PBL: Spinal Fluid Flashcards Preview

Liz's Microbiology Module 2 > PBL: Spinal Fluid > Flashcards

Flashcards in PBL: Spinal Fluid Deck (66):
1

List the anatomy of the skull starting w/ outer → inner

- Skull
- Dura mater
- Arachnoid
- Subarachnoid space
- Pia mater
- CSF

2

CSF is produced by the ____ ____ in the 4 ventricles of the brain

Choroid plexus

3

CSF flows from the two ____ ventricles to the ____ ventricle and enters the ____ ventricle via the ____ ____ ____

Lateral; third;fourth; aqueduct of Sylvius

4

CSF is absorbed primarily by the ____ ____ through tight junctions of the endothelium

Arachnoid villi

5

What are the 3 types of CSF specimens an MD can collect?

- Lumbar region (spinal tap)
- Subdural (for abscesses in the brain)
- Ventricular aspiration

6

Infectious disease characterized by the inflammation of the meninges (dura, arachnoid, pia mater)

Meningitis

7

A condition characterized by a lymphocyte pleocytosis in the CSF and lack of an identifiable causative agent after routine stains and culture of the CSF

Aspetic meningitis

8

The most common mycobacterial infection of the CNS caused by Mycobacterium tuberculosis

Tuberculosis meningitis

9

Inflammation of the brain

Encephalitis

10

Presence of meningococci (N. meningitidis) in the bloodstream

Meningoencephalitis (meningitis + encephalitis)

11

Meningeal inflammation that persists for more than 4 weeks; common in immunocompromised patients

Chronic meningitis

12

Inflammation in the meninges that persists for hours to days

Acute meningitis

13

____ is caused by inflammation and collection of infected material coming from local infectious source (e.g., ear infection and infection of paranasal sinuses)

Brain abscess

14

Increase in CSF cell count

Pleocytosis

15

Normal value for WBCs in CSF

ZERO

16

CSF is obtained by inserting a sterile hollow needle into the spinal subarachnoid space (b/w L3 and L4) in th elower back

Lumbar puncture

17

Used for treatment of chronic subdural hematomas, usually caused by severe head injuries
- Performed under local anesthesia, followed by partial shaving and disinfection

Subdural tap

18

Method used to treat conditions such as hydrocephalus which are due to excessie fluid accumulation in the ventricles
- Blood and CSF are drained to reduce intracranial hypertension

Ventricular aspiration

19

What is the preferred site of entry for a ventricular aspiration?

Right frontal cerebral hemisphere

20

Why is the right frontal cerebral hemisphere the preferred site of entry for a ventricular aspiration?

Due to its non-dominance for language function for 90% of patients

21

List the general signs and symptoms of meningitis

- Sudden onset of fever
- Headache
- Stiff neck
- Nausea
- Photophobia (↑ sensitivity to light)
- Altered mental status
- Vomiting

22

List the more severe symptoms, due to the progression of meningitis

- Seizures
- Coma
- Death

23

Signs and symptoms of meningitis in newborns

- Fevere, headache, and stiff neck may be absent or difficult to see
- Newborn appears to be slow or inactive

24

Signs and symptoms of meningitis in babies

- Bulging fontanelles (soft spot on head) due to ↑ CSF
- Abdominal reflex (restlessness)
- Poor feeding
- Irritability

25

2 methods to diagnose meningitis

- Kernig sign
- Brudzinski sign

26

Back pain occurs when physician flexes patient's hip and knee while extending the leg at the knee

Kernig sign

27

In this method, involuntary flexion of the patient's hip and knee when the physician lifts the patient's head flexing it towards his chest

Brudzinski sign

28

What complications may occur in patients w/ meningitis?

- Brain damage
- Hearing loss
- Seizures (epilepsy)
- Hydrocephalus (buildup of fluid inside the skull)
- Buildup of fluid b/w skull and the brain
- Issues w/ memory
- Partial vision loss

29

What is the function of CSF?

To act as a cushion protecting the brain and spine from injury

30

Normal values of CSF
- Pressure
- Appearance
- Total protein
- Glucose
- WBC count
- RBC count
- Differential

- Pressure: 70-180 mm H2O
- Appearance: clear, colorless
- Total protein: 15-60mg/100mL
- Glucose: 50-80mg/100mL
- WBC count: 0-5 (adults/children)
- RBC count: 0
- Differential: 60-70% lymphs, up to 30% monocytes/macrophages, other cells ≤ 2%

31

Bacterial meningitis
- WBCs
- Glucose
- Protein

- WBCs: > 500 cells (neutrophils predominate)
- Glucose: very low (< 40% of serum glucose concentration)
- Protein: significantly ↑

32

Fungal meningitis
- WBCs
- Glucose
- Protein

- WBCs: Normal; 500 lymphs
- Glucose: < 40 mg/dL
- Protein: 25-500 mg/dL

33

Tubercular meningitis
- WBCs
- Glucose
- Protein

- WBCs: 50-500 (lymphs predominate)
- Glucose: ↓
- Protein: 150 mg/dL

34

Viral meningitis
- WBCs
- Glucose
- Protein

- WBCs: Normal; 200 lymphs predominate
- Glucose: normal
- Protein: normal

35

Parasitic meningitis
- WBCs
- Glucose
- Protein

- WBCs: Normal; 200 lymphs and/or eosinophils predominate
- Glucose: Normal to ↓
- Protein: ↑

36

How do we route CSF tubes in the lab?

#1 → Chemistry
#2 → Microbiology
#3 → Hematology

37

Why does hematology get tube #3?

Possibility of being a bloody tap which could be clear by tube #3

38

If you recieve > 2 mL of CSF, what should you do?

Centrifuge for 20 minutes @ 1500-3000 Xg

39

If you receive < 1 mL of CSF, what should you do?

Vortex before processing
- Remove supernatant and vortex the sediment for 30 seconds to resuspend pellet before plating

40

What primary media is set up for CSF?

BAP, CHOC, THIO broth, 2 gram stains

41

What does THIO grow?

Grows anaerobes and detects small amounts of organisms

42

WHat do you incubate CSF plates at?

CO2 at 37°C

43

When do you plate CSF on an anaerobe plate?

If it's a brain abscess

44

How many slides do you set up for a CSF?

2! Gram stain them one at a time and have someone else look at the other one to confirm

45

What do you do if the gram stain is positive?

Read 2nd gram stain and then stain w/ acridine orange. If bacteria are present, CALL MD!

46

If you only have 1 drop of CSF what do you do?

Put it on a CHOC plate

47

If GPC in clusters are seen on a positive direct smear, what is set up?

Tube coagulase and ANA BAP

48

If GPC in chains are seen on a positive direct smear, what is set up?

Bile esculin, NaCl, ANA BAP

49

If GNRs are seen on a positive direct smear, what is set up?

MAC and ANA BAP

50

If yeast are seen on a positive direct smear, what is set up?

BAP

51

If GNCB are seen on a positive direct smear, what is set up?

ML and ANA BAP

52

What do you incubate MAC and SAB at?

CO2 for 2 days

53

What do you incubate ML plates at?

CO2 for 3 days

54

What do you incubate ANA BAPs at?

Anaerobic for 48 hours

55

What are common pathogens in neonate?

- S. agalacticae (Group B Strep) (GPC)
- Listeria (small GPR)
- E. coli (GNR)

56

What are common pathogens in infants?

- Haemophilus (GNR/GNCB)
- S. pneumoniae (GPC)
- E. coli (GNR)
- N. meningitidis (GN diplococci)
- S. agalacticae (Group B Strep)

57

What are common pathogens in older children and young adults?

- N. meningitidis (most common) (GN diplococci)
- S. pneumoniae (GPC)

58

If ANY infection w/ N. meningitidis is left untreated, it can result in ____ ____

Waterhouse-Friderichsen syndrome

59

What occurs in individuals w/ Waterhouse-Friderichsen syndrome?

- Hemorrhaging into adrenal glands
- Rapidly fatal (12-24 hours)

60

What are the common pathogens in older adults?

- S. pneumoniae (most common) (GPC)
- N. meningitidis (GN diplococci)
- L. monocytogenes (GPR)

61

WHat are the common pathogens in immunocompromised patients?

Anything listed previously plus fungi and Nocardia

62

What are the common pathogens in brain abscesses?

- S. intermedius (most common isolate) (GPC)
- Anaerobes (Prevotella spp, Bacteroides spp)
- Enteric GNRs (E. coli, Proteus spp, Enterobacter spp, etc.)
- Nocardia spp (immunocompromised patients)

63

How is CSF stored?

Always keep at RT (22-25°C), NEVER refrigerate!

64

Common causes of meningitis

Bacteria

65

Common causes of aseptic meningitis

Viruses (no growth on cultures)

66

Common causes of chronic meningitis

Fungi