Case study of cyanotic congenital heart disease

Baby J, a 3-week-old infant, was admitted to Ward 5A since birth due to severe central cyanosis caused by several congenital heart problems. Soon after birth, he suffered from respiratory distress, where his initial SaO2 was only about 70%. He was resuscitated and given 5 nanograms/kg/min of Prostin (Prostaglandin E2). On appearance, he was dusky-looking and his peripheries were cold and cyanosed. He was started on biphasic continuous positive airway pressure (CPAP) via an apnoea mask and also given positive end-expiratory pressure (PEEP) as an adjunct. His CPAP was delivered using nasal cannula the following day after his SaO2 increased to 80% and he remained on CPAP for the first 5 days after birth, which subsequently was weaned off. Antenatal scans found pulmonary atresia, overriding aorta and ventricular septal defect (VSD). Postnatally, cardiac catheterisation confirmed the antenatal findings with extra major aortopulmonary collateral arteries (MAPCAs).

He tolerated feeding via TPN and was given 6ml of EBM (expressed breast milk) at intervals of 2 hourly. Bottle feeding was attempted on 28/09/09 and he tolerated the feedings well. Recently, the feedings increased to 44ml 2 hourly. Baby J passed urine normally and his stools were of normal consistency.

Past Medical and Surgical History

Baby J underwent a cardiac surgery on 1/10/09 through a median sternotomy and a Melbourne shunt was inserted to create an aortopulmonary connection.

He was also diagnosed with Alagille’s syndrome (an autosomal dominant inherited disorder affecting the heart, liver, spine, kidney and central nervous system).

Family History

Baby J’s father was diagnosed with Alagille’s syndrome as a child. He has congenital spinal abnormalities, cardiac defects (atrial septal defect, ASD, pulmonary stenosis and right ventricular dysfunction).

Baby J’s mother suffered from depression for about 3 years now. She also has asthma and a high BMI of 40. During pregnancy, Baby J’s mother was on anti-depressant (Fluoxetine 20 mg OD) and inhalers (Becctide and Ventolin).

Drug History

NKDA

Medication

Dosage

Frequency

Aspirin

15mg

OD

Frusemide

3mg

BD

Spironolactone

3mg

BD

Social History

Baby J is the 3rd child in the family. He has one brother and 2 sisters. His brother was also diagnosed with Alagille’s and suffers from cardiac anomaly.

Baby J’s mother is a non-smoker and she did not drink alcohol while conceiving him.

Systemic Enquiry

Neurological

None to note.

Cardiovascular

See above.

Respiratory

Cyanotic.

Gastrointestinal

None to note. Opened bowel normally with normal stools.

Genitourinary

None to note. Passed urine normally.

Haematological

None to note. No fevers or rigors

Musculoskeletal

None to note.

Endocrine

None to note

PHYSICAL EXAMINATION

General Inspection

Not distressed or in pain.

Alert and non-lethargic.

Apyrexial (Temperature – 37.1 0C)

Mild bluish discolouration of lips and tongue. SaO2 83% on room air.

Heart rate: 156 bpm

RR: 48/min

Anterior fontanelle normal.

Cardiovascular Examination

Examination

Findings

BP

Pulse rate

78/ 45 mmHg

156 bpm

(regular, normal volume, character)

No radial-radial delay or radio-femoral delay.

Normal radial/ brachial/ femoral pulses.

Normal carotid pulses.

Inspection

Hands and nails

Face and tongue

Precordium

Ankle

Non-cyanotic fingers. CRT <2s

No finger clubbing/ splinter haemorrhages.

Non-pallor palmar creases.

Deep-set eyes, prominent forehead (features of Alagille’s syndrome)

Non-pallor conjunctiva

Mild central cyanosis (bluish tinge to tongue)

Median stenotomy scar.

No peripheral oedema (rarely seen in children)

Palpation

Central trachea.

No thrills or left parasternal heave.

Auscultation

HS=I+Single II (muscular pulmonary atresia) + Ejection click (due to high flow across aortic valve) and continuous murmur.

Respiratory Examination

Examination

Findings

Inspection

Hands

Mouth

Eyes

Chest wall

Not breathless or in distress. Breathing at ease.

No peripheral cyanosis.

No finger clubbing.

Mild bluish tinge to tongue.

No jaundice and non-pallor conjunctiva.

Normal AP diameter.

Symmetrical movement of chest wall with respiration

No accessory muscles used in respiration.

Trachea

Central, no tracheal tug

Percussion

Generally, resonant to percussion.

Auscultation

Vesicular breath sounds.

Normal air entry. No wheeze or added sounds.

Summary of Problems

Baby J suffered from severe cyanosis immediately post-delivery due to closure of ductus arteriosus. To maintain the patency of the duct, he was given prostaglandin E2. However, this was just a temporary measure to maintain a duct-dependent pulmonary circulation. A more definitive treatment for Baby J was to establish a direct connection between the aorta and the pulmonary artery by a shunt in order to promote growth of central pulmonary artery.

Differential Diagnosis

*Most likely differential for Baby J bolded.

Differentials of cyanosis:-

Primary pulmonary disease

Cyanotic congenital heart disease

Reduced or duct-dependent pulmonary circulation

Tetralogy of Fallot

Pulmonary atresia

Tricuspid atresia

Abnormal mixing

Transposition of great arteries

Total anomalous pulmonary venous drainage (all draining into right atrium)

Single truncus arteriosus

Persistent pulmonary hypertension due to persistent fetal circulation

Anaemia

Asphyxia

Sepsis

Metabolic disorder

Methaemoglobinaemia due to haemolytic anaemia

Management Plan

Initial management:-

Respiratory distress at birth – Resuscitation, give CPAP and PEEP to maintain oxygenation to lungs, immediate Prostin (5ng/kg/min)

Check breathing

Maintain circulation – IV fluids

Routine bloods and ABG

Continuous monitoring oxygen saturation and vitals

Cardiology review- echo and CXR

Echo findings consistent with Fallot tetralogy with MAPCAs

CXR found cardiomegaly

Feeding via TPN (6ml/kg/2 hourly)

Further management:-

Cardiac catherisation – to assess for cardiac anomaly

Cardiology experts advised surgery to establish connection between aorta and pulmonary artery to increase pulmonary blood flow.

Melbourne shunt was inserted via median sternotomy on 1/10/09.

Echo post-op showed good flow in small pulmonary arteries and patent central shunt.

Continue monitoring oxygen saturation – aim to keep above 75%

Perform ECG

Monitor temperature post-op – If pyrexial, culture blood and give vancomycin and gentamicin.

Start on aspirin, frusemide, spironolactone and paracetamol PRN.

Increase feed to 150ml/kg/day via bottle

Relevant Investigations and Results: Bloods results (2/10/09) after cardiac surgery

FBC

Hb

Platelets

WBC

15.2

230

10.5

U&E

Na+

K+

Cl –

Urea

Creatinine

142

4.7

100

3.9

77

LFTs

Alk P

AST

ALT

Pro

Alb

274

29

31

55

27

CRP

100

Echo

Results on 18/09/09

Pulmonary atresia, MAPCAs, VSD, overriding aorta.

Results on 2/10/09

Patent central shunt with good flow to small pulmonary arteries.

MAPCAs flow demonstrated from joined aortopulmary branches.

X-ray of whole spine

Single AP view of thoracolumbar spine – no abnormality found.

Reflective Commentary: Tetralogy of Fallot

Tetralogy of Fallot (TOF) is the commonest cause of cyanotic congenital heart disease. It has 4 cardinal anatomical anomalies:- [1]

Large outlet VSD

Overriding aorta with respect to ventricular septum

Right ventricular outflow obstruction (infundibular and valvular pulmonary stenosis)

Right ventricular hypertrophy

Epidemiology

TOF affects 3-6 infants in every 10, 000 births. [1]

Aetiology [4]

The aetiology is unknown, but evidence suggests a multifactorial cause. Antenatal risk factors are:-

Maternal rubella (or other viral infections during pregnancy)

Poor antenatal nutrition

Maternal alcohol use

Maternal age > 40 years

Diabetes

Children with Down syndrome have a higher risk of TOF.

Presentation [4]

Symptoms

Very few infants present with severe cyanosis in the first few days of life with duct-dependent pulmonary circulation.

Most infants are diagnosed by murmur at the age of 1-2 months.

Feeding difficulty and failure to thrive.

Tet spells – episodes of bluish pale skin during crying or feeding.

Squatting is classical of infants with TOF.

Exertional dyspnoea usually worsens with age.

Physical examination

Smaller than expected for age. Peripheral cyanosis is normally found at birth, and after 3-6 months, finger clubbing may develop.

Cardiac examination:-

A thrill – at left sternal border.

Ejection systolic murmur – heard over the pulmonic area and the left sternal border. In babies with aortopulmonary collaterals, continuous murmurs may be detected

The S2 is usually single.

Diagnosis

Diagnosis is through history and clinical examination, supported by chest x-ray and ECG, and confirmed by echocardiography.

Bloods

Haemoglobin and haematocrit are usually increased in relation to the degree of cyanosis.

The arterial oxygen saturation varies from 65-70%.

ECG

ECG shows right ventricular hypertrophy (+ right axis deviation) and may also show right atrial hypertrophy.

Imaging

Radiography

Classical boot-shaped heart.

Echocardiography

Used to diagnose ductus arteriosus, VSD, or ASD with Doppler echocardiography.

*Comparison of Baby J’s presentation to the classical presentation

Baby J had severe pulmonary atresia (muscular in origin) due to a severely malrotated infundibular septum. He suffered from life-threatening cyanosis at birth which had to be attended to promptly by maintaining the patency of ductus arteriosis using prostaglandin E2. As he was highly symptomatic, a palliative surgery to increase pulmonary blood flow had to be done where he underwent placement of Melbourne shunt connecting his aorta to MAPCA. This was done hoping to promote the development of main pulmonary artery. Baby J also had another problem which was the 50% possible chance of inheriting Alagille’s syndrome (autosomal dominant) from his father. His LFTs were checked for any liver abnormality which is commonly implicated in this syndrome. He also had spine X-ray to exclude spinal deformities. He will be having ophthalmology review soon as well.

GMC theme 2: Treatment

Acute treatment [4]

Neonates with severe cyanosis due to ductal constriction are given an infusion of prostaglandin E2(0.05 to 0.1 Î¼g/kg/min IV) to reopen the ductus arteriosus.

Tet spells are usually self-limiting and followed by a period of sleep. If prolonged (> 15 mins), treatment consists of:- [4]

placing infants in a knee-chest position

sedation and pain relief – morphine IM.

IV fluids are used for volume expansion.

Propanolol IV – acts as peripheral vasoconstrictor.

Bicarbonate to correct acidosis.

Muscle paralysis and artificial ventilator to reduce oxygen demand.

Symptomatic or palliative treatment in first few months

Palliative surgery can be performed in patients who are not suitable for complete repair or patients with tet spells. One of the commonly used procedures is the Blalock-Taussig shunt where the subclavian artery is connected to the ipsilateral pulmonary artery with a prosthetic graft.

Baby J had a relatively new shunt placement (first developed in Melbourne) which connects the major aortopulmonary collateral artery (MAPCA) to aorta. This has been shown to promote the growth of central pulmonary artery. [2]

Melbourne shunt: illustrates the completed shunt with the pulmonary artery anastomosed to the posterior and left lateral aspect of the ascending aorta close to the sinotubular junction. Adapted from Ref [2]

Corrective Surgery

Since TOF is a progressive disorder, Baby J will require a more definitive corrective surgery. Nowadays, surgery is commonly performed electively at around 6 months of age (or before 1 year). The timing of complete surgical repair on Baby J will depend on numerous factors like further symptoms, severity of lesions (multiple VSDs, pulmonary atresia),etc.

Complete repair is achieved by patch closure of VSD and widening of right ventricular outflow tract. Perioperative mortality rate is < 3% for uncomplicated TOF. For untreated patients, survival rates are 55% at 5 yr and 30% at 10 yr. [1]

Primary repair is beneficial in terms of preventing long-term right ventricular outflow obstruction and the consequential development of right ventricular hypertrophy, prolonged cyanosis, and postnatal angiogenesis. [1]

Summary

Survival in children with simple forms of TOF is promising and quality of life is good. Studies showed that survivors are in NYHA 1 class with minimal reduction in exercise capacity. However, Baby J has a rather severe form of TOF and it is difficult to predict his prognosis as for now. This will depend on his progress after corrective surgery repair done. He will need life-long cardiac review and this can be quite stressful for the child and the family as well. Baby J is fortunate to have good supportive parents who are both rather anxious about the child’s condition during the interview.