Diseases/Infections Visible in CSF

Question 1

Bacterial Meningitis: Adults

Answer 1

• Community-acquired: Streptococcus pneumonia, Neisseria meningitides, and Listeria monocytogenes
• Hospital-acquired: staphylococcus and gram negative bacilli

Question 2

Bacterial Meningitis: Children

Answer 2

• Group B streptococcus

Same as adults:

• Gram negative bacilli
• Strep pneumoniae
• Neisseria meningitides

Question 3

Bacterial Meningitis: Neonates

Answer 3

• E coli

Same as adults/children:

• Other gram negative bacilli
• Group B Streptococcus

Question 4

Fungal Meningitis

Answer 4

• Cryptococcus
• Histoplasma
• Candida

Usually in immunocompromised patients

Question 5

Cryptococcus in CSF

Answer 5

• Thick clear capsule surrounding a darker core, can be seen using India Ink prep
• Narrow neck when budding
• Slightly larger than histoplasma
• Round to oval yeast, can have “starburst” morphology due to cytospin artifact (looks like sea urchin)
• Variable in size 5-20um

Question 6

Trypanosomes in CSF

Answer 6

• Small and very pale-staining
• Found in CSF in advanced trypanosomiasis (African Sleeping Sickness) transmitted by the Tsetse fly

Question 7

Sporothrix shenkii in CSF

Answer 7

• Fungus normally infects cutaneous and subcutaneous tissue
• Infection usually occurs after inoculation of soil through the skin

Question 8

Naegleria fowleri in CSF

Answer 8

• Causes Primary Amebic Meningoencephalitis
• Presents with fever, stiff neck and lethargy, progessing to coma and death
• 10-30um organisms with a small nucleus
• Cytoplasm somewhat granular and can have vacuoles and ingested RBCs

Question 9

ALL appearance in CSF

Answer 9

Lymphoblasts are present in the CSF with the following features:

• About 2x size of mature lymphocyte
• Indistinct nucleoli
• Slightly irregular nuclear contours
• Scant basophilic cytoplasm
• Cytoplasm may contain vacuoles or granules (<10%)

Question 10

AML appearance in CSF

Answer 10

• Cells have large nuclei with immature chromatin and prominent nucleoli (more irregularly shaped compared to typical blasts)
• Some nuclei may be bilobed (sometimes referred to as “angel wings” or “butterfly” shaped
• Cytoplasm is granular, often with larger purple primary granules
• Often see one to many Auer rods

Question 11

Lymphoma appearance in CSF

Answer 11

• High-grade lymphomas include a distinct population of large cells with prominent nucleoli and irregularly shaped nuclei
• Cells with have more coarse, clumpy chromatin compared to blasts

Question 12

Medullaoblastoma in CSF

Answer 12

The cells are larger and irregular and more clumped together than you would expect to see for blasts