13 Flashcards
How do class Ia, Ib, Ic antiarrhythmics work?
- Ia – Lengthen AP duration
- Ib – Shorten AP duration
- Ic – No significant effect on AP
What are some common symptoms of pulmonary TB?
- Haemoptysis.
- Cough.
- Sputum.
- Chest pain.
- Systemic symptoms of infection.
Antimuscarinics MOA in asthma
o Block the activity of the muscarinic acetylcholine receptor (blocks ACh binding to muscarinic receptors)
o This results in bronchial dilation + decreased secretions
Side effects of amiodarone (class III anti-arrthymatic)
- Blue-grey skin discolouration
- Photosensitivity
- Lung fibrosis
- Corneal deposits
What is coarctation of the aorta?
Narrowing of a short section of the aorta
It’s rare
MOA of streptokinase
Activates plasminogen to plasmin which is a fibrinolytic enzyme
Used in acute MI
How are diffusion and perfusion affected in obstructive lung disease?
Not much, it is a ventilatory problem.
- Diffusion affected in emphysema due to parenchyma destruction.
- Perfusion affected in end stage (cor pulmonale).
What do Th2 cells produce?
IL-4 which stimulates IgE
IL-5 which activates eosinophils
What does an atheroma contain?
o Macrophage cells
o Lipids
o Calcium
o Variable amount of fibrous connective tissue
What 2 types of test for TB are there?
1) Mantoux tuberculin skin test.
2) Interferon gamma release assay.
Blue bloaters (bronchitis)
- Coughs up lots of sputum
- Oedematous ankles
- Cyanosed
- Overweight
- Sleep apnoea
- Do into ventilatory failure early on
Tissue changes in the kidney in hypertension
- Glomerular damage
- Shrink
- Renal artery stenosis
- Arteriosclerosis leading to progressive ischaemia of the nephrons
What happens when you breathe out if you lack alveolar integrity?
Pleural pressure will exceed > pressure in small airway, so it would collapse prematurely on exhalation.
Hyperexpanded chest in asthma and emphysema
What are arterial blood gases? When is it indicated?
Gives you:
- PaO2.
- PaCO2.
- Acid-base balance (pH, HCO3, H+ etc).
- When oxygen sats are 90-92% or lower.
Overview of pharmacological treatment of patients with LV HF
Patients w/ LV HF should be on ACE inhibitors, beta blockers + ARBs for the rest of their life – because the cumulative effect of these drugs doubles life expectancy (triple therapy)
What is the point of a granuloma? What happens within it in TB? What is the main disadvantage of this?
To try and contain the focus of infection.
- Caseating necrosis to prevent dissemination of TB.
- Dampens the host immune response.
1st degree heart block
QRS normal
P wave present
Long PR interval
What is wheeze?
A musical noise produced by air moving through narrowed airways (airway obstructed)
o Obstruction of airways within chest causes wheezing w/ expiration – airways get narrower because lungs get smaller
Contrast with stridor which occurs in inspiration – e.g. whooping cough, epiglottitis, foreign body
How is sinus bradycardia treated?
Investigate and remove cause:
- Beta blockers
- Hypothyroidism
- Heart block - recent MI, digoxin toxicity, B-blockers
Usually manged consevatively
Which cytokine is skewed in asthma?
Greater Th2 production
Haemodynamic model for progression of heart failure
- Sympathetics and RAAS activated
- Increased preload and afterload
- Consequence is very dilated heart
MOA and example of a biguanide
- Metformin
- Increases utilisation of glucose by increasing uptake and decreasing gluconeogenesis
List and explain the 3 factors regulating stroke volume
o Preload: the degree of stretch before contraction
o Contractility: the forcefulness of contractions
o Afterload: the pressure that must be exceeded for the ventricle to eject blood
Non-dihydropyridines
Calcium antagonists
- Verapamil, diltiazem (class IV anti-arrithymatics)
- Slow heart rate
- Useful for angina
- Not for use in heart failure
MOA of acarbose
Inhibits intestinal alpha-glucosidases and delays absorption of starch and sucrose
Antidiabetic drug for DM2
What does low compliance indicate?
Stiff lung which indicates high elastic recoil.
E.g. pulmonary fibrosis
Compliance affects how much energy is required to generate pressure gradient for ventilation.
Torsades de pointes
o Commonly seen in patients w/ pre-existing bradycardia especially if give class I anti-arrhythmic drugs
o A feared side-effect of drugs
o Exacerbated by low potassium and magnesium
o Treatment – magnesium
Microbiology of Mycobacterium Tuberculosis
- Gr+
- Obligate aerobe
- Stains with Ziehl-Neelson
- Bacilli are non-motile, non-sporing and non-capsulated
- Rod
What are the results of left ventricular dysfunction?
- SOB
- Peripheral oedema
- PND
- Raised JVP
- Orthopnoea
Name some common restrictive lung diseases.
- Pulmonary fibrosis (IPF).
- Chest wall deformity (kyphosis).
- Obesity.
- Neuromuscular disease.
Pheochromocytoma
- Adrenal medullary (neuroendocrine) tumours secreting catecholamines
- Alpha mediated vasoconstriction
- Beta mediated cardiac stimulation
- Raised BP and tachycardia (may cause cardiomyopathy)
MI treatment for STEMI
o Primary percutaneous coronary intervention (PCI)
o Thrombolysis >20% of patient given thrombolysis do not achieve reperfusion so start with PCI
Significantly lower mortality w/ PCI compared to thrombolysis because of high rate of reperfusion
What % of all CHD deaths are attributable to smoking?
20
Left bundle branch block
Negative V1 - W
Positive V6 - M
WiLLiaM
Causes of tachycardia due to increased SNS activity
- Exercise (after the 1st minute)
- Fear
- Heart failure
- Adrenaline
Cardiogenic shock
- Extreme version of heart failure
- Large heart attack where they kill off so much heart and become shocked
- Stop perfusing brain and kidneys properly
- Results in death
Step 3 asthma treatment
Corticosteroid + long acting beta agonist combination (salmeterol) - Regular use
Short acting beta agonist (symptomatic)
2nd degree type 1 heart block
- QRS irregular
- P wave present
- AV node slows till P wave delivered which doesn’t get conducted to ventricles
- PR interval becomes progressively longer until QRS fails to appearbu
Class IV example and effect on AP
Verapamil, Diltiazem
- Blocks Ca2+ channels
- Prolong conduction and refractoriness in SA and AV node
Pathophysiology of right sided heart failure
Fall in CO –> fall in renal perfusion –> increased ADH, increased aldosterone –> Na+ and H2O retention
What is alveolar ventilation?
The amount of air sitting in the terminal airways where gas exchange is taking place.
- (Tidal volume - dead space) x respiratory rate.
3 unique properties of cardiac cells
- Automaticity
- Excitability
- Refractoriness
When are beta blockers contraindicated?
Asthma Cardiogenic shock Hypotension AV block Untreated pheochromocytoma side effects (neuroendocrine tumour of medulla of adrenal glands)
What 3 factors contribute to the level of transmission of TB?
1) Number of individuals susceptible to the disease.
2) Number of people exposed to the disease.
3) Duration of time a person with TB is undiagnosed and infectious for.
What is cardiac neurosis?
Da Costa’s Syndrome
- A set of symptoms similar to heart disease e.g. chest pain, dyspnoea, fatigue etc.
- No physical findings
- It’s considered as a form of anxiety disorder
Causes of haemoptysis
o Lung cancer – haemoptysis is a red flag for lung cancer; is most common cause of cancer deaths
o TB – kills 3,000,000 people every year (more than AIDS +tropical diseases (malaria) combined)
o Bronchiectasis – chronic mucoid sputum production, may have v. inflamed, fragile airways so may
o Pulmonary oedema – causes pink frothy sputum
o Pulmonary embolism – sudden blockage of a major artery in the lung, usually by a blood clot
o Pneumonia – causes rusty sputum, blood is mixed through the purulent sputum
What tests would you perform prior to treating TB?
- HIV.
- Hep B and C.
- Liver function test, ALT.
- Visual acuity when using ethambutol.
Which sites are involved in TB?
Pulmonary TB (85% of all cases)
Extra-pulmonary sites
Aortic dissection
- Sudden, tearing, knife-like pain
- Excruciating
- Radiate to back
- Abdominal pain (20-40% of cases)
- Often seen in elderly population w/ hypertension
- Seen in people with stressful jobs with hypertension at a young age
Bronchopneumonia
- Inflammation of walls of bronchioles w/ multiple foci of consolidation, affecting 1 or more lobules
- Most common form
- Infants + elderly more susceptible
- Any organism
List rapid (hrs) causes of breathlessness
Acute asthma
Pneumonia
Pulmonary oedema
Acute hypersensitivity pneumonitis
Which immune cells are involved in asthma?
o Antigen presenting cells
o T cells (CD4+)
o B cells – produce IgE which stick to mast cells + eosinophils
o Mast cells – activate eosinophils vis leukotriene B4
o Eosinophils – cause late reaction
High eosinophil count means allergy or parasites (worms)
MOA of Isoniazid
Disrupts synthesis of mycolic acid
TB drug (bacteriostatic)
Class Ib example and effect on AP
Lidocaine
- Block Na+ channel
- Shortens AP
QRS narrow and ragged atrial spikes rather than P waves
Atrial fibrillation
How is any tachycardia with hypotension/collapse treated?
Emergency electrical cardioversion w/ sedation if necessary
Treatment for collapsed patient with VT same for VF
What happens to the granuloma in latent TB?
The TB bacilli become dormant inside the granuloma.
- Only pathogenic again upon reactivation.
When are class IV antiarrhythmics used?
Prevent recurrence of paroxysmal supra-ventricular tachycardia
Reduce ventricular rate in patients with atrial fibrillation
Tissue changes in the heart in hypertension
- Coronary atheroma
- Left ventricular hypertrophy
- Increased peripheral resistance
- Decreased flow in cardiac vessels and endothelial dysfunction
Define atheroma
A nodular accumulation of degenerative material in the tunica intima of the artery walls
How do ADH antagonists work?
E.g. tolvaptan
Bind to vasopressin receptors + block the action of ADH – this is a newer treatment
What happens in the early phases of hypertension?
Blood volume and cardiac output increase due to sodium and water retention
What is the primary site of infection known as in TB?
The Ghon focus.
Asthma spirometry findings
FEV1 - significantly reduced
FVC - normal
FEV1/FVC = <70%
How to diagnose aortic coarctation?
Compare femoral pulse to radial pulse.
What happens when exercise/stress level increases and expiration becomes more forceful?
Becomes an active process.
- Internal intercostals and abdo muscles used.
Innate defences of the respiratory tract
- Alveolar macrophages - phagocytose and produce cytokines
- Macrophages - phagocytose and APC
- Dendritic cells - APC and cytokine production
- Intravascular macrophages
- Cytokines important for inflammatory response
What type of diuretics are these?
o Bendroflumethiazide o Chlortalidone o Cyclopenthiazide o Metolaone o Indapamide
Thiazide (block Na+/K+¬¬ cotransport in DCT)
The combined presence of S3 and S4 is a quadruple gallop.
When does it occur?
Also known as a hello-goodbye gallop
Occurs in patients with heart failure
What is primary hypertension?
o 90-95% of patients with hypertension have primary hypertension
o Unknown cause
o Probably environmental (high salt intake) or genetic
o There are 2 phases of abnormally as people develop hypertension – early + late
Other than the SAN, what other pacemaker sites are there?
Bundle of His - 40 bpm
Purkinje cells - 15 bpm
MOA of Cholestyramine
A positively charged drug which binds to negatively charged bile acids, inhibiting their absorption.
It is a bile acid sequestant.
Cholestyramine may also be used to treat itching in people with too much bile acid caused by a certain type of liver/bile duct disease (partial biliary obstruction). This medication is known as a bile acid-binding resin. It works by removing bile acid from the body.
Causes of bardycardia caused by increased PNS activity
- Sleep
- Vasovagal syncope (fainting)
- Fitness – elite athlete may have HF of 30bpm
What is the definition of type 2 respiratory failure (hypercapnia)? What does it indicate?
- Low PaO2 (less than 8kPa).
- High PaCO2 (greater that 6kPa).
What causes the right heart to fail?
Left sided failure
Location of ectopic pacemakers can change its effect on SAN and its rhythm. List 3 different types of pacemakers
o Atrial pacemaker: an ectopic pacemaker located in the atria - can cause atrial conduction to be faster
o Junctional pacemaker: ectopic pacemaker located near AVN and septum
o Ventricular pacemaker: located in ventricles
o Other pacemakers can lie within the pulmonary vein and thoracic vein walls
What class of antiarrhythmics are the following?
Quinidine
Ajmaline
Procainamide
Disopyramide
Ia
MoA of amiodarone (class III antiarrhythmic)
Potassium channel blocker
Extends the action potential (refractory period) and delays repolarisation
Blocks transmission of abnormal signals and terminating arrhythmia
Also acts like a beta blocker (class II)
How do baroreceptors determine BP?
From moment to moment the firing of the baroreceptors (they are the most important system in BP control)
V. sensitive to changes in BP – change firing rate within course of a single heartbeat (diastolic vs systolic pressure)
How is pneumonia classified microbiologically?
Typical and atypical
Examples of obstructive lung diseases
- COPD
- Asthma
- Bronchiectasis
- CF
Myocardial rupture
- Fibrous scar tissue following MI
- Usually occurs within first 2 weeks
- Sudden deterioration
What happens to pleural pressure as you breathe out?
Pleural pressure increases which leads to collapsed airway wall
What is purulent sputum?
Yellow/green
- Due to myeloperoxidase from granulocytes (neutrophils/eosinophils)
- Myeloperoxidase involved in free radical generation pathway to kill bacteria
List causes of HF
o Past heart attacks o CHD o High blood pressure o Heart valve disease o Heart muscle disease or inflammation of the heart o Congenital heart defects o Lung conditions o Alcohol/drug abuse
What is pleuritic pain?
o Injured/inflamed parietal pleura
o Sharp, stabbing, worse on inspiration
o Pneumonia, pulmonary embolism, pneumothorax
Name some of the processes that contribute to respiratory physiology.
What are the 4 categories that they can be broken down into?
- Respiratory drive (CO2 or hypoxic drive).
- Ventilation (air flow): chest wall w/muscles, airway resistance, lung compliance.
- Diffusion (gas exchange): alveoli.
- Perfusion: blood O2 carrying capacity and pulmonary circ.
Colours of sputum
Mucoid (clear/creamy)
Purulent (yellow/green)
Bloodstained – haemoptysis
JVP waveform summary
- A wave– produced by atrial systole
- X – descent occurs when atrial contraction finishes
- C wave – caused by rapid increase in RV pressure before tricuspid valve closure
- V wave – develops as venous return fills the RA during ventricular systole
- Y descent – follows the V wave when the tricuspid valve opens (atrial empty into ventricle)
Adverse effects of thiazide diuretics?
o Hyponatraemia, hypokalaemia, hypomagnesemia
o Hyperuricemia, hypercalcaemia
What can cause acidaemia (low pH) in the blood?
- Resp: high CO2 (hypercapnia).
- Metabolic: low HCO3.
Stenosis vs sclerosis
Aortic stenosis is thickening and tightening of the valve that leads to the heart having to work harder and the possibility of not enough blood being delivered to the body.
Aortic sclerosis is thickening of the valve without any significant effect on the function of the valve itself.
Langerhans giant cells (TB)
What you see when looking at TB under microscope
Fused macrophages oriented around tuberculosis antigen w/ multiple nuclei in periphery
It represents the most successful type of host tissue response
When the population of activated lymphocytes reaches a certain size:
• Cutaneous delayed reactivity to tuberculin, or tissue hypersensitivity manifests
• The spread with which this occurs, varies, but generally will have development within 3-9 weeks after infection
Some macrophages may migrate to lymph nodes + carry bacterium spreads infection
Cause of type II respiratory failure
Alveolar hypoventilation
What are class V antiarrhythmics?
Agents that work by other or unknown mechanisms
3rd degree (complete) heart block
- QRS regular
- Unrelated P wave to QRS
- Ventricular rate usually less than 40bpm
Examples of upper respiratory tract infections
- Pharyngitis, tonsilitis, laryngitis, sinusitis
- Otitis media - due to eustachian tube
Describe Phase 3 cardiac myocyte action potential
Second period of repolarisation caused by continual outflow of K+ and closure of Ca2+ channels
MOA of cisplatin
- Forms a reactive complex that causes intrastrand cross-linking and denaturation of DNA
Atopy and asthma
- Dendritic cell presents to T cell which causes the production of IL-4 and IL-5
- Th2 signals to B cells to produce IgE
- Mast cells degranulate when antigen binds
- Cytokines activate T and B lymphocytes and attract eosinophils
What can cause normal ventilation but decreased perfusion?
- Right to left cardiac shunt (no oxygenation of blood).
- Pulmonary emboli (areas left un-perfused).
- V/Q mismatch.
Enough ventilation but not being perfused!
Course of heart failure
- First acute event e.g. MI
- Acute heart failure
- Treated and recovery OR chronic heart failure
- Chronic heart failure can only occur if acute is treated
MOA of digoxin
- Blocks Na+/K+ ATPase pump
- Increases intracellular Na+
- Decreases intracellular K+
- Increased Na+ reduces Ca2+ exchange by reducing Na+ gradient
- Overall result is increased intracellular Ca2+ producing a POSITIVE INOTROPIC EFFECT
Does eosinophilic and neutrophilic reactions produce green or yellow sputum?
Green
Chemo-reflexes in HF
o Reflex initiated by the stimulation of chemoreceptors (e.g. carotid + aortic bodies) by changes in CO2, H+, O2 conc. in blood
o This is abnormally activated in people with HF and leads to increased ventilation
What do alveolar macrophages produce?
Cytokines
How do beta blockers improve myocardial function?
- Protect cardio myocytes
- Slowing the heart
- Increases diastolic coronary blood flow and reduce myocardial oxygen demands
- Anti-ischaemic
- Anti-arrhythmic
What causes ventilatory failure?
- Ventilatory demand (amount of ventilation to exchange CO2) increases.
- Outweighs ventilatory capacity (amount of ventilation we can maintain before respiratory muscle fatigue).
- Can’t expel CO2 properly.
- Type 2 resp failure?
MOA and examples of sulphonylureas
- Gliclazide and tolbutamide
- Block ATP dependent K+ channels in membrane of pancreatic beta cells, causing depolarisation, calcium influx and insulin release
When are class III antiarrythmics used?
In Wolff-Parkinson-White syndrome
(Sotalol:) ventricular tachycardias and atrial fibrillation
(Ibutilide:) atrial flutter and atrial fibrillation
(Amiodarone): hemodynamically stable ventricular tachycardia[6]
How would you treat stable supraventricular tachycardia?
IV adenosine
What is anasarca?
Anasarca: gross fluid retention, extreme generalised oedema
Pitting oedema - Needs 5kg weight increase + is gravitational
Ascites
Pleural effusions
Develops over many days/weeks
Not all ankle oedema is due to HF, differential diagnoses include:
• Stasis
• Chronic venous insufficiency – varicose veins, DVT
• Drugs – dihydropyridines (calcium antagonists)
• Hypoalbuminaemia – e.g. due to nephrotic syndrome
Panacinar emphysema
Dilatation of terminal acinus
Describe changes in the brain due to hypertension
o Clear associated between hypertension + stroke
o Thrombotic
Increased carotid atheroma
Small penetrating arteries – internal capsule
o Haemorrhagic
Small arteries (charcot-bouchard aneurysms)
Tiny aneurysms develop in small arteries + may rupture causing intracerebral haemorrhage
MOA of minoxidil
- Opens K+ channels
- Good vasodilator - hence it’s used for hypertension
- Fall in peripheral resistance: reflex increase in CO and fluid retention
- Use with diuretic and beta-blocker
Examples of lower respiratory tract infections
- Bronchitis
- Pneumonia
- Lung abscesses
Would patients with obstructive lung disease have more difficulty breathing in or out?
Breathing out.
Treatment of AF
ABCDE treatment of AF:
• Anticoagulants - warfarin or NOACs not aspirin
• Beta blockers - ventricular rate control
• Calcium channel blockers (verapamil) - ventricular rhythm control
• Digoxin - ventricular rate control
• Electro-cardioversion - rhythm control
Atypical community acquired pneumonia - what is it caused by?
Cough and dyspnoea but usually no sputum
Caused by:
- Mycoplasma pneumonia
- Chlamydophilia pneumoniae
- Legionella pneumophilia
Children and young adults
Class III example and effect on AP
Amiodarone
- Blocks K+ channels
- Prolongs AP
ACS (acute coronary syndrome) is an umbrella term for what?
- Unstable angina
- ST elevation myocardial infraction (STEMI)
Blocked (full) coronary artery - Non-ST elevation myocardial infarction (NSTEMI)
Partially occluded coronary artery + raised troponi
- Acute chest discomfort that lasts more than 10 minutes
- Usually some myocardial necrosis, evident by rise in cardiac enzymes
Symptoms of simple bronchitis
- Illness begins with irritating, non-productive cough + discomfort behind the sternum
- Later the cough becomes productive with yellow or green sputum
What type of immune cells combat TB in the lungs?
Alveolar macrophages.
Tissue changes in the brain in hypertension
- Thromboembolic stroke - carotid atheroma, effects internal capsule
- Haemorrhagic stroke - small vessels
Give 6 factors that make TB more common in low/middle income settings.
1) Stigma (don’t seek treatment).
2) Infrastructure problems.
3) Conflict.
4) HIV (immunosuppression).
5) Migration.
6) Poverty (cramped conditions no healthcare).
Hypoxia can be caused by?
o Impaired diffusion
o Hypoventilation
o Ventilation/perfusion (V/Q mismatch)
Which beta blockers are used for heart failure?
o Carvedilol – blocks beta 1, 2 and alpha receptors
o Metoprolol
o Bisoprolol
What happens to the lungs in restrictive lung disease?
- SA reduces.
- Reduced compliance.
- Thickened alveolar membrane.
- Relatively normal airways and airflow
Impaired diffusion.
Silicosis
- Rare
- Caused by inhalational of silicone dust
- Upper lobe nodules and lymph node calcification
- Looks like sarcoidosis - this also affects upper lobes and is associated with granuloma formation
- Predisposes to TB and lung cancer
Chest wall compliance is affected by which factors
Curvatures of spine (kyphosis, scoliosis) Rib fractures Ossification of costal cartilage Obesity Position (supine/prone) Pneumothorax, hydrothorax
Typical pneumonia causative agents
- Streptococcus pneumonae
- Haemophilus influenzae
- Moraxella catarrhalis
Symptoms of heart block
- Dizziness
- Fainting
- Fatigue
- SOB
- Chest pain
Aortic valve stenosis
- Aortic S2 often soft
- Slow rising carotid pulse
- Often left ventricular hypertrophy on ECG
At what systolic pressure would you treat hypertension?
140
What does QRS complex correspond to?
Ventricular depolarisation
o Reflects slow conduction from the AVN, down the bundle of His and up the purkinje fibres
Why must TB droplets be small?
- To remain suspended in the air for a longer period of time.
- To reach the terminal air passages (alveoli).
Where on the cardiac action potential do class IV drugs work?
Phase 2
- Blockage of Ca2+ channels prevents Ca2+ influx
- Prolongs conduction and refractoriness in SA and AV nodes
Describe chronic primary hypertension
Usually blood volume + CO are normal
Confirming that the major underlying factor is an increase in systemic vascular resistance at this stage
o Thickening of wall of vessels
o Reduction in lumen diameters
What came first? – structural changes in the vasculature or increased BP
Abnormalities can be seen in small vessels
o E.g. renal glomerulus (L is normal, R shows hypertension – eosinophilic material fills vasculature)
What is protodiastolic gallop aka ventricular gallop?
S3 added heart sound
Sounds like Kentucky
• S1 = ken
• S2 = tuck
• S3 = y
Heard at beginning of diastole after S2
Low pitch
Benign in youth, some trained athletes, sometime in pregnancy
Occurs with cardiac problems – failing LV + dilated congestive HF
Caused by oscillation of blood back + forth between the walls of the ventricles after a rush of blood from atria
What class of antiarrhythmics are the following examples of?
Adenosine
Digoxin
Magnesium sulphate
Atropine
Class V
Small cell carcinoma treatment
Limited stage (to one side of chest, above diaphragm)
• Radical chemotherapy + radiotherapy
• Median survival time 18 months, <20% achieve cure, 5 year survival 25%
Extensive
• Palliative chemotherapy + radiotherapy
• Median survival time 9 months
List changes which cause fluid to leave capillaries and accumulate in tissues (oedema).
- Decreased colloid osmotic pressure – e.g. due to low albumin levels, less pressure pulling fluid into tissues so fluid leaks out
- Damage to alveolar-capillary membrane – becomes less resistance and causes pulmonary oedema
- Lymphatic blockage – e.g. in some cancers
• Increase in hydrostatic pressure (main factor):
o In the failing heart, heart requires progressively higher pre-load to work enough to keep you alive
o At a critical point, the increased filling pressure in the LV causes the hydrostatic pressure in pulmonary capillaries to go up so high that the fluid transudes out of capillaries into tissues faster than lymphatics can take it away - If this happens in the pulmonary circulation, it leads to pulmonary oedema
What does giant V waves (JVP waveform) indicate?
Tricuspid regurgitation
What could an incomplete rupture lead to?
- Frank rupture
- Formation of false aneurysm
- LV diverticulum
What is an acid-fast bacteria?
What type of test is used for this?
Maintains its colour integrity when acid is applied to it.
- Ziehl-Neelsen stain.
Acid-fast organisms like Mycobacterium contain large amounts of lipid substances within their cell walls called mycolic acids.
These acids resist staining by ordinary methods such as a Gram stain. It can also be used to stain a few other bacteria, such as Nocardia.
Causes of type I respiratory failure
- V/Q mismatch
- Asthma, pulmonary oedema, PE, pneumonia
Ectopic foci
Ectopic foci can initiate and maintain electrical impulses in emergency situations e.g. is SAN blocked
Phase 1 of cardiac action potential
- Closure of Na+ channels
- K+ still continues to move out down concentration gradient
- Voltage gated K+ channels open
- Cl- influx
MOA of alpha blockers (treats HTN)
- Block peripheral alpha-1 receptors
- First dose hypotension
- Example: doxazosin
Pulmonary oedema
- Abrupt (mins)
- Breathlessness
- Difficulty talking
- Orthopnoea – lying down may kill them becuasefluid accumulates in alveolar spaces.
- Frightening – experience ‘angor animi’ fear of certain impending death
- Use of accessory breathing muscles
- Pink, frothy sputum – alveolar fluid with blood
- Sweating
- Cold, clammy
What is the main virulence factor of TB and the reason it isn’t phagocytosed?
It’s thick waxy mycolic acid capsule.
What is NEP? How is it involved in diuresis?
- Neutral endopeptidase
- Converts ANP and BNP to breakdown products
- Blocking it gives more ANP and BNP so more diuresis
E.g. Sacubitril
What are the 2 types of drug resistant TB and what are they resistant too?
1) MDR (multi drug resistant) TB: Rifampicin and isoniazid.
2) XDR (extensively drug resistant) TB: Rifampicin, isoniazid, fluroquinolone, other drugs.
Law of Laplace
Tension in wall of left ventricle = pressure within ventricle x volume within ventricle DIVIDED by wall thickness (this ratio is the other factor in setting the afterload).
- As ventricle dilates, wall tension increases
- As heart starts to contract, it has to exceed wall tension before it contracts
- As afterload increases, CO decreases
How can you diagnose occupational asthma?
Ask if symptoms worse at work and better when they are away
What test is used to test lung (ventilation) function most accurately?
How can this be used to determine the type of lung disease a patient has?
Spirometry.
- FEV1/FVC ratio of 0.7 = obstructive.
- FEV1/FVC ratio of 1 = restrictive.
For obstructive FEV1 is reduced but FVC is normal.
For restrictive both FEV1 and FVC would be reduced so ratio remains normal.
What is tachypnoea?
Faster breathing that normal (>24 breaths per min)
MI treatment for NSTEMI
o Anti-platelets – aspiring and one of: clopidogrel, ticagrelor, prasugrel
o LMWH
o Statin – high dose to reduce cholesterol + stabilise plaque
o Anti-ischaemic (beta blocker, nitrates) – beta blocker therapy decreases heart rate + amount of stress of plaque
Workplace infections
Human sources - influenza, pneumococcus C, pneumoniae, ,tuberculosis.
Animal sources - anthrax, psittacossis (from birds).
Environmental sources - legionellosis.
QRS regular, P wave present, 35bpm
Sinus bradycardia
Dihydropyridines
Calcium antagonists (e.g. nifedipine)
- Block Ca2+ entry into smooth muscle so smooth muscle relaxes + vasodilates
Treatment of hypertension
MoA of calcium channel blockers
Slows the movement of calcium into the heart and blood vessel walls
Reduces heart rate, LV contraction, blood pressure and reduced myocardial O2 demand
Simple pneumoconiois
- Associated with dust inhalation
- Nodules on x-ray
Examples of angiotensin II receptor blockers (ARBs) and their suffix
- Losartan
- Valsartan
- Candesartan
-sarta
Used to lower blood pressure
What are the 2 types of presentation of TB by timing?
1) Primary TB.
2) Latent/reactivated TB
Large volume of sputum expected in?
Bronchiectasis and bronchioloalveolar carcinoma
What 3 features characterise asthma?
- Reversible airflow obstruction
- Airway inflammation
- Increased airway responsiveness
MOA of nicotinic acid
Vitamin B3
- Increases HDL + reduces release of VLDL from the liver
lipid disorders and atherosclerotic cardiovascular disease
What are U waves on ECGs?
The source of the U wave is unknown. 3 common theories regarding its origin are:
- Delayed repolarisation of Purkinje fibres
- Prolonged repolarisation of mid-myocardial “M-cells”
- After-potentials resulting from mechanical forces in the ventricular wall
Prominent U waves seen in bradycardia.
Abnormally prominent U waves are seen in severe hypokalaemia.
What are the 2 types of presentation of TB by site?
1) Pulmonary TB.
2) Extra-pulmonary TB.
Pathogenesis of hospital-acquired pneuomonia (HAP)
- Inhalation/aspiration
- Direct spread - ET tube
- Ventilator associated pneumonia - pneumonia 48hrs after being ventilated
List causes of chest pain
o Pleural pain o Cariac pain o Upper retrosternal pain (tracheitis) o Musculoskeletal pain o Retrosternal pain – mediastinal tumour o Bone pain – rib metastases o Spinal root pain o Herpes zoster (shingles)
What can cause normal perfusion but reduced ventilation?
- Pneumothorax.
- Obstructive lung disease.
Not enough ventilation!
Neurohormonal model for progression of heart failure
- ADH - drink more and retain more fluid
- Natriuretic peptide - ANP, BNP - excrete more Na+, and hence water
- Aldosterone (Na+ and water retention, K+ and Mg2+ loss)
- Endothelin - vasoconstrictor
- Neuropeptide Y - adrenaline
- VIP - parasympathetic
What is miliary TB? What is it an example of?
Invasion of a blood vessel by TB resulting in spread of TB around the bloodstream.
- Lungs and bone marrow most often affected.
- Appears as dots on a CXR.
- Miliary tuberculosis is present in about 2% of all reported cases of tuberculosis and accounts for up to 20% of all extra-pulmonary tuberculosis cases (liver, spleen, kidneys)
- Left untreated, miliary tuberculosis is almost always fatal
Modifiable risk factors for atheroma
- Smoking
- Hypertension
- Obesity
- Diabetes mellitus
What is “gas trapping” in obstructive lung disease?
When part of the lung cannot empty.
- Keep filling and filling, hyper-expansion.
- Ventilation-perfusion mismatching occurs.
- Results in hyperventilation.
Large cell carcinoma
- Poorly differentiated
- Poor prognosis
How is TB identified in a lab?
- Identification of TB bacillus.
- Send 3 sputum samples to lab for TB microscopy.
- Ziehl-Neelsen stain to test for acid fast bacteria.
What is Extra-pulmonary TB (EP.TB)?
What type of patient is it found in?
- TB that is outside the lung via haematogenous or lymphatic spread.
- More common in children and old people, immunosuppressed
- TB of spine can cause back pain
- TB of kidneys can cause blood in the urine
- Miliary TB
Atheroma risk factors
o Modifiable: smoking, DM, obesity, hyperlipidaemia, hypertension, lack of physical activity
o Non-modifiable: family history, gender, age, ethnicity
Consequences of pulmonary hypertension
Cor pulmonale
Second degree heart block type 1
Irregular QRS complexes:
3:2 heart block – 3 P waves for every 2 QRS
AV node is becoming refractory
There is an intermittent delay in conduction of normal sinus impulses from the atria to ventricles
PR interval becomes progressively longer until QRS complex fails to appear
This sequence is then typically repeated
Treatment of stable ventricular tachycardia
Check and correct hypokalaemia and hypomagnesaemia
Intravenous amiodarone (preferably via a central line)
Electrical cardioversion if goes on for 10-15 minutes
Class Ia example and effect on AP
Disopyramide
- Block Na+ channels
- Prolongs AP
Where is the infarction in an inferior MI?
Right coronary artery
Which TB drug may cause vision problems?
Ethambutol.
What is farmers lung?
- Allergic reaction to organisms in mouldy hay
- Inhalation of hat dust or mould such as aspergillus
- In CT scan you can see centriolobular nodules
What are type 2 cardiac cells?
Myocytes
They only fire when simulated (depolarised)
How does digoxin alter the frank-starling curve?
Up and to the left
- It is a positive inotrope
Physiological defences of the respiratory tract
- Cough
- Epiglottic reflex
- Nasopharynx clears organism for swallowing
- Epithelial cells produce airway surface liquid
Ventricular fibrillation
o Chaotic depolarisation of the ventricles, resulting in an arrested cardiac pump function and immediate death
o VF can only be treated by immediate defibrillation
o Rate is O – no QRS complexes
o Rates are so rapid that the ventricles twitch in a disorganised and chaotic manner
o ECG shows no identifiable waves, no pattern of impulses – hence no CO
Why do patients with heart failure under diuresis become hypokalemic?
- Aldosterone from RAAS causes K+ excretion
- Effect of diuretics results in more Na+ in DCT resulting in more K+ being lost
What happens if you decrease colloid osmotic pressure?
Movement of fluid out of the capillaries
Atypical pneumonia causative agents
- Legionella pneumophila
- Mycoplasma pneumoniae
- Chlamydiophila pneumoniae
Special points about digoxin
- Big loading dose
- Narrow therapeutic window
- Excreted unchanged by the kidneys - don’t use if kidney diseased
Emphysema
- Abnormal enlargement of airspace, distal to terminal bronchioles
- Destruction of alveoli walls
Which drugs should be avoided in HF?
o Calcium antagonists – e.g. amiodipine
o Positive inotropes – e.g. digoxin, levosimendan
o Antiarrhythmics – stop antiarrhythmic in people with HF except amiodarone which is ok
Give examples of normal perfusion but reduced ventilation
Pneumothorax
Pneumonia
Obstructive lung diseases (e.g. asthma)
What are the 2 mineralocorticoid (aldosterone) antagonists?
- Spironolactone
- Eplerenone - new + expensive
What type of immunity is important to keep TB in check?
Cell mediated
What is renal artery stenosis?
What is its effect on blood pressure?
- Fibromuscular hyperplasia
- In young women with hypertension which is difficult to control
- Kidneys don’t get enough blood so they think BP is low
- Decreased pressure in the afferent arteriole
- Increase in renin release = increase in angII and aldosterone
Where do loop diuretics work?
Block Na+/K+/2Cl- cotransporter in the thick ascending loop of Henle
• Work from lumen of the tubule – need some glomerular function to filter the drug into the tubule
Signs and symptoms of L sided heart failure
Increased rate + work of breathing
Dyspnea, orthopnoea, paroxysmal nocturnal dyspnoea
Fatigue
Rales or crackles heat in lung bases (if heard throughout the lung this indicates pulmonary oedema)
Cyanosis
Laterally displaced apex beat (occurs if the heart is enlarged)
Gallop rhythm
Heart murmurs may indicate the presence of valvular heart disease as either a cause (e.g. aortic stenosis) or as a result (e.g. mitral regurgitation) of the heart failure
At which phase of cardiac myocyte action potential do class III agents work?
Phase 3 – Second period of repolarisation caused by continual outflow of K+ and closure of Ca2+ channels
• Class III agents block these K+ channels and prolongs the duration of the AP
Ventricular tachycardia
o Is a sequence of 3(+) ventricular beats
o Frequency is usually 110-250bpm
o Often origin around old scar tissue in the heart – e.g. post-MI
o CO is strongly reduced during VT, resulting in hypotension and loss of consciousness
o Can deteriorate into ventricular fibrillation
o Due to rapid discharge of ectopic beats from multiple sites in vernicles
o Patient has palpations and need defibrillation
What is ventilation/perfusion mismatch?
- Part of the lung is not ventilated but IS being perfused.
- Part of the lung is being ventilated but IS NOT being perfused.
- Hypoxia.
- Results in shunt of deoxygenated blood from R -> L heart.
Treatment of asthma
o Inhaled corticosteroids and bronchodilators are fine for most people
o Some people make too much IgE (highly atopic) – some drugs can mop up excess IgE
o Monoclonal antibodies
o IL-5 blocker e.g. Mepoluzimab – work for people who have a high eosinophil count in airway + lungs
o If the patient is receiving treatment and not getting better may be due to:
Poor compliance – not taking medication
Poor technique – not using proper inhaler technique
Misdiagnosis
What are the causes of loss of consciousness?
Cardiac
o Sudden onset, no aura, no jerks/incontinence, injury common, very pale, immediate recovery
Neurological
o Prodrome/aura, convulsive movements, incontinence, self-harm (tongue), post-ictal confusion
Vasodepressor syncope
o After prolonged standing response to stress, gradual developing faintness, greying out of vision
Carotid sinus hypersensitivity
o Rubbing neck causes syncope
What are some of the side effects of Rifampicin?
- Orange secretions (pee, tears).
- Nausea.
- Abdo pain.
- Hepatitis.
Pre-load
Pressure in the ventricles before it starts to contract
- Also called filling pressure
Pink puffers (emphysema)
• Thin because of work of breathing
• Pursed lips breathing + leaning forwards
o To give ‘auto ‘PEEP’ expiratory resistance to prevent airway collapse
o Prominent use of accessory breathing muscles
• Go into ventilatory failure later
• May be very breathless but have normal blood gases up to end of disease
Mutations in non-small cell carcinoma
EGFR, KRAD, CD44, P16
LRT infections
o Pathogens that cause lower RTI - Viral, bacterial, mycobacterial, fungal, protozoal infections
o Includes: bronchitis, pneumonia, lung abscesses
o LRTI as the leading cause of death among all infectious diseases
Describe early primary hypertension
- Increased blood volume + cardiac output
- Increased sodium retention could account for increase in blood volume
- May mean that hypertensive patients cannot handle sodium appropriately, or cannot easily excrete sodium
- Unknown how initial increase in blood volume + CO initiates subsequent changes in systemic volume
What is the anterolateral papillary muscles blood supply?
LAD and Left circumflex
Name 2 classes of potassium sparing diuretics
Mineralocorticoid receptor antagonists (used to be called aldosterone antagonists because they block effects of aldosterone)
Epithelial sodium channel blockers (ENaC) - block K/Na pump
Frank-starling law
o The more the heart fills with blood, the greater the force of contraction
Increasing pre-load leads to increases ventricular work
o In people with HF, the curve falls downwards and to the right until patient needs an extremely high preload just to have heart function at rest
MoA of digoxin
Inhibits Na+K+ATPase membrane pump, resulting in increased intracellular Na+ and decreased intracellular K+
Sodium calcium exchanger tries to extrude the sodium by pumping in more calcium – positive inotropic effect
Strengthens ventricular contractions so that the heart is able to pump more blood with each beat
Chronic bronchitis involves?
o Mucus glands hypertrophy
o Smooth muscle hypertrophy
o Goblet cell hyperplasia
o Inflammatory cell infiltrate – lymphocytes + neutrophils (not eosinophils)
o Excess mucus – because goblet cells + mucus glands increase in number
Atrial flutter with 2:1 AV conduction
- 2 P waves for every 1 QRS
- Sawtooth appearance of P wave!!
- Narrow complex tachycardia
- Atrial rate 280bpm, ventricular 140bpm
What are some of the problems with the Mantoux test? (TST).
- False positives: Low specificity. Previous BCG or incorrect reading.
- False negatives: Low sensitivity. Immunosuppression could impact.
What are some systemic symptoms of infection?
- Fever.
- Chills.
- Weight loss.
- Fatigue.
- Appetite loss.
Chronic airway changes in asthma
Subepithelial fibrosis
Smooth muscle hypertrophy
Causes of pneumoconiosis
o Coal dust
o Silica
o Asbestos
What is essential hypertension?
- Primary hypertension
- 90-95% of cases
- No known causes
Chronic heart failure symptoms
o Exertional breathlessness, relieved by rest – may also be related ischaemia
o Orthopnoea
o Swollen abdomen – ascites caused by severe LV dysfunction, R heart failure
o Nocturnal cough
o Episodes of PND
o Ankle oedema
MOA of furosemide
Loop diuretics
- Block Na+/K+/2Cl- co-transpotrter in the thick ascending loop of Henle
- Can cause hyponatraemia, hypokalaemia and hyperuricaemia
Why is pyridoxine indicated in TB?
- To prevent peripheral neuropathy
- Side effect of isoniazid
- It is vitamin B6
Where is a murmur with aortic regurgitation best heard?
Left 4th IC space (pulmonary valve)
Pulmonary embolism
- Over infarcted area
- Pleuritic pain
- Associated with SOB
- Tachycardia/AF
- Tachypnoea
Which conditions can trigger acute heart failure?
o Infection o Kidney disease/poor kidney function o Anaemia o Abnormal heart rhythm o Overactive thyroid gland
Asthma medications
o Short acting beta agonists (SABA)
o Long-acting beta agonists (LABA) - Formoterol + salmeterol
o Inhaled corticosteroids
o Leukotriene receptor antagonists - Block leukotriene receptors, prevent bronchoconstriction
o Combination inhalers - Mixture of LABA + corticosteroid
QRS regular, P wave absent, Long PR interval
1st degree heart block
What does the PR segment represent?
PR segment – conduction from the AVN, down the bundle of his and up the purkinje fibres
What type of resp failure is seen in acute asthma (normal)?
Type 1.
- Hyperventilation with hypoxia.
- They have ventilatory capacity to match the demand.
What happens in complete heart block?
Blockage of normal electrical connection across annulus fibrosus
- SA node can’t dominate
- Bundle of His takes over - 40 bpm
How does renal artery stenosis cause secondary hypertension?
Narrowing of arteries that carry blood to kidneys leads to decreased pressure in afferent arteriole
Kidney thinks BP is low so it releases renin
Renin increases BP by increasing angiotensin II and aldosterone
Angiotensin II promotes cardiac and vascular hypertrophy
Increased blood volume, cardiac output, vascular resistance all leads to hypertension
How should diuretics be used?
- Administered IV to bypass oedematous gut
- Infusion better than bolus
- Change loop diuretic - bumetanide + torsemide are more predictable and have fewer side effects
- Progressive nephron blockade – can work down the nephron tubule + block different things, add thiazide
