Thursday, October 3, 2019
Case study of cyanotic congenital heart disease
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 Alagilles syndrome (an autosomal dominant inherited disorder affecting the heart, liver, spine, kidney and central nervous system). Family History Baby Js father was diagnosed with Alagilles syndrome as a child. He has congenital spinal abnormalities, cardiac defects (atrial septal defect, ASD, pulmonary stenosis and right ventricular dysfunction). Baby Js mother suffered from depression for about 3 years now. She also has asthma and a high BMI of 40. During pregnancy, Baby Js 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 Alagilles and suffers from cardiac anomaly. Baby Js 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 No finger clubbing/ splinter haemorrhages. Non-pallor palmar creases. Deep-set eyes, prominent forehead (features of Alagilles 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 UE 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 S2à 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 Js 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 Alagilles 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 0.1à ÃŽà ¼g/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 morphineà IM. IV fluids are used for volume expansion. Propanololà 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 isà 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 childs condition during the interview.
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