RESP Flashcards
D-dimer uses? When is it indicated?
Used to diagnose or exclude thrombotic clots
Indicated in CVT, PE, DIC (disseminated intravascular coagulation)
- can also be used to monitor the effectiveness of DIC tx
What can cause a false D-dimer?
If someone is on anticoagulant therapy
When would a D-Dimer be requested as a first line investigation?
DVT Wells Score less than 1
PE Wells Score less than 4
What are the 2 types of respiratory failure? How is it detected?
Type 1 RF = Hypoxic
Type 2 RF = Hypoxic and Hypercapnic
Blood gases are used to asses these levels of oxygen in the blood
When are capillary blood used?
Heel-pricks in babies
Indications for and ABG?
Drop in sats below 90% during sleep in a normal pt
deteriorating sats
increased breathlessness in a ot with stable hypoxaemia i.e. COPD
Indications for CXR?
Infection Major Trauma Acute chest pain Asthma/Bronchiolitis Acute/Chronic dyspnoea Haemoptysis Suspected mass, metastasis or lymphadenopathy
Indications for CT?
Evaulation of an abnormality detected on CXR
Evaulation of aortic disease (aneurysm/dissection or trauma)
Malignant disease - staging, detecting lymphadenopathy, assess suitability for biopsy
Evaluation of pleural disease (CTPA - suspected PE)
Respiratory Ix offered in Primary care?
PEFR, Spirometry, CXR, Blood tests
Main respiratory Ix in ED/2° care?
PEFR, Blood gases, D-Dimer, CXR, CTPAm VQ scan, viral swabs
What is spirometry and what is used for?
method allowing the assessment of lung function via the amount of air expelled after maximal inspiration
can help to differentiate between Obstructive and Restrictive Conditions
Normal Spirometry interpretation?
FEV 1 = >80%
FVC = >80%
FEV/FVC ratio >70%
Obstructive picture of spirometry?
Reduced FEV1 (<80% of predicted normal)
Reduced FVC (less than the FEV1 drop)
FEV1/FVC ratio <0.7
Restrictive picture of Spirometry?
Reduced FEV1 (<80%) Reduced FVC (<80%) Normal FEV1/FVC (>70%)
What is Bronchodilator reversibility and when is it used?
Patients asked to stop bronchodilator prior to therapy and then during the test the effect of the bronchodilator is observed
Baseline spirometry without use of inhaler - 400mcg of salbutamol administered and spirometry is repeated after 15mins
Interpretation of Bronchodilator reversibility?
Presence of reversibility - suggestive of asthma
Absence of reversibility - COPD
Partial reversibility - suggestive of coexisting conditions of asthma and COPD
What is Peak Flow?
mainly used in the diagnosis of asthma
- reduced PEFR in asthma
can also be used for the monitoring of asthma
What Ix are involved in TB?
- CXR (/CT)
- sputum smear - acid fast bacilli
- GOLD STD = Sputum culture
- NAATs
What does TB CXR usually show?
upper lobe focal infiltrates/caviating lesions
enlarged hilar lymphadenopathy
What does Acid-fast Bacilli tests involve?
- Pulmonary TB - 3 sputum samples of TB microscopy and culture (AAFB) - 8-24hr intervals
- microscopy of AFB
- stain used to visualise is the Ziehl-Nelson stain
What is the limitations of Acid fast bacilli test?
cannot distinguish between viable and dead bacterium - only used upon dx not monitoring of tx
Interpretation of sputum culture?
microscopy = granulomatous inflammation - characteristic caesating necrosis
what Ix are used in malaria?
giesma-stained blood film - microscopy of thick and thin smears
RDT - detect malaria parasite antigens - provides a qualitative result
What Ix is used in whooping cough?
PCR of Nasopharyngeal swab/aspirate
Anti-pertussis toxin IgG detected in serum or oral fluid
Screening involved in Cystic Fibrosis?
new-born screening test
meconium ileus (~2wks), failure to thrive, resp symptoms (14 wks)
Blood spot immunoreactive trypsinogen (IRT) conc
CFTR gene analysis
Other Ix in Cystic Fibrosis?
Sweat test
- pilocarpine soaked pad is placed onto arm - current passed through 5x for 5 mins
- skin washed & dried - then sweat collector is placed over stimualted area for 30mins
sweat chloride of >60mmol/L supports diagnosis of CH
>40 makes CF unlikely
What Ix are done in Alpha-1-antitrypsin deficiency?
How is A1AT diagnosed?
CXR
- findings include bullae at lung bases and emphysemtaous changes
DX
- serum a1-antitrypsin <18mmol/L
- Spirometry , BDR - obstructive picture
- imaging to determine extent of disease Pma
When can viral throat swabs be done?
used to identify cuasative organism in patients with a acute hx of …\
- fever
- headache
- cough
- sore throat
- myalgia
- corysal symptoms
Panel include = influenza, parainfluenza, adeno/corona/rhine/entero.metapneumovirus
mycoplasma pneumonia and RSV
Ix in Covid?
URT samples
- single throat swab
- throat and nose combined swab
- Nasopharyngeal aspirate
LRT
- sputum sample
- CXR?
What is asthma defined as?
- hx of wheeze, SOB, chest tightness, cough - vary with time & intensity
- variable expiratory air flow limitation
What Ix are done in Asthma
- Spriometry
- BDR
- FeNO
- Peak flow
Asthma Spirometry Interpretation
Error?
3 relaxed and 3 forced blows
Look for evidence of Obstruction - FEV, FVC, ratio all reduced
Errors include - early termination, slow start and extra breath
Asthma BDR test Interpretation?
evidence of obstruction
reversible in asthma
- improvement of >12% or 200mls
Asthma FeNO testing Interpretation?
consider asthma diagnosis in
adults >40ppb
children >35ppb
FeNO levels altered when…
may be higher in
- allergic rhinitis
- rhinovirus
- tall ppl & increased dietary nitrates
may be lower in
- children
- cigarette smokers
- administration oral/inhaled steroids
Peak Flow Asthma Interpretation?
BD for 2/52 - morning & evening - narrow at 4am and wide at 4pm
diurnal variability of >20% difference - 3 days in week for 2weeks
What is a bronchoscopy? When is it indicated?
bronchoscopy - test used to visualise the lungs/airways if seen on CT
suspected mass - allows diagnosis
treatment - can take a biopsy which allows histological evidence
What are sputum cultures used for? How are they taken?
To detect and identify the cause ofbacterialrespiratory tract infections;
to monitor the effectiveness of treatment
Excpectorated/induced samples coughed up
bronchoscopy - lavage
transtracheal/transoesophageal aspirates
Indications of sputum culture ?
abnormal CXR,
productive cough,
chest signs suggestive of LRTI e.g cough, fevers/rigors, SOB, myalgia, chest pain and confusion
Appearance if sputum?
Blood -?TB
Rusty - ?Pneumococcal
Purulent - ?green/yellow or milky opaque white
foamy - obstructive conditions or oedema
2WWR in Respiratory conditions
abnormal CXR findings, 40yrs+, unexplained haemotoptysis
CT confirm whether scan is needed -
Investigation in suspected aspiration pneumonia?
Bloods - FBC, CRP, U&Es, blood culture and gases
sputum culture
CXR - lung infiltrates or consolidation - usually in mid or lower lobes
if mechanical obstruction os present then bronchoscopy is used to remove it
Investigation in suspected Pneumonia?
CXR - classically consolidation is present (lower lobes)
Bloods - FBC, U&Es and CRP
ABG - if oxygen saturations are low or the patient gas a pre-exisiting respiratory disease
Scoring system used to Decipher whether Pneumonia is to be treated in community or hospital?
CURB65 Confusion of <8/10 on MMTS ureas above 7mmol/L resp rate above 30/min BP - sys <90 and dias <60 aged 65+
0 - community
1- assess sats and arrange CXR
2+ - hospital
Investigation in suspected acute bronchitis?
Usually a clinical diagnosis
CXRs are often normal
Investigation in suspected complicated Influenza?
Diagnosis confirmed by laboratory testing
- rapid testing done in all pts with complicated influenza
Investigation in suspected Croup?
vast majority are diagnosed clinically
CXR (PA) will show a steeple sign i.e. subglottic narrowing
Investigation in suspected RSV/bronchiolitis?
Immunofluorescence of nasopharyngeal secretuons
- may show RSV
Investigation in suspected Acute epiglottitis?
Diagnosis usually clinical. and often given by senior airway trained staff
XR may be done to rule out any FB once airway stable
CXR = ‘thumb sign’ on lateral view/plane
Investigation in suspected Pertusis/whooping cough?
nasal swab culture - PCR and serology
Investigation in suspected Emphyema?
Sputum culture
Blood test esp WCC and CRP
XR - collections of fluid around the lungs
Investigation in suspected Tuberculosis?
CXR - upper lobe caviations, pleural effusions, mediastinal or bilateral hilar lymphadenopathy
Sputum Culture = GOLD STANDARD
- NAATs
Sputum smear - 3 positive Acid fast bacilli positive specimens needed
what does screening for Tuberculosis involve?
Mantoux test
- intradermal injection
- results read 2-3days laters
- diameter of induration 6-15mm suggests a tuberculin protein sensitivity
Investigation in suspected Pulmonary fibrosis?
Spirometry
FEV1 = increased/normal
FEV1/FVC = increased
Reduced transfer factor/TLCO
Imaging CXR - bilateral interstitial shadowing
- ground glass appearance/honeycombing
high res CT = investigation of choice
Investigation in suspected in Sarcoidosis?
CXR
- earlier stages = bilateral hilar lymphadenopathy which can then lead to interstitial infiltrates
- very later stages = diffuse fibrosis
Investigation in suspected pneumoconiosis?
CXR = fibrosis o=in upper zones of lungs
Spirometry = restrictive picture
Investigation in suspected COPD?
spirometry - FEV/FVC <0.7
cosider alpha-1-antitrypsin deficiency
CXR
FBC - ?anaemia/polycythaemia
Investigation in suspected Asthma?
Spirometry
- FEV significantly reduced
- FVC normal,
- FEV1/FVC <70%
FeNO testing → 40ppb in 17yrs and older, 5-16yrs 35ppb
BDR → FEV1 improvement of 12% or more/ 200mL with SABA/ICS = positive
if imporvement is 4000mL = strongly suggestive of asthma
Peak flow → more than 20% varibalility - moniroting BD for 2-4weeks
Investigations in suspected Obstructive sleep Apneoa?
sleep studies (polysomnography) done at sleep clinic
→ monitoring of oximetry, EEG, resp airflow, snoring, throaco-abdo movement
Investigations in suspected Bronchiectasis?
clinical diagnosis mostly
Ix usually done to rule out other ddx - sputum culture, CXR, spirometry, O2 sats, FBC (wcc)
High-resolution CT - establishes the diagnosis of bronchiectasis
Investigations in suspected Cystic Fibrosis?
sweat test → CF abnormally high sweat chloride >60mEq
Investigations in suspected Pulmonary Hypertension?
ECHO - RV function assessment and estimate PAP
Right-heart catherization
CXR - exclude other lung diseases
ECG - RV hypertrophy and strain patterns
Investigations in suspected Pulmonary Embolism?
PE wells Scoring assessed
4+ = admit and urgent CTPA
<4 = D-dimer test - if raised to urgent CTPA
All patient have CXR - wedge shaped opacification
ECG changes = RBBB, S1Q3T3,
Leg USS = if initial CTPA is negative, if patient is pregnant
VQ scan = renal impairment
Investigations in suspected pleural effusions?
PA CXR should be done on all pts
US (pleural aspiration)
contrast CT - can help to investigate underlying cause
pleural fluid findings → low glucose, raised amylase and heavy blood staining
Investigations in suspected Pneumothorax?
CXR - darker areas chest X-ray indicating gas/no tissue
ABG - check extent of hypoxia
Investigation in suspected Pleurisy?
CXR - typically normal
Investigation in suspected Lung Cancer?
CXR ⇒ check for masses, areas of opacification
CT ⇒ investigation of choice
bronchoscopy ⇒ allows biopsy and thus histological diagnosis
Bloods ⇒ FBC → raised platelets
Investigations for suspected Mesothelioma?
CXR = pleural effusions or pleural thickening
Pleural CT
MC&S of any pleural effusion fluid
thoracoscopy
