Paeds - CVS Flashcards
1
Q
What are the 3 foetal shunts?
A
Ductus venosus = connects umbilical vein to inferior vena cava (allows blood to bypass liver)
Foramen ovale = connects RA to LA (allows blood to bypass RV and Pulmonary circulation)
Ductus Arteriosus = connects pulmonary artery with aorta (allows blood to bypass Pulmonary circulation)
2
Q
What happens to the foetal shunts and circulation at birth?
A
- first baby breath expands alveoli
- this decreases pulmonary vascular resistance, causing a fall in pressure in the RA
- When LA pressure becomes greater than RA pressure, this squashes the atrial septum and causes functional closure of the foramen ovale
- Foramen ovale gets sealed shut structurally after a few weeks and becomes the fossa ovalis
- Increased blood oxygenation causes a drop in circulating prostaglandins
- prostaglandins are required to keep the ductus arteriosus open
- Therefore this drop in P causes the ductus arteriosus to close and become the ligamentum arteriosum
- ductus venosus stops functioning immediately after birth as umbilical cord is clamped so there is no flow in the umbilical veins
- the DV structurally closes a few days later and becomes the ligamentum venosum
3
Q
Sometimes the DA doesn’t close for unknown reasons.
(potentially Rubella maternal infection or Prematurity)
What is the pathophysiology of a Patent Ductus Arteriosus.
A
- pressure in the aorta is higher than pressure in the pulmonary vessels so blood flows from the aorta to the pulmonary artery
- Blood crossing from the L to the R circulation = L to R shunt
- This causes increased pressure in the pulmonary vessels = pulmonary HTN
- this leads to R sided Heart Strain as the RV is having to work harder to contract against this higher resistance
- Pulmonary HTN + R Heart Strain = RV Hypertrophy
- The increased blood flowing through the pulmonary vessels and returning to the L side of the heart = L ventricular hypertrophy
4
Q
How would a patent ductus arteriosus present clinically?
A
- usually picked up during the newborn examination with a murmur
- small PDA may not have abnormal heart sounds
- significant PDA causes a normal S1 with a continuous crescendo-decrescendo “machinery” murmur that may continue into S2 (makes S2 difficult to hear)
- SOB
- Difficulty feeding
- Poor weight gain
- Lower Resp Tract Infections
5
Q
How would you deal with a suspected PDA?
A
- confirm PDA with echocardiogram and doppler flow studies to assess the size and characteristics of L to R shunt
- Monitor until 1 years old with Echocardiogram
- If it has not closed in 1 year, it is unlikely it will close spontaneously
- trans-catheter or surgical closure can be performed
- If PDA is symptomatic or there is evidence of heart failure, treat the PDA sooner
6
Q
What is the pathophysiology of an atrial septal defect?
A
- an ASD is a hole in the septum between the two atria
Embryology
- two walls grow down from the top of the heart and fuse to farm the endocardial cushion in the middle of the heart to separate the atria (septum primum and septum secondum)
- defects with these two walls can cause ASD
- the Foramen Ovale is a small hole in the septum secondum that closes at birth
Pathophysiology
- ASD leads to a shunt of blood from the LA to the RA (LA pressure is higher)
- so blood continues to flow through pulmonary vessels to lungs to be oxygenated, so the patient does not become cyanotic
- However increased flow to the R side of the heart = R sided overload and R heart strain.
- this eventually leads to R heart failure and Pulmonary HTN
- Eventually pulmonary HTN can lead to Eisenmenger syndrome (where pulmonary pressure gets greater than systemic pressure so the shunt reverses to be a R to L shunt across the ASD)
- the blood then just bypasses the lungs
- patient becomes cyanotic
7
Q
Name some atrial septal defects (commonest to least common)
A
- Commonest = ostium secondum (septum secondum fails to fully close)
- patent foramen ovale
- ostium primum (septum primum fails to fully close)
- typically results in atrioventircular valve defects though, so is classified as an atrioventricular septal defect
8
Q
What are some complications of an ASD?
A
-
Stroke!!!
- typically when patients have a DVT the clot travels to the R side of the heart and becomes stuck in the lungs as a PE
- in an ASD, the clot can travel across from the RA to the LA and can go through the LV, aorta, and up to the brain to cause a large stroke
- Atrial fibrillation and Atrial flutter
- Pulmonary HTN and R sided HF
- Eisenmenger syndrome
9
Q
How would an ASD present?
A
- usually either picked up on antenatal scans or newborn examinations
- Murmur = ejection-systolic, crescendo-decrescendo murmur
- loudest at the upper left sternal border with a fixed split S2
- the splitting of the S2 is where you hear the closure of the aortic and pulmonary valves at slightly different times
Some people are asymptomatic in childhood, then present in adulthood with dyspnoea, HF or stroke.
- Childhood symptoms:
- SOB
- difficulty feeding
- poor weight gain
- Lower Resp Tract Infections
10
Q
How would you manage an ASD?
A
- refer to a paediatric cardiologist
- if ASD is small and asymptomatic = watching and waiting
- Surgery = transvenous catheter closure via femoral vein
- or open heart surgery
- Anticoagulants (aspirin, warfarin, NOACs) to reduce risk of clots and stroke in adults
11
Q
What is the pathophysiology of ventricular septal defects?
A
- Can be tiny or involve the entire septum to form one large ventricle
- Often associated with Down’s Syndrome and Turners Syndrome
Pathophysiology:
-
Blood shunts from LV to RV (higher pressures in LV)
- blood is still flowing around the lungs and being oxygenated before going round the body so the patient is not cyanotic
- L to R shunt results in R Sided Overload, R HF and increased flow to Pulmonary vessels, leading to Pulmonary HTN
- Eventually pulmonary HTN can result in the R sided Heart pressures to be greater than the L, resulting in a R to L shunt
- this shunt means that blood avoids the lungs, resulting in cyanosis
- This is Eisenmenger Syndrome
12
Q
How would ventricular septal defects present?
A
- can present on antenatal scans or as a murmur on newborn baby check
- pansystolic murmur
- most prominently heard at Left Lower Sternal Border in the 3rd and 4th ICS
- Palpation may feel a systolic thrill
- initially symptomless and can present as late as adulthood
- Typical symptoms:
- poor feeding
- dyspnoea
- tachypnoea
- poor feeding
- failure to thrive
13
Q
What are other causes of a pansystolic murmur?
A
Think ventricular septal defect,
mitral regurgitation,
Tricuspid regurgitation
14
Q
How would you manage a ventricular septal defect?
A
- asymptomatic small VSD with no evidence of pulmonary htn or HF = watched as they can close spontaneously
- Surgery = transvenous catheter closure via femoral vein
- or open heart surgery
- Recommend antibiotic prophylaxis in surgical procedures as VSD patients are at a greater risk of infective endocarditis
15
Q
What 3 lesions commonly result in Eisenmenger syndrome?
A
- Atrial Septal Defect
- Ventricular Septal Defect
- Patent Ductus Arteriosus
16
Q
How would Eisenmenger syndrome present?
(findings associated with pulmonary htn, r to l shunt and chronic hypoxia, the different septal defects)
A
- typically presents in 1-2 years in those with large shunts, or in adulthood with small shunts
- can develop more quickly in pregnancy so monitor women with defects closely with echo
Examination findings associated with pulmonary htn…
- Right ventricular heave (RV pushing forcefully against higher pressure in the lungs)
- Loud S2 due to forceful shutting of pulmonary valve
- Raised JVP
- Peripheral Oedema
Examination findings related to R to L shunt and chronic hypoxia…
- cyanosis
- clubbing
- dyspnoea
- plethoric complexion (red complexion related to polycythaemia)
Examination findings associated with septal defect…
- ASD = ejection-systolic, crescendo-decrescendo murmur
- loudest at upper L sternal border
- VSD = pansystolic murmur
- loudest at L lower sternal border
- PDA = continuous crescendo-decrescendo “machinery” murmur
- Arrhythmias
17
Q
How would you manage Eisenmenger syndrome?
A
- the underlying defect should have been managed optimally or corrected surgically to avoid Eisenmenger syndrome
- Once the pulmonary htn gets high enough to cause Eisenmenger, the only definitive treatment is a heart-lung transplant
- Medical management:
- O2 can manage symptoms but does not affect outcomes
- treatment of pulmonary htn with sildenafil
- treatment of arrhythmias
- treatment of polycythaemia with venesection
- prevention and treatment of thrombosis with anticoagulation
- prevention of infective endocarditis using prophylactic antibiotics
18
Q
What is the pathophysiology of Coarctation of the aorta?
A
- a congenital condition where there is narrowing in the aortic arch, usually around the ductus arteriosus.
- narrowing reduces the pressure of blood flowing to the arteries distal to the narrowing
- it increases the pressure in areas proximal to the narrowing eg. the heart and the first 3 branches of the aorta
- associated with Turner’s Syndrome
19
Q
How would coarctation of the aorta present?
A
Initially in a neonate…
- weak femoral pulses
- when you do a 4 limb blood pressure, there will be high BP in limbs supplied from arteries that come before the narrowing and lower BP in limbs that are supplied from arteries that come after
- Ejection Systolic murmur at L upper sternal edge
- Tachypnoea and increased work of breathing
- poor feeding
- grey and floppy baby
- Rib notching on CXR = “3 sign”
Over time…
- Left ventricular heave due to LV Hypertrophy
- underdeveloped left arm (due to reduced flow from Left Subclavian artery)
- underdevelopment of the legs
20
Q
How would you manage coarctation of the aorta?
A
- In mild cases the patient won’t have symptoms or require surgery until adulthood
- In severe cases, they may need emergency surgery at birth
- Critical cases where there is a risk of HF and death shortly after birth:
- Prostaglandin E is used to keep the ductus arteriosus open while awaiting surgery shortly after birth
- this allows some blood to flow through the DA into systemic circulation distal to the coarctation
- surgery is then performed to correct coarctation and ligate ductus arteriosus
21
Q
Describe the pathophysiology of congenital aortic valve stenosis
A
- narrow aortic valve that restricts blood flow from the LV into the aorta
- the aortic valve is usually made up of 3 leaflets (the aortic sinuses of Valsalva) which prevent blood from backflowing back into the LV
- patients with Aortic Stenosis may have one, two, three or 4 leaflets.
22
Q
How would aortic stenosis present?
A
- can be totally asymptomatic and accidentally discovered as a murmur and other signs during routine examination:
- Ejection systolic murmur heard loudest at aortic area (2nd ICS, R sternal border)
- Crescendo-decrescendo murmur that radiates to carotids
- Ejection click before murmur
- Palpable thrill during systole
- Slow rising pulse and narrow pulse pressure
- severe aortic stenosis = fatigue, SOB, dizziness, fainting
- symptoms are typically worse on exertion as outflow from LV cannot keep up with demand
- Really severe aortic stenosis can present with HF within months of birth
23
Q
How would you manage aortic stenosis?
A
- diagnose with an echocardiogram
- follow up with echocardiograms, ECGs and exercise testing to monitor, as congenital AS worsens over time
- patients with significant stenosis may need to restrict physical activities
- Monitor for Left Ventricular Outflow Tract Obstruction, HF, Ventricular arrhythmia, Bacterial Endocarditis
Management of stenosis:
- percutaneous balloon aortic valvoplasty
- surgical aortic valvotomy
- valve replacement
31
Q
How would you investigate tetralogy of fallot?
A
-
Echocardiogram for diagnosis
- doppler flow studies show direction of bloodflow to assess severity of abnormality and shunt
- CXR can show “boot shaped” heart due to RV thickening
35
Q
Describe the pathophysiology of Ebstein’s anomaly
A
- a congenital heart condition where the tricuspid valve is set lower in the R side of the heart (towards apex)
- this results in a bigger RA and smaller RV
- This leads to poor flow from the RA to RV, and therefore poor flow to the pulmonary vessels
- Often associated with R to L shunt across the atria via an atrial septal defect
- when this happens, blood bypasses the lungs = cyanosis
- Also associated with Wolff-Parkinson-White syndrome
39
Q
Describe the pathophysiology of transposition of the great arteries
A
- This is where the attachments of the _aorta and the pulmonary trun_k to the heart, are swapped
- Ie RV pumps blood into the aorta and LV pumps blood into the pulmonary vessels
- Systemic circulation is on the Right and Pulmonary system is on the Left and there is no connection between the two
- This condition becomes life threatening at birth, as in the womb gas exchange happens across the placenta so blood flow to the lungs doesn’t matter
- There is no connection between systemic and pulmonary circulation, so baby becomes cyanosed
- immediate survival depends on if there is a shunt between the systemic and pulmonary circulation (eg. PDA, ASD, VSD)
50
Q
What are some clinical features of rheumatic fever?
(think about the diagnostic criteria)
A
Jones Diagnostic Criteria!!!
- Positive throat culture for Group A b-haem streptococcus OR elevated anti-streptolysin O titres OR anti-deoxyribonuclease B titre
AND
- 2 major OR 1major+2minor criteria
Major = SPECS
- Sydenham’s chorea
- Polyarthritis
- Erythema marginatum
- Carditis
- Subcutaneous nodules
Minor = CAPE
- CRP/ESR raised
- Arthralgia
- Pyrexia/Fever
- ECG - prolonged PR interval
Patient may also present with a recent hx of a sore throat or scarlet fever.
In sever disease you may hear a mitral diastolic murmur.
