Congenital defects — MCQs

A 9-year-old boy, otherwise healthy, presents with persistent bleeding following tooth extraction. The patient’s mother states that yesterday, the patient had a tooth extracted that was complicated intraoperatively by persistent bleeding that continued postoperatively. She also says he has had no bleeding issues in the past. The past medical history is unremarkable. The patient is fully immunized and has been meeting all developmental milestones. The vital signs include: temperature 37.0°C (98.6°F), blood pressure 101/65 mm Hg, pulse 101/min, respirations 22/min, and oxygen saturation 98% on room air. The physical examination is significant for a wound consistent with the extraction of the second upper right molar, which is slowly oozing blood with no sign of a stable clot. There are no signs of infection. The laboratory findings are significant for the following: Sodium 141 mEq/L Potassium 4.1 mEq/L Chloride 101 mEq/L Bicarbonate 25 mEq/L BUN 12 mg/dL Creatinine 1.0 mg/dL Glucose (fasting) 80 mg/dL Bilirubin, conjugated 0.2 mg/dL Bilirubin, total 1.0 mg/dL AST (SGOT) 11 U/L ALT (SGPT) 12 U/L Alkaline Phosphatase 45 U/L Prothrombin Time (PT) 14 s Partial Thromboplastin Time (PTT) 35 s WBC 8,500/mm3 RBC 4.00 x 106/mm3 Hematocrit 37.5% Hemoglobin 13.1 g/dL Platelet Count 225,000/mm3 This patient’s condition would most likely also present with which of the following symptoms?

A newborn is brought to the pediatric clinic by his mother because she has noticed a swelling in the belly while dressing her baby. On physical examination, the newborn is found to have a non-tender upper abdominal mass. The clinician also noticed absent irises and undescended testes in this baby. A magnetic resonance image (MRI) scan of the abdomen shows a mass of intra-renal origin. Which 1 of the following genetic disorders is most probably the cause of this neonate’s symptoms and signs?

An 18-month-old boy is brought to the physician by his parents for the evaluation of passing large amounts of dark red blood from his rectum for 2 days. His parents noticed that he has also had several episodes of dark stools over the past 3 weeks. The parents report that their child has been sleeping more and has been more pale than usual over the past 24 hours. The boy's appetite has been normal and he has not vomited. He is at the 50th percentile for height and 50th percentile for weight. His temperature is 37°C (98.6°F), pulse is 135/min, respirations are 38/min, and blood pressure is 90/50 mm Hg. Examination shows pale conjunctivae. The abdomen is soft and nontender. There is a small amount of dark red blood in the diaper. Laboratory studies show: Hemoglobin 9.5 g/dL Hematocrit 30% Mean corpuscular volume 68 μm3 Leukocyte count 7,200/mm3 Platelet count 300,000/mm3 Which of the following is most likely to confirm the diagnosis?

A 4-month-old girl is brought to the physician by her father because he is concerned that she appears sickly and lethargic. She has always had a pale complexion, but it has been getting worse over the past month. She was delivered at home at 36 weeks to a 26-year-old woman following an uncomplicated pregnancy. She has not yet been examined by a physician. She is in the 2nd percentile for head circumference, 10th percentile for length, and 8th percentile for weight. Physical exam shows a pale infant with facial features of micrognathia, flat nasal bridge, and microopthalmos. The eyes are set widely apart and strabismus is present. She has a high arched palate and there is fusion of the cervical vertebrae with flaring of the skin around the neck. A 4/6 holosystolic murmur is heard best on the left chest. Laboratory studies show: Hemoglobin 6.6 g/dL Hematocrit 20% Leukocytes 5400/mm3 Platelets 183,000/mm3 Mean corpuscular hemoglobin 41.3 pg/cell Mean corpuscular hemoglobin concentration 33% Hb/cell Mean corpuscular volume 125 μm3 This patient is most likely to have which of the following findings?

A 1-month-old boy is brought by his parents to an orthopaedic surgeon for evaluation of bilateral club feet. He was born at term to a G1P1 mother but had respiratory distress at birth. Furthermore, he was found to have clubfeet as well as other extremity contractures. Physical exam reveals limited range of motion in his arms and legs bilaterally as well as severe clubfeet. Furthermore, his face is also found to have widely separated eyes with epicanthal folds, a broad nasal bridge, low set ears, and a receding chin. Which of the following conditions was most likely seen with this patient in utero?

A 1-month-old male newborn is brought to the physician because of poor feeding, a hoarse cry, and lethargy for 1 week. The boy was born in Mozambique, from where he and his parents emigrated 2 weeks ago. He is at the 95th percentile for head circumference, 50th percentile for length, and 70th percentile for weight. Physical examination shows scleral icterus, an enlarged tongue, and generalized hypotonia. The abdomen is distended and there is a reducible, soft protruding mass at the umbilicus. Which of the following is the most likely cause of these findings?

A 6-week-old girl is brought to a pediatrician due to feeding difficulty for the last 4 days. Her mother mentions that the infant breathes rapidly and sweats profusely while nursing. She has been drinking very little breast milk and stops feeding as if she is tired, only to start sucking again after a few minutes. There is no history of cough, sneezing, nasal congestion, or fever. She was born at full term and her birth weight was 3.2 kg (7.0 lb). Her temperature is 37.0°C (98.6°F), pulse rate is 190/min, and respiratory rate is 64/min. On chest auscultation, bilateral wheezing is present. A precordial murmur starts immediately after the onset of the first heart sound (S1), reaching its maximal intensity at the end of systole, and waning during late diastole. The murmur is best heard over the second left intercostal space and radiates to the left clavicle. The first heart sound (S1) is normal, while the second heart sound (S2) is obscured by the murmur. Which of the following is the most likely diagnosis?

A 26-year-old woman with poor prenatal care and minimal antenatal screening presents to the emergency department in labor. Shortly thereafter, she delivers a baby girl who subsequently demonstrates symptoms of chorioretinitis on examination. A series of postpartum screening questions is significant only for the presence of multiple cats in the mother’s household. The clinical team orders an enhanced MRI examination of the infant’s brain which reveals hydrocephalus, multiple punctate intracranial calcifications, and 2 sub-cortical ring-enhancing lesions. Which is the most likely diagnosis?

A 2-year-old boy is brought to a pediatrician because his parents have noticed that he seems to be getting tired very easily at home. Specifically, they have noticed that he is often panting for breath after walking around the house for a few minutes and that he needs to take naps fairly often throughout the day. He has otherwise been well, and his parents do not recall any recent infections. He was born at home, and his mom did not receive any prenatal care prior to birth. Physical exam reveals a high-pitched, harsh, holosystolic murmur that is best heard at the lower left sternal border. No cyanosis is observed. Which of the following oxygen tension profiles would most likely be seen in this patient? (LV = left ventricle, RV = right ventricle, and SC = systemic circulation).

A child is born by routine delivery and quickly develops respiratory distress. He is noted to have epicanthal folds, low-set ears that are pressed against his head, widely set eyes, a broad, flat nose, clubbed feet, and a receding chin. The mother had one prenatal visit, at which time the routine ultrasound revealed an amniotic fluid index of 3 cm. What is the most likely underlying cause of this patient's condition?