Resp Flashcards
What is charles’s law, what units are required
Pressure is directly proportional to temperature
Kelvin
What is boyles law?
Pressure is indirectly proportional to volume of a fixed amount of gas
What is the universal gas law?
What is its significance to drs?
Boyles and charles combined
Pressure x volume = universal gas constant x temperature
Any testing done outside of the body will generate different results of pressure as temperature changes
What is daltons law?
Each gas exerts its own pressure as if no other gases were present which is the same fraction of the total mix pressure as the fraction of the volume the gas.
How can water interact with gasses?
Evaporation of water
Dissolving of gas
What effect does evaporation have on inhaled gasses?
Water evapourates creating a fixed saturated vapour pressure at a given temperature (6.28kPa in the body) this is always exerted no matter the total pressure so is proportionally more important if total pressure falls
What is the tension of a gas in water? What does it equal at equilibrium?
A measure of how readily a gas molecule will leave the liquid
Partial pressure
How is the amount of gas in a liquid calculated?
Content = solubility x tension
What is the effect on gases binding to molecules within a liquid on amount and tension?
Tension remains the same but amount goes up
In blood plasma what is the oxygen tension, what amount is dissolved in plasma at that tension given oxygens low solubility? How much is carried in whole blood? Why?
13.3kPa gives a dissolved content of 0.13mmol/L
Total blood has 8.93mmol/L due to haemoglobin binding
If an abg shows a pO2 of 13.3 is the patient definitely adequately oxygenated?
No - there could be a haemoglobin deficiency - anaemia
What is the partial pressure of oxygen in the atmosphere? What about alveolar air? Why the drop?
21.1kpa
13.3kpa
Oxygen is being removed and co2 and h2o added
What is the order of the airways?
Trachea Primary bronchi Secondary bronchi Bronchioles Terminal bronchioles Respiratory bronchioles Alveolar ducts Alveoli
What causes the alteration in nostril side during breathing?
Swelling of the venous plexuses in the lamina propria
What is the laryngeal epithelium?
Psudostratified ciliated columnar epithelium with mucous glands for the most part
Stratified squamous covering the vocal ligaments and the vocalis muscle
What is the change in epithelium from trachea to alveoli?
Psuedostratified ciliated (trachea, proximal bronchi)
Simple columnar ciliated (distal bronchi, proximal bronchioles)
Simple cuboidal ciliated (terminal bronchioles)
What changes occur to the secretory cells in the lower airways? Where?
In terminal bronchioles goblet cells are replaced with clara cells. In respiratory bronchioles clara cells are the predominant cell type.
What are the replacement for goblet cells in the lower airway? What do they produce?
Clara cells
Surfactant lipoproteins to prevent walls adhering in expiration
Where is bronchiole smooth muscle found?
Between the lamina propria and submucosa
What keeps the small airways open during expiration?
Direct pull from elasticity from neighbouring alveoli
Air pressure from the lumen exceeding that of the pleura due to elastic recoil of the alveoli in forced expiration
How does mucus secretion differ from bronchi to bronchioles?
Bronchi - mucus from goblet cells and submucosal glands
Bronchioles - no submucosal glands and goblet cells replaced with clara cells distally
Where do alveoli arise in the airways?
Other alveoli
Alveolar sacs
Alveolar ducts
Respiratory bronchioles
What are the cell types in the alveoli? What do they do?
Type 1 pneumocyte - squamous type that provides. Gas exchange surface
Type 2 pneumocyte - cuboidal type that secretes surfactant
Alveolar macrophages.
Where are the lungs by surface markings?
Apex 3cm above medial 1/3rd of pleural cavity
Nearly meet at mid sternal line at 2nd rib
Descend together to the 4th rib
Left moves to left sternal before descending to 6, right decends straight to 6
Both descend to 8 (pleura) / 6 (lung) at MCL
Both descend to 10 p 8 l at MAL
Both descend to 12 p 10 l at medial scapular boder
What are the two fissures of the right lung?
What are their surface markings?
Oblique T2 to 6th costal cartilage
Horizontal 4th rib at mid axillary line to anterior edge of lung
Where does the manubrium join the body of the sternum?
Sternal angle of louis at level of second costal cartilage
How are the ribs classified?
1-7 true
8-10 false
11-12 floating
Which ribs are typical? What are landmarks on their structure?
3-9
Two articular facets on head to articulate with body of vertebra or spine and vertebra above (i.e. 3rd rib with T2 and T3)
One articular facet to articulate with the transverse process of the vertebra
An inferior costal groove for vessels and nerves
Which ribs only have one facet on their head?
1,10,11,12
What makes rib 2 atypical?
Poorly marked costal groove
When the ribs elevate how does the shape of the chest change?
Upper ribs cause increase in sagittal diameter and lower ribs transverse diameter
What are the different intercostal muscles? Where are they and which way do they run?
External - costoverterbral junction to start of costal cartliage, runs down and anteriorly
Internal - sternal edge to just before costoverterbral junction, runs down and posteriorly
Innermost - only found laterally, run as with the internals
What muscles are used in normal inspiration and expiration?
Insp - diaphragm and external intercostal
Exp - none
What muscles are used in forced inspiration?
Sternocleidomastoid
Scalenes
Pectoralis minor
Serratus anterior
Which muscles are used in forced expiraiton?
Internal and innermost intercostals
Rectus abdomins
External and internal obliques
Transvers abdominus
What is the order superior to inferior, of the contents of the costal groove?
What about those vessels running on the superior surface?
Vein
Artery
Nerve
Reversed
Where do the intercostal nerves arise? Where do they run?
Anterior rami of t1-12
Between the internal and innermost intercostals
Where do the intercostal arteries arrise?
Anterior branch from internal thoracic
Posterior branch from thoracic aorta
Where do the intercostal veins drain?
Anteriorly to the internal thoracic vein
Posteriorly to the azygos system (azygos vein on the right, hemizygos and accessory azygos on left)
What are the levels of the openings through the diaphragm?
Vena cava t8
Oesophagus t10
Aortic hiatus t12
What does the phrenic nerve supply?
Sensation of the Pericardium Mediastinal parietal pleura Diaphragmatic parietal pleura Both sides of the diaphragm (except the margins supplied by the intercostal nerve)
Motor
Diaphragm
What are the various regions of the parietal pleura?
Cervical
Mediastinal
Costal
Diaphragmatic
What are the functions of the serous fluid?
Allows sliding of the pleura
Creates the pleural seal
At what level is the carina?
t4/t5
Which bronchi is more susceptable to obstruction, why?
Right
Shorter, wider, more verticle
What follows the main bronchi?
Lobar bronchi
Segmental bronchi
What do segmental bronchi supply? What is special about this?
A bronchopulmonary segment
Each has its own bronchi, pulmonary artery and pulmonary vein. Thus can be isolated and surgically removed
What are the three surfaces of the lung?
Costal
Mediasteinal
Diaphragmatic
What is the equivalent of the middle lobe in the left?
The lingula
How can the left and right hilum be distinguished?
Right - arteries are anterior to the bronchus
Left - arteries superior to bronchus
RALS
What is the lymphatic drainage of the lungs?
Hiliar nodes
Trachobronchial nodes (right and lower left up the right, upper left up the left)
Bronchiomediasteinal trunk to subclavian veins
What structures are associated with the hilum besides the obvious?
Phrenic nerve anteriorly
Left recurrent laryngeal nerve superiorly
Aorta on the left
Svc and azygos on the right
To what level do the bronchial arteries provide oxygen?
Where does the rest get o2 and nutrients from?
Terminal bronchioles
Gas exchange and pulmonary arteries for nutrients
How is the mediasteinum divided?
What is in each bit?
Anterior - between sternum and pericaridum
Middle - between anterior and posterior! Fibrous pericardial contents
Posterior - between vertebral bodies and pericardium
Superior - above line from sternal angle and t4
What is the pO2 and pCO2 of pulmonary arteriolar blood?
6
6.5 kPa
What influences the rate of diffusion across the alveolar membrane?
Area
Gradient
Resistance (nature of barrier and gas)
What 6 layers must an oxygen molecule travel from mid alveoli to inside a rbc?
Through the gas Alveolar cells Intersitial fluid Endothelial cells Plasma Red cell membrane
Which gas moves through gas easier?
Oxygen - it has a lower molecular weight
What gas diffuses faster through liquids (including phospholipid bilayer)? What is the result of this?
co2
As a result a problem with diffusion nearly always selectively effects O2
Why do small changes in diffusion resistance not affect concentration of blood gasses in the pulmonary veins?
Because blood passes next to alveoli for 1s but only takes 0.5s to reach equilibrium thus there is plenty of leaway
How does the body keep the concentrations of alveolar gasses constant during respiration?
Pulmonary ventilation only reaches the terminal bronchioles. From there gas diffuses into and out of the alveoli not fluctuating with the respiratory cycle. This is alveolar ventilation
What are the lung volumes?
Inspiratory reserve volume - 3.3L
Tidal volume - 0.5L
Expiratory reserve volume - 1.2L
Residual volume - 0.8L
What are the lung capacities?
Vital capacity - 5L
Inspiratory capacity - 3.8L
Functional residual capacity - 2L
Total capacity 5.8L
Why do we measure lung capacities?
Volumes change with patterns of breathing so are not fixed for an individual. As a result tests would vary time to time (poor consistency)
Capacities are all measured from fixed points in the cycle - max inspiration, max expiration, end of passive expiration
What is the term for the volume of air moved in a breath times the respiratory rate?
What is it typically?
Pulmonary ventilation rate
16x500ml = 8000ml/min
What are the dead spaces? Typical values?
Serial - conducting airway volume (0.15L
Distributive - non perfused alveoli volume (0.02L)
Physiological - serial + distributive (0.17L)
What is alveolar ventilation rate?
Typical values
AVR = pulmonary ventilation rate - dead space ventilation rate AVR = (16x500)-(16x170) AVR = 8000 - 2720 = 5280
What is the consequence of dead space in the lungs?
Rapid breathing is less efficient as dead space becomes proportionately more important.
What is the term for the connection between the two layers of pleura that means the lungs pull out with chest expansion?
Pleural seal
Why do we expire by relaxing after inspiration? Why does it stop?
At the end of inspiration we relax our muscles. Consequently the inward elastic pull of the lungs becomes greater than the outward pull of diaphragm and chest so they are pulled inwards. At the end of passive expiration the inward elastic pull equals the outward recoil of the chest and diaphragm so there is no movement.
What happens during forced expiration?
Muscles augment the inwards elastic pull of the lungs and pleural pressure exceeds atmospheric pressure (the only time this occurs) forcing the lungs to contract.
What is lung compliance?
A measure of the volume change per unit pressure change. A highly compliant lung has big volume changes for small pressure changes, a poorly compliant lung has the reverse.
What causes the elastic recoil of the lungs?
Elastin in the walls/interstitium
Surface tension
What is surface tension?
The tendency of a liquid to contract to its minimal volume as molecules on the surface are being pulled into the centre (attractive forces with other water molecules but not the air - thus pulled in)
Why do small alveoli tend towards collapse? How does surfactant prevent alveolar collapse?
Pressure required to keep alveoli open = (2x surface tension) / r
Thus small alveoli require a larger pressure to stay open than big
Surfactant reduces surface tension more when compact, thus reduces surface tension more in small alveoli so the pressure needed to stay open reduces more in these.
Functions of surfactant
Stopping alveolar collapse
Reducing compliance
Diseases with high compliance
Emphysema
Diseases with low compliance
Fibrosis
Respiratory distress syndrome of the newborn
Will FRC increase or decrease in a disease which increases compliance like emphysema? Why?
It will increase
The point at which FRC is reached is the point when inward pull of the lung is matched to outwards pull of the chest. As lung compliance has increased then at this volume inward pull will be less. For the forces to balance the volume must be greater - the new equilibrium is at a greater volume!
What will be the effect on FRC of a disease that decreases lung compliance like fibrosis?
Decreased frc.
Frc depends on an equilibrium between inward pull of the lung and outward pull of the chest wall. At a healthy FRC the stiff lung will be generating greater force than the outward pull - as a result FRC must reduce to reach equilibrium with outward pull.
What is hysteresis? How does it apply to the lungs?
The energy expanded increasing surface tension when surface area is increased is not all recovered when surface area reduces. Practically this means as pressure increases on inspiration the volume will increase as it overcomes surface tension - however, on expiration for each given pressure the lung volume will be greater.
During inspiration order atmospheric pleural and alveolar pressures from high to low
Atmospheric
Alveolar
Pleural
During expiration order atmospheric pleural and alveolar pressures from high to low
Alveolar
Atmospheric
Pleural
During forced expiration order atmospheric pleural and alveolar pressures from high to low
Pleural
Alveolar
Atmospheric
What law is relevant to the size of alveoli and pressure?
Laplaces
Pressure = 2 ST / r
What law is relevant to flow through tubes?
Poiseulles
Flow is directly proportional to:
(Pressure gradient x radius squared x radius squared) / (viscosity x
length)
Where is the highest resistance in the airways during normal respiration?
Trachea! Smaller airways are in parallel so their radius is actually greater!
Where is the highest resistance to airflow in forced expiration?
The small airways - they narrow as interpleural pressure increases
Why do you get airway obstruction in empysema?
On forced expiration inter-pleural pressure increases. Due to the lack of elasticity of the lungs there is less alveolar pressure. As a result the airways are compressed
What does spirometry show?
Inspired and expired volume with time
What is an issue with spirometry in determining vital capacity? What can effect both
Is a lowered value due to low max inspiration or low max expiration?
Low max insp - chest wall defect, chest muscle weakness (restrictive defect)
Low max exp - narrowed airways (obstructive defect)
How can we differentiate between restrictive and obstructive defects of the lung?
A vitalograph trace
What does a vitalograph trace involve? What values are derived from it?
Taking a single maximal inspiration then expiring into a spirometer as fast as possible
Forced Vital Capacity (FVC)
Forced Expiratory Volume in one second (FEV1)
What vitelograph reading would suggest an obstructive lung defect?
A FEV1 <70% of FVC
What suggests a restrictive defect on vitalograph?
A low FVC with a FEV1 >70% (note actual value of FEV1 will be lowered but it is the ratio that is important)
How can more information be gained from a vitelograph over and above fvc and fev1?
Conversion into a flow volume loop.
At what point of forced expiration does an individual produce PEFR?
Almost immediately as lungs are stretched so resistance is least
What is seen on an flow volume curve in obstructive airway disease? What is the advantage of this test over vitalograph?
A rapid decrease from maximal flow with increasing volume scooping out the curve
Why do we use PEFV is asthma?
Very cheap and simple to use. It is measuring large airway resistance but in severe asthma will become effected by small thus indicates a severe issue
How can we measure residual volume?
Breath in helium at a known concentration starting from end of passive expiration
Monitor how concentration of expired helium has reduced to determine volume of air already in the lungs
How can we measure serial dead space?
Perform a nitrogen washout
Breath pure O2
Measure percentage of nitrogen against volume on expiration
Initial expiration will have no nitrogen (as large airways replaced with o2 first)
Mid expiration will have increasing nitrogen from alveolar air diffusion
End expiration will have normal nitrogen
Draw a line midway down the curve - area to left represents serial dead space
How can we measure diffusion over alveoli?
Give carbon monoxide
Measure the amount on haemoglobin in blood
Why do we use CO to measure alveolar diffusion?
It binds fully to haemoglobin so exerts no partial pressure thus gradient is always (given concentration : 0)
What is a flaw with oxygen saturation measurements when considering amount of oxygen reaching the tissues?
Doesnt consider pigment concentration thus not amount of oxygen
What is the typical concentration (!) of o2 in pulmonary venous gas
Conc Hb = 2.2mmol/L
Each Hb can hold 4 O2 thus conc O2 is 8.8mmol/L
Add disolved O2 of 0.13mmol/L gives 8.93mmol/L
If 100% saturated blood in the lungs has a O2 concentration of 8.8mM what is the concentration in 65% saturated tissue?
0.65x8.8=5.8
How are active tissues adapted to get the most O2?
How much extra of the norm of 3mM drop in concentration can active tissues achieve? What does this mean?
High capillary density allowing lower pO2 with all cells still recieving sufficient
H+, co2 and temp high
Can double amount released to. 6mM
This means that an increased O2 demand can be matched with half the increase by the CVS
What is the concentration of CO2 in arterial blood? How does it change in venous?
What is the implication of this?
21.5mM
Raises by 2mM
The vast majority of CO2 in blood is nothing to do with respiration!
How is CO2 carried in blood? Percentages please
8% dissolved
12% as carbaminocompounds (mainly carboxyhaemoglobin)
80% reacts with water forming H+ and bicarbonate ions from carbonic acid
What happens to CO2 as it leaves a producing cell
Enters plasma. No CA in plasma so little reaction occurs
Enters RBC. CA converts it to carbonic acid
Carbonic acid to H and bicarbonate ion
H binds to Hb (HbH) causing stabilisation of T state releasing O2
Bicarbonate ion shunted into plasma in exchange for Cl-
Removal of products from RBC favours continued forward reaction
What is the consequence of high bicarbonate concentration in plasma?
Pushes the CO2 and Water to H and HCO3- to the left stopping the creation of H+ in the plasma
Why is venous pH not higher than arterial? There is more CO2 after all?
Less o2 thus H+ can bind more to Hb and thus more HCO3- in plasma
Also higher caboxyhaemoglobin
What. Happens in the lungs to cause CO2 exhalation?
High. O2 = HbH to Hb and H
H and HCO3- to CO2 and H2O
CO2 breathed out
What is the dilemma with respiratory control?
Compensating for hypoxia alone would cause hypocapnia and vica versa. Only works if hypoxic and hypercapnia
How is low oxygen detected? At what level?
By peripheral chemoreceptors
At 8kPa prior to significant fall in sats
What feature of peripheral chemoreceptors allows them to respond to oxygen conc. changes?
Very well supplied with blood so only become hypoxic if ppO2 drops below 8kPa
What is the response of the body to hypoxia?
Increased resps
Increased heart rate
Diversion of blood to the brain
What can increase the sensitivity of peripheral chemoreceptors to hypoxia?
Hypovolemia - become hypoxic more easily
What would a biochemical profile of resp acidosis look like?
Low ph
High co2
High bicarb (over several days - compensation)
Differentiate compensation and correction of acidosis/alkalosis
Compensation - other system trying to return ph to normal
Correction - effected system altering to oppose changes
What would a metabolic alkalosis look like biochemically?
High pH
High bicarb
High CO2
How would a resp alkalosis appear biochemically?
High pH
Low CO2
Low bicarb
How would a metabolic acidosis appear biochemically?
Low ph
Low bicarb
Low CO2
Why does compensation help stabilise pH?
Because its ratios that matter not actual componenets. Circa henderson hasselbach
Where and how are changes in pCO2 detected?
Mainly central chemoreceptors in medulla
Respond to pH changes in CSF
How does change in CO2 effect CSF pH?
Co2 diffuses freely into CSF whilst bicarbonate cannont
Thus acute rise in CO2 causes acidosis in CSF and increased respirations
But CSF doesnt like being acidic so choroid plexuses increase import of bicarbonate normalising pH in chronic high CO2 and resps return to normal thus CO2 builds up.
What is type 1 resp failure?
When does it normally occur?
Low O2, normal or low CO2
Usually from v/q mismatch or diffusion problems
Examples of vq mismatch resulting in type 1 resp failure
PE
Pneumonia
Early acute asthma
Why does poor perfusion of an alveoli lead to type 1 resp failure?
Alveoli still equally ventilated but more blood passing by some.
Alveoli with low V/Q (not effected) has lower pO2 due to more blood passing so lower pO2 in blood. CO2 removal can be increased however.
Alveoli with high V/Q (effected) cant raise pO2 as either no exchange at all if no blood, or, if some blood passing then already at maximum O2
Why does poor ventilation of some alveoli cause type 1 resp failure?
In alveoli with low V/Q (effected) alveolar pO2 falls and pCO2 increases. Passing blood becomes hypercapnic and hypoxic
Air is diverted to healthy alveoli:
In alveoli with high V/Q (not effected) blood cannot receive more O2 as already fully saturated, however, CO2 removal can increase
Examples of diffusion problems causing type 1 resp. Failure. How does this occur?
Fibrotic lung disease
Pulmonary oedema
Emphysema (early)
By increasing diffusion resistance, distance or reducing surface area oxygen is primarily effected as CO2 can diffuse more easily
What is type 2 resp failure?
Cause?
Decreased o2 and increased CO2
Cause is ventilation failure
- chest wall defect eg kyphosis or trauma
- resp depression eg opiates or stroke
- decreased compliance eg fibrosis
- increased airway resistance eg asthma or COPD
How can someone with type one resp failure be acidotic?
Decreased O2 means increased anaerobic resp means lactic acid
Long term complications of t2rf
Hypoxic drive
Resp acidosis
Cor pulmonale due to pulmonary htn
Increased Hb
Characteristics of asthma
Reversible airway obstruction
Increased airway responsiveness to stimuli
Airway inflammation and remodelling
What occurs in airway remodelling in asthma?
Increased sumbmucosa
Epithelial metaplasia increasing goblet cells
Epithelial damage increasing vulnerability to infection
Deposition of collagen in lamina reticularis causing BM thickening
Increased smooth muscle mass and responsivness
What causes airway remodelling in asthma?
Chronic inflammation releasing
- cytokines, leukotrienes, growth factors (for repair)
From inflammatory cells and epithelium
What is poiseuilles law? What does it mean for asthmatics?
Flow = (P x pi x r^4) / (8 x v x L)
Decrease in radius means marked decrease in flow or increase in pressure gradient to maintain flow
What can trigger the hyperresponsive smooth muscle in asthma?
Allergens (dust mites, pollen, pollution, smoke) Cold air Exercise NSAIDS Beta blockers Emotion Infection
Causes of asthma
Genetic (family risk)
Environment (hygiene hypothesis, pre/post natal smoke)
2 types of asthma
Atopic (other allergies, circulating IgE, +ve skin prick tests)
Non-atopic (drug induced, viral induced wheeze, occupational)
How does asthma present?
Wheeze Breathless Dry cough Chest tightness Variable airflow obstruction
Diagnostic tests used in asthma
Spirometry (pre and post bronchodilator)
CXR
PEF
Allergy testing
Non pharmacological management of asthma
Stop smoking Breast feeding Decreased exposure to allergens Fresh air Weight loss
What is copd?
A progressive non reversible ariflow obstruction that does not change markedly over several months. It is caused primerally by smoking
What is the pathological mechanism behind emphysema?
Destruction of terminal bronchioles and distal airspace leading to a loss of surface area and the formation of bullae (large redundant airspaces)
Destruction of supporting tissue causes decreased elasticity thus collapse of airways on forced expiration and decreased recoil so hyperinflation
Pathological mechanism of chronic bronchitis
Chronic mucosal hypersecretion due to inflammation
Chronic productive cough
Remodelling, metaplasia and narrowing of the large airways
How is copd graded?
MRC score 1 not troubled 2 breathless on hurrying 3 slower than contemporaries 4 stops for breath after 100m 5 too breathless to leave house
Signs of copd
Pursed lip breathing Tacyponea Accessory muscle use Hyperinflation of chest Wheeze Cyanosis Heart failure Co2 retention flap
If there is a good history, what test will confirm copd? What will it show? What is the cut off for severe
Spirometry
Low fev1:fvc ratio. (Severe <30%)
Decreased fvc
Other than spirometry what tests are useful in copd? Why?
Cxr to exclude other pathology
Ct if considering surgery
Abg for checking for resp failure
Alpha one antitrypsin test if young
Management of COPD
Stop smoking Bronchodilators Steroids Mucolytics Flu vaccine O2 if pO2 consistently below 7.3kPa Surgery Pulmonary rehabilitation
What is copd pulmonary rehabilitation
Encouraging light exercise to stop cycle of breathless, sedentary, breathless, sedentary
How are exacerbations of copd managed?
O2 Nebs Steroids Abx Aninophylline NIV ITU
Contraindications of NIV
Pneumothorax Gcs under 8 Facial injury Life threatening hypoxia Vomiting Agitated Excessive upper airway secretions
Why is tb on the risk in uk?
Immigration
Aids
Immunosuppressive meds
What can happen on initial tb exposure?
Containment with langerhans giant cells then granulomas with epitheloid macrophages.
Adaptive response over 3-8 weeks
Granuloma sealed off
Usually sub clinical but can cause vague illness
What happens if the immune response to TB infection was inadequate? How does it present?
Primary TB with tiredness, malaise, anorexia, weight loss, fever, night sweats, wheezing, lymphadenopathy, clubbing, haemoptysis.
Other than direct progression causing primary tb with inadequate response how can typical symptomatic tb develop?
Post primary tb Contained tb remains latent then reactivated by: Immunosuppression (meds, aids) Reinfection Malnutrition Malignacy
What is the location of the initial tb infection called? What about when it spreads locally (to what tissues)?
Primary focus (or ghons focus) Spreads to nearby lymph nodes forming primary complex
Where can tb spread? What are the infections at different places called?
Pleura - effusion Meningies - meningitis Diffuse intravascular - millary Spine - potts Skin - lupus vulgaris
What tests are appropriate in suspected tb? What test has a NPV of 100%?
CXR - NPV
3 x speutum ziehl neelsen stain
Culture
Treatment regime for TB with side effects
2 months of all followed by 4 of rif and iso
Rifampicin - liver, red secretions
Isoniazide - liver, peripheral neuropathy
Pyrizinamide - liver, gout
Ethanbutol - optic neuritis
Other than treating active tb when might anti. Tb. Antibiotics be used?
Prophylaxis in patients about to undergo immunosuppression who have had tb before
What forms of tb is the vaccine good against?
Menigeal
Milliary
What skin test is used for tb? What might cause problems with it?
Mantoux - if infected then stimulates inflammation of the skin.
Inflammation
When would you consider directly observing tb meds. Being taken?
Homeless Alcoholics Mental illness Immigrants Drug resistance
What is MDR tb resistant too?
Rifampicin and isoniazide
What is externsivly drug resistant tb resistant too?
Rifampicin
Isoniozid
Quinolones
And anther second line
How is lung cancer incidence changing?
Falling in men and rising in women mimicing smoking habits 15 years delayed
What percentage of lung cancer patients are due to cancer?
90% in males 80% in females
Many of the remaining due to passive
What are causes of lung cancer other than smoking
Copd Assbestos Radon Occupational Genetic
Symptoms from local tumour effects of lung cancer
Cough Dysponea Wheeze Haemoptysis Chest pain Weith loss Lethargy
Symptoms from regional lung cancer mets?
Svc obstruction
Horse voice
Dysponea
Dysphagia
Paraneoplastic symptoms of lung cancer
Hypercalcemia SIADH Cushings Anaemia Clubbing Encephalopathy
Where does lung ca commonly metastisise?
Bone
Brain
What are the histological differentiations of lung cancer? How do they appear?
Small cell carcinoma (small cells, little cytoplasm, necrosis)
Squamous cell carcinoma (angulated, keritinised, desmosome bridges)
Adenocarcinoma (glandular)
Large cell carcinoma (large rounded cells)
Which type of lung cancer is most common?
Squamous cell carcinoma
What lung cancer type isnt usually aminiable to surgery?
Small cell?
Which lung cancer type may be curable with chemo?
Small cell
How can radiotherapy be used in lung cancer?
Alone or in combo with chemo
Diagnositic techniques used in lung cancer
Chest xray Ct Mri Pet ct Isotope bone scans Bronchoscopy Endobronchial ultrasound with biopsy
Prognosis of lung cancer
Why is it like this
10-15% 10 yr survival
Tends to present late in high stages
Caught very early then 10 year survival is 40%
Other than late presentation why might lung cancer survival be so poor?
Professional nihilism
Variable standard of care
Lack of public pressure for campaign
Presents to Gp not specialist
What is the. Average survival post dx of untreated small cell lung cancer? What if chemo is given?
3 months
1 year
Examples of types of urti? What is the usual cause?
Pharyngitis Rhinitis Tracheitis Epiglottitis Laryngitis Sinusitis
Viral
Usual cause of pneumonia? What other LRTIs are possible?
Bacterial
Bronchiolitis
Bronchitis
Normal cause of bronchiolitis?
Respiratory syncytial virus
In what ways can pneumonia be classified?
Community vs hospital
Acute vs subacute vs chronic
Bacteria vs virus vs fungi
Lobar vs broncho vs interstitial
Typical bacteria that cause community pneumonia
Haemophillus influenza
Streptococcus pneumonia
Kleibesella pneumonia
Who is more at risk of community aquired haemophillus influenza infection?
Copd
Who is more at risk of community aquired strep pneumonia pneumonia?
Elderly
Common bacteria for hospital acquired pneumonia
Staphylococcus aureus inc MRSA
Psuedomonas aeruginosa
Gram neg enteric bacteria
What raises risk of hospital acquired staph aureus pneumonia?
Post viral infection
Common viral causes of pneumonia
Influenza
Parainfluenza
Respiratory syncytial virus
Atypical causes of pneumonia with risk factors
Legionella (air con / travel)
Chlamydia (birds)
Mycoplasma (young people)
Opportunistic causes of pneumonia?
Candida Aspergillus Pneumocystis jirovecii Cytomegalovirus HSV
What is the most common cause of lobar pneumonia?
Streptococcus pneumonia
What is the most common causes of bronchopneumonia?
Streptococcus pneumonia
Haemophillus influenza
Staph aureus
Coliforms
On investigation of a pneumonia multiple organisms are cultured? What could be the cause? What sort of pneumonia is it likely to be?
Aspiration
Bronchopneumonia
How can severity of pneumonia be assessed?
C - confused (AMT 7
R - resps >30
B - BP <90
65
How is mild to moderate pneumonia treated prior to cultures return?
Amoxicillin
How is severe pneumonia treated prior to culture?
Coamoxiclav
Indications for pneumonia onto ICU
Resp failure
Progressive acidosis
Shock
Hypercapnia
Complications of pneumonia in the long term
Fibrous scarring
Abcess
Bronchiectasis
Empyema
Risk factors for acquiring pneumonia in hospital
Itu Ventilated Suppressed immunity Atelectasis (post chest injury/surgery) Immobile
Signs of pneumonia
Wheeze
Crackles
Dull percussion
Low resonance
Symptoms of pneumonia
Fever Chills Sweats Productive cough Dysponea Pleuritic chest pains
What tests are performed in pneumonia?
Speutum culture and gram stain
Cxr
Fbc, urea, lft, crp
What special tests are performed in legionella pneumonia?
Legionella antibodies in urine
Things to check at the start of a chest xray
Field of view (1st rib to costophrenic angle)
Penetration (vertebra behind heart)
Rotation (spinous processes in midline between clavicles)
Volume (on inspiration with 5-7 ribs visible)
No artefact
Demographics!
What should you look for assessing airway on a CXR.
Trachea central
Clear angle at hila with left higher than right
What should you look for on breathing on a cxr?
Lungs equal both sides
No visible pleural space
No consolidation or masses
What should you look for on circulation onCXR?
Heart less than 50% of chest diameter
Aortic notch present
What should you. Look for on diaphragm/dem bones on CXR
No free gas
Not flattened
No bony fractures
What is sail sign? What else might indicate this pathology?
Double heart boder due to left lower lobe collapse
Also presents with lowered pressure causing mediastinal shift towards pathology and elevation of ipsolateral hemidiaphragm
What can cause consolidation on a cxr?
Pus
Blood
Fluid
Cells
What are the overall efffects of interstitial lung disease?
Loss of compliance
Increased alveoli to capillary diffusion distance
Destruction of alveoli and capillaries causing v/q mismatch
Signs and symptoms of interstital lung disease
Gradual onset sob Dry cough Diffuse crackles Clubbing Cynosis Right heart failure (cor pulmonale) Tachycardia and tachyponea
How does a ct show interstitial lung disease
Honeycombing
Hw does a cxr show interstitial lung disease?
Increased lung markings
Blurred boarders
Causes od interstitial lung disease
Idiopathic Treatment related Connective tissue disease Immunological Occupational
What are the two commonest causes of interstitial lung disease?
Idiopathic
Immunological
Examples of immunological causes of interstitial lung disease
Sarcoidosis
Hypersensitivity pneumonitis
Examples of connective tissue diseases causing interstitial lung disease
Sle
Ra
Examples of occupational exposures leading to interstitial lung disease
Asbestosis
Coal workers pneumoconiosis
Silicosis
Examples of treatments that cause interstitial lung disease
Amiodarone
Methotrexate
Bleomycin
Radiation therapy
How does the visceral pleura receive its blood supply?
Via the bronchials
How does the parietal pleura receive its blood supply
Costal - intercostals
Mediastinal - bronchials
Apex - subclavian
What can cause increased plural fluid production?
High hydrostatic pressure (eg chf)
Increased permeability (eg sepsis)
Decreased oncotic pressure (eg liver failure)
Increased Interstitial fluid
What can cause decreased pleural fluid absorption?
Lymph blockage
Elevated venous pressure
Other than pleural fluid what else can cause a pleural effusion?
Empyema (pus)
Haemothorax (blood)
Chylothorax (lymph)
What are complications of pleural effusion?
Fistula with bronchi or skin
Trapped lung
Functional restriction
Fibrothorax
Give some examples of congenital chest wall disease
Scoliosis and kyphosis
Pectus carinatum
Pectus excavatum
Other than congenital what sorts of chest wall diseases are there?
Traumatic
Iatrogenic (eg post tb surgery
