Respiratory Flashcards
What is the difference between type 1 and 2 respiratory failure? Give an example of each
T1: Hypoxemic + normocapnic
[Failure to Oxygenate] (“One for Oygenate”) e.g. Altitude, fibrosis, asthma.
T2: Hypoxemic + Hypercapnic
[Failure to Ventilate] e.g. Neuromuscular disorder, COPD, Obesity, Opiates.
What is the treatment for acute T1 respiratory failure?
Increase FiO2 via Oxygen (100%)
Increase mean airway pressure via CPAP (keeps alveoli open and maximises SA)
What is the treatment for Type 2 respiratory failure?
BiPAP to increase respiration rate (greater ventilation).
2 = Bi
Where is the VQ ratio lowest?
Lung bases
Perfusion increases dramatically in the bases due to gravity.
Where are the lungs best ventilated?
The apex
(Perfusion is relatively low in the apex thereofre V/Q ratio remains pretty high)
NB: TB tends to grow in the apex due to high level of ventilation.
What are the lobes of the lungs?
Right: Superior/Middle/Inferior
Left: Superior/Inferior
What neurotransmitters are at the pre and post synapses of the sympathetic nerves and parasympathetic nerves?
Sympathetic: [Short pre / Long post]
Pre = Acetylcholine @ Nictoninic receptors
Post = Noradrenaline @ Beta-adrenergic receptors.
[Therefore: Beta-adrenergic agonist –> bronchodilation]
Parasympathetic: [Long pre / Short post]
Pre = Acetylcholine @ Nicotinic
Post = Acetylcholine @ Muscarinic receptors
[Therefore: Muscarinic antagonist –> Bronchodilation]
What effect does sympathetic innervation have on the lungs?
Bronchodilation
What effect does parasympathetic innervation have on the lungs?
Bronchoconstriction
What causes smooth muscles to relax in the lungs following sympathetic stimulation?
Raised CAMP
Protein Kinase A inhibits Myosin Light Chain Kinase –> relaxation.
What causes smooth muscles in the lungs to constrict following parasympathetic innervation?
Raised Phospholipase C enzyme –> Protein Kinase C (C for calcium!) –> rasied intracellular calcium –> raised Myosin Light Chain Kinase –> Smooth muscle contraction
What type of B-adrenergic receptors are found in the lungs?
B2
[B1 = Heart]
What type of muscarinic receptors are found in the lungs?
M3
[M1 salivary glands / M2 Heart]
What is asthma?
Reversible airway obstruction caused by bronchospasm
True or false, asthma is typically worse at night?
True
{It is not known why. Possibly due to airways cooling, or circadian hormonal changes]
What is the test to determine if asthma is eosinophilic?
FeNO test.
Nitric Oxide level check as eosinophils produce NO.
How do you test the reversibility of asthma? What level is diagnostic?
Peak flow before and after B2 agonist e.g. salbutamol.
12% improvement = diagnostic.
What is the treatment for an acute asthma attack?
Nebulised salbutamol (SABA) Ipratropium bromide (SAMA) Oxygen Hydrocortisone [+Aminophylline IV]
[NB: MgSO4 IV bolus is a potent bronchodilator and can be used in severe attacks]
Give an example of a SABA, SAMA, LABA, LAMA and preventer
SABA: Salbutamol LABA: Salmeterol SAMA: Ipratropium bromide LAMA: Tiotropium Preventer: Beclomethasone
Give a cause of lobar collapse
Mucus plugs
Foreign body
Tumour
What is atelectasis?
Collapse or closure of part of a lung/lobe.
Can be obstructvie e.g. tumour or mucus plug or non-obstructive e.g. due to air pressure or general anaesthesia.
What is the difference between pneumothorax and atelectasis?
Pneumothorax is a collapse of a whole lung. Drain this.
Atelectasis is a collapse of part of the lung. Don’t drain this.
What is poiseuille’s law?
Resistance in a tube is inversely proportional to the 4th power of the radius.
Doubling the radius decreases resistance 16 times.
Which type of cell makes up 90% of the SA of the lungs and is responsible for gas exchange?
Type 1 pneumocytes
Squamous epithelium
10% of the cells
What type of epithelium are Type 2 pneumocytes?
Cuboidal
90% of the cells but only around 10% of the surface area. Produce surfactant.
What does surfactant do in the lungs?
Decreases surface tension allowing lung expansion and contraction.
[Starts to be produced around 35 weeks gestation]
What enzyme catalyses the conversion of carbon dioxide + water to carbonic acid?
Carbonic Anhydrase
[Carbonic Acid Equation]
CO2 + H2O H2CO3 HCO3- + H+
What is the Henderson-Hasselbalch Equation?
pH (blood plasma) = 6.1 + Log[HCO3-]/[0.03 xpCO2]
[0.03 = solubility of CO2 in blood]
What is the normal pH range of blood?
7.35 - 7.45
How is the anion gap calculated? What does the anion gap indicate?
Positive cations (Na + K) - Negative anions (Cl + HCO3)
A large anion gap can indicate acidosis e.g. DKA as bicarbonate is used to compensate.
What happens to pH and Co2 in metabolic and respiratory acidosis/alkalosis?
saMe = Metabolic Reverse = Respiratory
In the oxygen dissociation curve, which direction does it move with higher pH and lower temperature?
Left = left on Hb
[Increased Hb affinity]
Right = Goes right into the tissues.
[Decreased affinity]
Therefore it shifts left
What is the diagnostic for obstructive and restrictiv lung disease?
Obstructive: FEV1:FVC ratio <70%
Restrictive: FEV1:FVC >80%
FVC reduced
What is the normal tidal volume?
500ml
What is the average total lung capacity?
5L
What is the residual volume?
The volume that remains in the lungs after VC (vital capacity) is breathed out.
What spirometry metric is used to stage COPD?
FEV1
1 = >80 2 = 50-80 3 = 30-50 4 = <30
What piece of patient information does the BODE index take into account when assessing patients with COPD?
Body mass
[This measure predicts how much the COPD will affect them]
Give two signs of chronic bronchitis and two signs of emphysema
Chronic Bronchitis: [Blue Bloater] - Cyanosis - Obesity - Peripheral oedema - Crackles/Wheeze
Emphysema: [Pink Puffer] - Pink skin - Cachetic appearance - Decreased breath sounds - Pursed lip breathing - Barrel chest
What is the normal number of ribs (anterior + posterior) you should see on CXR?
No more than 6 anterior and 10 posterior.
More than this suggests hyperinflation.
Give a common causes of community and hospital acquired pneumonia
Community: Strep pneumoniae Mycoplasma pneumoniae H influenzae Viral
Hospital: Staph aureus Pseudomonas aeruginosa Enterobacter Virus
What is the CURB65 score?
Indicates whether a patient with pneumonia requires hospital care
Confusion Urea >7mmol/L Resp Rate >30/min BP <90 /<60 Age 65+
0-1 = Low risk 2 = Probably admit 3 = Admit
True or false, Small Cell Lung Cancer [SCLC] is typically inoperable?
True
[Rare ~20% of lung cancers but much more aggressivethan than Non-small cell lung cancer]
Which is the most common type of lung cancer Small Cell or Non-Small Cell?
NSMLC = 80%
- Adenocarcinoma (40%)
- Squamous (30%)
- Large cell (10%)
What is the most common type of lung cancer among smokers?
Squamous cell (30% of all lung cancers)
[Adenocarcinoma is the most common generally and is the most common in non-smokers]
Where does lung cancer typically spread?
Typically via blood
In order…
Liver Adrenal glands Bones Brain Kidneys
Where would you find a pancoast tumour? What is it associated with?
Lung cancer (mostly NSCLC) Occurs in the apex of the lungs.
Can cause Pancoast syndrome when it impinges on the brachial plexus –> pain in the inner arm and shoulder swelling.
Give two complications of lung cancer
Horner’s Syndrome: Ptosis, Miosis, Anhydrosis.
Pancoast syndrome: Brachial plexus impingement with pain and swelling in the arm.
Hoarse voice: Impingement on the laryngeal nerve.
Hiccoughing/Breathing difficulty: Impingement on the phrenic nerve.
Paraneoplastic syndrome: Neurological or hormonal effects due to cancer.
What investigations would you do in a patient you suspect of having lung cancer?
CXR Chest CT Bronchoscopy CT guided biopsy PET (Staging) Spirometry LFT
If you suspect a patient as having a neuroendocrine tumour with carcinoid syndrome (paraneoplastic), what test would you do?
Urine test for 5-HIAA
Which part of the lung is most affected by mesothelioma?
Pleura
What investigations do you do for mesothelioma?
CXR
Thoracentesis + pleural biopsy
After the lungs, where does mesothelioma tend to spread?
To the pritoneum
Pleura –> lungs –> hilar lymph nodes –> peritoneum
Name two professions at risk of asbestosis
Engineers
Boiler makers
Construction workers
Give two signs of TB
Weight loss
Night sweats
Cough
Haemoptysis
True or false, the Interferon Gamma Release Assay (IGRA) and Tuberculin (Mantoux) test can differentiated between active and latent TB?
False. Neither can.
CXR is used to determine if active.
Which TB test is most specific?
Interferon Gamma Release Assay [IGRA] - Blood test.
[Better than Mantoux]
How many sputum samples must be taken to diagnose TB? What test is run on it?
At least 3 samples!
Acid Fast Bacilli
[Ziehl Neelsen stain]
What is the treatment regimen for active TB?
[RI-PE]
Rifampicin + Isoniazid [6M]
Pyrazinamide + Ethambutol [First 2M]
What is the treatment regimen for latent TB?
[RI]
Rifampicin + Isoniazid [3M]
True or false, TB patients should be in positive pressure room?
False. They should be in a negative pressure room.
Which TB drug causes red/orange urine?
Rifampicin
[Red pissin]
Which TB drug causes optic neuritis and colour blindness?
Ethambutol
[E for Eyes!]
Give a side effect of Isoniazid
Neuropathy
Constipation
True or false Pyrazinamide can cause anaemia?
True
What is bronchiectasis? Give a common cause
Irreversible dilation of the bronchial tree caused by a bronchial obstruction e.g. Cystic fibrosis or TB
What tests would you do for cystic fibrosis?
Sweat electrolyte test (1st line)
Sputum sample
CXR
Gene testing (CFTR)
Which ion is assessed in a sweat test for cystic fibrosis?
Chloride ion concentration
What is a mycetoma? What is the most common cause?
A fungus or bacterial ball in a pre-existing lung cavity.
Aspergillus is the most common cause. The cavity is often the result of a previous TB infection.
True or false, if you have had the BCG vaccination, this may cause the tuberculin skin test to read a false positive?
True
What are the 4 types of hypersensitivity reaction?
1) “Allergic” IgE mediated <1hr.
Anaphylaxis, drug allergy.
2) “Cytotoxic”. IgG/M hrs-days
Goodpastures, Haemolytic reaction.
3) “Immune Complex”. IgG/M + Complement activation.
SLE, Serum sickness, hypersensitivity pneumonitis (aka extrinsic allergic alveolitis)
4) “Delayed”. T-Cell mediated + cytokines e.g. contact dermatitis (nickel, latex etc).
[ACID]
True or false, Byssinosis is a hypersensitivity reaction?
False. It is just lung irritation cause by exposure to dust.
Extrinsic Allergic Alveolitis is what kind of hypersensitivity reaction?
Type 3 (Immune complex, IgM/G + complement activation).
It can progress in chronic form to Type 4 (delayed T cell mediated)
What would you see on CXR in a case of Extrinsic Allergic Alveolitis?
Honeycombing/Ground glass appearance.
Name a scoring tool for breathlessness
MRC Breathlessness Scale
Borg Scale
NYHA
WHO Functional Class
What inheritance pattern does cystic fibrosis follow?
Autosomal Recessive
What is the treatment for cystic fibrosis?
Nebulised saline
Antibiotics
PPI
Pancreatic enzyme replacement
What does a faecal elastase test assess?
Pancreatic insufficiency
(May be a sign of cystic fibrosis)
[Guthrie screening looks for CF too]
Which two organs are most affected by Alpha-1 antitrypsin deficiency?
Lungs and liver
Lack of A1AT results in increased protease enzyme activity. Made worse by smoking. Presents like COPD.
True or false, patients who smoke who have alpha 1 antitrypsin deficiency still have a normal life expectancy?
False.
Smoking reduces it.
Non-smokers it is normal.
What causes pneumoconiosis?
Dust exposure
True or false, amiodarone can cause pulmonary fibrosis?
True
Name two drugs used for smoking cessation.
Varenicline (Champix)
[Most effective] Only 18+
Not in pregnancy.
Bupropion (Zyban)
Not if history of seizures. Start while smoking.
Nicotine Replacement Therapy. Safe from 12 years old and in pregnancy.
True or false, Nicotine Replacement Therapy is safe during pregnancy?
True
What ECG changes do you observe in a PE?
S1Q3T3
S waves lead I
Q wave lead 3
T inverted lead 3
Sinus tachycardia is the most common sign!
What is the first line investigation for PE?
D-Dimer to rule out
If high then CTPA
VQ perfusion if allergic to contrast
What is it called when 3 or more ribs are broken in at least 2 places?
Flail chest
High risk of pneumothorax
In a tension pneumothorax does the trachea move away or towards it?
Pushed away
What is it called when there is air in the subcutaneous tissues surrounding the lungs?
Surgical emphysema
What is the first line treatment for pulmonary embolism?
LMWH or Fondaparinux
What is the test for legionella?
Urine antigen test
What is the treatment for legionella?
IV Abx + O2
Azithromicin (macrolides), Cephalosporins
What are the target O2 sats for a patient with type 2 respiratory failure?
88-92%
True or false, sarcoidosis is more common in women?
True
How is sarcoidosis diagnosed?
CXR
Chest CT
Bronchoscopy + biopsy
How is sarcoidosis treated?
NSAIDs/Paracetamol for flareup pain
Corticosteroids to reduce autoimmune response
What further test would you perform in a patient presenting with PCP?
Pneumocystis Pneumonia
HIV test
What is carbocysteine used for in the treatment of COPD?
Mucolytic
True or false, ACE is raised in 2/3rds of patients with sarcoidosis?
True
True or false, E-cigarettes are available on the NHS?
False
