7.3 Cerebrospinal, Serous, and Synovial Fluids

Question 1

Cerebrospinal fluid (CSF) is formed by ultrafiltration of plasma through the:
A. Choroid plexus
B. Sagittal sinus
C. Anterior cerebral lymphatics
D. Arachnoid membrane

Answer 1

A. Choroid plexus

Question 2

Which statements regarding CSF is true?
A. Normal values for mononuclear cells are higher for infants than adults
B. Absolute neutrophilia is not significant if the total WBC count is less than 25/uL.
C. The first aliquot of CSF should be sent to the microbiology laboratory
D. Neutrophils compose the majority of WBCs in normal CSF

Answer 2

A. Normal values for mononuclear cells are higher for infants than adults

Question 3

When collecting CSF, a difference between opening and closing fluid pressure greater than 100 mm H2O indicates:
A. Low CSF volume
B. Subarachnoid hemorrhage
C. Meningitis
D. Hydrocephalus

Answer 3

A. Low CSF volume

Question 4

Which of the following findings is consistent with a subarachnoid hemorrhage rather than a traumatic tap?
A. Clearing of the fluid as it is aspirated
B. A clear supernatant after centrifugation
C. Xanthochromia
D. Presence of a protein in the sample

Answer 4

C. Xanthochromia

Question 5

The term used to denote a high WBC count in the CSF is:
A. Empyema
B. Neutrophilia
C. Pleocytosis
D. Hyperglycorrhachia

Answer 5

C. Pleocytosis

Pleocytosis refers to an increase in WBCs within CSF. Bacterial meningitis causes a neutrophilia pleocytosis, viral meningitis a lymphocytic pleocytosis, and tuberculous and fungal meningitis a mixed-cell pleocytosis. Other causes of pleocytosis include multiple sclerosis (MS), cerebral hemorrhage or infarction, and leukemia.

Question 6

Which of the adult CSF values in the table below are consistent with bacterial meningitis?
A. WBCs: 50/uL, Lymphs: 44%, Monos: 55%, Eos: 0%, Neutrophils: 0%, Neuroectodermal cells: 1%
B. WBCs: 300/uL, Lymphs: 75%, Monos: 21%, Eos:3%, Segs: 0%, Neuroectodermal cells: 1%
C. WBCs: 2,000/uL, Lymphs: 5%, Monos: 15%, Eos: 0%, Segs: 80%, Neutroectodermal cells: 0%
D. WBCS: 2,500, Lymphs: 40%, Mono: 50%, Eos: 0%, Seg: 10%, 0%

Answer 6

C. WBCs: 2,000/uL, Lymphs: 5%, Monos: 15%, Eos: 0%, Segs: 80%, Neutroectodermal cells: 0%

Normal WBC counts for CSF are 0 to 5/uL for adults and 0 to 30/ uL for children. Neutrophils predominate the differential in bacterial meningitis, whereas lymphocytes predominate in viral meningitis. Hemorrhage and traumatic tap will also cause increased PMNs, and WBC counts should be corrected using the CSF RBC count.

Question 7

Given the following data, determine the corrected CSF WBC count.

RBCs - CSF value: 6,000/uL, Peripheral Blood value: 4.0 x 10^6//uL

WBCs - CSF value: 150/uL, Peripheral Blood value: 5.0 x 10^3/uL

A. 8/uL
B. 142/uL
C. 120/uL
D. 145/uL

Answer 7

B. 142/uL

Corrected WBC count = WBCs in CSF - [(Blood WBCs x CSF RBCs) / Blood RBCs]

Corrected WBC count = 150/uL - [(5,000/uL WBCs x 6,000/uL RBCs) / 4,000,000/uL RBCs]

Corrected WBC count = 150/uL - 7.5 uL

Corrected WBC count = 142/ uL

Question 8

SITUATION: What is the most likely cause of the following CSF results?

CSF glucose 20 mg/dL; CSF protein 200 mg/dL;
CSF lactate 50 mg/dL (reference range 5-25 mg/dL)

A. Viral meningitis
B. Viral encephalitis
C. Cryptococcal meningitis
D. Acute bacterial meningitis

Answer 8

D. Acute bacterial meningitis

Question 9

Which of the following conditions is most often associated with normal CSF glucose and protein?
A. Multiple sclerosis
B. Malignancy
C. Subarachnoid hemorrhage
D. Viral meningitis

Answer 9

D. Viral meningitis

Question 10

The diagnosis of MS is suggested by which finding?
A. The presence of elevated protein and low glucose
B. A decreased IgG index
C. The presence of oligoclonal bands by electrophoresis
D. An increased level of CSF Beta-microglobulin

Answer 10

C. The presence of oligoclonal bands by electrophoresis

Question 11

Which of the following results is consistent with fungal meningitis?
A. Normal CSF glucose
B. Pleocytosis of mixed cellularity
C. Normal CSF protein
D. High CSF lactate

Answer 11

B. Pleocytosis of mixed cellularity

Question 12

In what suspected condition should a wet prep using a warm slide be examined?
A. Cryptococcal meningitis
B. Amoebic meningoencephalitis
C. Mycobacterium tuberculosis infection
D. Neurosyphilis

Answer 12

B. Amoebic meningoencephalitis

Question 13

Which of the following CSF test results is most commonly increased in patients with MS?
A. Glutamine
B. Lactate
C. IgG index
D. Ammonia

Answer 13

C. IgG index

IgG Index = (CSF IgG / serum IgG) / (CSF albumin / serum albumin.
An IgG-albumin index is the ratio of CSF IgG: serum IgG divided by the CSF albumin: serum albumin ratio. Values greater than 0.85 indicate CSF IgG production, as seen in MS; or increased CSF production combined with increased permeability, as seen in CNS infections. MS is characterized by the presence of oligoclonal banding in the CSF in greater than 90% of patients with active disease. The total protein and myelin basic protein are often increased, and glucose is decrease. Reye syndrome results in hepatic failure, causing high CSF levels of ammonia and glutamine. CSF lactate is usually normal in patients with MS.

Question 14

Which of the following is an inappropriate procedure for performing routine CSF analysis?
A. A differential is done only if the total WBC count is greater than 10/uL
B. A differential should be done on a stained CSF concentrate
C. A minimum of 30 WBCs should be differentiated
D. A Wright-stained slide should be examined, rather than a chamber differential

Answer 14

A. A differential is done only if the total WBC count is greater than 10/uL

Question 15

Which cell is present in CSF in greater numbers in newborns than in older children or adults?
A. Eosinophils
B. Lymphocytes
C. Monocytes
D. Neutrophils

Answer 15

C. Monocytes

Question 16

Neutrophilic pleocytosis is usually associated with all of the following except:
A. Cerebral infarction
B. Malignancy
C. Myelography
D. Neurosyphilis

Answer 16

D. Neurosyphilis

Question 17

Which statement about the CSF protein is true?
A. An abnormal serum protein electrophoretic pattern does not affect the CSF pattern
B. The upper reference limit (URL) for CSF total protein in newborns is one half the adult level
C. CSF IgG is increased in panencephalitis, malignancy, and neurosyphilis
D. Antibodies to Treponema pallidum disappear after successful antibiotic therapy

Answer 17

C. CSF IgG is increased in panencephalitis, malignancy, and neurosyphilis

Question 18

Which of the following statements regarding routine microbiological examination of CSF is true?
A. A Gram stain is performed on the CSF prior to concentration
B. The Gram stain is positive in fewer than 40% of cases of acute bacterial meningitis
C. India ink and acid fast stains are indicated if neutrophilic pleocytosis is present
D. All CSF specimens should be cultured using sheep blood agar, chocolate agar, and supplements broth

Answer 18

D. All CSF specimens should be cultured using sheep blood agar, chocolate agar, and supplements broth

Question 19

Which organism is the most frequent cause of bacterial meningitis in neonates?
A. Neisseria meningitidis
B. Group B Streptococcus
C. Haemophilus influenzae
D. Klebsiella pneumoniae

Answer 19

B. Group B Streptococcus

Question 20

Following a head injury, which protein will identify the presence of CSF leakage through the nose?
A. Transthyretin
B. Myelin basic protein
C. Tau protein
D. C-reactive protein

Answer 20

C. Tau protein

Question 21

Which of the following statements regarding serous fluids is true?
A. The normal volume of pleural fluid is 30 to 50 mL
B. Mesothelial cells, PMNs, lymphocytes, and macrophages may be present in normal fluids
C. Radiography can detect a 10% increase in the volume of a serous fluid
D. Normal serous fluids are colorless

Answer 21

B. Mesothelial cells, PMNs, lymphocytes, and macrophages may be present in normal fluids

Question 22

The term effusion refers to:
A. A chest fluid that is purple t
B. A serous fluid that is chylous
C. An increased volume of serous fluids
D. An inflammatory process affecting the appearance of a serous fluid

Answer 22

C. An increased volume of serous fluids

Question 23

Which of the following laboratory results is characteristic of a transudative fluid?
A. SG= 1.018
B. Total protein = 3.2 g/dL
C. LD fluid/serum ratio = 0.25
D. Total protein fluid: serum ratio = 0.65

Answer 23

C. LD fluid/serum ratio = 0.25

Question 24

Which observation is least useful in distinguishing a hemorrhagic serous fluid from a traumatic tap?
A. Clearing of fluid as it is aspirated
B. Presence of xanthochromia
C. The formation of a clot
D. Diminished RBC count in successive aliquots

Answer 24

C. The formation of a clot

Question 25

Which of the following laboratory results on a serous fluid is most likely to be caused by a traumatic tap?
A. An RBC count of 8,000/uL
B. A WBC count of 6,000/uL
C. A hematocrit of 35%
D. A neutrophil count of 55%

Answer 25

A. An RBC count of 8,000/uL

Question 26

Which of the following conditions is commonly associated with an exudative effusion?
A. Congestive heart failure
B. Malignancy
C. Nephrotic syndrome
D. Cirrhosis

Answer 26

B. Malignancy

Question 27

Which of the following conditions is associated with a chylous effusion?
A. Necrosis
B. Pulmonary infarction or infection
C. Systemic lupus erythematosus or rheumatoid arthritis (RA)
D. Lymphatic obstruction

Answer 27

D. Lymphatic obstruction

Question 28

Which of the following conditions is most often associated with a pleural fluid glucose below 30 mg/dL?
A. Diabetes mellitus
B. Pancreatitis
C. Rheumatoid arthritis
D. Bacterial pneumonia

Answer 28

C. Rheumatoid arthritis

Question 29

In which condition is the pleural fluid pH likely to be above 7.3?
A. Bacterial pneumonia with parapneumonic exudate
B. Rheumatoid pleuritis
C. Esophageal rupture
D. Pneumothorax

Answer 29

D. Pneumothorax

The pH of pleural fluid is approx 7.64 and values below 7.30 are usually associated with a poorer prognosis and usually require drainage. Esophageal rupture produces the lowest pH with value in the …

Pneumothorax results from air entering the pleural space and does not produce a low pH.

Question 30

Which of the following hematology values best frames the URLs for peritoneal fluid?
A. WBC count: 300/uL, Percentage of PMNs: 25%, RBC count: 100,000/uL
B. WBC count: 10,000/uL, Percentage of PMNs: 50%, RBC count: 500,000/uL
C. WBC count: 50,000/uL, Percentage of PMNs: 50%, RBC count: 500,000/uL
D. WBC count: 100,000/uL, Percentage of PMNs: 75%, RBC count: 1,000,000,/uL

Answer 30

A. WBC count: 300/uL, Percentage of PMNs: 25%, RBC count: 100,000/uL

Question 31

Which of the following characteristics is higher for synovial fluid than for the serous fluids?
A. Specific gravity
B. Glucose
C. Total protein
D. Viscosity

Answer 31

D. Viscosity

Question 32

In which type of arthritis is the synovial WBC count likely to be greater than 50,000/uL?
A. Septic arthritis
B. Osteoarthritis
C. Rheumatoid arthritis
D. Hemorrhagic arthritis

Answer 32

A. Septic arthritis

Question 33

What type of cell is a “ragocyte”?
A. Cartilage cell seen in inflammatory arthritis
B. A PMN with inclusions formed by immune complexes
C. A plasma cell seen in RA
D. A macrophage containing large inclusions

Answer 33

B. A PMN with inclusions formed by immune complexes

Question 34

Which of the following crystals in the cause of gout?
A. Uric acid or monosodium irate
B. Calcium pyrophosphate or apatite
C. Calcium oxalate
D. Cholesterol

Answer 34

A. Uric acid or monosodium irate

Question 35

Which crystal causes “pseudogout?
A. Oxalic acid
B. Calcium pyrophosphate
C. Calcium oxalate
D. Cholesterol

Answer 35

B. Calcium pyrophosphate

Question 36

A synovial fluid sample is examined by using a polarizing microscope with a red compensating filter. Crystals are seen that are yellow when the long axis of the crystal is parallel to the slow vibrating light. When the long axis of the crystal is perpendicular to the slow vibrating light, the crystal appear blue. What type of crystal is present?
A. Calcium oxalate
B. Calcium pyrophosphate
C. Uric acid
D. Cholesterol

Answer 36

C. Uric acid

Question 37

In which condition is the synovial fluid glucose most likely to be within normal limits?
A. Septic arthritis
B. Inflammatory arthritis
C. Hemorrhagic arthritis
D. Gout

Answer 37

C. Hemorrhagic arthritis

Synovial fluid glucose is normally less than 10 mg/dL below serum glucose, and should be collected after an 8-hour fast to ensure that the fluid and plasma are equilibrated. In septic arthritis, the glucose level is often greater than 40 mg/dL below the serum level and about 25 to 40 mg/dL lower in inflammatory arthritis, which includes gout. Osteoarthritis and hemorrhagic arthritis are not usually associated with low joint fluid glucose.

Question 38

Which statement about synovial fluid in RA is true ?
A. Synovial: serum IgG is usually 1:2 or higher
B. Total hemolytic complement is elevated
C. Ninety percent of RA cases test positive for rheumatoid factor in synovial fluid
D. Demonstration of rheumatoid factor in joint fluid is diagnostic for RA

Answer 38

A. Synovial: serum IgG is usually 1:2 or higher

Rhematoid factor can be present in both serum and synovial fluids from patients with RA, SLE, and other inflammatory diseases. Rheumatoid factor is present in synovial fluid of approximatley 60% of patients with RA. Normally, IgG in synovial fluid is about 10% of the serum IgG level. CH50 levels in serum and synovium are more differential. Both are increased in Reiter syndrome but are often low in SLE; synovial CH50 is decreased and serum CH50 is normal (or increased) in RA.

Question 39

Which of the following organisms accounts for the majority of septic arthritis cases in young and middle-age adults?
A. H.influenzae
B. Neisseria gonorrhoeae
C. Staphylococcus aureus
D. Borrelia burgdorferi

Answer 39

B. Neisseria gonorrhoeae

Synovial fluid is normally sterile, and all of the organisms listed may cause septic arthritis. N. gonorrhoeae is responsible for about 75% of septic arthritis cases occuring young and middle-aged adults. Staphyloccocus is responsible for the majority of cases involving older adults and is the most frequently found isolate from infected joint replacements. Haemophilus spp., Staphylococcus spp., and Streptococcus spp. are the most common causes of arthritis in young children.

Question 40

Which of the following hematology values best frames the URLs for synovial fluid?
A. WBC count: 200/uL, Percentage of PMNs: 25%, RBC Count: 2,000/uL
B. WBC count: 5,000/uL, Percentage of PMNs: 50%, RBC Count: 10,000/uL
C. WBC count: 10,000/uL, Percentage of PMNs: 50%, RBC Count: 50,000/uL
D. WBC count: 20,000/uL, Percentage of PMNs: 5%, RBC Count: 500,000/uL

Answer 40

A. WBC count: 200/uL, Percentage of PMNs: 25%, RBC Count: 2,000/uL