AIPGMEE 2015

A 13-month old male has decreased numbers of B cells and very low levels of all isotypes of immunoglobulins. This patient would be expected to be unable to clear infections by

• Extracellular bacteria (e.g., Streptococcus spp).
• Intracellular bacteria (e.g., Mycobacterium spp)
• Intracellular protozoa
• Viruses
• Fungi

B cells make antibodies and are the precursors of plasma cells that both synthesize and secrete antibodies. Antibodies are the primary means for inhibiting and killing extracellular bacteria. This patient is likely to have Bruton disease, an agammaglobulinemia that results in increased susceptibility to infection with encapsulated bacteria.

Recommendations for use of antenatal corticosteroids

Recommendations for use of antenatal corticosteroids

The benefits of antenatal administration of corticosteroids to fetuses at risk of preterm delivery vastly outweigh the potential risks. These benefits include not only a reduction in the risk of RDS, but also a substantial reduction in mortality and IVH.

All fetuses between 24 and 34 weeks of gestation at risk of preterm delivery should be considered candidates for antenatal treatment with corticosteroids.

The decision to use antenatal corticosteroids should not be altered by fetal race or gender or by the availability of surfactant replacement therapy.

Patients eligible for therapy with tocolytics should also be eligible for treatment with antenatal corticosteroids.

Treatment consists of either two doses of 12 mg of betamethasone given intramuscularly 24 hours apart or four doses of 6 mg of dexamethasone given intramuscularly 12 hours apart. Optimal benefit begins 24 hours after initiation of therapy and lasts seven days.

Because treatment with corticosteroids for less than 24 hours is still associated with significant reductions in neonatal mortality, RDS, and IVH, antenatal corticosteroids should be given unless immediate delivery is anticipated.

In premature rupture of membranes at less than 30 to 32 weeks of gestation in the absence of clinical chorioamnionitis, antenatal corticosteroid use is recommended because of the high risk of IVH at these early gestational ages.

In complicated pregnancies where delivery prior to 34 weeks of gestation is likely, antenatal corticosteroid use is recommended unless there is evidence that corticosteroids will have an adverse effect on the mother or delivery is imminent.

RDS: respiratory distress syndrome; IVH: intraventricular hemorrhage.

Adapted from: data in the Report of the Consensus Development Conference on the Effect of Corticosteroids for Fetal Maturation on Perinatal Outcomes. National Institute of Child Health and Human Development. November 1994. NIH Publication No. 95-3784.
Antenatal Corticosteroids Revisited: Repeat Courses—National Institutes of Health Consensus Development Conference Statement, August 17–18, 2000. Obstet Gynecol 2001; 98:144-150.

AIPGMEE 2015

Salmonella infections in resource-rich countries are almost always acquired by ingestion of contaminated food. This is because:

• There is a large reservoir of Salmonella in animals, especially poultry.
• Salmonella is relatively sensitive to stomach acid, so only large numbers of bacteria can establish infection.
• Salmonella may be shed in the feces for several weeks after an infection has resolved, facilitating food contamination.
• Water treatment suppresses infection due to drinking contaminated water.
• All of the above statements are correct.

In resource poor countries, Salmonella can be spread by contaminated water. In discussing routes of infection, it is interesting to contrast Salmonella with Shigella infections. Shigella is much more resistant to stomach acid, and so infections can be caused by a small number of organisms. This greatly facilitates spread of shigellosis in settings such as day care centers, where fecal-oral transmission occurs via contaminated surfaces.

AIPGMEE 2015

Which of the following conditions is most likely to produce a murmur in early diastole?

• Ventricular septal defect (VSD)
• Mitral stenosis
• Tricuspid regurgitation
• Aortic regurgitation
• Pulmonary stenosis

The murmurs of VSD, tricuspid regurgitation and pulmonary stenosis all occur in systole. Mitral stenosis typically produces a mid-diastolic murmur. The soft early diastolic murmur of aortic regurgitation is best heard with the patient sitting forward in held expiration, and is often described as ‘the absence of silence’ following the second heart sound. The link below provides a comprehensive guide to the evaluation of heart murmurs.

AIPGMEE 2015

A female newborn has a single perineal orifice. The chance that this baby has associated urologic problems is:

• <10%
• 30%
• 60%
• 90%
• None of the above

More than 90% of the time the diagnosis in girls can be established on perineal inspection. The presence of a single perineal orifice is a cloaca. Patients with a persistent cloaca have a 90% risk of urologic defects. (See Chapter 336, page 1358.Nelson Pediatrics 19th edn)

AIPGMEE 2015

A heart murmur is noted during the preschool physical examination of a 4-year-old girl. An echocardiogram reveals a defect between the right and left atrium involving the limbus of the foramen ovale. What is the most likely diagnosis?

• Atrial septal defect (ASD), ostium primum
• ASD, ostium secundum
• Tetralogy of Fallot
• Truncus arteriosus
• Ventricular septal defect

Ostium secundum: type ASD accounts for 90% of all ASDs. It reflects a true deficiency of the atrial septum and should not be confused with patent foramen ovale. Ostium secundum defects commonly occur in the middle portion of the septum and vary in size from a trivial opening to a large defect of the entire fossa ovalis. A small ASD is unlikely to be functional, but left-to-right shunting may occur in large defects, causing dilation and hypertrophy of the right atrium and ventricle. The ostium primum anomaly occurs adjacent to the AV valves and is usually associated with a cleft anterior mitral leaflet. Ventricular septal defect (choice E) occurs in the interventricular septum. The diagnoses in choices C and D are characterized by multiple congenital abnormalities and early cyanosis.
Diagnosis: Atrial septal defect

AIPGMEE 2015

1. This is a multiplicative effect between exposure variables
   1. Biologic plausibility
   2. Confounder
   3. Effect modifier
   4. External validity
   5. Internal validity
   6. Intervening variable
   7. Measurement bias
   8. Necessary cause
   9. Recall bias
   10. Sufficient cause
   11. Synergism
        Answer K
2. When the combined effect of two or more variables on an outcome is greater than the sum of the separate effects of the variables, their interaction is called synergy or synergism. Cigarette smoking and asbestos exposure have a synergistic effect on the risk of lung cancer.† If the relative risk or risk ratio for lung cancer in smokers is X and if the relative risk for lung cancer in asbestos workers is Y, the relative risk in those with both exposures is closer to X × Y than to X + Y.