ANSWERS OF MCQS PUBLISHED YESTERDAY 

MCQS#01

C. Noonan syndrome

Hypertrophic cardiomyopathy is characterized by a disorganized arrangement of myocardial fibers. Noonan syndrome is the most common cause of hypertrophic cardiomyopathy in neonates and children under age 4 years. It is an autosomal dominant disorder with an incidence of approximately 1 in 1,000 to 2,500 live births. In addition to hypertrophic cardiomyopathy, features of Noonan syndrome include the following:

•Pulmonic stenosis (60% incidence)

•Hypertelorism

•Downward slanting palpebral fissures

•Low-set ears

•Short stature

•Short webbed neck

•Pectus excavatum

•Cryptorchidism

•Cognitive deficits

•Bleeding disorders

•Lymphedema

Beckwith-Wiedemann syndrome, trisomy 21, Costello syndrome (also known as fasciocutaneoskeletal syndrome), and Eagle-Barrett syndrome (also known as prune belly syndrome) have also been associated with hypertrophic cardiomyopathy. The other options listed in this question are not typically associated with hypertrophic cardiomyopathy.

Reference: Wallis G, Fricker F. Neonatal cardiomyopathy. NeoReviews. 2012; 13:e711-e723

MCQS#02

D. The majority of mothers of neonates diagnosed with congenital heart block have symptoms of systemic lupus erythematosus

Neonatal lupus erythematosus (NLE) results from transfer of anti-SSA/Ro and anti-SSB/La antibodies from a pregnant woman to her fetus, potentially injuring fetal tissue. These antibodies are nearly universally found in the serum of women whose fetuses are diagnosed in utero with congenital heart block. One of the most devastating fetal/neonatal consequences of this passively acquired autoimmune disorder is involvement of the cardiac conducting system with subsequent rhythm abnormalities such as congenital heart block. This abnormal cardiac rhythm is typically diagnosed between 16 and 24 weeks’ gestation and is associated with a 20% mortality rate in the fetus/newborn. Complete congenital heart block is generally irreversible and surviving children typically require pacing. Fewer than one-third of mothers of affected infants have a diagnosis of systemic lupus erythematosus and many women are asymptomatic.

Reference: Buyon J, Nugent D, Mellins, E, Sandborg C. Maternal immunologic diseases and neonatal disorders. NeoReviews. 2002; 3:e3-e10

MCQS#03

E. Rashkind balloon septostomy

D-Transposition of the great arteries (D-TGA) is the most common cyanotic lesion to present in the first week of life and accounts for 5% to 10% of all congenital heart disease. The severe cyanosis results from having two circulations in parallel with poor mixing. Affected patients typically do not have a murmur unless a ventricular septal defect or pulmonary stenosis (PS) is present. Commonly, a single loud S2 is auscultated because the pulmonary valve is further from the chest wall, limiting the ability to detect a P2 sound. A typically chest radiograph of patients with D-TGA include a normal heart size, increased pulmonary vascular markings, and an “egg on a string” narrow mediastinum appearance that results from the anterior-posterior aorta and main pulmonary artery relationship.

Initial management of a patient with D-TGA includes prostaglandin therapy and in the setting of inadequate mixing (as described above), a palliative emergent Rashkind procedure is necessary to improve mixing. An arterial switch procedure is the definitive corrective operation for D-TGA but is not done until adequate mixing is ensured.

The Blalock-Taussig shunt is used to ensure adequate pulmonary blood flow for lesions such as tetralogy of Fallot/severe PS, tricuspid atresia, or pulmonary atresia. Pulmonary artery banding can be required if a patient has increased pulmonary blood flow with lesions such as tricuspid atresia and a single ventricle. Inhaled nitric oxide therapy leads to dilation of the pulmonary arteries and can increase pulmonary blood flow. In patients with D-TGA, inhaled nitric oxide therapy would not be helpful because the cyanosis results from inadequate mixing of the two circulations rather than inadequate pulmonary blood flow.

References:

Brodsky D, Martin C. Neonatology Review. 2nd Edition. Lulu. 2010

Keane JF, Fyler DC, Lock JE (ed). Nadas’ Pediatric Cardiology. 2nd edition. Philadelphia: WB

Saunders Co; 2006.

MCQS#04

C. Endocarditis

Complications of an untreated PDA depend largely on the size and degree of blood flow. Congestive heart failure and pulmonary hypertension may result from over circulation as a result of left-to-right shunting. Endarteritis is an increasingly rare complication, though infective vegetations may be seen in the pulmonary artery and PDA. A ductal aneurysm may also occur, most likely after surgical closure, coiling, or an infective arteritis. About a quarter of cases of aneurysm have been found in conjunction with aneuploidy or soft-tissue disorders such as Marfan syndrome.

Reference: Schneider DJ, Moore JW. Congenital heart disease for the adult cardiologist. Circ. 2006; 114:1873-1882

MCQS#05

E. All of the above

Congenital heart defects are more prevalent in the recipient twin of twin-to-twin transfusion syndrome. Studies report a three-fold increase in the frequency of congenital heart defects. The most frequent defects are ventricular septal defects, atrial septal defects and pulmonary stenosis.

References:

Bahtiyar MO, Dulay AT, Weeks BP, et al. Prevalence of congenital heart defects in monochorionic/diamniotic twin gestations: a systematic literature review. J Ultrasound Med.

2007;26:1491–1498

Karatza AA, Wolfenden JL, Taylor MJ, et al. Influence of twin–twin transfusion syndrome on fetal cardiovascular structure and function: prospective case–control study of 136 monochorionic twin pregnancies. Heart. 2002; 88:271–277