Chapter 2 : Meningen and Cerebrospinal Fluid (4)

Question 1

1. A 25-year-old housewife complains of headaches of 4 months’ duration. She is obese and has bilateral papilledema, and her vision is deteriorating. Her opening CSF pressure is elevated; other CSF findings are normal. CT and magnetic resonance imaging (MRI) scans are normal. These signs are due to impairment of CSF egress. Obstruction at which of the following loci is most likely? (A) Arachnoid villi (B) Cerebral aqueduct (C) Foramen of Luschka (D) Foramen of Magendie (E) Foramen of Monro

Answer 1

1–A. This condition, called pseudotumor cerebri (benign intracranial hypertension), is seen primarily in young obese women. Impaired absorptive function of the arachnoid villi is thought to be the cause.

Question 2

2. The total volume of CSF found in the subarachnoid space and cerebral ventricles is (A) 110 ml (B) 140 ml (C) 160 ml (D) 170 ml (E) 190 ml

Answer 2

2–B. The total volume of CSF found in the subarachnoid space and ventricles is 140 ml.

Question 3

3. Which of the following pathogens would most likely be seen in bacterial meningitis of the newborn? (A) Streptococcus agalactiae (B) Haemophilus influenzae (C) Neisseria meningitides (D) Streptococcus pneumoniae (E) Herpes simplex type 2

Answer 3

3–A. Streptococcus agalactiae is seen frequently in newborns. Haemophilus influenzae immunization has greatly reduced this type of meningitis. S. pneumoniae is frequently the cause of meningitis in older adults. Neisseria meningitides is seen in older children to middle-aged adults. Herpes simplex type 2 is a virus.

Question 4

4. Which part of the ventricular system contains choroid plexus? (A) Frontal horn (B) Occipital horn (C) Cerebral aqueduct (D) Third ventricle (E) Terminal ventricle

Answer 4

4–D. The third ventricle has a choroid plexus; the frontal lobe, the occipital lobe, and the cerebral aqueduct all are devoid of a choroid plexus; a terminal ventricle is a localized dilation of the caudal end of the central canal with no choroid plexus.

Question 5

5. Which one of the following circumventricular organs is solely innervated by postganglionic fibers from the superior cervical ganglion of the ANS? (A) Area postrema (B) Pineal body (C) Organum vasculosum of the lamina terminalis (D) Subfornical organ (E) Subcommissural organ

Answer 5

5–B. The pineal body (epiphysis) is innervated solely via postganglionic fibers from the superior ganglion of the autonomic nervous system; it synthesizes melatonin; it has antigonadotrophic function; the area postrema is a chemoreceptor zone that triggers vomiting in response to circulating emetic substances; the organum vasculosum of the lamina terminalis is a vascular outlet for luteinizing hormone–releasing hormone and somatostatin; the subfornical organ is a central receptor for angiotensin II; the subcommissural organ has a capillary bed with nonfenestrated endothelial cell and a blood–brain barrier.

Question 6

6. Choose the normal quantity of CSF daily production. (A) 300 ml (B) 400 ml (C) 500 ml (D) 600 ml (E) 700 ml

Answer 6

6–C. The choroid plexus produces CSF at a rate of 500 ml/day.

Question 7

7. Which one of the following tumors contains cellular whorls and psammoma bodies? (A) Astrocytoma (B) Acoustic schwannoma (C) Glioblastoma multiforme (D) Oligodendroglioma (E) Meningioma

Answer 7

7–E. Meningiomas contain cellular whorls and calcified psammoma bodies; are associated with neurofibromatosis-2; gender females males; astrocytomas type II have near normal cellularity, little nuclear pleomorphism, no endothelial proliferation, and no necrosis; acoustic schwannomas are benign tumors arising from Schwann cells—histopathology shows Antoni A and Antoni B tissue and Verocay bodies; oligodendrogliomas show calcification in 50% of cases—cells look like fried eggs (perinuclear halos); glioblastoma multiforme represents 55% of gliomas, is malignant and rapidly fatal; most common primary brain tumor; contains pseudopalisades, perivascular pseudorosettes, and microvascular proliferation.

Question 8

8. Olive

Answer 8

8–E. The olive is a prominent surface structure of the medulla.

Question 9

9. It contains the trochlear nerve (CN IV)

Answer 9

9–D. The ambient cistern contains the trochlear nerve (CN IV).

Question 10

10. Its stenosis results in hydrocephalus

Answer 10

10–C. Stenosis of the cerebral aqueduct prevents CSF from entering the fourth ventricle; this results in a noncommunicating hydrocephalus.

Question 11

11. Contains a calcified glomus

Answer 11

11–B. The trigone of the lateral ventricle contains a large tuft of choroid plexus called the glomus. It is usually calcified and highly visible in CT images.

Question 12

12. Receives CSF from the arachnoid villi

Answer 12

12–A. The superior sagittal sinus receives CSF via the arachnoid villi.

Question 13

13. Superior cistern

Answer 13

13–C. The superior (quadrigeminal) cistern overlies the dorsal aspect of the midbrain.

Question 14

14. Blockage resulting in hydrocephalus

Answer 14

14–B. Blockage of the interventricular foramen of Monro (e.g., due to a colloid cyst of the third ventricle) results in hydrocephalus involving the lateral ventricle.

Question 15

15. Lateral ventricle

Answer 15

15–A. The lateral ventricle is seen between the corpus callosum and the fornix.

Question 16

16. Contains the two foramina of Luschka

Answer 16

16–D. The fourth ventricle contains the two foramina of Luschka, which drain into the two cerebellopontine angle cisterns.

Question 17

17. Receives CSF via the foramen of Magendie

Answer 17

17–E. The cerebellomedullary cistern receives CSF via the foramen of Magendie.