Cardiology - Heart Failure and CM Flashcards
What is heart failure
A syndrome characterised by fatigue, breathlessness and fluid retention
Caused by impaired cardiac function leading to circulatory insufficiency
What does dx of heart failure rely on
Clinical judgement based on several factors e..g symptoms and signs, severity, underlying cardiac abnormality, co-morbidities
Classification of heart failure based on LVEF
HF w/ reduced LVEF (HFrEF) - <40%
HF w/ mid-range LVEF (HFmrEF) - 40-49%
HF w/ preserved LVEF (HFpEF) - >50%
LVEF
LV ejection fraction
Calculating Ejection fraction
End diastolic volume - end systolic volume / end-diastolic volume
How can we measure EF
Echo
MRI
Myocardial perfusion scan
What is a lower ejection fraction associated with
Higher risk of mortality
What is a lower ejection fraction associated with
Higher risk of mortality
What does EF look at
How much blood is pumped out of the heart vs the volume in ventricles before
Normal EF
55%
What are causes of systolic heart failure
IHD
DCM
Myocarditis
Causes of diastolic heart failure
HCM/ HOCM
Restrictive CM
Cardiac tamponade
Main causes of high-output cardiac failure
Anaemia and pregnancy
Pathophysiology of heart failure
Initial event causing myocardial damage –> increase in wall stress –> activates multiple neuroendocrine systems causing further damage to myocardium
Epidemiology of heart failure
CAD is leading cause of HF in UK
Incidence increases w/ age - age at first px is 76 yrs, M > F
Prognosis of HF
Usually poor - 3yrs survival from dx, 40% die within 1 yr
Presentation of HF
SOB Fatigue Orthopnoea PND Swollen ankles Palpitations
NYHA clinical classification of HF
Class I - no limitations on activity
Class II - symptoms brought on by ordinary physical activity (mild HF)
Class III - Marked limitation of physical activity (moderate HF)
Class IV - pts have symptoms at rest (severe HF)
Ix in HF
Standard bloods Other bloods Urinalysis BNP & N-terminal pro BNP ECG Echo CXR Cardiac imaging
Standard bloods for HF ix
FBC
Renal function
Extra bloods for HF ix
LFT
TFT
Glucose
Cholesterol
Urinalysis for HF ix
Looking for protein and glucose
What happens if BNP is normal in suspected HF
Normal BNP generally rules out HF
When does BNP increase
In ventricular stretch/ LVEDP (preload)
CXR in a/c HF
Cardiomegaly - cardiothoracic ratio > 0.5
Pulmonary oedema
Bilateral blunting of costophrenic angles
Mx of a/c pulmonary oedema
Oxygen
Diuretics
Nitrates
Morphine
Weight pt daily and take daily U&Es
Key imaging method for pts w/ suspected heart failure
Echo
Provides info on structure and function of cardiac chambers, valves and pericardium
When can you not do an echo
If the ‘window’ is poor
What do stress echos look for
Reversible ischaemia
What does a cardiac MR provide info about
Extent of fibrosis and perfusion abnormalities
When is a cardiac MR particularly useful
When echo images are poor due to obesity or COPD
What is usually required for cardiac MR
Specialist referral
Ddx of HF
Chest diseases Venous insufficiency in LL Drug-induced ankle swelling/ fluid retention Angina Hypoalumineamia Intrinsic renal/ hepatic failure Severe thyroid disease Bilateral renal artery stenosis
General measures for managing HF
Pt education Wt control Reducing salt and fluid Smoking cessation Mx of co-morbidities
Poor prognostic factors in HF
Low EF (<30%) - most important Low systolic BP Coronary disease Raised creatine/ eGFR Hyponatremia DM Anaemia Arrhythmia AF
Aims of therapy in HF
Improve life expectancy
Improve QoL
Aims of treatment of a/c HF
Improve haemodynamic & symptomatic profile
Prevent myocardial & renal damage
A/c HF mx
PODMAN
Positioning - sit up (high Fowler's position) Oxygen Diuretics (loop) Morphine Antiemetics Nitrates (IV)
May also give IV dobutamine and non-invasive ventilation (CPAP, BiPAP)
Diuretics therapy for HF
Rapid relief of congestive symptoms and fluid retention w/ loop diuretics e.g. furosemide, bumetanide
May be titrated according to need after adding new meds
Which HF symptoms do loop diuretics improve
Breathlessness
Exercise performance
Drugs for c/c HFrEF
ACEi/ ARB
BB - reduce HR
Aldosterone receptor blockers (spironolactone, eplerenone)
Sacubitril/ valsartan
When would you use sacubitril/valsartan in c/c HF
Replaces ACEi/ ARB when EF <35%
Other potential treatments for c/c HF
Ivabradine (similar to BB)
Digoxin (esp w/ AF)
Amiodarone (pts w/ arrhythmias)
Anticoags
Why does ACE cough develop
ACE inactivates bradykinin
ACE inhibition therefore leads to increase in bradykinin levels —> cough and angiodema
Mx of pts w/ HF due to LV systolic dysfunction
ACEi (titrated up to correct dose)
Treatment should be initiated before BB introduced
MOA of sacubutril/ valsartan
Neprilysin inhibits naturietic peptides and sacubutril is a neprilysin inhibitor (prevents breakdown)
Also inhibits angiotensin pathway
Treating HF and AF
Anticoag - consider for those w/ hx of thromboembolism, LV aneurysm or intracellular cardiac thrombus
Amiodarone - effective against most ventricular arrhythmias
Side effects of amiodarone
Thyroid dysfunction
Pulmonary fibrosis
Liver damage
Neuropathy
Surgery and devices for c/c HF
Coronary revascularisation Transplantation LVAD CRT - biventricular pacing Ablation for AF ICD Valve repairs if indicated
LVAD
LV Assist Device
Revascularisation for HF
PCI/ CABG may relieve ischaemic symptoms and improve mortality in heart failure pts w/ multi-vessel disease and stable angina
CRT for HF
~30% of HF pts have dyssynchronous ventricular contraction (LBBB)
When should CRT be considered in HF pts
LVSD (EF < 35%) on medical therapy and a QRS duration > 120msec
Heart transplant for HF
Limited availability of donor organs
Few UK centres
c/c immunotherapy required
Mechanical support for HF pts
Implanted mechanical pumps can provide circulatory support for short/medium term
When should mechanical support be considered for HF pts
Specialists consider this in pts w/ severe refractory symptoms, or refractory symptoms or refractory cardiogenic shock
What is HFpEF associated with
Older age and HTN/ LV hypertrophy, obesity, DM
Mutation seen in Marfan syndrome
FBN1 gene –> less functional fibrillin-1 produced
Inheritance pattern for Marfan syndrome
Autosomal dominant
Mutations seen in Long QT syndrome
KCNQ1, KCNH2 and SCN5A genes
Inheritance pattern for long QT syndrome
Autosomal dominant
Fabry disease
Results from build up of fat, globotriaosylceramide
What mutations cause Fabry disease
GLA –> absence of alpha-galactosidase A –> globotriaosylceramide isn’t broken down
Inheritance pattern of Fabry disease
X-linked
Mutations causing familiaal hypercholesterolaemia
Mutations in APO8, LDLR, LDLRAP1 or PCSK9
Most common cause of familial hypercholesterolaemia
Changes in LDLR –> less LDL receptors made –> less LDLs removed from blood stream
Inheritance pattern of familial hypercholesteolaemia
Autosomal dominant pattern
Genetic variation affecting mx of pts w/ CVD
Some pts treated w/ statins have bad ADRs e.g. myopathy associated w/ simva and a variant of gene SLCO1B1
Some pts treated w/ clopi don’t benefit as variants of cytochrome P450 can alter conversion of inactive prodrug to its active metabolite
Cardiomyopathy
Disorder in which heart muscle is structurally and functionally abnormal (in absence of other heart condns severe enough to cause the heart muscle abnormality)
Commonest types of cardiomyopathies
Hypertrophic
Dilated
Arrhythmogenic
What type of impairment is seen in HCM
Diastolic
What type of impairment is seen in DCM
Systolic
Commonest CM
HCM
HCM
Unexplained LV hypertrophy - Pattern is usually asymmetric septal hypertrophy
Most common inherited cardiac disease (autosomal dominant)
Commonest cause of sudden death in young (<35yrs) and in athletes
What % of HCM pts have Fhx
50%
Usual px of HCM
HCM can px at any age - birth to >90
Most cases are asymtpmatic
What % of HCM pts have an obstructive form
25%
What is HCM a disease of
Sarcomere
Mutated peptides incorporated into sarcomere –> impaired contractile function –> increased myocyte stress –> compensatory hypertrophy and increased fibrosis
Which proteins in the sarcomere are affected by HCM
Myosin binding protein c
B myosin heavy chain
Hypertrophy vs hyperplasia
Hypertrophy is increase in muscle cell SIZE
Hyperplasia is increase inn cell no.
Examination findings in HCM
May be normal
Double apical impulse
S4
Features of systolic outflow obstruction
Features of systolic outflow obstruction
Jerky pulse
Systolic murmur - obstruction –> murmur at LSE (dynamic - changes depending on preload and afterload), MI
Jerky pulse
Brisk carotid upstroke which suddenly stops
ECG in HCM
Typically, v abnormal showing LVH w/ strain pattern
Imaging tests of choice in suspected HCM
Echo or MRI
Mx of HCM
General measure Treat symptoms Manage AF risk Assess risk of sudden death Family screening
General measures for HCM
Avoid competitive sports
Reassure pt w/out high-risk features
Overall prognosis is good
Treating symptoms of HCM
BB (or verapamil)
- Decreased HR –> increased diastolic filling time
- Decreased force of contraction —> decreased myocardial oxygen demand
Myomectomy (or septal ablation) if still symptomatic
Myomectomy
Surgeon removes small amount of thickened septal wall to widen outflow tracts from LV to aorta
Family screening for HCM
Screen by ECG and echo (and genetic testing if mutation known)
What is DCM characterised by
Enlargement of one or both ventricles w/ impaired contractile function
What does DCM commonly cause
Systolic HF
Pathophysiology of DCM
Myocyte injury –> decreased contractility –> decreased SV
This leads to increased ventricular filling pressure, LV dilatation, decreased CO
Types of DCM
Idiopathic Familial Infl Toxic Metabolic Tachycardia induced Neuromuscular
Infl DCM
Infectious - post viral
Non-infectious - CTD, peripartum mypoathy, sarcoidosis
When does peripartum myopathy occur
Between 6th to 9th month of pregnancy
Toxic DCM
Alcohol - may be reversible by stoping alcohol intake
Chemotherapy
Metabolic DCM
Caused by hypothyroidism
Tachycardia-induced DCM
May recover fully w/ treatment of arrhythmia
Neuromuscular DCM
Muscular or myotonic dystrophy
Px of DCM
Usually presents w/ signs of CCF
What should you ask a DCM pt when they px
Fhx
Alcohol
Exposure to chemotherapeutic drugs
Ix for DCM
Bloods ECG CXR Echo/ MRI Angiography
Bloods for DCM
U&E’s
Ca
P
TFTs
ECG for DCM
No spp features
Finding incl non-spp ST/T wave changes, conduction defects (incl BBB)
CXR findings for DCM
Cardiomegaly
Eco/ MRI findings for DCM
Enlargement of all 4 chambers w/ decreased systolic function
Angiography for DCM
To exclude IHD
Arrhythmogenic CM
An inherited heart muscle disorder characterised by replacement of RV myocardium by fibrofatty tissue
What is arrhythmogenic CM a disease of
Desmosome
Px of arrhythmogenic CM
Presents in young-middle age
May be asymptomatic or present w/ palpitation, syncope or SCD
SCD
Sudden cardiac death
CCF
Congestive cardiac failure
ECG for arrythmogenic CM
Usually abnormal, showing T wave inversion nd localised prolongation of QRS interval in R precordial leads (V1 - V3)
Typical arrhythmia seen in arrhythmogenic CM
LBBB morphology VT
Dx of arrhythmogenic CM
Combi of ECG, imaging, Fhx, biopsy
ICD for arrhythmogenic CM pts
Pts who have survived cardiac aresst
Pts who’ve had haemodynamically unstable ventricular arrhythmias
Pts who have severe cardiac impairment
What do desmosomes do
Bind muscle cells together
Restrictive CM
Rare
Due to myocardial fibrosis or infiltration (usually amyloid)
Poor prognosis
Pathophsyiology of restrictive CM
Rigid myocardium leads to increased diastolic ventricular pressure –> venous congestion
As well as decreased ventricular filling –> decreased CO
Myocarditis
Infl of heart muscle
Which groups can the causes of myocarditis be divided into
Infection
Immune mediated
Toxic
Infection as a cause of myocarditis
Viral (commonest) - coxsackie (enterovirus), adenovirus, others e.g. Chaga disease
What is the commonest infection causing myocarditis worldwide
Trypanosoma cruzi
Endemic in Central and South America
Immune-mediated myocarditis
Incl giant cell myocarditis, sarcoidosis
Toxic causes of myocarditis
Drugs (anthracycline)
Alcohol
Radiation
Which drugs can induce swelling
CCB
Which drugs can induce fluid retention
NSAIDs
Px of myocarditis
Classically presents w/ febrile illness w/ resp/ GI symptoms followed by any cardiac symptoms (fatigue, SOB, chest pain, palpitations, HF)
Spectrum of disease for myocarditis
Asymptomatic to cardiogenic shock
Cardiogenic shock
Life-threatening condn where heart suddenly cannot pump blood to meet body’s needs
Px of myocarditis on young pts vs older pts
A/c flulike px is commoner in younger pts
Older pts are more likely to px w/ DCM and HF
Ix for myocarditis
Bloods
ECG
Imaging
Endomycoardial biopsy
Blood results for myocarditis
Increased troponin
ECG changes in myocarditis
Non-spp ST/ T wave changes
May mimic MI
Arrhythmias
Imaging of choice for myocarditis
CMR
Endomyocardial biopsy
Gold standard test for myocarditis
Not performed as is invasive and hit & miss
Generally reserved for sickest pts
Layers of pericardium
Parietal pericardium
Visceral pericardium
Functions of pericardium
Anchors heart to thorax
Barrier to infection
Limits a/c dilatation of heart
Is the pericardium essential
No
Congenital absence or surgical removal aren’t associated w/ adverse effects
What can go wrong w/ the pericardium
Infl (pericarditsi) Fluid accumulation (effusion --> tamponade) Fibrosis (constriction)
How can the causes of a/c pericarditis be split up
Infectious
Non-infectious
Infectious causes of a/c pericarditis
Idiopathic/ viral - Coxsackie B, influenza, mumps, rubella (80% of cases) Other infections (bacterial, TB, fungal)
Non-infectious causes of a/c pericarditis
Post MI (Dressler syndrome) Uraemia Malignancy from mediastinal tumours CTD (SLE, RhA) Radiation induced Drug induced
Examples of mediastinal tumours
Lung
Breasts
Lymphoma
Clinical features of a/c pericarditis
Severe, sharp retrosternal/ left sided chest pain
Low grade fever is common
Sometimes tamponade can occur
Pericardial rub - evanescent
Pain in pericarditis
May radiate to back and trapezius ridges
Pleuritic
Positional (worse lying down, better leaning forward)
Pericardial rub
High pitches, scratchy sound heard at LSE
Ix for pericarditis
Bloods
ECG
CXR
Echo
Bloods for pericarditis
Increased infl markers and WCC Normal troponin (unless concomitant myocarditis)
CXR in pericarditis
Look at heart size - cardiomegaly suggests effusion, lung lesions?
Echo for pericarditis
Assessing for pericardial effusion
ECG in a/c pericarditis
Concave ST elevation - widespread (no pattern)
PR segment depression
ECG in MI vs pericarditis
MI - ST elevation - dome shaped and regional
Pericarditis - concave and widespread
Mx of pericarditis
In most pts, idiopathic/ viral pericarditis is self-limiting w/out significant complications
Should be advised to restrict activity
Drugs for pericarditis
Anti-infl drugs - high dose ibuprofen/ aspirin for 1-2/52 AND colchicine for 3/12
Low dose steroids can be used if necessary
When would you give low dose steroids for pericarditis
NSAIDs & colchicine have either failed, are contraindicated or there’s an autoimmune cause e.g. SLE
How can the causes of pericardial effusions be split up
Infl
Non-infl
Haemopericardium
Infl causes of pericardial effusion
Any cause of pericarditis e.g staph, strep, pneumo
Non-infl causes of pericarditis
Increased capillary permeability (e.g hypothyroidism)
Increased capillary hydrostatic pressure (HF)
Reduced plasma oncotic pressure (nephrotic syndrome, cirrhosis)
Haemopericardium
Bleeding into pericardial sac
Haemopericardium as a cause of pericarditis
Rupture of free wall post MI
Trauma
Cardiac procedure related (e.g. following angioplasty)
Dissecting aortic aneurysm
Commonest causes of pericardial tamponade
Malignancy
Post-idiopathic/ viral pericarditis
What can pericarditis cause
Heart failure
In which condn is electrical alternans seen
In large pericardial effusion
Electrical alternans
Seen in V1
Height of QRS complex varies from beat to beat due to electrical axis constantly hanging as the heart swings from side to side in pericardial effusion
One large wave then a small one and it continues
Pathophysiology of cardiac tamponade
Impaired diastolic filling of ventricles leading to elevated venous pressure and impaired SV –> decreased CO
Symptoms of cardiac tamponade
Medical emergency
Anxiety
SOB
Chest pain
Signs seen in cardiac tamponade
Tamponade quadrad
Tachycardia
Hypotension
Elevated JVP
Pulsus paradoxus
Pulsus paradoxus
Abnormally large decrease in SV, systolic bp and pulse during inspiration
Pulsus alternans
Alternations of one strong beat and one weak beat, without change in cycle length
Treatment of pericardial effusion
Draining fluid in heart using a large needle between paraxiphoid area and apical area - pericardiocentesis
Constrictive pericarditis cause
Rare
Most commonly idiopathic (but can be due to any cause of pericarditis)
Pathophysiology of constrictive pericarditis
Thickened fibrosed pericardium forms a rigid shell around heart –> inhibits normal filling of chambers
Clinical features of constrictive pericarditis
Decreased output (fatigue, hypotension, tachycardia) Increased systemic venous pressure
Symptoms of constrictive pericarditis
Increased JVP, hepatomegaly, ascites, peripheral oedema (systemic venous congestion)
Treatment of constrictive pericarditis
Surgical removal of pericardium
How does LV rupture usually present
W/ a/c heart failure and signs of cardiac tamponade
What is pulsus alternans a sign of
LV failure
Syncope definition
Rapid onset Transient LOC due to global cerebral hypo perfusion Short duration (9 secs to 1/2 mins)
Usual cause of syncope
Usually benign w/ vasovagal syncope by far being commonest cause
What is syncope characterised by
Rapid onset
Short duration
Spontanoeus, complete recovery
Causes of syncope by %
60% reflex
15% orthostatic
15% cardiac
10% unknown
Types of reflex syncope
Situational
Vasovagal
Carotid sinus syndrome
Common triggers of vasovagal syncope
Pain
Fear
Prolonged standing
Having blood taken
Symptoms of vasovagal syncope
Dizziness or light-headedness
Blurred or tunnel vision
Sweating
Turning pale
Situational syncope
Form of reflex syncope caused by spp triggers e.g. defecations, coughing, laughing, swallowing
Micturition syncope
Fainting occurring shortly after or during urination
Who does situational syncope usually occur in
Men
Situational syncope in younger men
Usually benign
May be precipitated by alcohol
What is situational syncope in older pts often associated w/
Comorbidities and postural hypotension
Triggers of situational syncope
Genito-urinary
Resp
GI
Carotid sinus reflex
Dilatation at the base of the internal carotid artery that contains baroreceptor which monitor BP
Carotid sinus massage
Simple, bedside test to test the carotid sinus reflex
Normal response to carotid sinus syndrome
Slight drop in HR and/or BP
When do we see an exaggerated response to carotid sinus massage
Carotid sinus hypertrophy
Carotid sinus syndrome
Syncope w/out warning and exaggerated CSM response w/ reproduction of syncope
When can pacing help w/ carotid sinus syndrome
If CSM mainly causes decreased HR
Who does carotid sinus syndrome usually occur in
Older pts (particularly men)
Triggers
Head turning
Shaving
Tight collar
Orthostatic hypotension explanation
Standing from a supine position causes 10-15% of our blood volume to be redistributed to the abdomen and LL thereby reducing venous return and CO
W/out, compensatory mechanisms there would be a fall in BP —> syncope
What may orthostatic hypotension cause
Syncope
Dizziness on standing
Falls
Orthostatic hypotension definition
Decreased SBP of >20 mmHg (or >DBP of 10 mmHg) < 3 mins of standing OR
Decreased SBP <90 mmHg on standing
Who gets OH
Those with autonomic failure, hypovolaemia or taking certain drugs
Primary autonomic failure causing OH
Parkinsons
Secondary autonomic failure causing OH
Aging/ DM
Hypovoleamia causing OH
Antihypertensives Anti-anginals Anti-BPH Anti-depressants Anti-psychotics Anti-Parkinsonian Alcohol
Why are elderly pts most susceptible to the hypotensive effects of drugs
Reduced baroreceptor sensitivity
Decreased cerebral blood flow
Renal Na wasting
Impaired thirst mechanisms
When are OH symptoms worse
On standing In the morning After meals After exercise In hot environments
When are OH symptoms better
When lying down or sitting
OH doesn’t occur when pt is supine
Mx of reflex syncope and OH - everyone
Reassurance
Education
Lifestyle changes - increase water, decrease salt
Stop/ reduce BP lowering drugs (if possible)
Mx of reflex syncope and OH - if still symptomatic
Counter pressure manœuvres
Mx of reflex syncope and OH - in selected pts
Increase BP - fludrocortisone, midodrine
Pacing - selected pts w/ reflex syncope only to increase HR
When should pacing be considered for reflex syncope pts
Recurrent syncope despite medical therapy
Bradycardia and systolic pauses
Will only benefit pts whose main problem is bradycardia and not low BP
Why does pacing help w/ reflex syncope
Newer pacemakers can detect when the ventricle is underfilled (happens before the bradycardia has been triggered) and increase HR to try and maintain BP
What causes cardiac syncope
Arrhythmia
Structural
Arrhythmias causing cardiac syncope
Brady - sinus node disease, AV block
Tachycardia - VT, SVT
Structural causes of cardiac syncope
Cardiac - AS, ACS, CM
Vascular - PE, aortic dissection
Syncope red flags - symptoms
Exertion
Supine
No warning
Syncope red flags - PMH
Structural heart diseases
CAD
Heart failure
Syncope red flags - Fhx
SCD
Syncope red flags - other symptoms
Chest pain Palpitations SOB Abdo pain Headaches
Syncope red flags - examination
Low BP
Slow HR
Undiagnosed systolic murmur
Key points in syncope hx
6 P’s
Before - Provoking factors, posture, prodrome, PMH (DH, FH)
During - passer-by account
After - post-event
Key points in syncope exam
Arrhythmia
Lying and standing BP
Carotid sinus hypersensitivity
Systolic murmur - AS, HCM
High risk feature on ECG of syncope pts
Arrhythmia A/c MI Channelopathy - Brugada, LQT1 Structural heart disease - LVH, LBBB Conduction disease
Ix in syncope
ECG
Echo - if structural heart disease is suspected
Cardiac rhythm monitoring
Tilt test
Cardiac rhythm monitoring
Holter
Loop recorder
Cardiac rhythm monitoring - Holter
Symptoms happening frequently, and arrhythmic cause suspected
Cardiac rhythm monitoring - Loop recorder
Symptoms happening infrequently by arrhythmic cause suspected
When is the tilt test done
Syncope of unknown cause where reflex syncope is suspected
Implanatable Loop Recorder
Useful in dx of recurrent syncope of unknown origin
What does implantable loop recorder dx
Arrhythmic syncope if it records an arrhythmia when pts has syncope
Suggests arrhythmic syncope when high risk arrhythmias are detected in an asymptomatic pt
Tilt table test
Provokes reflex syncope in a lab setting
Used to confirm dx of reflex syncope in a pt w/ syncope of unknown cause (where reflex syncope is suspected but not been proven)
What is a +ve tilt table test
Decrease in SBP
Decrease in HR
Hypersensitivity
Exaggerated or inappropriate immune response against a foreign or self-antigen
Hypersensitivity classification
Allergic
Cytotoxic
Immune Compex
Delayed
Most common hypersensitivity
Allergic/ atopic hypersensitivity
Up to 40% of people in developed countries suffer from Type 1 HS
What is allergic HS mediated by
IgE
Th2 cells
Mast cells
Eosinophils
Associated diseases w/ allergic HS
Allergic rhinitis
Asthma
Atopic dermatitis
Anaphylaxis
Key phases in Type I HS
Sensitisation
Activation
Effectors
Sensitisation in Type I HS
IgE produced by B cells in response to allergen
IgE binds to FcR on mast cell & basophils
Activation in Type 1 HS
Re-exposure to allergen (reaction doesn’t happen 1st time)
Allergen cross-link IgE —> immediate degranulation
Effectors in Type I HS
Tissue damage - vascular permeability, mucus secretion, immune cell infiltration
Mediators secreted during Type I HS reaction
Histamine
Prostaglandins and leukotrienes
IL-4
IL5
Outcomes of mediator secretion in Type I HS reaction
Vascular leak Broncho-constriction Interstinal hyper motility Infl Tissue remodelling
Typical allergens causing asthma
Pollens
Dust mites
Animal dander
Asthma allergens route of entry
Inhalation
Main symptoms of asthma
Wheezing, dyspnoea, tachypnoea
Allergic rhinitis
Hay fever
Typical allergens causing allergic rhinitis
Pollen spores
Animal dander
House dust mite faeces
Main symptoms of allergic rhinitis
Runny nose
Redness
Itching of eyes
Atopic dermatitis
Eczema
Typical allergens for atopic dermatitis
Dust mites
Pet fur
Pollen
Moulds
Main symptoms of eczema
Itchy, dry, cracked, sore and red skin
Allergic gastroenteropathy
Food allergies
Main symptoms of allergic gastroenteropathy
Vomiting
Diarrhoea
Main symptoms. of anaphylaxis
Shock
Hypotension
Wheezing
How long does early phase of asthma last
15-30 mins
How long does late phase of asthma last
6 - 9 hrs
C/c infl in asthma
Goblet cell/ smooth muscle hyperplasia
Collagen deposition
Non-spp bronchial hyperactivity
Systemic atopy
Food allergy
Anaphylaxis shock
Urticaria
Hives
Potentially fatal consequences of an anaphylaxis
Laryngeal oedema
Bronchial constriction
Peripheral oedema
2’ mediators cause prolonged effects later - late phase reactions
Clinical tests for allergies
Skin prick tests
Blood test
Test diet or food challenge
Skin prick test for allergies
Intradermal injection of antigen
30 min readout for wheal/ flare
Blood test for allergies
Determine serum IgE levels (total or against spp antigens)
Test diet for allergies
Pt placed on diet free from common allergen various foods added over time
CNS symptoms of anaphylaxis
Lightheadedness LOC Confusion Headache Anxiety
Treatment of Type 1 HS
Allergen avoidance
Desensitisation
Drugs
Desensitisation for Type I HS
Repeated injection of small but increasing doses of purified allergenic over several months —> modification of Th2 response (IgG, allergen binding and less IgE)
Drugs given for Type I HS
Antihistamines
Corticosteroids
Adrenaline (Epipen and Anapen)
Which allergic condns have genetic components
Hayfever, asthma, and atopic dermatitis
30% chance of allergy w/ one allergic parent and 50% w/ 2 parents
Hygiene hypothesis sand risks of allergy
Limiting market -life infection impeded natural immune system development and causes predisposition to allergic disease
Type II hypersensitivity
Cytotoxic HS
Directed against cell surface on extracellular matrix antigens
What do most common Type II reactions involve
RBCs
How are cytotoxic HS reactions activated
Via IgM or IgG
What does the complement pathway create
Membrane attack complex
Creates holes in membrane, cells become leaky and die
Associated diseases of cytotoxic HS reactions
Autoimmune haemolytic anaemia
Myasthenia gravis
Goodpastures disease
Incompatible blood tranfusions as a Type II HS reaction
Incompatible donor cells are lysed as they enter the blood stream
Intravascular haemolysis via complement
Leads to renal failure and death
How is blood typing done
Haemoaggluitination
How do we prevent incompatible blood transfusions
Cross-matching pt serum w/ donor RBC
Haemolytic disease of newborn
Occurs in pregnancy - when Rh-ve mother is exposed from Rh+ve foetus it causes sensitisation
Subsequent pregnancies cause mother to create anti-Rh antibodies causing Rh+ve foetus and lysis of their blood cells
Drug induced haemolytic anaemia
Drugs (or their metabolites) can provoke HS reactions against RBCs and platelets
Drug binds to surface protein on RBC —> Antibody binds to drug and activates complement –> complement causes haemolysis
When do we see autoimmunity
IgG directed against self Ag on tissues
Autoantigen against autoimmune haemolytic anaemia
Rh blood group antigens
Autoantigen against Goodpasture’s syndrome
Collagen type IV (basement membrane)
Pathogenesis of Goodpasture’s syndrome
Necrosis of glomeruli –> nephritis, lung haemorrhage
Autoantigen against Myasthenia graves
Ach receptor
Pathogenesis of Myasthenia gravis
Blocked transmission at neuronal synapses –> muscle weakness
Glomerulonephritis
Group of kidney disease caused by infl in glomeruli
Type III HS
Immune complex-mediated HS
Similar to Type II HS but Abs directed against soluble Ags
How are immune complexes normally removed from the body
RBC binding and phagocytosis by liver/ spleen
How do Type III HS reactions cause damage
Deposition and build up of complexes in tissues or walls of small blood vessels
Examples of infections that can form immune complexes
Hepatitis Endocarditis Malaria Leprosy Haemorhagic fever
Examples of Type II HS reactions
Rheumatoid disorders (SLE, Henoch-schonlein, 1' Sjorgens) Arthus reaction Inhaled antigens (e.g. Farmers lung)
Rheumatoid disorders as Type III HS reaction
Continued production of auto-Abs –> immune complex formation and deposition in tissues → cutaneous vasculitis
Arthus reaction as Type III HS reaction
Formation of Ag/IgG complexes after intradermal Ag injections (e.g. vaccines, sting) into sensitised individuals
Deposition in dermal blood vessels –> local vasculitis
Farmer’s lung as a Type III HS reaction
Repeated exposure to high Ag quantities (e.g. fungi in mouldy hay) induce IgG –> immune complex formation in lung
Type IV HS
Delayed
What are delayed HS reactions mediated by
Ag-spp T cels (mostly Th1)
What happens in Type IV HS reactions
Ag internalised by dendritic cell —> migration to lymph node and activation of T cells/ memory cell formation (priming phase)
Re-exposure: recruitment of memory T cells causes tissue damage
How long does the reaction take in Type IV HS
2-3 days
Type IV HS - contact HS
Small antigens (haptens) penetrate skin and combine with tissue protein and mediate immune reactions
Principal APCs in the skin
Langerhans cells
What can cause localised eczematous skin reactions
Contact with: o Nickel salts in jewellery o Drugs o Components in hair dye o Chromates o Chemicals in leather/ rubber o Poison ivy
What is the Mantoux test used for
Dx of latent TB
What is the clinically most important form of DTH
Granulomatous Type IV HS
Ag persistence causing c/c T cell and macrophage activation —> granuloma formation
When does granulomatous DTH develop
After 21-28 days
What does DTH cause
Caesation and tissue necrosis inside granuloma
When are granulomas seen
TB
Leprosy
Infection w/ parasites - Leishmaniasis, Schistosomiasis
Signs of L side HF
Bibasal lung crackles
LV heave (due to hypertrophy)
Dilated LV
Displaced apex beat
Cor pulmonale
R HF due to pulmonary HTN
Which drug can cause pitting oedema
CCB
Signs of R HF
Pitting oedema in peripheries RV heave Raised JVP Ascites Scrotal oedema
Why do we see fluid retention in symptoms of HF
RAAS
How can AF cause HF
Can cause atrial failure which leads to ventricular failure
When is S3 heard
HF
Categories of disease causing HF
Reduced ventricular contraction Ventricular outflow obstruction Ventricular inflow obstruction Venticular volume overload Arrhythmia Diastolic dysfunction
Reduced ventricular contraction causing HF
IHD
Myocarditis
Ventricular outflow obstruction
AS
HTN
Ventricular inflow obstruction causing HF
MS
Ventricular volume overload causing HF
AR
MR
Arrhythmia causing HF
AF
Diastolic dysfunction causing HF
HCM
RCM
Cardiac tamponade
Why might oromorph be given for c/c HF
Vasodilation
Rhabdomyolysis caused by statin
Blood in urine but -ve for RBC
Cardiorenal syndrome
Heart and renal failure together
Which drugs can cause angiodema
ACEi
Pathophysiologic difference between HFrEF and HFpEF
Reduced - cardiomyocytes dysfunction
Preserved - due to endothelial dysfunction
Why do HF pts experience SOB
Increased filling pressure
Low CO
What is v suggestive fo SOB being caused by HF
Orthopnea and PND
Measuring cardiothoracic ratio on Xray
Draw midline and mark largest bulge on R and L
Choose the highest number and divide by sternal diameter of thorax
Dx algorithm for HF
IF pt has risk factors, symptoms& signs and an abnormal ECG –> measure NT-pro BNP –> if elevated do an Echo
Does furosemide have an effect on mortality
Yes, increases mortality as is a disease-modifying drug
Drug therapy for systolic heart failure
Diuretics - furosemide 40mg od, Spiro 25mg od
Ramipril 2.5mg note
Bisoprolol 2mg od
Class I therapies in HFrEF
Quadruple therapy: ACEi/ Entrestro BB Spiro - MRA Dapagliflozin
Add loop diuretic if signs of congestion
When is CRT suggested for HF pt
After drug therapies failed and if pts has broad QRS
When is an ICD suggested for HF pts
If pt has narrow QRS w/ LVH
Why might c/c HF pts lose wt
Impaired absorption due to GI congestion
Why might we see skeletal muscle atrophy in c/c HF
Immobility
CXR for HF
Alveolar oedema (batwing opacity) Kerly B lines Cardiomegaly Dilated upper lobe vessels Pleural effusion
Cardiac MR in HF
Ventricular volumes
Mass and evidence of remodelling
Physiologic changes seen in a/c Left HF
Pulmonary oedema
Physiologic changes seen in c/c Left HF
Reflex pulmonary vasoconstriction to protect from oedema, increased resistance and pulmonary HTN
Physiologic changes seen in Right HF
Reduced RV output
Increased RA and systemic venous pressure
What should me be done is PODMAN isn’t effective for a/c HF
Give inotropic agents e..g IV dobutamine
Insert intra aortic balloon pump
When should a HF pt have ventilation
Non-invasive - if cardiogenic pulmonary oedema w/ severe dyspnoea
Invasive - resp failure or reduced consciousness
Bilateral oedema ddx
Congestive heart failure Hepatic failure Renal failure Neohrotic syndrome Malnutrition Immobility Drugs (NSAIDs or CCBs)
Unilateral oedema ddx
DVT
Cellulitis
Ruptured Baker’s cyst
Lymphatic obstruction
Mx of bilateral oedema
Diuretics - monitor renal function
If oedema is resistant, diuretic and thiazide
Spiro or amiloride (K sparing diuretics)
When is ivabradien indicated for hF failures
NYHA classification ois II to IV w/ systolic dysfunction AND sinus rhythm of 75+bpm
BB contraindicates/ not tolerated
LVEF of 35% or less
How do ACEi improve mortality and morbidity in hF
Reduce afterload to improve EF
Reduce preload to decrease pulmonary congestion
Improves oxygen supply
Prevents cardiac remodelling
What is the best time to give statins
Nocte
Except atorva which can be taken any time
Interaction between ACEi and ARBs
Hyperkalaemia
Hypotension
Renal impairment
How doe BBs improve mortality and morbidity in HF pts
Reduces HR –> increasing filling time –> increase EF
Reduces cardiac remodelling
MOA of aldosterone antagonists
Antagonises effects of aldosterone so more Na and water can be excreted, preventing fluid retention
Interactions of aldosterone antagonists
ACEi and aldosterone antagonists = hyperkalaemia (Monitor K+ levels)
In which condn do we see a displaced apex beat
LV dilatation - HF