important pathologies

Question 1

Patent ductus arteriosis

Answer 1

• a vessel that runs from the bifurcation of a fetuses pulmonary artery to the aorta, just distal to the left subclavian artery
• it prevents blood from circulating to the fetuses undeveloped lungs
• it should close at, or shortly after birth
• this condition is more likely to occur in premi infants
• after birth, blood pressure is greater on the systemic of the heart than on the pulmonary side, so some of the blood in the aorta, gets shunted back to the pulmonary trunk through patent ductus arteriosis.
• the increased blood flow in the pulmonary arteries, lungs, left atrium and ventricle, and proximal aorta causes enlargement of these affected anatomic parts
• pulmonary hypertension can ultimately balance or reverse the left-to-right shunt

Question 2

Atrial septal defect

Answer 2

• foramen ovale normally closes off during the first year of life, but in this condition it fails to do so
• blood from the higher pressure left atrium is shutter to the lower pressure right atrium after birth, which in turn increases the workload of the right ventricle and leads to increased blood flow to the lungs
• increased lung markings due to increased blood flow in the lungs

Question 3

Ventricular septal defect

Answer 3

• an abnormal opening between the right and left ventricles that causes a left to right shunting of blood
• increased blood flow to and from the lungs. Increased workload for the left atrium and ventricle leading to enlargement of these chambers
• the right ventricle does not enlarge as shunting occurs only during systole, so blood shunted to the right ventricle is immediately pushed into the pulmonary artery

Question 4

Tetrology of fallot

Answer 4

• a combination of 4 defects
  1. Pulmonary valve stenosis
  2. High (superior) ventricular septal defect
  3. Overriding aorta (the opening of the aorta arches over the ventricular septal defect so that it ends up opening into both the right and left ventricles)
  4. Hypertrophy of right ventricle
• the pulmonary valve stenosis causes increased pressure in the right atrium leading to hypertrophy
• it also prevents the normal amount of blood from reaching the lungs for oxygenation
• deoxygenated blood is pumped out to the body because of the overriding aorta and ventricular septal defect
• x ray will show enlarged right ventricle causing upward lateral displacement of apex of the heart
• wooden shoe appearance

Question 5

Coarctation of aorta

Answer 5

• a stenosis of the descending aorta, just distal to the arteries that branch off to supply blood to the head, neck, and upper extremities
• because of the location of the stenosis, circulation to the upper extremities and head is normal, but there is decreased blood flow to the lower limbs and abdomen
• most common cause of hypertension in children
• can be treated with aortic resection
• figure 3 can be visualized
• bony erosions occur in ribs due to enlargement of collateral vessels

Question 6

Left sided heart failure

Answer 6

• aka congestive heart failure
• occurs when LV cannot pump blood effectively
• usually caused by CAD, valve disease or hypertension
• decreased systemic pumping pressure causes widespread fluid retention in body tissues, cardiomegaly, and back up of blood in pulmonary circulation

Question 7

Right sided heart failure

Answer 7

• most often occurs secondary to severe left-sided heart failure because back up of blood in the lungs is too much for the RV to overcome
• can be caused by pulmonary valve stenosis, emphysema, and pulmonary emboli
• dilation of the RA, RV, and SVC and edema in the lower extremities
• liver congestion may elevate the right hemi-diaphragm