causing bumps and patches that look red or darker than surrounding skin.) rarely chest signs
for the majority, 85% of initial lesion +local lymph node (primary complex) health without scar may calcify
associated with the development of immunity to tubercoloprotein
primary infection 3 outcomes usually
progressive disease
contained latent (in granulomas contained)
cleared/cured
what happens when primary TB infection progresses
Tuberculosis bronchopneumonia
- primary focus continues to enlarge (cavitation) - enlarge hilar lymph compress bronchi, lobar collapse, enlarge lymph node discharges into bronchus = poor prognosis
what is miliary TB
(look like millet seeds on autopsy) develops with hematogenous spread of bacteria to multiple organs
fine mottling on x-ray widespread granulomata
CNS TB in 10-30%
Post primary disease TB
only in humans. most animals succumb to primary TB and never develops to post-primary TB
two hypothesis
- tb bacteria entering a dormant stage with low or no replication over long periods of time
- balances state of replication and destruction by immune mechanisms
clinical presentation of TB
- cough
- fever
- sweats (mainly at night)
- weight loss
crp normal in 15% esr normal in 21%
Diagnosing active TB xray post-primary
tb likes oxygen - apices
soft fluffy/nodular upper zone
cavitation 10-30%
lymphadenopathy rare
for assessing TB when would you consider a CT
if you have a normal chest x-ray but clinical suspicion
- military TB
cavitation and nother differential
lymphadenopathy, alternative diagnosis
How to diagnose active pulmonary TB in chest x-ray
Chest x-ray
mediastinal lymphadenopathy (mainly unilateral 15% bilateral)
pleural effusion
miliary (haematogenous spread 1-3%)
** if pt short history (few weeks) unwell and looks lobar pneumonia (usually pneumococcal cause) + large hilar lymph nodes think tb could be primary **
if a patient has short history (few weeks) of feeling unwell and xray looks like lobar pneumonia and xray shows large hilar lymph nodes what should you also consider?
if a patient has a short history (few weeks) of feeling unwell and xray looks like lobar pneumonia and xray shows large hilar lymph nodes think tb as it could could be primary TB
how to test for TB
get the bug - get 2 sputum samples 8-24 hour gap at least one early morning sample
- induced sputum - saline to encourage cough - bronchoscopy with BAL (bronchial alveolar lavage)
endobronchial ultrasound (EBUS) with biopsy
- lumbar puncture in CNS TB - urine in urogenital tb
aspirate/biopsy from tissue (lymph-node, bone, joint, brain, access
Mantoux or IGRA (interferon-gamma release assays) are NOT routinely used in diagnosing active TB (mainly dormant or latent TB)
medications used for TB
- isoniazid (h)
pryazinamide (z)
Riampicin (r)
ethambutol (e)
rules for treating TB
- multiple drug therapies essential - Therapy must continue for at least 6 months
- single-agent treatment leads to drug resistance organisms within 14 days
- TB therapy is a job for specialists only - legal requirement to notify all cases
- test for HIV, Hep b and Hep C also
Standard treatment regime for TB
4:2/2:4 = 4 drugs treat for 2 month / 2 drugs treat for 4 month = 6 months total
R/H/Z/E = Rafimpicin (R), Isoniazid (H), Pyrazinamide (Z), Ethambutol (E) 2 months
R/H = Rafimpicin (R), Isoniazid (H), 4 months
standard 70kg patient takes 12 tabs daily
give 2-9 month if monoresistance
12 months for cns tb, h monoresistance extensive disease
9-12 or 18-20 months for MDR, TT TB
what other treatments do we give for patients undergoing TB treatment?
risk of isoniazid induced retinopathy - add vitamin b6 to reduce risk
steroids (sometimes)
vitamin - D substitution?
what are the side effects of TB treatment?
rifampicin - orange ‘irn bru’ tears/urine/lenses. induces liver enzymes, prednisolone, anticonvulsants. all hormonal contraceptive ineffective, hepatitis
Isoniazid - hepatitis, peripheral neuropathy (pyridoxine b6)
pyrazinamide - hepatitis, gout
ethambutol - optic neuropathy (check visual activity)
+ all 4 drugs can cause rash
what is screening methods for latent TB criteria
screen - contact of people aged <65 (hepatotoxicity increased with age)
- new entrants from high endemic areas
pre-biologics (TNF alpha inhibitors) - are of outbreaks
asymptomatic with normal chest x-ray and examination and positive either Mantoux test or IGRA
what is latent TB
where the immune system controls the TB infection and bacteria are still viable in the body but don’t cause disease.
Treating latent TB
always rule out active TB
- rifampicin + isoniazid for 3 months or isoniazid only for 6 month
- *or_ Rifampicin only for 6 months _or** rifapentine and isoniazid once weekly for 12 weeks (underserved population)
Rusty brown sputum is a symptom of Staphylococcal pneumonia.
Select one:
True
False
False – rusty brown sputum is classically seen with pneumonia caused by Streptococcus pneumonia.
A pneumonia is labelled “hospital-acquired” if it occurs at least 24 hours after admission to hospital.
Select one:
True
False
False - the cut-off is at least 48 hours after admission to hospital.
TB can be spread by physical contact, e.g. shaking hands or kissing.
Select one:
True
False
False – TB is an airborne pathogen, and is not spread by physical contact.
Coxiella burnetti pneumonia is classically associated with exposure to birds.
Select one:
True
False
False – C. burnetti is classically associated with exposure to farm animals. Bird owners are classically prone to pneumonia from Chlamydia psittaci.
Nasal high flow oxygen can deliver oxygen at 1-6L/min.
Select one:
True
False
False – high flow nasal oxygen can be delivered up to 70L/min! The oxygen is warmed and humidified, otherwise this would be prohibitively drying and uncomfortable. It is important to be aware that this is classed as an aerosol-generating procedure.
Most patients with TB will present during their primary infection.
Select one:
True
False
False – the primary infection (i.e. the point at which the person becomes infected; the first exposure to TB) is often asymptomatic, and in the majority of people it will either be cleared completely or contained within a granuloma as latent TB. Most symptomatic presentations of TB result as a reactivation of latent TB.
Acute epiglottitis is dangerous and can be fatal.
Select one:
True
False
True –Most upper respiratory tract infections are self-limiting. However, rarely, the epiglottis can become inflamed from a bacterial infection (such as Haemophilus influenzae) and this can lead to airway obstruction and even death. This used to be more common in children than it is now, but fortunately incidence is falling due to the Hib vaccine.
Bronchiolitis is usually a bacterial infection.
Select one:
True
False
False – it is usually caused by a respiratory syncytiovirus, and is most common in babies.
Latent TB does not require any treatment.
Select one:
True
False
False – latent TB (positive Mantoux or IGRA test in a person who has had contact with TB, but is asymptomatic and has a normal CXR) is treated to reduce the chance of developing active TB. The same antibiotics are used, for a slightly shorter course, usually 3 to 6 months.
Influenza can lead to secondary bacterial infection by impairing the body’s ability to make antibodies.
Select one:
True
False
False – secondary bacterial infection after flu is usually due to damage to the mucociliary escalator, which results in bacteria and mucus accumulating in the lower respiratory tract.
Pseudomonas aeruginosa pneumonia is typically associated with cystic fibrosis.
Select one:
True
False
True – pseudomonas infection is typically seen in cystic fibrosis and other bronchiectatic disease. It causes copious, green, foul-smelling sputum.
A reservoir mask can provide oxygen up to 15L/min.
Select one:
True
False
True – a reservoir or “non-rebreathe” mask uses a bag to create a reservoir of oxygen and increase the concentration of oxygen being delivered to around 60-90%.
Miliary TB is a rare complication of primary TB infection.
Select one:
True
False
True – this involves the wide dissemination through the bloodstream of TB granulomata, and commonly involves spread to the brain and meninges.
Staphylococcus aureus pneumonia is associated with intravenous drug abuse.
Select one:
True
False
True – Intravenous drug users are at higher risk of S. aureus bacteraemia (as S. aureus is a common skin commensal) and S. aureus pneumonia. It is also classically seen following influenza infection.
The respiratory tract is protected from infection by free-moving lymphocytes which clear pathogens and debris by phagocytosis.
Select one:
True
False
False – the key cells in the respiratory system’s innate defence mechanism are macrophages. They participate in the macrophage-mucociliary escalator, and clear debris from the lungs by phagocytosis.
