High Yield Exam Cram Flashcards
Which muscles are used during inspiration?
External intercostals and diaphragm
Is expiration active or passive at rest?
Passive
Which muscles are used in forced expiration?
Internal intercostal and abdominal muscles
What is meant by ‘lung compliance’?
The lung’s ability to stretch and expand
What is an average tidal volume?
500ml
What is the average volume of ‘dead space’?
150ml
What is ‘dead space’?
Places in the respiratory system where gas exchange cannot happen (e.g. trachea, bronchi, bronchioles)
What does residual volume prevent?
Alveolar collapse
Does breathing air in cause an increase or a decrease in pressure inside the chest?
decrease
how is pulmonary ventilation calculated?
respiration rate x tidal volume
What is the definition of pulmonary ventilation?
total air movement into/out of the lungs
What is the definition of alveolar ventilation?
the volume of fresh air getting to alveoli and therefore available for gas exchange
How is alveolar ventilation calculated?
{Tidal volume-dead space volume] x respiratory rate
Where in the lung is alveolar ventilation rate at it’s greatest and worst- why?
is greatest at the base of the lung and worst at the apex bc compliance is lowest at apex and highest at base
What is compliance?
The lung’s ability to stretch out when you breathe in?
What is elasticity?
The lung’s ability to recoil when you breathe out
Name the two different alveolar cells and their role
Type 1 - Gas exchange
Type 2 - Surfactant production
What is the function of surfactant?
reduces surface tension and makes alveoli less likely to collapse
At what stage in gestation does surfactant production begin and by what stage of gestation is production of surfactant adequate?
Production begins - 25 weeks
Surfactant levels adequate - 36 weeks
What is the ideal V/Q ratio in the lungs and what does that number mean?
V/Q= 1
this means that ventilation and perfusion match
Where in the lung would you find a V/Q <1?
in the lung base
Where in the lung would you find a V/Q >1?
In the lung apex
What is meant by the term ‘shunt’?
Shunt = alveoli are perfused but under ventilated
What is meant by the term ‘alveolar dead space’?
Alveolar dead space = alveoli that are well ventilated but under perfused
What is theme given to the natural arrhythmia that keeps the V/Q as close to 1 as possible?
Respiratory sinus arrhythmia
Describe how gas moves across a pressure gradient
From high pressure to low pressure
How is CO2 carried around the body?
70% carried as carbonic acid (which can dissolve to form bicarbonate and H+ driven by carbonic anhydrase)
23% carried as carboamino compounds inside erythrocytes
7% remains dissolved in plasma
describe the chemoreceptors involved in breathing control (where are they and what do they detect?
Central medullary chemoreceptors = detect CO2 in CSF
Carotid and aortic chemoreceptors = detect O2 and pH in arterial blood
Which parts of the brain process the information from chemoreceptors and send out signals to maintain homeostasis?
Medulla and pons
Describe the physiology of hypoxic drive
PaCO2 is chronically elevated in chronic lung disease.
Central chemoreceptors get desensitised and the individual instead begins to rely on changes in PaO2 to stimulate ventilation
Which lung diseases exhibit an obstructive pattern on spirometry?
Problems with the airway and COPD
Which lung diseases exhibit a restrictive pattern on spirometry?
Problems with the lung itself, neuromuscular disorders and obesity
What happens to the FEV1/FVC in obstructive lung diseases?
reduces (FEV1 tends to reduce more than FVC so the ratio gets thrown off)
What happens to the FEV1/FVC in restrictive lung diseases?
normal (both FEV1 & FVC reduces the ratio stays equal)
what is the difference between type 1 and type 2 respiratory failure?
Type 1 = O2 reduced
Type 2 = O2 reduced + CO2 increased (retained)
The presence of CO2 makes blood __________ (acidotic/alkalotic)
ACIDOTIC
Name 5 conditions that make patients acidotic
CCAPS
COPD + Compensation due to renal issues
Asthma
Pulmonary oedema
Sedative drugs (e.g. benzos and opiates)
Name 6 things that make you alkalotic
CHAPPS
CNS (e.g. stroke, encephalitis)
High altitudes
Anxiety
PE + Pregnancy
Salicylate poisioning
What is myoglobin and what does it indicate?
Myoglobin stores O2 in cardiac and skeletal muscle. it indicates tissue damage
What type of hypersensitivity reaction does asthma fall into?
Type 1
which tests can be used to diagnose asthma?
Spirometry with bronchodilator reversibility
FEV/FVC<70%
FENO >40 (adult) >35 (children)
What is the stepwise order of inhalers in asthma?
SABA + LOW DOSE ICS + LTRA + LABA
What is the PEFR in moderate asthma?
PEFR 50-75%
What is the PEFR in life threatening asthma?
PERF <33%
Name the other features of life threatening asthma
O2 SATS <92%
silent chest
hypotension
cyanosis
exhaustion
confusion
low CO2
What finding indicates near fatal asthma?
Raised or normal CO2
How should asthma be managed?
O2
Steroids (hydrocortisone), salbutamol
Ipatropium bromide
Magnesium sulphate aminophylline
ITU
What is the most common cause of bronchiectasis?
H. Influenzae
What is the gold standard test for diagnosing bronchiectasis?
High resolution CT
What CT sign indicates bronchiectasis?
Signet ring sign
What two conditions make up COPD?
Bronchitis and emphysema
Does COPD cause clubbing?
NO
How can the severity of COPD be graded?
MRCP breathlessness scale
Describe the MRCP breathlessness scale
Grade 1: Breathless on strenuous exercise
Grade 2: Breathless on walking uphill
Grade 3: Breathlessness that slows walking on the flat
Grade 4: Breathlessness stops them from walking more than 100 meters on the flat
Grade 5: Unable to leave the house due to breathlessness
State the FEV1 (%) in COPD stage 1-4
Stage 1 (mild)- >80%
Stage 2- (moderate)- 50-79%
Stage 3- (severe)- 30-49%
Stage 4-(very severe)-<30%
What treatments should be given to manage an acute exacerbation of COPD
O2
Nebulised salbutamol & ipratropium
Hydrocortisone
ABX if indicated
Ventilation if indicated
What are the indications for NIV in COPD?
< 7.35 or RR>30
What are the indications for invasive ventilation in COPD?
pH < 7.25
What are the chronic management options in COPD?
SABA/SAMA
then
LABA +ICS if asthatic features OR LABA + LAMA if no asthmatic features
What are the indications of LTOT?
if PaO2 <7.3 KPa on 2 readings more than 3 weeks apart.
if PaO2 7.3 - 8 KPa with nocturnal hypoxia, polycythaemia, peripheral oedema, pulmonary hypertension.
What is the inheritance pattern in cystic fibrosis?
Autosomal recessive
On which chromosomes the mutated gene in cystic fibrosis?
Chromosome 7
What molecular structure is affected in cystic fibrosis sufferers?
transmembrane cAMP-activated chloride channel.
What is the most common type of lung cancer?
Adenocarcinoma
What are the 3 most common types of lung cancer?
Adenocarcinoma (60%)
Squamous cell (20%)
Small cell (20%)
Which type of lung cancer is seen more commonly in non-smokers?
Adenocarcinoma
What are the additional features seen in adenocarcinoma?
Gynaecomastia and HPOA
What are the additional features seen in squamous cell carcinoma?
PTHRP, Ectopic TSH, HPOA, Clubbing
What are the additional features seen in small cell carcinoma?
Labert Eaton, SIADH, ectopic ADH release
Which type of lung cancer carries the worst prognosis?
Small cell lung cancer
What is the first line treatment for lung cancer?
Lobectomy
When is lobectomy contraindicated?
stage 3/4
FEV1<1.5L
SVCO
pleural effusion
tumor near hilum
vocal cord affected
What is the second line treatment in lung cancer if lobectomy is not possible?
Curative radiotherapy
What is the treatment in metastatic small cell lung cancer?
Palliative chemotherapy
What is the most common cause of pulmonary fibrosis?
Idiopathic
What are the names of the 2 medications licences to slow the progression of idiopathic pulmonary fibrosis?
Pirfenidone and nintedanib
What sign on CT is indicative of pulmonary fibrosis?
Ground glass appearance
Name the causes upper and lower zone pulmonary fibrosis
Upper zone: CHARTS
- Coal worker’s pneumoconiosis
- Histiocytosis/
hypersensitivity pneumonitis - Ankylosing spondylitis,
- Radiation
- Tuberculosis
- Silicosis/sarcoidosis
Lower zone: RAIDS
- Rheumatoid
- Asbestosis
- Idiopathic
- Drugs
- Sarcoidosis
How do you differentiate between a transudate and an exudate
< 25g/L = transudate
25-30g/L = light’s criteria
> 30g/L = Exudate
Describe light’s criteria
Light’s Criteria
The effusion is exudative if protein is 25-30g/L and one of the following is present:
Pleural fluid/Serum protein >0.5
Pleural fluid LDH/Serum LDH >0.6
Pleural fluid LDH > 2/3rds upper limit of normal serum LDH
Is an exudative effusion usually unilateral or bilateral?
Unilateral
Is a transudative effusion usually unilateral or bilateral?
Bilateral
List the causes of an exudative effusion
Infection (put in chest drain!!)
Pulmonary issues
Inflammation
Malignancy
Dressler’s yellow nail
List the causes of a transudative effusion
Increased hydrostatic or decreased oncotic pressure
Meig’s syndrome (benign ovarian tumour, pleural effusion & ascites. Pleural effusion & ascites resolve once tumour is removed)
How are the following managed:
Primary pneumothorax (no lung disease)
<2cm and stable =
<2cm & breathless =
>2cm =
<2cm and stable = discharge
<2cm & breathless = aspiration
> 2cm = chest drain
How are the following managed:
Secondary pneumothorax (lung disease)
<1cm =
1-2cm =
>2cm =
<1cm = admit
1-2cm = aspiration
>2cm = chest drain
How should a tension pneumothorax be managed?
needle decompression THEN chest drain (once pressure is relieved)
How should a bilateral pneumothorax be managed?
chest drain
What are the boundaries of the ‘safe triangle’ for chest drain insertion?
5th intercostal space, edge of latissimus dorsi and edge of pectoralis major
Where should the needle the placed in needle decompression of a pneumothorax?
2nd intercostal space, midclavicular line
When is a pneumonia classed as ‘community acquired’ vs ‘hospital acquired’
Within 48hrs of admission = community admission
> 48 hours after admission = hospital acquired
Explain how CURB-65 helps guide where a patient is treated
- 0-1- home
- 2- hospital
- 3-5-ITU
What are the parameters of CURB-65
C - confusion
U - Urea >7
R - RR>30
B - BP <90 systolic or <60 diastolic
65 - >65 years old
Which type of pneumonia is associated with herpes labialis?
Strep pneumoniae
What is the most common cause of pneumonia?
strep pneumonia
Which type of pneumonia is associated with cystic fibrosis and bronchiectasis?
pseudomonas
Which type of pneumonia is associated with COPD and immunocompromisation
Moraxella
Which type of pneumonia is associated with bilateral diseases in IV drug users, cystic fibrosis suffered, the elderly and those who have recently received their influenza vaccine?
Klebsiella
What are patients with klebsiella pneumonia at risk of developing?
Empyema and lung abscess
Which type of pneumonia is associated with poor air conditioning or water sources?
Legionella
What electrolyte derangement is seen in patients with legionella pneumonia?
Hyponatraemia
How can legionella pneumonia be detected?
Urinary antigens
Which type of pneumonia can be acquired from birds?
Chlamydophila Psittaci
Which type of pneumonia is known as Q fever and is acquired from the bodily fluids of animals (often affects farmers)
Coxiella Burnetti
Which type of pneumonia is common in young children and causes headache, cold autoimmune anaemia and erythema multiform?
Mycoplasma
Which scores are used to assess the likelihood of a PE?
PERC then WELLS
How should a PE be managed if provoked?
3 months of DOAC
How should a PE be managed if unprovoked?
3 months of DOAC
If a patient with cancer develops a PE, how long should they receive treatment for?
6 months
Which patient’s shouldn’t have their PE treated with a DOAC? What should be given instead?
Renal impaired patients (eGFR,15ml/min) or those with antiphospholipid syndrome - give LMWH instead
What are the most common causes of pulmonary hypertension?
idiopathic, L heart failure, chronic lung/vascular disease
What medications do you give in pulmonary hypertension? (3)
CCBs
IV prostaglandins
endothelin receptor antagonists
What ECG changes do you see in pulmonary hypertension?
peaked P, R axis deviation, RBBB
What is the gold standard test for diagnosing TB?
Sputum culture
How is acute TB treated?
RIPE for first 2 months
RI for next 4 months
How is latent TB managed?
pyridoxine
3 months of IR
6 months of I
What are the side effects associated with rifampicin?
hepatitis
orange secretions
flu like symptoms
What are the side effects associated with Isoniazid?
hepatitis
agranulocytosis
peripheral neuropathy
What are the side effects associated with Pyrazinamide?
hepatitis
gout due to hyperuricemia
Arthralgia
myalgia
What are the side effects associated with Ethambutol?
optic neuritis
(E for Eyes)
What is the composition of a sarcoid lesion?
granuloma (macrophage driven)
Name three major clinical features of sarcoidosis
Hilar lymphadenopathy
Erythema nodosum
Calcium derangement
How can sarcoidosis be screened for?
Serum ACE
How is sarcoidosis managed?
Conservative management (if no symptoms), long term steroids, methotrexate
What respiratory conditions can untreated sarcoidosis cause?
pulmonary fibrosis and pulmonary hypertension
