Congenital CNS malformations — MCQs

A 32-year-old woman, gravida 2, para 1, at 14-weeks' gestation comes to the physician for a prenatal visit. Routine first trimester screening shows increased nuchal translucency, decreased β-hCG concentration, and decreased levels of pregnancy-associated plasma protein A. Amniocentesis shows trisomy of chromosome 13. This fetus is at increased risk for which of the following?

A 21-year-old G3P2 woman presents to her obstetrician at 6 weeks gestation for routine prenatal care. Her past medical history includes obesity and gestational diabetes. She has had two spontaneous vaginal deliveries at term. One infant was macrosomic with hypoglycemia, but otherwise, she has had no complications. Her physician informs her that she must start taking a multivitamin with folic acid daily. The defect that folic acid supplementation protects against arises in tissue that is derived from which germ cell layer?

A 29-year-old primigravid woman at 18 weeks’ gestation comes to the physician for her first prenatal visit. She works as a paralegal and lives with her husband. Her current pregnancy was unexpected, and she did not take any prenatal medications or supplements. Physical examination shows a uterus 2 inches above the umbilicus. The concentration of α-fetoprotein in the maternal serum and concentrations of both α-fetoprotein and acetylcholinesterase in the amniotic fluid are elevated. Ultrasonography of the uterus shows an increased amniotic fluid volume. The fetus most likely has which of the following conditions?

A 58-year-old man comes to the physician because of burning pain in his neck and arms for a year. He has also had paresthesias in his hands during this period. He has had increasing weakness in both hands during the past 3 months. He has type 2 diabetes mellitus, hypercholesterolemia, and hypertension. He was involved in a motor vehicle collision 3 years ago. Current medications include metformin, sitagliptin, enalapril, atorvastatin, and aspirin. He has had 7 sexual partners in his lifetime; he uses condoms inconsistently. He is oriented to time, place, and person. Vital signs are within normal limits. The pupils are equal and reactive to light. Examination of the upper extremities shows decreased muscle strength, absent reflexes, and decreased hand grip with fasciculations bilaterally. Sensation to temperature and pain is absent over the chest and bilateral upper arms. Vibration and joint position sensations are present in the upper limbs. Cranial nerve examination shows no focal findings. Examination of the lower extremities show no abnormalities. Which of the following is the most likely diagnosis?

A 6-year-old boy is brought in for evaluation by his adopted mother due to trouble starting 1st grade. His teacher has reported that he has been having trouble focusing on tasks and has been acting out while in class. His family history is unknown as he was adopted 2 years ago. His temperature is 36.2°C (97.2°F), pulse is 80/min, respirations are 20/min, and blood pressure 110/70 mm Hg. Visual inspection of the boy's face shows a low set nasal bridge, a smooth philtrum, and small lower jaw. Which of the following findings would also likely be found on physical exam?

A 47-year-old man presents to you with gradual loss of voice and difficulty swallowing for the past couple of months. The difficulty of swallowing is for both solid and liquid foods. His past medical history is insignificant except for occasional mild headaches. Physical exam also reveals loss of taste sensation on the posterior third of his tongue and palate, weakness in shrugging his shoulders, an absent gag reflex, and deviation of the uvula away from the midline. MRI scanning was suggested which revealed a meningioma that was compressing some cranial nerves leaving the skull. Which of the following openings in the skull transmit the affected cranial nerves?

A 2-year-old boy is brought to the emergency department by his mother for evaluation of severe abdominal pain that began one hour ago. On examination, the patient is afebrile and has diffuse rebound tenderness with acute epigastric pain. A stool guaiac test is positive. A small bowel perforation is suspected. What is the embryologic structure that is the underlying cause of this patient’s presentation?

An 8-year-old boy is brought to the pediatrician because his mother is concerned about recent behavioral changes. His mother states that she has started to notice that he is slurring his speech and seems to be falling more than normal. On exam, the pediatrician observes the boy has pes cavus, hammer toes, and kyphoscoliosis. Based on these findings, the pediatrician is concerned the child has a trinucleotide repeat disease. Which of the following trinucleotide repeats is this child most likely to possess?

A 35-year-old woman presents with headaches and seizures. MRI shows a well-circumscribed, calcified frontal lobe mass. Histology reveals oligodendroglioma with 1p/19q codeletion and IDH1 mutation. She undergoes gross total resection. Two years later, surveillance MRI shows a new enhancing nodule at the resection margin. Biopsy shows increased mitotic activity, microvascular proliferation, and retained 1p/19q codeletion but new CDKN2A/B homozygous deletion. What is the most critical factor in determining management strategy?

A 55-year-old man presents with progressive supranuclear gaze palsy, axial rigidity, and frequent falls. MRI shows midbrain atrophy with hummingbird sign. He dies 7 years later. Autopsy reveals globose neurofibrillary tangles in the basal ganglia and brainstem. Tau immunostaining shows 4-repeat tau predominance. His brother had similar symptoms. Genetic testing reveals a MAPT mutation. How does this change the pathogenic understanding and potential therapeutic approach?