Congenital Cyanotic Disease- Pediatrics

Question 1

4 cardinal anatomical features of tetralogy of Fallot (B)

Answer 1

o A large VSD (subaortic outlet type)
o Overriding of the aorta with on the ventricular septum
o Subvalvular pulmonary stenosis (infundibular 50%). It may also be valvular (10%) or a combination of both (30%).causing RV outflow tract obstruction.
o Right ventricular hypertrophy as a result of PS.

Question 2

Clinical symptoms of TOF (A++)

Answer 2

Minimal obstruction: may have normal saturations (pink TOF) behave more like large VSD with heart failure and poor growth by 4-6 weeks.

o Moderate obstruction:
✓ Usually detected by the presence of murmur in first 2 months or progressive cyanosis later on.
✓ The classical description of severe cyanosis, hyper-cyanotic spells and squatting on exercise, developing in late infancy
o Severe obstruction: → in neonates→ cyanosis due to ↓↓ pulmonary blood flow and increased RT to LF shunting across VSD (blue TOF)

Question 3

Examination clinical presentation of TOF (A++)

Answer 3

o A loud harsh ejection systolic murmur (PS) at the left sternal edge from day 1 of life
o In very severe PS → it may have very soft or no murmur due to minimal blood flow across the pulmonary valve.
o Clubbing of the fingers and toes will develop in older children.

Question 4

Investigations of TOF (A++)

Answer 4

• Chest X-ray: → small heart with uplifted apex giving ‘boot shaped heart’ or ‘coeur en sabot’ due to RVH and increased cardiac waist, and oligemic lung fields.
• ECG: right axis deviation and RVH.
• Echocardiography: confirm diagnosis

Question 5

Complications of TOF (A++)

Answer 5

• Infective endocarditis
• Hyper cyanotic spells
• Polythycemia, stroke
• Brain abcess
• Pulmonary TB risk

Question 6

TTT of TOF (A++)

Answer 6

1. PGE1 infusion: in neonates with pulmonary atresia or very severe PS, aims to keep PDA which allows blood to the pulmonary artery for oxygenation. This is done until palliative surgery is prepared.
2. Palliative surgery: only for extreme cases with very small PA branches, or pulmonary atresia. Modified Blalock Taussing operation: anastomosis between subclavian A. and pulmonary A. using Gore-Tex conduit. Later second stage total repair is done.
3. Total surgical repair: by relieving the PS and closure of VSD.
4. Avoid digitalis (↑↑infundibular pul. stenosis) &dehydration (↑ risk of thrombosis)
5. Iron supplementation to ↓↓ incidence of thromboembolic complications due to relative iron deficiency.
6. Prophylaxis against infective endocarditis.
7. Treatment of hyper cyanotic episodes.

Question 7

Hyper cyanotic spells (A++)

Answer 7

• Definition: sudden onset or worsening of cyanosis are due to acute increase in pulmonary obstruction and more RT to LF shunting at the VSD level in the setting of agitation / crying or dehydration.
• If prolonged (beyond about 15 min), they require prompt treatment with:
  o Comfort the patients and relieve any stress. With Sedation and pain relief (morphine is excellent)
  o Flex the knee or squatting position.
  o IV propranolol, (phenylephrine) relieve the infundibular spasm and act as peripheral

Question 8

Basic information on TGA (B)

Answer 8

• It is most common cyanotic heart disease at birth.
• Definitions and pathophysiology:
  o Aorta arises from right ventricle, and pulmonary artery arises from left ventricle. Systemic and pulmonary circulations are parallel circuits.
  o The blue blood is therefore returned to the body and the pink blood is returned to the lungs, this condition is incompatible with life.
  o Fortunately, there are a number of naturally occurring associated anomalies, e.g. VSD, ASD, PDA, and coronary abnormalities as well as therapeutic interventions which can achieve this mixing in the short term.

Question 9

Physical signs and symptoms in Clinical presentation of Transposition of great arteries (B)

Answer 9

• Symptoms
  o Cyanosis is the predominant symptom. Presentation is usually on second day of life when ductal closure occurs.
  o Cyanosis will be less severe and presentation delayed if there is more mixing of blood from associated anomalies, e.g. an ASD.
• Physical signs:
  o Cyanosis is always present
  o The second heart sound is often loud and single
  o Usually no murmur, but may be a systolic murmur from increased flow or stenosis within the left ventricular (pulmonary) outflow tract

Question 10

Investigations of Transposition of great arteries (B)

Answer 10

• Chest X-ray:
  o Characteristic ‘egg on side’ appearance of the cardiac shadow (due to the anteroposterior relationship of the great vessels, narrow vascular pedicle and hypertrophied right ventricle, respectively).
  o ↑↑ BVM are common due to ↑↑ pulmonary blood flow.
• Echocardiography: confirm diagnosis.
• Cardiac catheterization: evaluate coronary anatomy

Question 11

ttt of transposition of great arteries (A++)

Answer 11

• This is not duct dependent lesion, although a patent duct can be helpful to increase mixing.
• Immediate goal: allow oxygenated blood to reach systemic circulation
  o Start prostaglandin (PGE1) to keep PDA open.
  o Progressive cyanosis may need emergent balloon atrial septostomy as mixing occurs predominantly at the atrial level (ASD) (Rashkind procedure).
• Definitive treatment is surgical repair: (arterial switch operation)
  o Usually done in the first week of life. Surgical repair in the proper position and coronaries need to be re-implanted in the “neo-aortic” roo

Question 12

Eisenmenger syndrome short note (B)

Answer 12

• Untreated large Lt to Rt shunt (ASD, VSD, PDA) may gradually experience pulm. overflow→Pulm. hypertension → Pulm. pressure gradually increases till it exceeds the Lt side pressure →blood shunt is reversed to be from the Rt to Lt through the defect → cyanosis.

➢  This manifests by appearance of cyanosis and clubbing in older child with untreated CHD with Lt to Rt shunt.

➢  Surgery is contraindicated after reversal of the shunt (Closure of the shunt after occurrence of Eisenmenger → severe HF → death)