Good evening friends! Let us begin the discussion for yesterday's question

Good evening friends! Let us begin the discussion for yesterday’s question.
Yes the answer is A,that is,central cyanosis and clubbing.
Tetralogy of Falot is a very very important topic, both as an undergraduate student as well as a Neet aspirants. I’ll try to simplify it for you guys, let me know what you think about the explanation.
TOF is the most common cyanotic heart disease beyond infancy. It has 4 components:

  1. Infundibular stenosis or pulmonary stenosis
  2. VSD
  3. Over riding aorta

It presents as central cyanosis, clubbing (at least 6 months disease duration),dyspnoea on exertion and cyanotic spells. There is a right to left shunt with decreased pulmonary blood flow.
Cyanotic spells are the most important complication of tof and potentially life threatening. It is caused by increased crying, decrease systemic vascular resistance and increased pulmonary stenosis. The child become increasingly blue and assumes a squatting position. Management aims at breaking the cycle by giving humidified oxygen and morphine to calm the child and knee chest position to increase the venous return.Vasopressors like methoxamine and phenylephrine increases the SVR and bicarbonate for correcting the acidosis. Lastly, propranolol also is beneficial, and at this stage you should consider corrective surgery if the spells are becoming more and more frequent, and treat anemia if there’s any.

Severity of the disease is directly proportional to the pulmonary stenosis degree and inversely proportional to the length of the murmur( in right second intercostal area,that is pulmonary area).

Investigations: Anemia,polycythemia,cxr will show characteristic boot shape heart and pulmonary oligemia,and ecg will show right axis deviation.

Palliative treatment:
1)Modified BT shunt( connects subclavian artery to pulmonary artery)
2)Potts shunt(connects descending aorta to pulmonary artery)
3)Waterson shunt (connects ascending aorta to pulmonary artery)
Definitive surgery now a days is being performed as early as by 4-6 months of age.
Complications: Cyanotic spells, infective endocarditis, brain abscess, stroke,renal vein thrombosis and renal and retinal infarcts.
Trilogy of Fallot- TOF minus over riding aorta
Pentalogy of Fallot: TOF plus ASD

This was TOF in a nutshell. I hope you find it interesting and helpful. Do let me know what you think.

Best wishes!

Dr Manoj Malhotra
MBBS (MAMC) MD pediatrics (LHMC)