Lecture 2 Neuropathology of CNS Infections Flashcards

1
Q

How do infectious organisms access the CNS?

A
  1. hematogenous spread
  2. local extension (middle ear)
  3. retrograde transport
  4. direct implantation (surgery)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Pachymeningitis

A

spread of infection into layers of the dura mater

-“pachy” = thick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Meningitis/Leptomeningitis

A

inflammation of the pia and arachnoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does lepto mean

A

“thin”…so leptomeningitis = thin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Encephalitis

A

inflammation of the brain parenchyma with MONONUCLEAR cells

-usually caused by VIRAL agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mononuclear infiltration of brain parenchyma

A

Encephalitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cerebritis

A

inflammation of the brain parenchyma with neutrophils

-usually caused by a bacterial agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Polynuclear infiltration of brain parenchyma

A

Cerebritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Myelitis

A

inflammation of the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Poliomyelitis

A

inflammation of spinal gray matter (like the ventral root/horn)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Ganglionitis

A

inflammation of the dorsal root ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Radiculitis

A

inflammation of the intradural spinal nerve roots

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is granulamatous inflammation associated with in brain?

A
  • mycobacteria
  • spirochetes
  • fungi
  • parasites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are microglial nodules associated with?

A

Viral encephalitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the most common bacterial infections?

A
  1. Acute bacterial meningitis ACUTE
  2. Bacterial abscess ACUTE
  3. Mycobateria (tuberculosis) CHRONIC
  4. Multisystem bacterial infections CHRONIC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What layer of the brain most commonly gets fucked in bacterial CNS infections?

A

Subarachnoid space (leptomeningitis/meningitis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the most common bacteria that cause acute bacterial meningitis in NEONATES (0-6months)?

A
  1. Group B Streptococcus
  2. E. coli
  3. Listeria monocytogenes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the most common bacteria that cause acute bacterial meningitis from 6mos – 60 years?

A
  1. Streptococcus pneumonia
  2. Neisseria meningitides
  3. Haemophilis influenza
    (accounts for 80% of all cases)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the most common bacteria that cause bacterial meningitis in >60 y.o. and immunosuppressed patients?

A
  1. Strep pneumonia

2. Listeria monocytogenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does acute bacterial meningitis present in gross examination? histological examination?

A
  1. Pus

2. Polys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are abscesses?

A

Focal, destructive lesions of the brain parenchyma due to necrosis
Mediated by ACUTE inflammation in response to bacterial infection
Bacterial meningitis = second most common CNS infection?

22
Q

What is most common CNS infection? Second most?

A
  1. bacterial meningitis

2. bacterial abscess

23
Q

What are the characteristics of brain abscesses and what are the most common organisms?

A

Transmitted either locally (sinusitis otitis) or hematogenously (septic or cardiac emboli)
-infectious emboli can travel from heart
Oragnisms:
-staph
-streptococci

24
Q

-What are the three most common causes of bacterial chronic inflammation?

A
  1. Mycobacterium tuberculosis (most common)
  2. Neurosyphilis (Treponema pallidum)
  3. Neuroborreliosis (Borrelia burgdoferi … Lyme disease)
25
Q

What are the symptoms of CNS TB?

A

Meningitis present over 2-3 weeks

  • combination of headache, lethargy, nausea and vomiting
  • involves CRANIAL NERVE PALSIES
  • lymphocytosis in CSF
  • affects basal part of brain, hence cranial nerve involvement
26
Q

What organism causes neurosyphilis?

A

Treponema Pallidum

27
Q

What are the three symptomatologies of neurosyphilis?

A
  1. Meningovascular neurosyphilis (chronic basal meningitis…lots of lymphocytes seen)
  2. Paretic neurosyphilis (fucks with cerebral cortex, loss of neurons, gliosis and microglia proliferation
  3. Tabes dorsalis (Treponema pallidum spirochetes invade the dorsal columns)
28
Q

What are symptoms of neuroborreliosis (Lyme disease)?

A

Caused by spirochete Borrelia burgdorferi

  • facial nerve palsy
  • polyradiculitis
  • encephalopathy
  • aseptic lymphocytic meningitis
29
Q

What are the four most classic manifestations of viral infections?

A
  1. Aseptic meningitis (meninges)
  2. Polioencephalitis/poliomyelitis (grey matter)
  3. Panencephalitis/panmyelitis (grey and white matter)
  4. Leukoencephalitis (white matter)
30
Q

What are most cases of aseptic meningitis caused by?

A

Enteroviruses

-less severe than bacterial

31
Q

What are arboviruses?

A

Arthropod Born viruses
RNA motherfuckers
Causes SEASONAL acute viral encephalitis

32
Q

What are the common causes of ACUTE viral encephalitis?

A

SEASONAL, ARBOVIRUSES
-West nile virus, Japanese encephalitis, St. Louis encephalitis, Eastern/Western equine encephalitis
NONSEASONAL:
-HSV 1, 2, 6; VZV; EBV; CMV; Rabies; H1N1

33
Q

What are the four pathological features of acute viral encephalitis?

A
  1. perivascular lymphocytic infiltrate
  2. neuronophagia (ingestion of dying neurons by macrophages)
  3. Intranuclear viral inclusions
  4. Microglial nodules
34
Q

What are the delineating features of herpetic encephalitis (HSV-1)?

A

Necrosis of TEMPORAL LOBES

-bilateral, asymmetrical hemorrhagic necrosis

35
Q

When you see bilateral, asymmetrical hemorrhagic necrosis of the temporal lobes, think what?

A

HSV-1

-most common cause of encephalitis

36
Q

Where do you see CMV encephalitis most commonly?

A
  1. Intrauterine infection (congenital CMV)

2. Immunosuppression (post-transplant, HIV)

37
Q

What is the significance of VZV encephalitis?

A

Very rare viral cause of encephalitis

  • seen in zoster patients of advanced age or immunosuppressed patients
  • causes granulamotous arteritis mimicking CNS vasculiitis
38
Q

What are key characteristics of rabies encephalitis?

A
  1. negri bodies
  2. can be furious (insomnia agitation, aggressive behavior) or dumb rabies (ascending paralysis of one or more limbs, simulating Guillain-Barre)
39
Q

What do negri bodies look like histologically?

A

Round to oval eosinophilic inclusions in neuronal cytoplasm of Purkije cells, hippocampal pyramidal neurons

40
Q

What is the DDx of ringed lesion in brain?

A

Bacterial Abscess OR fungal infection

41
Q

What are the most common fungal infections of CNS?

A
  1. Cryptococcus neoformans (in immunosuppressed hosts)
  2. Aspergillosis (hemorrhagic infarcts)
    • hemorrhage  abscess  capsule/granulomas
  3. Zygomycosis (seen in diabetic ketoacidotic patients…seizures)
    - immunocompromised patients
42
Q

What are the most common parasitic infections?

A
  1. Amoebic encephalitis (Naegleria fowleri)

2. Cysticercosis (cysticerci from taenia solium)

43
Q

What is the classic helminthic (worm or worm parasite) organism that lives in brain?

A

Cysticerci

-larvae of Taenia solium, a tapeworm

44
Q

What are Naegleria fowleri?

A

An amoeba that is transmitted through olfactory bulbs

-causes fulminant, acute meningoencephalitis

45
Q

What is cysticerosis?

A

Most common helminthic CNS disease
Caused by cysticerci
Causes a shitload of cysts

46
Q

What are the most common CNS infections of the immunocompromised hosts?

A
  1. cryptococcal meningitis
  2. taxoplasmosis
  3. HIV encephalopathy
  4. Progressive multifocal encephalopathy
47
Q

What are the delineating characteristics of cyrpotococcal meningitis?

A
  1. most common cause of fungal meningitis
  2. Identified in CSF via India ink
  3. Produces cystic dilations of VIRCHOW-ROBIN spaces (“bubbles) with little surrounding gliosis/inflammation
  4. fever, debility, headache, irritability, insomnia…can worsen over weeks, months or years
48
Q

Domestic Cats

A

Definitive host for toxoplasma gondii

-leads to ring-enhancing lesions/brain abscesses

49
Q

What are key characteristics of HIV encephalitis?

A
  1. multinucleated giant cells
  2. leukoencephalopathy with patchy demyelination and variable gliosis
  3. low-grade inflammation with perivascular and parenchymal lymphocytes/microglial nodules
50
Q

What is leukoencephalopathy?

A

A type of change associated with WHITE matter

51
Q

What are the delineating features that separate fungal and viral meningitis?

A

CSF composition

52
Q

What are the key characteristics of progressive multifocal leukoenceophalopathy

A

Caused by: JC = John Cunningham Virus; Polyomavirus JC

  • tropism for oligodendroglia…WHITE MATTER ONLY BITCHES
  • ill defined demyelinating lesions; lipid laden macrophages; intranuclear viral inclusion; bizarre astrocytes with atypia