Paediatrics Notes

PAEDIATRICS

Contents:

Cardiology

• Cyanotic defects

  • Tetralogy of Fallot

  • Transposition of the great arteries

  • Tricuspid atresia

  • Hypoplastic left heart syndrome

  • Persistent truncus arteriosus

  • Total anomalous pulmonary venous return

  • Pulmonary atresia

  • Ebstein’s anomaly

Respiratory

• Bronchiolitis

• Cystic fibrosis

Gastroenterology

• Meckel’s diverticulum

• Pyloric stenosis

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CARDIOLOGY

CYANOTIC DEFECTS

Only right to left shunts cause cyanosis. The cyanotic defects in children are:

• Tetralogy of Fallot

• Transposition of the great arteries

• Tricuspid atresia

• Hypoplastic left heart syndrome

• Persistent truncus arteriosus

• Total anomalous pulmonary venous return

• Pulmonary atresia

• Ebstein’s anomaly

It is important to understand the fetal anatomy to have a good understanding of these conditions.

Be aware of signs of decompensation:

• Poor feeding

• Dyspnoea

• Hepatomegaly

• Engorged neck veins

• Tachycardia or bradycardia

• Weak pulse

• Acidosis

• Pulmonary venous congestion

1. Tetralogy of Fallot

Summary Points

• Tetralogy of Fallot is the presence of a ventricular septal defect, right ventricular hypertrophy, right ventricular outflow obstruction and an overriding aorta

• Patients are cyanosed, are classically dyspnoeic after prolonged crying, and failure to thrive

• It is confirmed by examination, ECG and ECHO

• It is managed surgically, usually with a Blalock-Taussig shunt

Aetiology and Pathophysiology

There are four abnormalities:

• Ventricular septal defect – usually large and just below the aortic valve

• Right ventricular hypertrophy

• Right ventricular outflow obstruction (usually pulmonary stenosis)

• Overriding aorta (lying over VSD)

This causes mixing of blood, poor blood flow to lungs, poor blood flow to body and inadequate pumping of blood resulting in cyanosis.

TOF is seen with a right sided aortic arch in 20% of patients, and an atrial septal defect in ~10%.

Epidemiology and Associated Risk Factors

Has an incidence of 1 in 3600 live births.

Associated with:

• Fetal alcohol syndrome

• Maternal Phenylketonuria

• Fetal hydantoin syndrome

• CATCH 22 –

  • Cardiac defects

  • Abnormal faces

  • Thymic hypoplasia

  • Cleft palate

  • Hypocalcaemia

  • 22q11 (DiGeorge’s Syndrome)

Presentation

Severely cyanosed

Poor feeding, breathlessness, agitation

Faints

Dyspnoea on exertion (usually after prolonged crying)

May experience hypoxic spells (aka Tet spells) – potentially lethal

In older children:

• Delayed development and puberty

• Scoliosis

• Haemoptysis

Rarely missed before adulthood.

Assessment

- O/E –

Clubbing

Failure to thrive

Auscultation –

• Absent pulmonary part of S2 (valve closure not heard)

• Systolic thrill at lower left sternal border

• Harsh systolic murmur at left sternal base

• Pan or ejection systolic murmur over right ventricle (can hear it at the back also) due to RVOT obstruction

• Cyanotic patients have greater obstruction and a softer murmur

• Aortic ejection click

Ophthalmoscopy – in older children, retinal vessels may be engorged

- Ix –

ECG – right axis deviation (right atrial and ventricular hypertrophy (RVH))

Transthoracic ECHO – demonstrates obstruction and hypertrophy

CXR - boot-shaped heart (aka coeur-en-sabot) and RVG

Picture - http://radiology.rsna.org/content/246/1/328/F1.expansion.html

Bloods – FBC, Ferritin, consider ABGs (acidosis), BNP levels correlate well with ventricular function

Rx

Conservative

• Positional

• Activity restriction

• Neonates – give oxygen, keep warm

Medical

• Tet hypercyanotic spells –

  • Oral B-blockers may reduce their frequency

  • During attack – oxygen, morphine and IV propanolol

Surgery

Usually performed age 3-6 months.

Give IV prostacyclin E1 to keep ductus arteriosus open while waiting for surgery

Surgery is often in two stages, with a palliative procedure first and then a second for a complete repair.

• Blalock-Taussig shunt (from subclavian to pulmonary artery) – used as palliative surgery for symptomatic relief

• Implantable cardioverter defibrillator – should be considered for all patients following repair

• Corrective open heart surgery

Prognosis and Complications

Poor prognosis. <10% live to 40y. 95% live more than 8 years with surgery.

Without surgical treatment, 30% die in infancy, 75% die before aged 10.

Blalock-Taussig shunt is a relatively safe procedure.

Surgical repair in adulthood is associated with high early mortality.

A sustained high haemoglobin level tells of chronic cyanosis and predicts early mortality.

Complications:

• Sudden death (a late complication of surgically treated patients)

• Congestive heart failure

• Iron deficiency anaemia

• Neurodevelopmental delay

• Aortic root dilation

• VT

• Reduced exercise capability (5-20 years after surgery)

2. Transposition of the great arteries

Summary Points

• Transposition of the great arteries is where the aorta and pulmonary artery are swapped anatomically

• Patients present with worsening cyanosis aged 2-3 days if they lack a compensatory defect

• Confirm with ECHO and chest X-Ray showing an egg-on-side appearance

• It is corrected surgically, with an arterial switch

Aetiology and Pathophysiology

The aorta and pulmonary artery are swapped (so the aorta comes off of the right ventricle and the PA from the left). The aetiology is unknown and is likely to be multi-factorial.

There are 2 main variants – levo and dextro:

• Levo-transposition – aorta is anterior and left to the pulmonary artery

• Dextro-transposition (60%) – aorta is anterior and right to the pulmonary artery

The coronary vessels are abnormal in 1/3 of patients.

Often associated with other heart defects, often as a method of compensating, as the neonate will require mixing of blood to survive:

• VSD

• LV outflow obstruction

• ASD

• Patent ductus arteriosus

Epidemiology and Associated Risk Factors

Overall annual incidence 2-3/10,000 live births.

More common in males, 3:1.

Maternal factors that increase its risk:

• Rubella infection or other viral illness during pregnancy

• Alcoholism

• Maternal age >40yrs

• Diabetes mellitus

Presentation

Most affected infants present...

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