1
Q
Describe foetal blood circulation
A
- 40% of cardiac output goes to placenta
- large R to L shunt -> patent foramen ovale + patent ductus arteriosus
- blood enters RA ⇒ FO ⇒ LA ⇒ LV ⇒ systemic circ
- some blood goes from RA ⇒ RV ⇒ PA ⇒ DA ⇒ systemic circ
- low oxygen tension helps pulmonary vasoconstriction
- hence little pulmonary flow
- pulmonary pressure = systemic pressure
2
Q
Describe the changes that occur around the time of birth in the CVS
A
- w/ baby’s 1st breath ⇒ fluid is expelled from alveoli into capillaries ⇒ lungs fill with air (and hence oxygen) ⇒ arterioles dilate ⇒ pulmonary resistance decreases ⇒ pulmonary blood flow increases ⇒ allows volume of blood flowing to the lungs to increase ⇒ blood can be oxygenated at the lungs
- this in turn causes the pressure in the left atrium to increase
- this pressure increases to greater than the right atrial pressure resulting in the foramen ovale to force shut
- additionally, umbilical artery vasoconstriction raises systemic BP
- PDA closes within the first few days w/ higher oxygen tensions and falling PGs
3
Q
What are the normal values for heart rates in children?
A
- <1yr ⇒ 110-160
- 2-5yrs ⇒ 95-140
- 5-12yrs ⇒ 80-120
- >12yrs ⇒ 60-100
4
Q
Congenital heart disease (CHD) is the most common birth defect, although still relatively rare.
What are left-to-right shunts?
A
- lesions that allow blood to shunt from left to right side of heart
- typically acyanotic
- cyanosis only occurs if the lesions are large + not repaired in childhood + if pt develops pulmonary vascular obstructive disease (Eisenmenger’s)
- primary imaging modalitiy: echocardiography
- intervention: cardiac catheterisations
- examples: VSD, ASD, AVSD, PDA, PAPVC
5
Q
What are right-to-left shunts + examples?
A
- lesions that result in de-oxygenated blood reaching the aorta + associated w/ an increased or decreased pulm blood flow
- typically cyanotic
- examples:
- tetralogy of Fallot (ToF)
- pulm valve atresia +/- VSD
- Transposition of great arteries (TGA)
- truncus arteriosus
- Ebstein’s anomaly
- Hypoplastic left heart syndrome
6
Q
Most congenital heart defects result from problems early in the child’s heart development, the cause of which is unknown. However, certain environmental and genetic risk factors may play a role.
What are the risk factors for congenital heart defects and which defects do they commonly result in?
A
- MATERNAL
- infection - rubella ⇒ PDA, PS
- autoimmune - SLE ⇒ complete heart block
- diabetes mellitus ⇒ all
- meds - lithium, thalidomide, ACEi, statins, isotretinoin, warfarin
- foetal alcohol syndrome ⇒ ASD, VSD ToF
- INFANT (chromosomal abnormalities)
- Down’s ⇒ AVSD, VSD
- Edwards (18) ⇒ complex
- Patau (13) ⇒ complex
- Turner’s (45XO) ⇒ AS, CoA
- C 22q11.2del ⇒ aortic arch anomalies, tetralogy of aorta
- Williams (c7 micro del) ⇒ AS, PS
7
Q
Innocent murmurs are not associated with cardiac disease + are generated by turbulent flow in an outflow tract or large blood vessels near the heart. They are very common in young children.
They are more likely to be noticed when there is increased cardiac output eg. during exercise, febrile illness or anaemia.
What are the characteristics of an innocent murmur?
A
- systolic → diastolic murmurs always pathological
- soft → never above grade II intensity
- small → localised, does not radiate to a large area
- single → never accompanied by additional noises
- sensitive → sound varies w/ respiration + movement
- asymptomatic → symptoms like syncope + cyanosis would suggest pathology
8
Q
What are examples of innocent murmurs?
A
- Still’s murmur → systolic, soft, generated in outflow tract of either side of heart, heard over lower left sternal edge (resolve by 10-12y)
- Pulmonary Flow murmur → ejection systolic murmur, heard at upper left sternal edge in toddlers + adolescents, best heard supine, no radiation
- Venous hum → continuous low-pitch grumble below right clavicle, decreases when pt supine, generated in head + neck
9
Q
How do you investigate an innocent murmur?
A
- neonates → circulation changing rapidly so murmur may indicate developing cardiac disease, hence all neonates w/ murmur should have a CXR + ECG and an echo if these are abnormal
- children → not necessary to investigate innocent murmur as child’s CVS stable
10
Q
Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. What are the components of Tetralogy of Fallot?
A
- infundibular pulmonary stenosis → causes a “right outflow tract obstruction”, making it difficult for RV to pump blood to lungs for oxygenation, leads to the next component…
- right ventricular hypertrophy → secondary to RV being exerted to pump adequate amounts of blood into pulmonary circulation
- ventricular septal defect → defect allows deoxygenated blood to flow from RV (operating at a higher that normal pressure due to outflow tract obstruction) into the left, RIGHT ⇒ LEFT shunt
- overriding aorta → this abnormality of insertion of aorta simply means that its opening lies directly over VSD, so both the left + right ventricles pump blood into it
11
Q
ToF is often picked up during routine antenatal scanning. This allows better preparation at birth (delivery at cardiac unit).
For patients that present postnatally, particuarly those without antenatal care, presentation depends upon the degree of outflow obstruction.
What is the clinical presentation of Tetralogy of Fallot?
A
- mild (‘pink’ ToF) → mild PS/RVH, usually asymptomatic, disease progresses as child + heart grows thus by age 1-3yrs they will develop cyanosis. Presentation may co-incide w/ HF
- moderate-severe (cyanotic) → may present in first few weeks of life, heart murmur picked up due to pulmonary stenosis rather than VSD (systolic murmur best heard over left upper sternal edge)
- extreme → pulmonary atresia or absent pulmonary valves possible: these are duct-dependent lesions where only way deoxygenated blood can flow into lungs is through PDA. These infants often detected on antenatal scanning, however if undetected in pregnancy they will present within first few hours of life w/ resp distress + cyanosis
12
Q
What physical signs can be picked up on examination in ToF?
A
- inspection: central cyanosis, clubbing
- palpation: thrill (depending on murmur), heave (RVH)
- auscultation:
- loud, single S2 → absent/reduced pulmonary valve closure
- ejection systolic murmur → mid or upper LSE, the smaller VSD the louder the murmur
- ejection click → dilated aorta
- continuous, machinery murmur → PDA, upper LSE or left infraclavicular area
- murmurs may decrease in intensity during “tet” spells due to reduced pulmonary BF
- signs of congestive heart failure: sweating, pallor, tachycardia, hepatosplenomegaly, generalised oedema, bilateral basal crackles or gallop rhythm may be auscultated
13
Q
What is a hypoxic/hypercyanotic “Tet” spell?
A
- peak age of incidence usually between 2-4months of life
- paroxysm of hyperpnoea: rapid, deep inspirations due to inc R-L shunting → CO2 accumulates → stimulating central resp centre → further R-L shunting → perpetuating hypoxia
- irritability: prolonged, unsettled crying
- increasing cyanosis
May be preciptated by dehydration, anaemia or prolonged crying (induces tachycardia + reduced systemic vascular resistance)
14
Q
What investigations should be done for ToF?
A
- pulse oximetry
- echocardiogram → definitive/gold standard
- ECG → RVH?
- CXR → boot-shaped heart (RVH)
- hyper-oxygenation test → pulmonary or cardiac lesion?
15
Q
An infant with TOF and hypercyanotic spells is a medical emergency because a prolonged hypercyanotic spell can result in brain ischaemia and death.
What is the initial management for a tet spell?
A
- calming child + manouveres to inc amount of blood exiting RV to pulm vasculature instead of to aorta ie. trying to get more blood to the lungs
- squatting: infant should be positioned knees to chest to increase venous return to heart + systemic afterload
- give oxygen but take care as if infant is still profoundly cyanotic, acidosis will result
- saline 0.9% bolus - volume expander to inc pulm blood flow through RVOTO
16
Q
ToF: If the previous initial management for a hypercyanotic spell does not work, what are the next steps for medical therapy?
A
- morphine → reduces resp drive + hyperpnoea
- beta-blockers → propranolol used in tet spells + prophylaxis, reduces HR
- phenylephrine → to increase systemic venous resistance + force more blood to lungs
17
Q
In tetralogy of Fallot treatment, who may benefit from prostaglandins?
A
- acutely unwell neonates w/ severely limited pulm blood flow causing cyanosis
- PGs help to maintain patency of ductus arteriosus
- either alprostadil or dinoprostone used
- SEs: apnoea, bradycardia, hypotension
- this provides alternative source of blood flow while infant awaits surgical intervention
18
Q
What is the palliative surgical management for ToF?
A
- Transcatheter RVOT stent insertion: this is sometimes done in the neonatal period for infants with severe-extreme TOF to relieve RVOTO. This is done to buy time until the child is bigger whilst providing a patent passage for pulmonary blood flow.
- Modified Blalock-Taussig (BT) shunt: This procedure aims to mimic a PDA and increase pulmonary blood flow before definitive repair. It can be done either by anastomosis of the subclavian artery to the pulmonary artery or by creating an artificial shunt using synthetic material (usually GoreTex). The latter is called a modified BT shunt.
19
Q
What is the definitive surgical repair for ToF?
A
- performed under cardiopulmonary bypass via median sternotomy
- involves RVOT stenosis resection
- RVOT/pulm artery augmentation + VSD patch closure
- depending on degree of PS, PV is either repaired or spared
- timing depends on severity of symptoms but usually not performed younger than 3 months old or older than 4 yrs
- post-op care: immediately following surgery child will require stabilisation in CICU, once they are well enough they will be stepped down to the cardiology ward prior to discharge
20
Q
Ventral septal defects are the most common cause of congenital heart disease. They close spontaneously in around 50% of cases. Congenital VSDs are associated w/ chromosomal disorders such as Down’s syndrome, Edward’s syndrome and Patau syndrome.
What is the pathophysiology of VSDs?
A
- usually in VSD blood is pumped at a higher pressure in the LV than the RV → blood shunted LEFT to RIGHT
- this means oxygenated blood is then travelling towards the lungs
- a small restrictive defect leads to minimal L-R shunting across the ventricles + is asymptomatic
- if defect is moderate or severe → pulmonary hypertension → heart failure
21
Q
What is Eisenmenger’s syndrome?
A
- where pressure in RV exceeds that of the RV
- caused by significant gradual increase in pulmonary vascular resistance
- results in shunt reversal → deoxygenated blood flows from RV to LV + enters systemic circulation → decreased systemic oxygen saturation → cyanosis
22
Q
What are the clinical features of VSDs?
A
- fatigue
- pansystolic (or early systolic) murmurs → detected in infancy, left parasternal region, does not increase w/ inspiration, smaller defect = louder murmur
- failure to thrive
- shortness of breath
- feeding problems
- cyanosis (if severe)
- finger clubbing
- recurrent pulmonary infections
- intolerance to exercise, dizziness, chest pain, ankle swelling
23
Q
What investigations can be done for VSDs?
A
- ECG → ? LVH or bilateral VH
- septic screen, U+Es
- Microarray → if genetic syndromes suspected
- CXR → large VSDs show cardiomegaly + pulm oedema/effusions
- Echo → gold standard
- Cardiac CT angiography
- MRI
- Cardiac Catheterisation → diagnose + treat CHDs, determine relative pressures + pulm vasc resistance, significance of shunt + help plan future treatments
24
Q
The type of management required depends on the size of the VSD. A small, asymptomatic VSD does not require surgical or medical therapy, though it is advised that these patients maintain good oral hygiene to decrease the risk of infective endocarditis.
What is the medical management of VSDs?
A
- ensure adequate weight gain
- diuretics → furosemide decreases pulm oedema, spironolactone can be added to minimise potassium loss
- ACE inhibitors → second stage treatment, reduce L-R shunt by reducing afterload + allowing more blood through aortic valve and less through VSD – can increase potassium, so may need to discontinue spiro
- digoxin → for congestive heart failure
- no need for exercise restriction
25
Though many babies born with a small VSD won’t need surgery to close the hole, those with medium or large VSDs which are causing **significant symptoms**, or smaller VSDs that could possibly cause **complications** in later life, may need surgery to close the defect.
In adults, the guidelines recommend that surgical closure of a VSD is indicated when there is a Qp/Qs (pulmonary-to-systemic blood flow ratio) of 2.0 or more.
What are the **surgical** procedures involved?
* **surgical repair**: open heart surgery, under cardiopulm bypass via median sternotomy, a patch material or stitches are used to close hole
* **catheter procedure**: less common, catheter inserted via femoral artery and specially sized mesh device deployed to close the hole
* **hybrid approach**: surgeon creates small access through left ventricle for the interventional cardiologist to deploy the closing device
26
What is involved in the **palliative** surgery for VSDs?
* **pulmonary artery banding**
* *rarely* performed unless additional lesions make complete repair difficult
* band is wrapped around pulmonary artery and tightened to decrease its diameter and decrease pulmonary blood flow in order to minimise damage to pulmonary vessels
* full surgical repair usually performed in a later stage
27
What is the **long-term** management of VSDs?
* repaired or not, there is an increased risk of infections of the heart walls + valves ie. **endocarditis**
* to help prevent this, it's important to maintain **good dental hygeine**
* also _avoid_ non-medical procedures eg piercings + tattoos
* possibility of endocarditis should always be investigated esp if there is fever without focus
* prophylactic abx for dental procedures are **no longer** routinely recommended
* regular cardiac follow-up needed life-long w/ follow-up intervals being more spaced apart as patients get older + remain asymptomatic
* activity should not be restricted unless complications have resulted from surgery
28
What are examples of the **cyanotic** heart defects?
* Tetralogy of Fallot
* Transposition of the great arteries
* Truncus arteriosus
* Total anomalous pulmonary venous drainage (TAPVD)
* Hypoplastic left heart syndrome
* Tricuspid Atresia
* Complete atrioventricular septal defect (AVSD)
* Eisenmenger's (severe VSD)
29
What are the common **signs and symptoms** of _cyanotic_ heart defects?
* clubbing
* patient assuming a crouching position
* cyanosis
* crying
* irritability
* feeding problems
* failure to thrive
30
What is **transposition of the great arteries** (TGA) and its presentation?
Aorta attaches to the right ventricle and pulmonary artery connects to the left ventricle (in a swapped position). This results in two separate unconnected circuits where oxygen blood is pumped between left atrium, ventricles + lungs and deoxygenated blood pumped through right atrium, right ventricle + around body.
* most **common** cyanotic disease to present in neonatal period
* **incompatible** with life _unless_ further **defect** permits shunting of blood across heart to allow oxygenated blood into systemic circulation (eg. duct dependent)
* severe cyanosis at birth or 2-3 days after + circulatory compromise
* ECG is normal
* CXR shows cardiac outline of "egg on side" + inc pulmonary vascular markings
* echo essential to demonstrate abnormality
31
What is the **treatment** of **TGA**?
* **prostaglandin** infusion to reopen ductus arteriosus
* emergency cardiac catheterisation + **therapeutic balloon atrial septostomy** (Rashkind procedure) → opens foramen ovale for blood mixing
* **atrial switch procedure** surgery after 1st few days of life → pulm artery and aorta are transected + switched over
32
What is **truncus arteriosus** and its presentation?
* only **one** great vessel arises from both ventricles
* aorta + pulmonary artery both originate from this structure
* it is always accompanied by a VSD
* initial mild-moderate **cyanosis** may be the only finding
* later signs of pulmonary congestion + **HF** occur over the next few days/weeks
33
What is **total anomalous pulmonary venous drainage** (**TAPVD**) and its presentation?
* the 4 pulmonary veins drain into **RA** _instead_ of LA
* this means oxygenated blood is pumped **back into the lungs** rather than into systemic circulation
* child has two separate non-communicating circulation systems
* only chance of survival for these children is **mixing** of the blood via VSD, ASD or PDA
* this presents antenatally w/ cyanosis + circulatory compromise
* ECG = normal in neonate
* CXR shows outline of "**snowman in snowstorm**" or "cottage loaf" from congested atria + pulmonary veins, giving rise to pulm oedema
34
What is **hypoplastic left heart syndrome** + its presentation?
* a group of defects affecting left side of heart
* valves + chambers, in which structures are **too small** to support systemic output
* usually **antenatally** diagnosed w/ an aim for delivery at a cardiac centre
* it presents as a **breathless**, _severely_ **cyanotic** + compromised neonate soon after birth
* ECG shows absent ventricular forces
35
What is **tricuspid atresia** and its presentation?
* valve is blocked or absent
* therefore deoxygenated blood cannot flow into the pulmonary circulation from the right ventricle
* this defect is **incompatible** w/ life _unless_ it is accompanied by both a VSD + an ASD or a PDA
* **cyanosis** is present soon after birth
* a **systolic** **murmur** is heard at the left lower sternal edge if a VSD is present or a continuous murmur below the left clavicle if a PDA is present
36
What is a **complete atrioventricular septal defect (AVSD)** and its presentation?
* a large AVSD which is continuous w/ a large VSD
* **all 4 chambers** of heart are communicating w/ one another
* this causes **increased blood flow to the lungs** as well as less effective drainage
* thereby promoting **pulmonary hypertension** + **heart failure** as well as cyanosis
* this is the abnormality most often associated w/ **Down's Syndrome**
* **ejection systolic murmur** at left upper sternal edge (pulmonary flow murmur)
* pansystolic murmur at apex (mitral regurgitation)
37
Describe how to assess + treat a neonate w/ suspected cyanotic heart disease
* duct is your friend - until you can get child to a cardiac centre
* **prostaglandin** to keep duct open
* be careful w/ oxygen if duct dependent as the duct can close
* heart failure treatment → diruetics, ACEi
* CHD surgery
* **palliative** → achieve stable but abnormal circulation
* **corrective** → achieve normal circulation, definitive repair
* close: do not need bypass, open: need bypass
38
What are examples of **acyanotic** heart defects?
* ventricular septal defect
* atrial septal defect
* patent ductus arteriosus
* aortic stenosis
* pulmonary stenosis
* coarctation of the aorta
39
What are the **signs and symptoms** of **acyanotic** heart defects?
* shortness of breath
* congested cough
* fatigue
* tachycardia
* tachypnoea
* respiratory distress
40
What is **PDA** and its presentation?
* failure of **ductus** **arteriosus** to close following birth
* blood flow from aorta to pulm artery: L-R shunt
* usually **asymptomatic**
* can present w/ HF and pulmonary hypertension
* **continuous** **machinery murmur** under L clavicle
* + early systolic murmur in left sternal upper edge
* **collapsing** or **bounding** pulses may also be felt
* closure w/ coil or occlusion device via cardiac cath at 1yo
41
What is an **ASD** and its presentation?
* communication between atria causing right shunting of blood across defect
* may be **ostium primum** (inferior portion of atrial septum)
* or **secundum** (usually arises from an enlarged foramen ovale)
* usually a well child but may present w/ HF (if large) or recurrent chest infection/wheeze
* can present w/ arrhythmia
* ostium primum may be associated w/ **mitral regurg** → _pansystolic_ murmur
* a soft systolic murmur heard in upper left sternal edge w/ fixed splitting of S2
*
42
**Coarctation** of the arota is a narrowing of the descending aorta. It is characterised by weak femoral pulses + relative hypertension in the upper limbs compared to the lower limbs. It is also associated w/ **Turner** syndrome.
What are the clinical features?
* neonates may be initially asymptomatic _if_ coarctation is accompanied by **PDA**
* **hypertension** presenting at a young age or resistant to treatment; most commonly presents w/ upper extremity hypertension
* diminished lower extremity pulses
* differential upper + lower extremity BP (→ radio-femoral delay)
* systolic ejection murmur audible over left sternal border + back
CXR shows rib notching and '3' sign - notch in the descending aorta. ECG may show LVH. Echo can also be done.
43
What is the treatment for coarctation?
* main goal is **complete repair** of coarcted segment w/ minimal complications and no residual gradient across the narrowed segment
* type of repair depends on age of pt at diagnosis + severity of coarctation
* no clear evidence to support the superiority of either surgical or catheter-based treatment for coarctation of the aorta
* pre-ductal - **PGs** to keep PDA open while awaiting surgery
* post-ductal - **stent** via cardiac catheter
44
**Kawasaki disease** is the most common systemic vasculitis of childhood. It is an **acute febrile vasculitis**, involving small + medium sized arteries. Kawasaki tends to affect children between 6 months - 6 years, more prevalent in people of Japanese and A-C origin.
What are the **clinical features** of Kawasaki?
* children present w/ **high fever**, difficult to control
* irritability
* biochemically → **elevated inflammatory markers** but no clear focus of infection
* kids may also report **abdo pain**, **diarrhoea** + **vomiting**
* may have characteristic thrombocytosis on FBC, although this does not usually occur till at least a week later
45
What is the **diagnostic criteria** for Kawasaki disease?
Defined by a **fever lasting 5+ days** without any clear focus of infection, plus _any 4_ of the following:
* **bilateral non-purulent conjunctivitis**
* **mucositis** → dry red lips / strawberry tongue
* **cervical lymphadenopathy**
* **extremity changes** → red or indurated hands or feet, eventually leading to desquamation (peeling)
* **polymorphous rash**
46
What is the **treatment** for Kawasaki disease?
* **high dose aspirin** (acting as an anti-platelet + anti-inflammatory)
* **intravenous immunoglobulin** (IV IG)
* aspirin therapy continued for several weeks + longer if any abnormal findings observed on echo
Medicine: Paediatrics
flashcards
Decks in class (14)
# Cards
-
Neonatology (1s)38
-
Neonatology (2s + 3s)23
-
Respiratory (1s)44
-
Respiratory (2s + 3s)40
-
Cardiovascular46
-
Neurology + Development (1s)39
-
Neurology + Development (2s + 3)40
-
Nephrology45
-
Gastrointestinal Disease45
-
Metabolic, Endocrine + Growth47
-
Immunology, Allergy + Derm33
-
Infections37
-
MSK + Joint4
-
Haemotology + Oncology21
