Which structures produce most of the cerebrospinal fluid?

Choroid plexuses of the ventricles

Ependymal cells of the spinal cord

CSF and other body fluids

48 Kerala MSc MLT Entrance practice questions on CSF and other body fluids, part of Pathology. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Easy
The total volume of CSF in a normal adult is about:
1. AAbout 500 mL
2. B10-60 mL
3. C90-150 mL
4. D300-400 mL
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Answer: C · 90-150 mL
An adult has about 90-150 mL of CSF, while a newborn has about 10-60 mL. The fluid is replaced several times a day, as about 500 mL is produced daily. This is why only a limited volume, usually three or four tubes, is taken at lumbar puncture. Removing too much can cause headache.
- A: About 500 mL is the daily production, not the volume present.
- B: 10-60 mL is the newborn volume.
- D: 300-400 mL is far above the adult volume.
Question 2 · Medium
In diagnostic peritoneal lavage after blunt abdominal trauma, which red cell count in the lavage fluid indicates intra-abdominal bleeding?
1. AOver 100,000/µL
2. BOver 5,000/µL
3. COver 500/µL
4. DOver 1,000,000/µL
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Answer: A · Over 100,000/µL
In peritoneal lavage, saline is run into the abdomen and drained back. A red cell count above about 100,000/µL in the return fluid is taken as a positive result, indicating significant bleeding. Lower counts can come from the procedure itself. A white cell count above 500/µL in the lavage suggests peritonitis from a bowel injury.
- B: 5,000/µL is far too low and can come from the procedure.
- C: 500/µL is the white cell cut-off, not the red cell one.
- D: A million per µL is far above the accepted cut-off.
Question 3 · Medium
Lumbar CSF from a patient with a spinal tumour is yellow, has a very high protein and clots on standing. This picture is called:
1. AFroin syndrome
2. BSubarachnoid haemorrhage
3. CTraumatic tap
4. DTuberculous meningitis
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Answer: A · Froin syndrome
When a tumour blocks the spinal canal, the CSF below the block stagnates and gains protein from the tumour and vessels. It becomes yellow (xanthochromic), and the very high protein, including fibrinogen, makes it clot spontaneously. This is Froin syndrome. A tuberculous CSF forms only a fine cobweb clot and is usually not deep yellow.
- B: Subarachnoid haemorrhage gives evenly bloody CSF that does not clot.
- C: A traumatic tap clears in later tubes and is not xanthochromic.
- D: Tuberculous meningitis gives a fine cobweb clot, not a heavy clot with deep yellow fluid.
Question 4 · Easy
Which structures produce most of the cerebrospinal fluid?
1. AEpendymal cells of the spinal cord
2. BMeningeal blood vessels
3. CChoroid plexuses of the ventricles
4. DArachnoid granulations
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Answer: C · Choroid plexuses of the ventricles
About 70% of CSF is made by the choroid plexuses in the ventricles, mostly the lateral ventricles, by selective filtration and secretion. It flows through the ventricles into the subarachnoid space. It is reabsorbed into the venous sinuses through the arachnoid granulations. About 500 mL is made each day.
- A: Ependymal cells line the ventricles and canal and make only a small part.
- B: Meningeal vessels are not the main source.
- D: Arachnoid granulations reabsorb CSF; they do not make it.
Question 5 · Hard
Turbid CSF from a febrile child is diluted 1 in 10 with WBC diluting fluid. In the improved Neubauer chamber (depth 0.1 mm), 60 cells are counted in the four large corner squares. The WBC count is:
1. A600/µL
2. B150/µL
3. C6,000/µL
4. D1,500/µL
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Answer: D · 1,500/µL
Each large square is 1 mm x 1 mm x 0.1 mm = 0.1 µL, so four squares hold 0.4 µL. Cells/µL = cells counted x dilution / volume counted = 60 x 10 / 0.4 = 1,500/µL. Leaving out the dilution gives 150/µL; leaving out the volume gives 600/µL. A count this high in turbid CSF supports bacterial meningitis.
- A: 600/µL leaves out division by the 0.4 µL volume counted.
- B: 150/µL leaves out the 1 in 10 dilution.
- C: 6,000/µL multiplies by 100 instead of the correct factor of 25.
Question 6 · Hard
After a fall, a man's swollen knee is aspirated. The fluid is evenly bloody in every syringe, does not clear, and has fat droplets floating on top that stain with Sudan. The most likely cause is:
1. APigmented villonodular synovitis
2. BTraumatic tap during aspiration
3. CHaemophilic haemarthrosis
4. DIntra-articular fracture with marrow fat
Answer and explanation in LearnFree account
Question 7 · Hard
Ascitic fluid from a man with cirrhosis: neutrophils 4,800/µL, total protein 2.6 g/dL, glucose 30 mg/dL, LD 520 U/L (serum upper limit 225 U/L), Gram stain shows several kinds of bacteria. What is the most likely diagnosis?
1. ASecondary peritonitis from a perforated viscus
2. BUncomplicated cirrhotic ascites
3. CSpontaneous bacterial peritonitis
4. DTuberculous peritonitis
Answer and explanation in LearnFree account
Question 8 · Medium
Synovial fluid from a patient on long-term haemodialysis contains envelope-shaped and rod-shaped birefringent crystals. What are they most likely to be?
1. ACalcium pyrophosphate
2. BCalcium oxalate
3. CCholesterol
4. DMonosodium urate
Answer and explanation in LearnFree account
Question 9 · Medium
A pleural fluid-to-serum creatinine ratio above 1.0 points to:
1. AAcute pancreatitis
2. BChronic kidney failure with uraemia
3. CUrinothorax from urinary tract obstruction
4. DOesophageal rupture
Answer and explanation in LearnFree account
Question 10 · Medium
A pleural fluid differential shows 25% eosinophils. What does this finding most often follow?
1. AUncomplicated community-acquired bacterial pneumonia
2. BCongestive heart failure
3. CTuberculous pleurisy
4. DAir or blood entering the pleural space
Answer and explanation in LearnFree account
Question 11 · Medium
Apart from bleeding, a yellow (xanthochromic) CSF supernatant is seen when the CSF total protein rises above about:
1. A45 mg/dL
2. B20 mg/dL
3. C150 mg/dL
4. D60 mg/dL
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Question 12 · Hard
A 66-year-old man with long-standing heart failure has ascites. Serum albumin 3.4 g/dL, ascitic albumin 1.9 g/dL, ascitic total protein 3.1 g/dL; neutrophils 40/µL. Liver tests are normal. Which cause best fits these results?
1. APeritoneal carcinomatosis
2. BCardiac ascites from heart failure
3. CTuberculous peritonitis
4. DCirrhosis with portal hypertension
Answer and explanation in LearnFree account
Question 13 · Medium
A healthy full-term 5-day-old baby has a lumbar puncture to rule out sepsis. The CSF is clear with 20 white cells/µL, mostly monocytes and lymphocytes. How should the count be reported?
1. ARaised, consistent with bacterial meningitis
2. BRaised, consistent with viral meningitis
3. CFalsely high from blood contamination
4. DWithin the normal neonatal range
Answer and explanation in LearnFree account
Question 14 · Medium
In India, a recognised cause of chylous ascites and chylous hydrocele through blockage of lymphatics is:
1. AAmoebic liver abscess
2. BHookworm infection
3. CHepatitis B infection
4. DBancroftian filariasis
Answer and explanation in LearnFree account
Question 15 · Medium
Pandy's test for raised CSF globulin uses which reagent?
1. ATen percent trichloroacetic acid
2. BThree percent sulphosalicylic acid
3. CSaturated aqueous phenol
4. DHalf-saturated ammonium sulphate
Answer and explanation in LearnFree account
Question 16 · Hard
After a pelvic fracture, a man has abdominal distension and passes little urine. Peritoneal fluid: clear and straw-coloured, creatinine 14.0 mg/dL, urea 210 mg/dL; serum creatinine 1.6 mg/dL. The most likely explanation is:
1. APancreatic injury with ascites
2. BHaemoperitoneum from a pelvic vessel
3. CAcute kidney injury with transudate
4. DIntraperitoneal rupture of the bladder
Answer and explanation in LearnFree account
Question 17 · Medium
A young man in Kerala has severe headache and neck stiffness two weeks after eating raw snails. His CSF has 400 white cells/µL with 35% eosinophils. Which cause is most likely?
1. AAngiostrongylus cantonensis infection
2. BHerpes simplex encephalitis
3. CPneumococcal meningitis
4. DTuberculous meningitis
Answer and explanation in LearnFree account
Question 18 · Medium
In the string test, a drop of synovial fluid from a swollen knee forms a string of only 1 cm before breaking. This finding suggests:
1. ANormal joint fluid with intact hyaluronic acid
2. BDilution of the sample by anticoagulant
3. CLow viscosity from breakdown of hyaluronate in inflammation
4. DExcess hyaluronate from synovial overgrowth
Answer and explanation in LearnFree account
Question 19 · Medium
In the manual CSF white cell count, the diluting fluid contains dilute acetic acid. Its purpose is to:
1. APrevent the CSF from clotting in the chamber
2. BFix white cells so they do not lyse
3. CLyse red cells so white cells are counted clearly
4. DStain cytoplasmic granules for the differential
Answer and explanation in LearnFree account
Question 20 · Easy
In normal adult CSF, the few cells present are mainly:
1. AEpendymal and choroid cells
2. BLymphocytes and monocytes
3. CNeutrophils and lymphocytes
4. DNeutrophils and eosinophils
Answer and explanation in LearnFree account
Question 21 · Hard
A traumatic lumbar puncture gives CSF with a total protein of 85 mg/dL and a red cell count of 30,000/µL in the same tube. If about 1 mg/dL of protein is subtracted for every 1,000 red cells/µL, the corrected CSF protein is:
1. A115 mg/dL
2. B55 mg/dL
3. C82 mg/dL
4. D25 mg/dL
Answer and explanation in LearnFree account
Question 22 · Medium
In older Indian laboratory practice, a markedly low CSF chloride was taught as a pointer to which condition?
1. AViral meningitis
2. BTuberculous meningitis
3. CGuillain-Barré syndrome
4. DSubarachnoid haemorrhage
Answer and explanation in LearnFree account
Question 23 · Hard
A 72-year-old woman with knee swelling has synovial fluid with rhomboid crystals. Under polarised light with a red compensator, the crystals appear blue when their long axis is parallel to the slow ray and yellow when perpendicular. The diagnosis is:
1. ACholesterol crystals in a chronic effusion
2. BMonosodium urate deposition (gout)
3. CCalcium pyrophosphate deposition (pseudogout)
4. DCorticosteroid crystals after an injection
Answer and explanation in LearnFree account
Question 24 · Medium
A CSF sample is centrifuged and the supernatant is pink. The colour is mainly due to:
1. AMethaemoglobin from an old clot
2. BBilirubin from haemoglobin breakdown
3. COxyhaemoglobin from lysed red cells
4. DCarotene from the patient's diet
Answer and explanation in LearnFree account
Question 25 · Hard
Undiluted clear CSF is loaded into an improved Neubauer chamber (depth 0.1 mm). A total of 27 white cells are counted in all nine 1 mm² large squares. The white cell count is:
1. A3 cells/µL
2. B30 cells/µL
3. C27 cells/µL
4. D300 cells/µL
Answer and explanation in LearnFree account

23 more CSF and other body fluids questions

Answer them one by one, keep your score and see your weak topics in Learn. Signed-out visitors try 25 per exam; sign in with Google to see them all.

Study Pathology

CSF and other body fluids

The total volume of CSF in a normal adult is about:

In diagnostic peritoneal lavage after blunt abdominal trauma, which red cell count in the lavage fluid indicates intra-abdominal bleeding?

Lumbar CSF from a patient with a spinal tumour is yellow, has a very high protein and clots on standing. This picture is called:

Which structures produce most of the cerebrospinal fluid?

Turbid CSF from a febrile child is diluted 1 in 10 with WBC diluting fluid. In the improved Neubauer chamber (depth 0.1 mm), 60 cells are counted in the four large corner squares. The WBC count is:

After a fall, a man's swollen knee is aspirated. The fluid is evenly bloody in every syringe, does not clear, and has fat droplets floating on top that stain with Sudan. The most likely cause is:

Ascitic fluid from a man with cirrhosis: neutrophils 4,800/µL, total protein 2.6 g/dL, glucose 30 mg/dL, LD 520 U/L (serum upper limit 225 U/L), Gram stain shows several kinds of bacteria. What is the most likely diagnosis?

Synovial fluid from a patient on long-term haemodialysis contains envelope-shaped and rod-shaped birefringent crystals. What are they most likely to be?

A pleural fluid-to-serum creatinine ratio above 1.0 points to:

A pleural fluid differential shows 25% eosinophils. What does this finding most often follow?

Apart from bleeding, a yellow (xanthochromic) CSF supernatant is seen when the CSF total protein rises above about:

A 66-year-old man with long-standing heart failure has ascites. Serum albumin 3.4 g/dL, ascitic albumin 1.9 g/dL, ascitic total protein 3.1 g/dL; neutrophils 40/µL. Liver tests are normal. Which cause best fits these results?

A healthy full-term 5-day-old baby has a lumbar puncture to rule out sepsis. The CSF is clear with 20 white cells/µL, mostly monocytes and lymphocytes. How should the count be reported?

In India, a recognised cause of chylous ascites and chylous hydrocele through blockage of lymphatics is:

Pandy's test for raised CSF globulin uses which reagent?

After a pelvic fracture, a man has abdominal distension and passes little urine. Peritoneal fluid: clear and straw-coloured, creatinine 14.0 mg/dL, urea 210 mg/dL; serum creatinine 1.6 mg/dL. The most likely explanation is:

A young man in Kerala has severe headache and neck stiffness two weeks after eating raw snails. His CSF has 400 white cells/µL with 35% eosinophils. Which cause is most likely?

In the string test, a drop of synovial fluid from a swollen knee forms a string of only 1 cm before breaking. This finding suggests:

In the manual CSF white cell count, the diluting fluid contains dilute acetic acid. Its purpose is to:

In normal adult CSF, the few cells present are mainly:

A traumatic lumbar puncture gives CSF with a total protein of 85 mg/dL and a red cell count of 30,000/µL in the same tube. If about 1 mg/dL of protein is subtracted for every 1,000 red cells/µL, the corrected CSF protein is:

In older Indian laboratory practice, a markedly low CSF chloride was taught as a pointer to which condition?

A 72-year-old woman with knee swelling has synovial fluid with rhomboid crystals. Under polarised light with a red compensator, the crystals appear blue when their long axis is parallel to the slow ray and yellow when perpendicular. The diagnosis is:

A CSF sample is centrifuged and the supernatant is pink. The colour is mainly due to:

Undiluted clear CSF is loaded into an improved Neubauer chamber (depth 0.1 mm). A total of 27 white cells are counted in all nine 1 mm² large squares. The white cell count is: