Cardiology Flashcards
1
Q
Define acute rheumatic fever
A
Systemic illness that occurs 2-4 weeks after pharyngitis in some people
- due to cross-reactivity to group A beta-haemolytic streptococcus (GAS)
- also called streptococcus pyogenes
2
Q
Epidemiology of acute rheumatic fever
A
4 million children worldwide
94% of cases in developing countries
Most common in tropical countries
Most common in females
3
Q
Pathophysiology of acute rheumatic fever
A
Streptococcus pyogenes is a gram-positive cocci
- produces two cytolytic toxins - streptolysin O and S
Rheumatogenic strains contain M proteins in cell wall
- B cells stimulated to produce anti-M protein antibodies
- also cross-react with other tissues - heart, brain, joints and skin
- exacerbated by production of activated cross reactive T cells
4
Q
Risk factors for acute rheumatic fever
A
Children and young people Poverty Overcrowded and poor hygiene Family history of rheumatic fever D8/17 B cell antigen positivity
5
Q
Clinical features of acute rheumatic fever
A
Revised Jones Diagnostic Criteria
- positive throat culture for group A strep or elevated anti-streptolysin O or anti-deoxyribonuclease B
- 2 major criteria or 1 major criteria and 2 minor criteria
6
Q
Major criteria for acute rheumatic fever
A
Sydenham's chorea Polyarthritis Erythema marginatum Carditis Subcutaneous nodules
7
Q
Minor criteria for rheumatic fever
A
CRP or ESR raised
Arthralgia
Pyrexia/fever
Prolonged PR interval
8
Q
Differential diagnosis of acute rheumatic fever
A
Septic arthritis - usually only one joint - positive gram stain, culture and elevated WCC of aspirated synovial fluid Reactive arthropathy - commonly males - a/w urethritis and conjunctivitis Infective endocarditis - positive blood culture - vegetation on valves on echocardiogram - janeway lesions, osler nodes, splinter haemorrhages Myocarditis - troponin and CK elevated - saddle ST segments or T wave changes on ECG
9
Q
Investigations for acute rheumatic fever
A
Bloods - ESR, CRP, FBC Blood cultures - exclude sepsis Rapid antigen detection test Throat culture - may be negative by time rheumatic symptoms Anti-streptococcal serology - ASO and anti-DNASE B titres ECG - prolonged PR interval CXR - if carditis suspected Echo cardiology
10
Q
Management of acute rheumatic fever
A
Initial
- abx - benzathine benzylpenicillin
- aspirin or NSAIDs
- assess for emergency valve replacement
- glucocorticosteroids and diuretics in severe carditis
Definitive
- secondary prophylaxis with IM benzathine benzylpenicillin every 3-4 weeks
- oral phenoxymethylpenicillin twice daily
- oral sulfadiazine daily
- oral azithromycin in penicillin allergy
11
Q
Complications of acute rheumatic fever
A
Permanent damage to heart valves
Chronic rheumatic heart disease
12
Q
Define infective endocarditis
A
Infectious disease of heart and surrounding vessels
13
Q
Pathophysiology of infective endocarditis
A
Triad of
- endothelial damage
- platelet adhesion
- microbial adherence
Structural abnormalities cause significant pressure gradient -> endothelial damage through sheer stress forces
Prosthetic material -> endothelial damage and promote sterile platelet-fibrin deposition
Bacteremia then occurs - adhere to lesion and invade underlying tissue
14
Q
Common causative organism of infective endocarditis
A
Have specific surface receptors to fibronectin - allow microbe to adhere to thrombus at outset
- staphylococcus aureus
- streptococcus viridans
- streptococcus pneumoniae
- alpha-haemolytic streptococci (S.viridans) - a/w dental procedures
- enterococci - post genitourinary or gastrointestinal surgery
15
Q
Clinical features of infective endocarditis
A
Persistent low grade fever Heart murmur - changing Splenomegaly Cutaneous manifestations uncommon in paediatric population - petechiae - osler's nodes - janeway lesions - splinter haemorrhages
16
Q
Investigations for IE
A
Blood cultures Echocardiography Anaemia Leukocytosis Raised ESR Microscopic haematuria
17
Q
Modified Duke criteria for IE
A
MAJOR Positive blood culture - typical microorganism from 2 separate cultures Evidence of endocardial involvement MINOR Predisposition - heart condition of IV drug use Fever - temp > 38 Vascular phenomena - major arterial emboli, septic pulmonary infarcts, intracranial haemorrhage, conjunctival haemorrhage, Janeway lesions Immunologic phenomena - Glomerulonephritis, Osler's nodes, rheumatoid factors Microbiological evidence - positive blood culture ECHO findings
18
Q
Diagnosis of IE
A
2 major criteria OR 1 major and 3 minor OR 5 minor
19
Q
Aims of management of IE
A
Systemic embolisation Abscess formation Pseudoaneurysms Valvular perforation Heart failure
20
Q
Indications for surgical management of IE
A
Vegetation
- highly mobile vegetation
- persistent vegetation after systemic embolisation
- > 1 embolic event in first 2 weeks of medical management
Increase in vegetation size
Valvular dysfunction
- acute aortic or mitral insufficiency with signs of ventricular failure
- heart failure unresponsive to medical management
- valve perforation or rupture
Perivalvular extension
- valvular dehiscence, rupture or fistula formation
- new onset heart block
- large abscess or extention of abscess
21
Q
Antibiotic choice for IE
A
Aerobic cover usually sufficient
- IV penicillin or IV ceftriaxone for 4 weeks
- add gentamicin if penicillin resistant organisms
Methicillin-susceptible staphylococcus = beta-lactamase resistant penicillin for 6 weeks
Methicillin-resistant = vancomycin for 6 weeks
Enterococcus = 4-6 weeks IV penicillin with gentamicin
HACEK = ceftriaxone with gentamicin for 4 weeks
22
Q
Prophylaxis for IE
A
No longer routinely offered to at risk groups
23
Q
Those at higher risk for IE
A
Acquired valvular heart disease with stenosis or regurgitation Hypertrophic cardiomyopathy Previous IE Structural congenital heart disease Valve replacement
24
Q
Define Tetralogy of Fallot
A
Most common cyanotic congenital heart disease Tetrad of - Ventricular Septal Defect (VSD) - Pulmonary Stenosis (PS) - Right Ventricular Hypertrophy (RVH) - Overriding aorta
25
Epidemiology of Tetralogy of Fallot
Up to 10% of all congenital heart disease
| Prevalence of 3-6 per 10,000 births
26
Risk factors for TOF
```
Males
1st degree family history of CHD
Teratogens
- alcohol - foetal alcohol syndrome
- warfarin - foetal warfarin syndrome
- trimethadione - antiepileptic drug used in treatment resistant epilepsy
Genetics
- CHARGE syndrome - coloboma, heart defects, atresia choanae, retardation of growth/development, genitourinary anomalies, ear anomalies
- Di George Syndrome
- VACTERL association - vertebral abnormalities, anorectal malformation, cardiac defects, tracheo-oesophageal fistula, renal anomalies, limb abnormalities
Associated congenital defects
- right aortic arch
- congenital diaphragmatic hernia
```
27
Pathophysiology of TOF
VSD
- perimembranous, muscular or doubly committed (located near pulmonary and aortic valves)
- left-to-right shunt = acyanotic
- in severe disease due to increased right ventricular pressure -> right-to-left shunt = cyanotic
PS
- classified by location - infundibular septum, septum or combination
- impaired flow of deoxygenated blood in main pulmonary artery
- severe leads to intermittent RVOT obstruction -> hypoxic episodes (tet spells)
RVH
- due to high pressure to overcome PS
- develops in utero
- boot sign on CXR
Overriding aorta
- dilated and displaced over intraventricular septum
- in severe disease multiple aorto-pulmonary collateral arteries may form to increase pulmonary blood flow
28
Clinical features of TOF
Mild
- usually asymptomatic
- develop cyanosis at age 1-3
Moderate-severe
- present in first few weeks of life with cyanosis and respiratory distress
- prone to recurrent chest infections or fail to thrive
Extreme
- TOF with pulmonary atresia or with absent pulmonary valves
- duct dependent lesions - deoxygenated blood can only flow through lungs via patent ductus arteriosus
- often detected on antenatal scans
- if undetected present within first few hours of life with marked resp distress and cyanosis
29
Features of hypoxic (Tet) spells
Peak incidence months 2-4 months
Paroxysm of hyperpnoea
- rapid deep respirations
- due to increased right-to-left shunting, CO2 accumulates stimulating central respiratory centre
- causes further right-to-left shunting perpetuating hypoxia
Irritability - manifested by prolonged, unsettled crying
Increasing cyanosis
May be precipitated by dehydration, anaemia or prolonged crying (induces tachycardia and reduced systemic vascular resistance)
30
Features of examination for TOF
```
General
- central cyanosis
- clubbing
Palpation
- thrill or heave
Auscultation
- loud single S2 - closure of aortic valve in diastole with absent pulmonary valve closure due to stenosis
- pansystolic murmur - VSD, mid or upper left sternal edge
- ejection click - dilated aorta, immediately after S1
- continuous, machinery murmur - PDA, upper LSE or left infraclavicular area
Signs of congestive heart failure
- sweating
- pallor
- tachycardia
- hepatosplenomegaly
- generalised oedema
- bilateral basal crackles
- gallop rhythm
```
31
Differential diagnosis of TOF
```
Other cyanotic CHD
- critical PS
- transposition of the great arteries
- totally anomalous pulmonary venous drainage
- hypoplastic left heart syndrome
Isolated VSD
Sepsis - resp distress and hypoxia
```
32
Investigations for TOF
ECG - right axis deviation and RVH
Microarray - if genetic syndromes suspected
CXR - boot shaped heart (RVH) and reduced pulmonary vascular marking (decreased pulmonary blood flow)
Echocardiogram - gold standard for diagnosis confirmation
Cardiac CT angiogram - delineate anatomy if coronary abnormalities suspected
Cardiac MRI
Cardiac catheter
33
Medical management of TOF
Squatting
- helps increase venous return increasing systemic resistance
- advised to put child in this position whilst awaiting medical review
Prostaglandin infusion
- helps maintain PDA
- PGE1 (alprostadil) or PGE2 (dinoprostone)
- side effects = apnoeas, brachycardia, hypotension
Beta-blockers
- propranolol
- reduces HR reduces venous return
Morphine
- reduces respiratory drive reduces hyperpnoea
Saline 0.9% bolus
- used in tet spells as a volume expander to increase pulmonary blood flow through RVOTO
34
Surgical management of TOF
PALLIATIVE
Transcatheter RVOT stent insertion
- done in neonatal period for infants with severe TOF to relieve PS
- by time till child is bigger
Modified Blalock-Taussing shunt
- mimic PDA and increase pulmonary blood flow before definitive repair
- anastomosis of subclavian artery to pulmonary or artificial material
DEFINITIVE
- cardiopulmonary bypass via medial sternotomy
- RVOT stenosis resection, RVOT/pulmonary artery augmentation and VSD patch closure
- between 3 months and 4 years
35
Complications of TOF
```
Polycythaemia
Cerebral abscess
Stroke
IE
Death - up to 25% in 1st year of life
Congestive cardiac failure
Death
Even with corrective surgery
- pulmonary regurgitation
- arrhythmias
- exercise intolerance
- sudden death
```
36
Follow-up of TOF
Lifelong
- regular ECG, ECHO
- cardiopulmonary exercise testing in the case of exercise intolerance
37
Define transposition of the great arteries
Ventriculoarterial discordance - aorta arises from morphologic right ventricle and pulmonary artery arises from the left
- parallel circulation
38
Classification of transposition of the great arteries
Dextro-transposition = 60%
- aorta anterior and to the right of pulmonary artery
Levo-transposition
- aorta anterior and left of pulmonary artery
39
Epidemiology of transposition of the great arteries
Most common cause of cyanosis in newborn
5-7% of all CHD
20-30 per 100,000 live births
Higher incidence in males
40
Pathophysiology of transposition of the great arteries
Dextro-TGA
- pulmonary and systemic circulation run parallel
- cyanosis unless there is mixing of circulation
- patent foramen ovale or atrial septal defect
- VSD
- PDA
Levo-TGA
- ventricles switched place
- acyanotic - deoxygenated blood returned from systemic circulation
- tricuspid regurgitation
41
Aetiology of TGA
Goor and Edwards theory
- aorta does not rotate normally towards left ventricle
De la Crux theory
- no rotation of aorta-pulmonary septum at infundibular level
- causes fourth aortic arch
42
Risk factors for TGA
```
Mother over 40
Maternal diabetes
Maternal rubella
Maternal poor nutrition
Maternal alcohol consumption
```
43
Clinical features of TGA
```
Cyanosis
- appears in 1st 24 hours
Signs of congestive heart failure
- tachypnoea
- tachycardia
- diaphoresis
- failure to gain weight
Prominent right ventricular heave
Single second heart sound
Systolic murmur - if VSD present
No signs of resp distress
```
44
Differential diagnosis of TGA
```
Tetralogy of Fallot
- boot-shaped heart on CXR
- ECHO
Tricuspid Atresia
- left axis deviation on ECG
```
45
Investigations for TGA
Pulse ox shows cyanosis
Capillary blood gas - metabolic acidosis with decreased PaO2
ECHO - definitive for diagnosis
- abnormal position of aorta and pulmonary arteries
CXR
- egg on a string
- narrowed upper mediastinum, cardiomegaly and increased pulmonary vascular markings
46
Management of TGA
Initial
- emergency prostaglandin E1 infusion - keep PDA
- correct metabolic acidosis
- emergency atrial balloon septostomy
Definitive
- surgical correction - arterial switch operation
- long term follow up and counselling in female patients who wish to get pregnant
47
Complications of TGA
```
Neopulmonary stenosis
Neoaortic regurgitation
Neoaortic dilation
Coronary artery disease
Further intervention - balloon angioplasty, transcatheter stenting
Obstructed coronary arteries
Sudden cardiac death
Neurodevelopmental abnormalities
- low gestational age and high pre-operative lactate are important predictors for poor developmental outcomes
```
48
Define VSD
Ventricular Septal Defect
- hole in septum separating left and right ventricles
- most commonly perimembranous
49
Epidemiology of VSD
50% of all children with CHD - 20% as isolated lesion
| Isolated VSD 4.2 per 1000 births
50
Pathophysiology of VSD
Increased flow through pulmonary circulation
| Pressure in left ventricle greater than right ventricle -> left-to-right shunt = acyanotic
51
Classification of VSD
Restrictive
- minimal flow so usually asymptomatic
Moderate sized
- dilation of left atrium and ventricle
- risk of developing congestive heart failure and arrhythmias
- progressively develop pulmonary hypertension and right ventricular hypertrophy
Large VSD
- early heart failure (1st week of life) and severe pulmonary hypertension
52
Features of Eisenmenger's syndrome
Condition where pressure in right ventricle exceeds that of left ventricle
- caused by significant gradual increase in pulmonary vascular resistance
- shunt reversal
- deoxygenated blood flows from right ventricle to left
- decreased systemic oxygen
- cyanosis
53
Risk factors for VSD
```
Maternal diabetes
Maternal rubella infection
Foetal alcohol syndrome
Uncontrolled maternal phenylketonuria
Fhx of VSD
Congenital conditions a/w
- Down's syndrome (trisomy 21)
- Trisomy 18 syndrome
- Trisomy 13 syndrome
- Holt-Oram syndrome
```
54
Clinical features of VSD
Pansystolic murmur at left sternal edge
Small
- mild or no symptoms
Moderate
- symptoms obvious by 2-3 months
- excessive sweating, become easily fatigued and tachypnoea
Large
- shortness of breath, problems feeding, developmental issues regarding weight and height, frequent chest infections
- Eisenmenger's syndrome may develop -> cyanosis
55
Differential diagnosis of VSD
Mitral regurgitation
- holosystolic murmur
Tricuspid regurgitation
- increase in murmur intensity with inspiration
Atrial septal defect
- murmur higher up left parasternal region
- mid or ejection systolic
PDA
- continuous systolic and diastolic murmur at base of heart
Pulmonary stenosis
- ejection systolic murmur at left upper parasternal border
TOF
- symptoms more severe
56
Investigations for VSD
EGC - left ventricular hypertrophy
Bloods - septic screen
CXR - larger VSD may show cardiomegaly
ECHO - gold standard
57
Management of VSD
Medical
- increase caloric density of feedings - ensures adequate weight gain
- diuretics - relieve pulmonary congestion
- ACEi - reduce shunt by reducing systemic arterial pressure
- digoxin - treat congestive heart failure
- no need for exercise restriction
Surgical
- pulmonary-to-systemic blood flow ratio of 2.0 or more
- surgical repair via open heart surgery
- catheter procedure - less common
58
Complications of VSD
```
Congestive heart failure
Growth failure
Aortic valve regurgitation due to prolapse of a valve leaflet through the defect
Pulmonary vascular disease that in severe cases can lead to Eisenmenger’s Syndrome
Frequent chest infections
Infective Endocarditis
Arrhythmias
Sudden death
```
59
Complications post-surgical repair of VSD
Permanent heart block requiring pacemaker
Wound infection
Reoperation of significant residual VSDs
60
Prognosis of VSD
75% of small close spontaneously by 10
61
Causes of acyanotic heart disease
Left to right shunts
- VSD, ASD, PDA
- excessive pulmonary blood flow -> development of congestive cardiac failure
- pink but breathless child
Outflow obstruction
- aortic stenosis, pulmonary stenosis, coarctation of the aorta
- extra pressure required to pump blood -> ventricular hypertrophy and insufficient cardiac output
- pink but breathless child
62
Heart sound for acyanotic heart disease
VSD = grade 3-6 pansystolic murmur
ASD = fixed, split, loud S2 + ejection systolic murmur over pulmonary area
PDA = constant machinery murmur through systole and diastole
Aortic stenosis = loud ejection systolic murmur loudest over aortic area
Pulmonary stenosis = loud ejection systolic murmur loudest over pulmonary area
Coarctation of the aorta = weak or absent femoral pulses, no murmur
63
Define innocent heart murmur
Extra sound usually due to blood travelling through child's heart
- children have small slim chests, heart rate is faster, blood has to negotiate tight bends
64
Define cyanotic cardiac defects
Occur if sufficient deoxygenated blood enters the systemic circulation
- may be because flow to lungs is obstructed of because blood is being shunted from right to left
65
Causes of cyanotic cardiac defects
Right-to-left shunts
- transposition of great arteries, tetralogy of fallot
- cyanosed if sats less than 85%
- if decreased pulmonary flow then child will not be breathless
Mixed shunts
- AVSD, truncus arteriosus
- intracardiac mixing of oxygenated and deoxygenated blood -> milder cyanosis
- blue (due to mixing) and breathless (due to increased pulmonary flow)
Outflow obstruction
- hypoplastic left heart, interrupted aortic arch
- duct dependent circulation - all blood in pulmonary or systemic circulation is via ductus arteriosus
- when ductus arteriosus closes the child will present in circulatory collapse -> shock, acidosis and death
- presents typically day 2-3 of life
66
Mx of TOF
General
- surgical management around 6 years
- manage CHF and iron deficiency if present
Tet spell
- hold child knee-to-chest - increase venous return
- small morphine dose to settle rapid breathing and relax ventricular outflow tract
- occasionally propranolol
67
Pathophysiology of ASD
Primum - involving the endocardial cushion
Secundum - affecting middle portion of septum (80%)
Defect caused volume overload to RHS of heart
Increased pulmonary blood flow -> pulmonary hypertension, HF and Eisenmenger syndrome
68
Risk factors for ASD
Female sex
Maternal alcohol intake in pregnancy
FHx
69
Clinical features of ASD
Usually asymptomatic - no signs before 3-4
Older children may present with recurrent infections of CHF
Adulthood - development of pulmonary hypertension, HF and arrhythmias
Ejection systolic murmur - loudest in pulmonary area
Fixed split S2
Signs of CHF - tachycardia, tachypnoea, hepatomegaly, failure to thrive
70
Ix for ASD
Echo
CXR - cardiomegaly and increased vascular markings
ECG - right axis deviation, RBBB, RVH
71
Mx of ASD
```
Small defects (3-8mm) close spontaneously by 18 months
Larger defects (>8mm) need surgical or cardiac catheter
All primum defects that do no spontaneously resolve need surgical closure
CCF - diuretics
```
72
Pathophysiology of coarctation of the aorta
Narrowing of thoracic aorta - where ductus arteriosus originates from
Severe coarctation -> circulatory collapse with weak/absent femoral pulses soon after birth
Less severe -> systemic hypertension later in life
73
Clinical features of coarctation of the aorta
Severity dependent
- severe = neonatal collapse in first few days of life
- less severe = incidentally due to hypertension
Differential in BP = higher in arm than legs
Absent/weak/delayed femoral pulses
74
Ix of coarctation of the aorta
CXR - cardiomegaly, increased vascular marking, rib notching
ECG
ECHO - diagnostic
75
Mx of coarctation of the aorta
```
Symptomatic neonate
- prostaglandin E1 to maintain patent duct arteriosus
- treat hypertension
- urgent surgical repair
Asymptomatic child
- surgery indicated in hypertension, CHF or collateral blood vessel formation
- hypertension mx
- monitor for secondary organ damage
```
76
Clinical features of PS
```
Usually asymptomatic
Exertional dyspnoea and fatigue
Heart failure if stenosis severe
Widely split S2 and click (if valvular)
Ejection systolic murmur heard over pulmonary area - radiates to back
```
77
Mx of PS
```
Critical in neonate
- prostaglandin infusion
- urgent transfer to cardiac centre
Balloon valvuloplasty
Surgery
```
78
Clinical features of cyanotic heart disease
Cyanosis
Digital clubbing
Hypoxic tet spells
Polycythaemia - low arterial oxygen sats stimulates EPO production -> increases RBC production from bone marrow
79
Define pericarditis
Inflammation of pericardial sac
| - usually due to viral infection
80
Risk factors for pericarditis
Rheumatic fever
Viral illness
Cardiac surgery
Inflammatory arthritis
81
Clinical features of pericarditis
```
Stabbing or aching central chest pain
- may radiate to head/neck
- worse on inspiration and lying down
Tachycardia, tachypnoea, pyrexia
Pericardial friction rub
Signs of cardiac tamponade
- quiet heart sounds, distended neck veins
```
82
Mx of pericardiits
Urgent decompression of any tamponade
Viral - conservative
Bacterial - IV abx for 4-6 weeks
Constrictive - complete resection of pericardium
