Heterotaxy

Heterotaxy

1. Heterotaxy

2. Define Known as situs ambiguous, is defined as the abnormal and disorganised arrangement of organs and vessels within the abdominal cavity

3. Differential diagnosis This is in contrast to the orderly arrangement that occurs in situs inversus or situs solitus

4. 2 Categories situs ambiguous with polysplenia Left isomerism Bilateral left-sidedness Midline position of the abdominal organs and multiple spleens/ splenules Lower prevalence of congenital heart disease (50–90%) Less severe defects than Situs ambiguous with asplenia Right isomerism Complex CHD

5. Left isomerism: No cyanosis Many spleen Bilaterally symmetrical liver Bilateral bi-lobed lungs Bilateral hypo-arterial bronchi (left isomerism) Bilateral SVC Intrahepatic interruption of the IVC with azygous or hemi-azygous continuation Common atrium AVCD Hypoplasia or absence of one ventricle LVOT/RVOT obstruction DORV 50% dextrocardia Kartagener’s syndrome

6. Right isomerism :Cyanosis No left atrium to receive pulmonary venous drainage(TAPVC) Venous drainage into a systemic vein is seen in > 50% Infancy Transposition of the great arteries AVCD Ventricular hypoplasia or single ventricle physiology Pulmonary atresia Pulmonary vein obstruction 80%-90% die in the first year

7. Easy to follow http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116098/