13 Flashcards
What are some common symptoms of pulmonary TB?
- Haemoptysis.
- Cough.
- Sputum.
- Chest pain.
- Systemic symptoms of infection.
Antimuscarinics MOA in asthma
Block muscarinic acetylcholine receptor which prevents ACh binding to muscarinic receptors
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
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)
- Sputum cough
- Oedematous ankles
- Cyanosed
- Overweight
- Sleep apnoea
Tissue changes in the kidney in hypertension
- Glomerular damage
- Shrink
- Renal artery stenosis
- Arteriosclerosis leading to progressive ischaemia of the nephrons
Types of calcium channel blockers.
All calcium channel blockers inhibit the L-type calcium channel on cells.
They are divided into 2 major categories based upon their predominant physiologic effects:
- Dihydropyridines: are predominantly vasodilators, have chronotropic and inotropic effects
- Non-dihydropyridines: are less potent vasodilators, slow cardiac contractility and conduction
Dihydropyridines:
- Nifedipine, isradipine, felodipine, nicardipine, nisoldipine, lacidipine, and amlodipine
- Potent vasodilators that have little or no negative effect upon cardiac contractility or conduction
- Indication: hypertension, chronic stable angina
- Longer-acting agents are generally safer and are increasingly preferred
Non-dihydropyridines
- Verapamil and diltiazem
- Indication: hypertension, chronic stable angina, cardiac arrhythmias, proteinuria reduction
- Are somewhat less potent vasodilators compared with dihydropyridines, but they have a greater depressive effect on cardiac conduction and contractility
What are arterial blood gases? When is it indicated?
Gives the:
- PaO2
- PaCO2
- Acid-base balance (pH, HCO3, H+ etc)
Indicated when oxygen sats are 90-92% or lower.
Pharmacological treatment of patients with LV HF
- 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.
What is wheeze?
A musical noise produced by air moving through narrowed airways (airway obstructed)
o Obstruction of airways within chest causes wheezing with 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 managed conservatively
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 channel antagonists
- E.g. verapamil, diltiazem (class IV antiarrhythmics)
- 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
- Not used anymore
- Cause unpleasant GI side effects
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 with 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
Mycobacterium tuberculosis
- Gr+
- Obligate aerobe
- Stains with Ziehl-Neelson
- Bacilli are non-motile, non-sporing and non-capsulated
- Rod
Consequences of left ventricular dysfunction?
- SOB
- Peripheral oedema
- Paroxysmal nocturnal dyspnoea (PND)
- Raised JVP
- Orthopnoea
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 with PCI compared to thrombolysis because of high rate of reperfusion
What % of all CHD deaths are attributable to smoking?
20
Left bundle branch block ECG pattern
Negative V1 - W
Positive V6 - M
WiLLiaM
Cardiogenic shock
- Extreme version of heart failure
- Large heart attack where they kill off so much heart that brain and kidneys profusion drops
- Results in death
Pathophysiology of right sided heart failure
Fall in cardiac output
Fall in renal perfusion
RAAS:
- Increased ADH and 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 with hypertension
- Seen in people with stressful jobs with hypertension at a young age
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)
QRS narrow and ragged atrial spikes rather than P waves
Atrial fibrillation
How is any tachycardia with hypotension/collapse treated?
Emergency electrical cardioversion with sedation if necessary
Treatment for collapsed patient with VT same for VF
Tissue changes in chronic 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 is the primary site of infection known as in TB?
The Ghon focus.
How to diagnose aortic coarctation?
Compare femoral pulse to radial pulse.
Innate defences of the respiratory tract
- Alveolar macrophages - phagocytose and produce cytokines
- Dendritic cells - APC and cytokine production
- Cytokines important for inflammatory response
What type of diuretics are these?
o Bendroflumethiazide o Chlortalidone o Cyclopenthiazide o Metolaone o Indapamide
Thiazide and thiazide like diuretics
Inhibits sodium reabsorption in the distal convoluted tubule (DCT) by blocking Na+/Cl- co-transporter in the luminal membrane
Act on thiazide-sensitive Na+-Cl− symporter.
The combined presence of S3 and S4 is a quadruple gallop. (Aka hello-goodbye gallop)
When does it occur?
Heart failure
What is primary hypertension?
o 90-95% of all hypertension
o Unknown aetiology
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
Cholestyramine
A positively charged drug which binds to negatively charged bile acids, inhibiting their absorption.
It is a bile acid sequestrant.
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.
What is the definition of type 2 respiratory failure (hypercapnia)?
- Low PaO2 (less than 8kPa).
- High PaCO2 (greater that 6kPa).
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
Other pacemakers can lie within the pulmonary vein and thoracic vein walls
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)
Examples of obstructive lung diseases
- COPD
- Asthma
- Bronchiectasis
- CF
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 Hypertension o Heart valve disease o Heart muscle disease or inflammation of the heart o Congenital heart defects o Lung conditions o Alcohol/drug abuse
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
Colours of sputum
Mucoid (clear/creamy)
Purulent (yellow/green) - myeloperoxidase from granulocytes
Bloodstained – haemoptysis
JVP waveform summary
- A wave – atrial systole
- X descent – atrial relaxation
- C wave – tricuspid valve bulging into atria with ventricular contraction
- V wave – passive atrial filling
- Y descent – atrial empty into ventricle (tricuspid valve opens)
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 with 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
Cisplatin
Folate antagonist
- Interferes with thymidylate synthesis (essential for DNA synthesis)
- Forms a reactive complex that causes intrastrand cross-linking and denaturation of DNA
Indication:
- Testicular cancer
- Ovarian cancer
- Cervical cancer
- Bladder cancer
- Lung cancer
- Head and neck cancer
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
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
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
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
Panacinar emphysema
Dilatation of terminal acinus
Nicorandil
Minoxidil
Diazoxide
Potassium channel opener
- 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
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.
Organisms that cause atypical community acquired pneumonia?
- Mycoplasma pneumonia
- Chlamydophila pneumoniae
- Legionella pneumophila
ACS (acute coronary syndrome) is an umbrella term for what?
- Unstable angina
- ST elevation myocardial infarction (STEMI)
- Blocked (full) coronary artery - Non-ST elevation myocardial infarction (NSTEMI)
- Partially occluded coronary artery + raised troponin
- 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
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)
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)
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
Aortic valve stenosis
- Aortic S2 often soft
- Slow rising carotid pulse
- Often left ventricular hypertrophy on ECG
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).
What is protodiastolic gallop aka ventricular gallop?
S3 added heart sound
- 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
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
What does giant V waves (JVP waveform) indicate?
Tricuspid regurgitation
What is an acid-fast bacteria?
What type of test is used for this?
Bacteria which 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.
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.
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
MI treatment for NSTEMI
o Antiplatelets: aspirin and clopidogrel or ticagrelor or prasugrel
o LMWH
o Statin: high dose to reduce cholesterol and stabilise plaque
o Anti-ischaemic (beta blocker, nitrates) – beta blocker therapy decreases heart rate + amount of stress of plaque
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
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
Examples of angiotensin II receptor blockers (ARBs) and their suffix
- Losartan
- Valsartan
- Candesartan
-sartan
Used to lower blood pressure
Large volume of sputum expected in?
Bronchiectasis and bronchioloalveolar carcinoma
Nicotinic acid
Vitamin B3
- Increases HDL
- Reduces release of VLDL from the liver
Indication:
- Lipid disorders
- Atherosclerotic cardiovascular disease
MOA of nicotinic acid
Vitamin B3
- Increases HDL + reduces release of VLDL from the liver
lipid disorders and atherosclerotic cardiovascular disease
What are the 2 types of presentation of TB by site?
1) Pulmonary TB.
2) Extra-pulmonary TB.
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
Risk factors for atheroma
Modifiable:
- Smoking
- Hypertension
- Obesity
- Diabetes mellitus
- Hyperlipidaemia
- Lack of physical activity
Non-modifiable:
- Family history
- Gender
- Age
- Ethnicity
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
What is extra-pulmonary 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
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 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 causes K+ excretion
- Diuretic use leads to more Na+ in DCT which leads to resulting in greater K+ excretion
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. amlodipine
o Positive inotropes – e.g. digoxin, levosimendan
o Antiarrhythmics – stop in people with HF except amiodarone which is ok
What are the 2 mineralocorticoid (aldosterone) antagonists?
Spironolactone
Eplerenone - new + expensive
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
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.
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
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
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
Why is pyridoxine indicated in TB?
- To prevent peripheral neuropathy
- Side effect of isoniazid
- It is vitamin B6
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) (salbutamol_
o Long-acting beta agonists (LABA) (formoterol + salmeterol)
o Inhaled corticosteroids
o Leukotriene receptor antagonists
o Combination inhalers - Mixture of LABA + corticosteroid
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.
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
Interleukins
o IL4 – stimulates production of IgE
o IL5 – Activates locally recruited eosinophils
o IL13 – stimulates mucus secretion from bronchial submucosal glands + also promote IgE production by B cells
Mycobacterium species
M. tuberculosis – main cause of TB
o Rod shaped bacterium
o Mycolic acid present in cell wall making it acid-fast
o Aerobic + non-motile
o Multiplies slowly and can remain dormant for decades
M. afriticanum – important opportunistic infection in HIV; commonly found in West Africa
M. bovis – Widespread; causes bovine TB in cattle, cats, dogs, badgers, deer, possums…
o Nonvirulent vaccine strain of M bovis used in the BCG vaccine
M. canatii – emerging disease in East Africa
M. microti – mostly infects voles, human infections are rate (more common in immunocompromised patients
Extra-pulmonary TB
Metastatic spread to any organs: abdomen, bone, brain, retina, muscles, lymph nodes
~30% of TB cases are exclusively extra pulmonary
o TB of spine may cause back pain + kyphosis
o TB of kidney may cause blood in the urine
o Extra-pulmonary TB should be considered in the differential diagnosis of ill persons who have systemic symptoms + who are at high risk for TB
Why is the SAN the pacemaker?
Fastest intrinsic firing - 105 bpm
Pioglitazone
Reduce peripheral insulin resistance, leading to reduction in plasma glucose
Drug for DM II
What is the Mantoux tuberculin skin test? (TST).
- Intadermal injection of tuberculin.
- If T cells have been previously sensitised, inflammatory response at the site within 48-72 hours.
Bundle branch block
- Block either in right or left bundles that branch from the Bundle of His
- Wide double peak QRS
- Inverted T wave
What are Janeway lesions?
- Non-painful, black spots on thenar + hypothenar eminences of hands + feet
- Septic emboli within dermis of skin
Left sided heart failure
L side is responsible for receiving oxygen rich blood from the lungs + pumping it forward to the systemic circulation
Failure of the L side of the heart causes blood to back up into the lungs, causing respiratory symptoms as well as fatigue due to insufficient supply of oxygenated blood
There are 2 types of left-sided heart failure:
- Systolic failure: L chamber lacks the force to push enough blood into the circulation
- Diastolic failure: L chamber fails to relax normally because the muscle has become stuffer + filling is impaired
When are calcium channel blockers (class IV) contraindicated?
- Pregnancy
- Cardiogenic shock
- Severe bradycardia
- Moderate to severe heart failure
Alteplase
Tenecteplase
Streptokinase
Thrombolytics
Enzymatically activates plasminogen to give plasmin which digests fibrin and fibrinogen, lysing the clot.
Indication:
- Thrombolysis in STEMI
- Massive pulmonary embolism
- Acute ischaemic stroke
Contraindications:
- Recent surgery (10 days)
- GI bleeding (3 months)
- Active bleeding or haemorrhagic disorder
- Previous cerebrovascular accident
- Pregnancy
- Aortic dissection
- Acute pericarditis
Grade I to III cancer cells.
Grade I: Cancer cells that resemble normal cells and aren’t growing rapidly
Grade II: Cancer cells that don’t look like normal cells and are growing faster than normal cells
Grade III: Cancer cells that look abnormal and may grow or spread more aggressively
What is Fick’s Law of Diffusion? How does it apply to the lungs?
The rate of transfer of a gas through a tissue is proportional to the tissue area, and inversely proportional to thickness.
- Large and thin = lots of transfer.
- Large SA in the lungs (50-100sq. metres) and extremely thin alveoli.
Commensals of the respiratory tract
- Streptococcus pneumoniae
- Haemophilus influenzae
- Streptococcus viridian’s group
Ventricular flutter
o Mostly caused by re-entry with a frequency of 300bpm
o The ventricles depolarise in a circular pattern, which prevents good function
o Most often this results in a minimal CO and subsequence ischaemia
o Often deteriorates into VF
Omapatrilat
A combined ACEi and NEP inhibitor which increases diuresis
Omapatrilat is an experimental antihypertensive agent that was never marketed. It inhibits both neprilysin (NEP) and angiotensin-converting enzyme.
NEP inhibition results in elevated natriuretic peptide levels, promoting natriuresis, diuresis, vasodilation.
How can hypokalaemia be prevented in patients with HF under diuresis?
Give K+ sparing diuretic e.g. spironolactone or amiloride
What is presystolic gallop (aka atrial gallop)?
S4 added heart sound
Heard just after atrial contraction + end of diastole before S1
Best heart at the cardiac apex
Produced by the sound of blood being forced into a stiff or hypertrophic ventricle
- Aortic stenosis
- Hypertension
- Hypertrophic cardiomyopathy
Describe changes in the heart due to hypertension
o Coronary atheroma – increases risk of MI
o Atheroma in L side circulation doesn’t affect pulmonary artery – pulmonary atheroma only seen in pulmonary hypertension, this shows that hypertension is vital in pathogenesis of atheroma
o Concentric LV hypertrophy (fairly early on in hypertension) - myocyte number remains constant but individual cells hypertrophy
There also may be fibroblast proliferation and LV fibrosis which would lead to impaired LV relaxation
