Cerebrospinal fluid MCQs With Answer

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Cerebrospinal fluid MCQs With Answer is an essential revision resource tailored for B. Pharm students preparing for pharmacology, physiology, and clinical pharmacy exams. This concise, keyword-rich introduction focuses on cerebrospinal fluid (CSF) physiology, composition, production by the choroid plexus, circulation, blood-brain barrier interactions, CSF analysis, and implications for drug distribution in the central nervous system. These MCQs emphasize CSF diagnostic parameters, sampling techniques, pathology (meningitis, hemorrhage, hydrocephalus), and principles of intrathecal and systemic drug delivery to the CNS. Clear explanations will strengthen understanding of neuropharmacology and therapeutic decision-making. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the primary site of cerebrospinal fluid (CSF) production?

  • Choroid plexus of the ventricles
  • Arachnoid villi
  • Subarachnoid space
  • Pia mater capillaries

Correct Answer: Choroid plexus of the ventricles

Q2. Approximately how much CSF is produced per day in a healthy adult?

  • ~150 mL/day
  • ~500 mL/day
  • ~1,500 mL/day
  • ~50 mL/day

Correct Answer: ~500 mL/day

Q3. What is the normal total CSF volume in an adult?

  • ~150 mL
  • ~500 mL
  • ~50 mL
  • ~1,000 mL

Correct Answer: ~150 mL

Q4. Through which structure does CSF flow from the lateral ventricles to the third ventricle?

  • Foramen of Monro
  • Cerebral aqueduct
  • Foramen of Magendie
  • Foramina of Luschka

Correct Answer: Foramen of Monro

Q5. Which of the following best describes the blood-brain barrier (BBB)?

  • Tight junctions between cerebral endothelial cells limiting solute diffusion
  • Fenestrated capillaries in the brain allowing free exchange
  • Loose junctions in meninges allowing protein passage
  • Endothelial cells lacking transporters

Correct Answer: Tight junctions between cerebral endothelial cells limiting solute diffusion

Q6. Which cell type contributes end-feet that support the BBB and regulate CSF environment?

  • Astrocytes
  • Microglia
  • Oligodendrocytes
  • Ependymal cells

Correct Answer: Astrocytes

Q7. Which structure is primarily responsible for CSF absorption into the venous system?

  • Arachnoid granulations (villi)
  • Choroid plexus
  • Dural sinuses directly
  • Pial capillaries

Correct Answer: Arachnoid granulations (villi)

Q8. Normal adult CSF opening pressure in lateral decubitus position is typically measured in which range?

  • 70–180 mmH2O
  • 5–20 mmHg
  • 300–500 mmH2O
  • 10–40 cmH2O

Correct Answer: 70–180 mmH2O

Q9. Which CSF parameter is most helpful to differentiate bacterial from viral meningitis?

  • Markedly low glucose and high neutrophil count suggests bacterial meningitis
  • Slightly elevated protein and lymphocytic predominance suggests bacterial meningitis
  • Normal glucose with eosinophil predominance suggests bacterial meningitis
  • High chloride and no cells suggests bacterial meningitis

Correct Answer: Markedly low glucose and high neutrophil count suggests bacterial meningitis

Q10. CSF glucose is normally approximately what proportion of plasma glucose?

  • About two-thirds (≈60–70%) of plasma glucose
  • About equal to plasma glucose
  • About one-third of plasma glucose
  • Negligible compared to plasma glucose

Correct Answer: About two-thirds (≈60–70%) of plasma glucose

Q11. A CSF total protein concentration of 0.5–1.0 g/L (50–100 mg/dL) is most consistent with which condition?

  • Blood–brain barrier disruption or inflammation
  • Normal CSF
  • Hyperhydration state
  • CSF hyperfiltration due to reduced production

Correct Answer: Blood–brain barrier disruption or inflammation

Q12. Which finding indicates subarachnoid hemorrhage when observed as xanthochromia in CSF?

  • Yellow discoloration due to bilirubin from hemoglobin breakdown
  • Green discoloration due to bile pigments
  • Red centrifuged supernatant due to intact RBCs
  • Cloudy CSF due to high neutrophils

Correct Answer: Yellow discoloration due to bilirubin from hemoglobin breakdown

Q13. Oligoclonal bands in CSF are most commonly associated with which disease?

  • Multiple sclerosis
  • Bacterial meningitis
  • Subarachnoid hemorrhage
  • Normal pressure hydrocephalus

Correct Answer: Multiple sclerosis

Q14. Which lumbar puncture site is most commonly used for CSF sampling in adults?

  • Between L3–L4 or L4–L5 interspace
  • Between T12–L1 interspace
  • At the level of the sacral hiatus
  • Between C1–C2 interspace

Correct Answer: Between L3–L4 or L4–L5 interspace

Q15. A progressive decrease in RBC count across sequential CSF tubes suggests which cause?

  • Traumatic tap
  • Subarachnoid hemorrhage
  • Intracerebral tumor bleeding
  • Contamination from venous bleed

Correct Answer: Traumatic tap

Q16. Which of the following antibiotics has generally good CSF penetration, especially during meningitis?

  • Third-generation cephalosporins (e.g., cefotaxime, ceftriaxone)
  • Vancomycin without inflammation
  • Macrolides (e.g., erythromycin)
  • High-molecular-weight glycopeptides always penetrate well

Correct Answer: Third-generation cephalosporins (e.g., cefotaxime, ceftriaxone)

Q17. Which factor most increases a drug’s passive diffusion across the BBB into CSF?

  • High lipid solubility and small molecular size
  • High plasma protein binding
  • Large hydrophilic molecular weight
  • Negatively charged at physiological pH

Correct Answer: High lipid solubility and small molecular size

Q18. Intrathecal administration of drugs primarily delivers medication to which compartment?

  • Subarachnoid space/CSF bypassing the BBB
  • Systemic circulation via oral absorption
  • Intracellular neuronal compartments directly
  • Extradural fat tissue

Correct Answer: Subarachnoid space/CSF bypassing the BBB

Q19. Which CSF finding is most typical in viral meningitis?

  • Lymphocytic predominance with normal or mildly decreased glucose
  • Markedly low glucose with neutrophilic pleocytosis
  • High eosinophils and elevated protein only
  • Completely acellular and high protein

Correct Answer: Lymphocytic predominance with normal or mildly decreased glucose

Q20. Which reagent or test is used to detect bacterial antigens in CSF rapidly?

  • Latex agglutination test
  • Gram-negative oxidase test
  • India ink for cryptococcus only
  • ELISA for viral DNA only

Correct Answer: Latex agglutination test

Q21. What is the clinical significance of an elevated CSF opening pressure?

  • Indicator of raised intracranial pressure (ICP) due to mass effect, hydrocephalus, or meningitis
  • Normal variation without clinical consequence
  • Specific sign of spinal cord compression only
  • Always indicates dehydration

Correct Answer: Indicator of raised intracranial pressure (ICP) due to mass effect, hydrocephalus, or meningitis

Q22. Which CSF change is most indicative of bacterial meningitis?

  • Low glucose, high protein, and neutrophilic pleocytosis
  • High glucose, low protein, lymphocytic pleocytosis
  • Normal glucose with oligoclonal bands
  • High chloride and eosinophilic pleocytosis

Correct Answer: Low glucose, high protein, and neutrophilic pleocytosis

Q23. Which pathogen is best identified in CSF using India ink preparation?

  • Cryptococcus neoformans
  • Neisseria meningitidis
  • Streptococcus pneumoniae
  • Herpes simplex virus

Correct Answer: Cryptococcus neoformans

Q24. In pharmacokinetics, the CSF/plasma ratio is used to estimate what?

  • Relative drug penetration into the central nervous system
  • Hepatic clearance of the drug
  • Oral bioavailability of the drug
  • Renal tubular secretion rate

Correct Answer: Relative drug penetration into the central nervous system

Q25. Which condition is characterized by enlarged ventricles with normal CSF pressure clinically in elderly patients?

  • Normal pressure hydrocephalus
  • Obstructive hydrocephalus
  • Ex vacuo ventriculomegaly only from atrophy
  • Subarachnoid hemorrhage

Correct Answer: Normal pressure hydrocephalus

Q26. Which of the following is a contraindication to performing a lumbar puncture?

  • Focal intracranial mass lesion with risk of herniation
  • Suspected meningitis that requires CSF analysis
  • Stable anticoagulation within normal limits
  • Localized skin infection at insertion site properly prepped

Correct Answer: Focal intracranial mass lesion with risk of herniation

Q27. CSF cell counts should be processed quickly because:

  • Leukocytes rapidly lyse and underestimate pleocytosis if delayed
  • CSF protein increases immediately upon standing
  • Glucose spontaneously increases ex vivo
  • CSF color changes only after several days

Correct Answer: Leukocytes rapidly lyse and underestimate pleocytosis if delayed

Q28. Which analyte in CSF is most useful for diagnosing neurosyphilis?

  • VDRL/RPR reactivity in CSF
  • CSF chloride concentration
  • High CSF glucose
  • Elevated CSF potassium

Correct Answer: VDRL/RPR reactivity in CSF

Q29. The presence of malignant cells on CSF cytology most directly suggests:

  • Leptomeningeal carcinomatosis
  • Bacterial meningitis
  • Viral encephalitis
  • Normal aging process

Correct Answer: Leptomeningeal carcinomatosis

Q30. Which of the following best explains why albumin concentration in CSF is lower than in plasma?

  • Restricted transfer across the blood–CSF and blood–brain barriers
  • Active transport of albumin from CSF to plasma increases CSF levels
  • Albumin is synthesized primarily in the CSF
  • Albumin is degraded rapidly by CSF enzymes raising its concentration

Correct Answer: Restricted transfer across the blood–CSF and blood–brain barriers

Q31. In bacterial meningitis, empirical intrathecal antibiotic therapy is indicated primarily when:

  • Pathogen resistant and systemic therapy inadequate or poor CSF penetration
  • Systemic therapy achieves high CSF levels reliably
  • The patient has no signs of raised intracranial pressure
  • The organism is known to be highly susceptible to oral antibiotics

Correct Answer: Pathogen resistant and systemic therapy inadequate or poor CSF penetration

Q32. Which CSF parameter is often elevated in multiple sclerosis due to intrathecal IgG synthesis?

  • IgG index and presence of oligoclonal bands
  • CSF glucose markedly decreased
  • CSF neutrophils extremely elevated
  • CSF chloride extremely low

Correct Answer: IgG index and presence of oligoclonal bands

Q33. Compared to plasma, CSF typically has:

  • Lower protein and lower cellular content
  • Higher protein and higher cellular content
  • Equal protein but higher glucose
  • High plasma protein binding molecules concentrated

Correct Answer: Lower protein and lower cellular content

Q34. Which ventricular structure is the narrow channel between the third and fourth ventricles?

  • Cerebral aqueduct (aqueduct of Sylvius)
  • Foramen of Monro
  • Foramen of Magendie
  • Lateral aperture

Correct Answer: Cerebral aqueduct (aqueduct of Sylvius)

Q35. Which diagnostic marker in CSF is most specific for early neuronal injury, such as in stroke or severe trauma?

  • NSE (neuron-specific enolase) or S100B elevations
  • High CSF chloride
  • Increased CSF glucose
  • Elevated CSF albumin only

Correct Answer: NSE (neuron-specific enolase) or S100B elevations

Q36. CSF lactate is most useful clinically for distinguishing:

  • Bacterial from viral meningitis (higher in bacterial)
  • Multiple sclerosis from Guillain–Barré syndrome
  • Subarachnoid hemorrhage from traumatic tap
  • Normal pressure hydrocephalus from Alzheimer’s disease

Correct Answer: Bacterial from viral meningitis (higher in bacterial)

Q37. Which physiological mechanism contributes to CSF flow and turnover?

  • Arterial pulsations and pressure gradients promoting bulk flow
  • Passive diffusion only without pulsatile contribution
  • Active ciliary pumping across the arachnoid villi only
  • Renal filtration driving CSF circulation

Correct Answer: Arterial pulsations and pressure gradients promoting bulk flow

Q38. Which statement about CSF chloride is correct?

  • CSF chloride is usually slightly higher than plasma and not highly diagnostic alone
  • CSF chloride is the primary indicator of fungal infection
  • CSF chloride is always decreased in bacterial meningitis
  • CSF chloride equals CSF protein in concentration

Correct Answer: CSF chloride is usually slightly higher than plasma and not highly diagnostic alone

Q39. The presence of neutrophils predominating in CSF with very low glucose suggests infection by which organism class?

  • Bacteria (pyogenic meningitis)
  • Viruses
  • Protozoa only
  • Autoimmune processes

Correct Answer: Bacteria (pyogenic meningitis)

Q40. Which pharmacologic factor reduces drug delivery to CSF when binding to plasma proteins is high?

  • High plasma protein binding reduces free drug available to cross the BBB
  • High protein binding increases free fraction and CSF entry
  • Protein binding has no effect on CNS distribution
  • Protein-bound drugs actively transported across the BBB

Correct Answer: High plasma protein binding reduces free drug available to cross the BBB

Q41. What is the typical cellularity of normal adult CSF?

  • 0–5 white blood cells/mm3, predominantly lymphocytes
  • 50–100 white blood cells/mm3
  • 100–500 red blood cells/mm3
  • 10–20 eosinophils/mm3

Correct Answer: 0–5 white blood cells/mm3, predominantly lymphocytes

Q42. Which CSF abnormality is most characteristic of tuberculosis meningitis?

  • Lymphocytic pleocytosis with low glucose and markedly elevated protein
  • Neutrophilic pleocytosis with normal protein
  • No cells and very high glucose
  • High chloride with decreased protein

Correct Answer: Lymphocytic pleocytosis with low glucose and markedly elevated protein

Q43. In evaluating suspected subarachnoid hemorrhage, CSF xanthochromia is best detected when lumbar puncture is performed how long after symptom onset?

  • At least 12 hours after onset to allow bilirubin formation
  • Within 1 hour for maximum sensitivity
  • After 7 days only
  • Only immediately during the hemorrhagic event

Correct Answer: At least 12 hours after onset to allow bilirubin formation

Q44. Which CSF test is most useful for diagnosing viral encephalitis due to HSV?

  • PCR for HSV DNA in CSF
  • India ink preparation
  • Latex agglutination for bacterial antigen
  • CSF Gram stain only

Correct Answer: PCR for HSV DNA in CSF

Q45. A markedly elevated CSF protein with an albuminocytologic dissociation is characteristic of which condition?

  • Guillain–Barré syndrome
  • Acute bacterial meningitis
  • Viral meningitis
  • Subarachnoid hemorrhage

Correct Answer: Guillain–Barré syndrome

Q46. Which CSF feature can help distinguish traumatic tap from true subarachnoid hemorrhage?

  • Persistence of xanthochromia and uniformly high RBC count across tubes suggests SAH
  • Decreasing protein over sequential tubes indicates SAH
  • Rapid clearing of xanthochromia indicates SAH
  • Increase in glucose across tubes indicates SAH

Correct Answer: Persistence of xanthochromia and uniformly high RBC count across tubes suggests SAH

Q47. For intrathecal drug delivery, which property of the drug is most desirable?

  • Water solubility and sterility with appropriate molecular size for CSF distribution
  • High lipophilicity to remain in meningeal fat only
  • Large protein binding so it stays in plasma
  • Unstable in CSF to allow rapid metabolism

Correct Answer: Water solubility and sterility with appropriate molecular size for CSF distribution

Q48. Which of the following is TRUE about the choroid plexus epithelium?

  • It forms the blood–CSF barrier with tight junctions and active transport mechanisms
  • It lacks tight junctions and freely permits plasma proteins into CSF
  • It is the main site for arachnoid granulation absorption
  • It synthesizes neurons for CNS repair

Correct Answer: It forms the blood–CSF barrier with tight junctions and active transport mechanisms

Q49. Which imaging-guided precaution is often recommended before lumbar puncture in patients with focal neurological signs?

  • Perform brain CT or MRI to exclude mass lesion and risk of herniation
  • Always proceed to LP without imaging regardless of signs
  • Only check spinal XRays before LP
  • Perform abdominal ultrasound instead

Correct Answer: Perform brain CT or MRI to exclude mass lesion and risk of herniation

Q50. Which CSF parameter change reflects a compromised blood–CSF barrier?

  • Elevated CSF/serum albumin ratio (albumin index)
  • Decreased CSF lactate only
  • Lowered CSF IgG index with oligoclonal bands
  • Increased CSF glucose relative to plasma

Correct Answer: Elevated CSF/serum albumin ratio (albumin index)

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