Respiratory Flashcards
What is type 1 respiratory failure?
Hypoxic on room air PaO2 < 8kPa and normal or low PaCO2. Ventilation profusion mismatch
What is type 2 respiratory failure?
Hypoxic on room air PaO2 < 8kPa and raised CO2 >6kPa. ventilatory failure
What are some causes of respiratory failure?
Acute asthma, exacerbation of COPD, PE, pneumonia, Pulmonary oedema, opiate or benzodiazepines overdose, guillian barre syndrome
What might you give in opiate overdose?
Naloxone 400mcg IV bolus ± IV Flumazenil 200mcg over 15s
What is a genetic cause of COPD?
Alpha 1 antitrypsin deficiency
A seriene protease inhibitor
Panacinar emphysema
What is Chronic Bronchitis?
Production of sputum for most days for at least 3 months in at least 2 years. Productive cough and lots of mucus. Elevated Hb (polycythaemia)
What type of respiratory failure happens in chronic bronchitis?
Type 2 - Low respiratory drive
hypoxic and hypercapnia. Loss of central sensitivity to CO2 and so reliant on hypoxia to stimulate breathing. aim for 88-92%
What is Emphysema?
Abnormal, permanent enlargement of the airspaces distal to the terminal bronchioles. Elasticity reduced and alveoli collapse - Air trapping
What type of respiratory failure occurs in emphysema?
Type 1 - hight respiratory drive
Hypoxia due to air trapping and hyperinflation of the chest - inefficient gas exchange.
Desaturate on exercise
What is panacinar emphysema?
Uniform enlargement from the level of the terminal bronchiole distally
What might be seen on spirometry in COPD?
Obstructive pattern
FEV1/FVC < 70%
What is first line in COPD management?
SABA - Salbutamol or
SAMA - Ipratropium
What other treatment would you give a COPD patient on SAMA or SABA who is still symptomatic?
Add LABA or
Stop SAMA and add LAMA
If further exacerbations - ICS - prednisolone or budesonide.
If further exacerbations consider -
Oral Theophylline, Roflumilast, azithromycin, Carbocisteine.
What is COPD?
Airflow obstruction that is usually progressive and not usually reversible, it does not change markedly over several months
What are some symptoms of an exacerbation of COPD?
Increasing cough, breathlessness, impaired consciousness, wheeze, decreased exercise capacity
What is the criteria for hospital admission in an exacerbation of COPD?
Marked increase in symptoms
New physical symptoms (cyanosis, peripheral oedema)
Significant co-morbidities
Not responding to initial management at home
> 70
Inadequate home support
In a COPD exacerbation, if there is no response to NIV or mechanical ventilation, what can you use?
Respiratory stimulant - Doxapram IV 1.5-4mg
How would you treat an acute exacerbation of COPD?
- Nebulised bronchodilators (Salbutamol 5mg/4h or ipratropium bromide 500mcg/6h)
- Controlled oxygen therapy - aim for 88-92%
- Steroids - IV hydrocortisone 50-100mg or oral prednisolone 30mg
- Antibiotics - amoxicillin 500mg/8h or clarithromycin 500mg or doxycycline 200mg
- Physiotherapy to aid sputum expectoration
IF NO RESPONSE - IV aminophylline
IF NO RESPONSE - a. NIV if RR > 30 pH < 7.35
b. Intubation and ventilation if paCO2 still rising with NIV pH <7.26 - Consider a respiratory stimulant - Doxapram 1.5-4mg
also may need to give enoxaparin 40mg
What is asthma
Inflammation of the airways characterised by intermittent airflow obstruction, hyper-responsive airways and reversible airflow obstruction
How do you define reversible airflow obstruction.
An improvement in FEV1 of >/=15% or 400ml after 5mg of nebulised salbutamol
Define a positive bronchial hypersensitivity test.
A fall in FEV1 by 20% after less than 8mg/ml of methacholine (or histamine or mannitol)
How does salbutamol/terbutaline work and what are potential SE?
Relaxes bronchial smooth muscle via increasing cAMP.
SE - tremor, hypokalaemia, hyperglycaemia, muscle cramps
What is the management options in asthma?
- SABA
- SABA + low dose ICS
- SABA + low dose ICS + LABA
- SABA + LABA + Medium dose ICS
- SABA + LABA + high dose ICS
How so SA and LA muscarinic antagonists work?
Works on M1 and M3
M1 counteracts bronchconstriction directly
M3 causes NO release - vasodilation
Nebulised risk of Acute angle closure glaucoma
What are methylxanthines MoA?
Relax bronchial smooth muscle, improve mucocillary clearance and have an anti-inflammatory effect
In an acute asthma attack 2g of magnesium sulphate may be given over 2 min. What is its MoA?
relaxes bronchial smooth muscle. Blocks histamine production from mast cells, reduces Ach production from nerve endings
SE. hypermagnesamia, muscle weakness, respiratory failure.
What monoclonal antibodies can be used as maintenance drugs in asthma?
Omalizumab - anti IgE - reduces circulating IgE. SC injection every 4 weeks
Mepolizumab - anti- IL5, reduces circulating eosinophils. SC injection every 4 weeks.
Given an example of the maintenance drug Leukotriene receptor antagonist and its MoA?
Montelukast and Zafirlukast
Reduces airway oedema and smooth muscle contraction
How would you manage life threatening asthma?
silent chest, low respiratory effort, PEF <33% predicted, sats <92%, altered consciousness, agitation/confusion
O SHIT ME
- High flow oxygen - aim >/=92%
- Nebulised salbutamol 500mg
- IV hydrocortisone 100mg or oral prednisolone 40mg
- Ipratropium bromide 500mcg
- Theophylline IV
- Magnesium sulphate 2g over 2 min
- Escalate care - intubation and ventilation
If chest infection suspected - Doxycycline 200mg Oral
What is brittle asthma?
A rare form of severe asthma that is hard to control due to being unstable or unpredictable.
Type 1: wide variation of PEF despite intense and regular therapy
Type2: sudden severe asthma attacks on a background of apparently well controlled asthma
What is near fatal asthma?
Raised PaCO2 ± the need for mechanical ventilation with raised inflation pressures.
What are some characteristics of severe asthma?
PaO2 <92% PEF 33-50% predicted Too breathless to talk or feed RR >30 HR >125 use of accessory muscle audible wheeze
What are some characteristic of life threatening asthma,s?
PaO2 <92%
PEF < 33% predicted
Silent chest, agitated, confused, cyanotic, poor respiratory effort, altered consciousness, exhaustion
What are some antibiotics that can be takes in a suspected chest infection in an asthmatic?
Amoxicillin 500mg/8h Orally or 1g/8h IV. Caution in renal problems as renal excreted.
Co-moxiclav 625mg/8h Orally or 1.2g/8h IV. Caution in Renal impairment as renal excreted
Clarithromycin 500mg /12h orally (IV causes phlebitis). Caution in hepatic impairment and renal impairment. Risk of adverse drug reactions - Can’t Give with methlyxanthines, cardiac caution (QT prolongation)
Doxycyline 200mg then 100mg orally - Caution in hepatic impairment. Avoid in children or pregnant women
What symptomatic triad may be present in acute severe asthma?
Wheeze
Increasingly breathless
Cough
What is obstructive sleep apnoea?
Recurrent episodes of complete or partial upper airway (pharyngeal) obstruction during sleep, with intermittent hypoxia and sleep fragmentation
Define apnoea.
Cessation or near cessation of airflow. 4% o2 desaturation lasting >/=10s
Define hypoapnoea
Reduction of airflow to a degree insufficient to meet the criteria for apnoea
What is Respiratory related arousal?
Arousals associated with a change in airflow that does not meet the criteria for apnoea or hypoapnoea
What is the apnoea hypo apnoea index.
Calculated by the number of apnoeas and hypo apnoeas divided by the total hours of sleep
>30 is severe
>/=15 is OSA
What fungus may cause fungal meningitis?
Crytococcus neoformans.
Inhaled opportunistic infection usually in people with HIV.
2 weeks of IV amphotericin B 250mcg/kg daily for meningitis
For non-CNS like lungs - Fluconazole 400mg daily PO/IV or Flucytosine 200mg/kg IV
What is allergic bronchopulmonary aspergillosis?
An allergic reaction to a fungal infection with aspergillum fumigatus.
Prednisolone 50-80mg PO 5 days
What is invasive pulmonary aspergillosis?
When the fungal infection becomes systemic and spreads throughout the body. In immunocompromised. IV amphotericin B 3mg/kg daily or voriconazole 200-400mg/12 hours for first 2 doses then 100-200mg/12h
What is an aspergillioma?
A fungal ball that develops in an area of past lung disease or scarring like an abscess. Do not treat unless bleeds - surgery
How would you treat pneumocystic pneumonia and what organism causes it?
Pneumocystic jivoreci
Co-trimoxazole 120mg/kg or if intolerant or contraindicated
Trimethroprim 5mg/kg/6-8h
How do the antifingals -azole work? E.g. fluconazole, voriconazole, ketoconazole
They inhibit the synthesis of ergosterol which is a component of the fungal plasma membrane
What are some possible signs of PE?
Breathlessness, syncope, pleuritic chest pain, haemoptysis
Hypotension, tachycardia, tachypnoea, raised JVP, reduced Ox sats
Define a massive PE?
PE associated with SBP < 90mmHg or there is a drop in SBP by >40mmHg from baseline for >15min that can’t be explained by another cause (hypovolaemia, new arrhythmia or sepsis)
How would you manage a massive confirmed heamodynamically unstable PE?
IV unfractioned heparin bolus (5000 units) then infusion 18Units/kg/hr until APTT 1.8-2.8 (in pts getting anticoagulant normal is 1.5-2.5)
O2, IV fluids, inotropic support?
Alteplase IV 10mg over 1-2min then 90mg over 2 hours
If persistent hypotension and CTPA confirms or echo shows RV dilation or dysfunction
What are some signs of pneumothorax?
Pleuritic chest pain Breathlessness, respiratory distress Hyper-resonant to percuss, reduced vocal resonance Ipislateral reduced air entry Treacheal deviation away if tension Reduced breath sounds
Describe the pathophysiology of a primary pneumothorax.
Subpleural bleb or bullae at the lung apex.
Spontaneous rupture causes a tear in the visceral pleura.
Air flows from airways into pleura space, increasing pressure in intrapleural space.
Elastic lung collapses
How would you manage a large (>2cm) primary sponaneous pneumothorax and (1-2cm) secondary?
Aspirate with a small bore cannula (16-18G) 2nd intercostal space midclavicular line
In a large 2ndary Pneumothorax, >2cm, that fails to respond to a chest drain, what would you do?
VATS - video assisted thoracic surgery if not resolves in 5 days
Talc pleurodesis
What are some physiological problems in tension pneumothorax?
Reduced venous return and so reduced CO and so BP fall –> Hypotensive, tachycardia, sweating, cyanotic, distressed, tachypnoea
Why does transudate occur?
these are causes of pleural effusion
Increased hydrostatic pressure or low plasma oncotic pressure
Nephrotic syndrome, congestive heart failure, hypothyroidism, cirrhosis, sarcoidosis
Why does Exudate occur?
causes are causes of pleural effusion
Inflammation and increased capillary permeability
Malignancy, pneumonia, TB, AI, pericarditis, pancreatitis, mets, viral infection
What type of lung cancer does smoking increase your risk of?
Squamous cell and Small cell (these are centrally located- arise in and around the hilum)
What is the most aggressive type of lung cancer?
Small cell - mets early and widely
From APUD neuroendocrine cells
Nuclear moulding, oval to spinal shaped cells, scant cytoplasm
What scoring system Is used in pneumonia?
CURB65 Confusion Urea > 7mmol/L RR >/=30 DBP = 60 or SBP =90 >/=65 years old
What antibiotic(s) would you give for a CURB65 score of 1?
PO 500mg/8hourly Amoxicillin 7 days
OR
200mg stat then 100mg daily PO Doxycycline 7 days
Or
500mg/12 hourly Clarithromycin 7 days
What antibiotic(s) would you give for a CURB65 score of 2?
Po 500mg/8h Amoxicillin AND
Either 200mg stat then 100mg doxycycline
Or 500mg/12h clarithromycin 7 days
if penicillin allergy
just clarithromycin 7 days
What antibiotic(s) would you give for a CURB65 score of 3+ plus sepsis?
IV or oral clarithromycin 500mg/12h
and either IV Amxocillin 1g/8h or
IV co-amoxiclav 1.2g/8h
if true penicillin allergy:
IV or oral Levofloxacin 500mg/12h 7-10d
14d if atypical
What is interstitial lung disease?
non-infective, non-malignant infiltrations of the lung parenchyma.
Cause restrictive lung disease with a reduced transfer factor
What is Sarcoidosis?
A multi-system granulomatous disorder of unknown cause, that predominantly affects the lungs and intrathoraic LN, characterised by non-necrotising granulomas.
Asteroid bodies on histology
What are some clinical signs of sarcoidosis?
Fever, anorexia, night sweats, uveites, conjunctivitis, organomegaly, restrictive cardiomyopathy, chest pain, dry cough, CN palsies, peripheral neuropathy, reduced exercise tolerance, weight loss, Diabetes insidious (cranial)
What is extrinsic allergic alveolitis or hypersensitivity pneumonitis?
Immune mediated (T cell) inflammatory reaction in the alveoli and respiratory bronchioles
What are the borders of the triangle of safety in a thoracocentesis?
Base of the axilla (top)
Lateral edge of pectorals major (anterior)
Lateral edge of latissimus dorsi (posterior)
5th intercostal space (inferior)
How can you tell the difference between collapse, consolidation and effusion on CXR?
Collapse - uniform soft tissue density and smaller affected lobe, tracheal pulled towards collapse
Effusion - uniform SFD, meniscus sign, trachea pushed
Consolidation - Non-uniform STD blotchy white, perihilar air bronchograms visible
What causes a cough?
Acute or chronic sinusitis, Post nasal drip
GORD, pharyngeal pouch, oesophageal dysmobility
Mediastinal mass, ACEi, Ipratropium, CNS disease leading to impaired swallowing/ aspiration
URTI/LRTI/TB, chronic bronchitis, OSA, ILD, foreign body, lung cancer, CF, Asthma COPD, HF, LA enlargement
What are causes of a chronic cough?
Allergic rhinitis, post-nasal drip, lung cancer, COPD, GORD, smoking, HF, ACEi
Acute - Rhinovirus, pneumonia, COVId, PE
What is central bronchiectasis and what are the signs seen on HR CT?
Dilated bronchi with thickened walls. Chronic productive cough due to recurrence –> scarring
Tram track sign and signet rings on CT
What are the fat soluble vitamins and their functions.
Vit A - Important in vision, reproduction, bone health and immune system
Vit D- bone strength and calcium absorption
Vit E - Immune function - an antioxidant
Vit K - role in blood clotting
What should be done before discharging a patient after a severe asthma attack?
Asthma review - optimise inhaled therapy and inhaler technique assessed
Stable on discharge medication for >24 hours
PEFR > 75% predicted
Short course of oral and inhaled corticosteroids
PEF meter and asthma action plan
What is pulmonary HTN?
Increased pressure and resistance of blood flow in the pulmonary arteries. Causes right heart strain, also causes back pressure of blood into the systemic venous system.
Pul arterial pressure >25mmHg at rest and > 30 with exercise of a systolic pulart >40mmHg at rest
Assess with right heart catheterisation
What are the 5 groups of causes of pulmonary hypertension?
Group 1: Primary pulmonary arterial hypertension or due to a connective tissue disease. (idiopathic, hereditary, drug to toxin induced, HIV, schistosomiasis, SLE)
Group 2: MOST COMMON - left heart failure due to MI or systemic HTN
Group 3: Chronic lung disease e.g. COPD, or hypoxia
Group 4: pulmonary vascular disease such as PE
Group 5: miscellaneous - sarcoidosis, haematological disorders, glycogen storage disorder.
What is cor pulmonale?
Right heart failure due to chronic pulmonary arterial hypertension. Causes:
Lung disorders: COPD, Pul fibrosis, bronchiectasis
Pul Vascular: sickle cell, PE, Pul vasculitis, ARDS
Neuro - Myasthenia gravis, MND, poliomyelitis
Skeletal - scoliosis, kyphosis
What are some causes of bronchiectasis and what are some organisms that cause it?
Obstruction - Tumour, foreign body
Post -Infection - TB, pneumonia, pertussis, allergic bronchopulmonary aspergillosis, measels
Impaired defence - Hypogammaglobulinaemia, CF, ciliary dysfunction
S.aureus, H.influenza, strep pneumonia, pseudomonas aeruginosa
What are some causes of Horners syndrome?
Brainstem stroke, pan coast tumour, demyelination diseases, inflammation of LN of neck
Describe the SNS supply that is interrupted in Horners.
1st order neurone, originated from posteriolateral hypothalamus and descends via brainstem to terminate in ciliospinal centre in C8-T2 2nd order (preganglionic), exits into paravertebral sympathetic chain, over the lung apex and terminates in superior cervical ganglia at ~C4 - Angle of mandible and bifurcation of common carotid 3rd (postganglioic) forms a plexus around internal carotid and then into cavernous sinus - eye. some follows external carotid for face supply
Define respiratory failure.
When gas exchange becomes significantly impaired. Diagnosed by a ABG
What are some causes of respiratory failure?
Breathing centre affected - stroke, drug overdose
Blood flow to lungs affected - PE
Weak breathing muscles - MG, GB, SC injury
Ventilation to lungs affected - COPD, asthma, CF
Failure of gas exchange - pneumonia, ARDS
What scoring tools can you use in PE?
Wells score, revised Geneva, D-dimer, PERC
How would you manage a suspected PE?
O2 therapy ± analgesia
LMWH until CTPA result
If confirms - switch to DOAC for 3 months
What drugs are used to reduce exacerbations in COPD and what are their MoA?
Roflumilast - inhibits hydrolysis of cAMP in inflam cells - Inc IC cAMP - reduces release of pro-inflam mediators and cytokines
Azithromycin - macrolide abx - inhibits pro-inflam AP-1, NFkappaB and mucin release
Carbocysteine - reduces sputum viscosity, facilitating mucocilary clearance
What is the classes in MRC dyspnoea scale?
1- mild
2,3 - moderate
4,5 - severe
1 - breathless only on strenuous exercise
2 - breathless when hurrying or walking up a slight hill
3 - Walks slower than others their age on level ground or has to stop for a breath when walking at own pace
4 - Stops for a breath after walking 100m
5 - too breathless to leave the house, breathless while dressing
An atypical bacteria causing pneumonia is called mycoplasma pneumonia, what are some Sx and complications of this?
Fever, breathless, pleuritic chest pain, cough
Malaise, headache, myalgia *
complications - arthritis, haemolytic anaemia (cold agglutinant) **, Gillian barre, erythema multiform
penicillin resistant
An atypical bacteria causing pneumonia is called legionella pneumonia, what are some Sx and a test of this?
fever, cough, pleuritic chest pain, breathlessness
myalgia, malaise, headache, deranged LFTs, hypoNa** due to SIADH
Neurological Sx
Got by inhaling contaminated water mist - so ask about if they have been exposed to water - hot tub?
Legionella urinary antigen test!!
penicillin resistent
Abx treatment in pneumonia?
CURB65 0-1 = ORAL Amox 500mg/8h or doxycycline 200mg then 100mg or clarithromycin 500mg/12h 7 days
2 = ORAL Amox + dox or clarith OR if penicillin allergy just clarithromycin 7 days
>/=3 or sepsis = clarithromycon 500mg/12 + either IV amoxicillin 1g/8 or co-amox 1.2g/8h OR if penicillin allergy levofloxacin 500mg/12h
7-10d if atypical 14d
What might a swinging pyrexia with pneumonia mean?
A cavitation lesion or collection of pus somewhere with and effusion- empyema?
What might cause pneumonia in an immunocompromised person?
Pneumocytic jivorecii
What classes a HAP over CAP?
Got with 48hr of admission or 5 days with leaving
What cause pneumonia in alcoholics?
Klebsiella as they aspirate
Red current sputum
What bacteria that causes pneumonia is associated with parrots?
Chalymdiophile Psittaci
