CNS Infections Flashcards
Subdural empyema in which locations would require craniotomy?
Interhemispheric, subtemporal or posterior fossa
Dural sinuses most commonly involved by thrombophlebitis
Transverse
Cavernous
Petrous
Less frequently, sagittal sinuses
Organisms most often incriminated in intracranial septic thrombophlebitis
Streptococci and Staphylococci
True or False:
Anticoagulation, as in aseptic venous occlusion, has been shown to be beneficial in the treatment of intracranial septic thrombophlebitis.
False.
It is still of uncertain value but is still usually administered with high-dose antibiotics
Infection from one cavernous sinus spreads to the opposite side through which structure?
Circular sinus
Visual loss associated with septic cavernous sinus thrombophlebitis may occur without visible changes of the fundus and tend to persist. This has been associated with what finding?
Infarction of retroorbital part of the optic nerve
Brain abscess is always (90%) secondary to bacteremia and a bacterial focus elsewhere in the body except for cases of:
Compound fractures of skull
Bullet wounds
Intracranial infection
Metastatic Abscesses from hematogenous spread are usually situated in which vascular territory?
Distal territory of the MCA
Which organisms that cause endocarditis have the propensity to cause abscesses?
S. Aureus
Gram-negative bacteria
Percentage of congenital heard disease complicated by brain abscess?
5%
What congenital anomaly is most commonly implicated in brain abscess?
Tetralogy of Fallot
But abscesses may occur with any R to L shunt where venous blood enter systemic circulation without first passing through the lungs.
Which organisms, commonly implicated in bacterial meningitis, rarely cause abscess?
Pneumococci
Meningococci
H. Influenzae
The capsule of a brain abscess is frequently thinner on its
A. Medial or paraventricular side
B. Lateral or cortical side
A.
This accounts for propensity to spread in WM, produce daughter Abscesses and rupture into the ventricles.
Most frequent initial symptom of ok intracranial abscess
Headache
Other early sx in order of freq
- Drowsiness & confusion
- Focal or generalized sz
- Focal motor, sensory or speech disorders
Findings of cerebritis on MRI
Cerebritis or immature abscess appear as
Dot-sized areas of dec density that enhance with GAD
When should total excision of an abscess be attempted?
Only if:
Solitary, superficial, well-encapsulated or associated with a foreign body
Untreated, TB meningitis has a fatal outcome within _____?
4-8weeks
INH, RMP, PZA, EMB, moxifloxacin have the capacity to penetrate the BBB, however which 2 drugs have better penetration over the others?
INH and PZA
Dose of pyridoxine given to prevent neuropathy from isoniazid in TB treatment?
50mg pyridoxine daily
Anti TB drugs can be given only orally or via stomach tube except the following with parenteral forms:
INH and RMP
Cranial nerve most frequently involved in neurosarcoidosis.
CN VII or Facial nerve
True or False:
Serum reagin tests (VDRL) may be negative in neurosyphilis or those with neurosyphilis.
True.
There is seronegative syphilis.
What is Heubner arteritis and with what infection is it associated?
In secondary Neurosyphilis, inflammation and fibrosis of small arteries, usu distal territories of medium and small caliber lenticulostriate branches from MCA and ACA, that lead to narrowing and occlusion.
What is granular ependymitis?
A pathologic change in Meningovascular Syphilis wherein the ependymal surfaces of the ventricles are studded with granular elevations protruding bet ependymal cells.
Other patho changes include:
Meningeal thickening, brain atrophy, ventricular enlargement
The early/ initial skin manifestation of Lyme disease
Erythema chronicum migrans - a solitary enlarging, ring-like erythematous lesion that may be surrounded by annular satellite lesions
What is Bannwarth or Garin-Bujadoux Syndrome?
European variant of Borrelia burgdorferi infection with acute radicular pain ff by chronic lymphocytic meningitis with peripheral and cranial neuropathies
Neurologic manifestations of Lyme
Aseptic meningitis or fluctuating meningoencephalitis lasting for mos
Cranial neuropathies - about half
Multiple radicular or peripheral nerve lesions - 1/3-1/2 of patients
European:
Meningoradiculitis of the cauda equina
Also:
GBS
Proposed criteria for neuroborreliosis
4 out 5
- NO past hx of neuroborreliosis
- Active CSF ELISA serology
- Anti-Borrelia Ab index >2
- Favorable outcome after specific antibiotic treatment
- NO alternative diagnosis
What is probably the most effective antibiotic therapy for neuroborreliosis once meninges and central or peripheral nervous system implicated?
Ceftriaxone 2g daily IV x 14 days
Other than bacterial infections, the following may rarely cause in the a persistent polymorphonuclear pleocytosis of the CSF
Tuberculosis Nocardiosis Actinomycosis Aspergillus Other causes: Coccidiomycosis, Histoplasmosis, Blastomycosis
Among patients without AIDS, cryptococcal meningitis patients do not have fever on first examination in this percentage of patients
20-40%
Level of Blood Urea Nitrogen at which the administration of Amphotericin B for cryptococcal meningitis should be discontinued.
40mg/dL
AmphoB may be resumed when it descends to normal levels.
Rickettsias are maintained in nature by a cycle involving an animal reservoir, an insect vector and humans except
Epidemic typhus (only lice and human beings) Q fever contracted by inhalation
Most common cause of focal cerebral lesions in patients with AIDS
Toxoplasma
What are Dürck nodes
In cerebral malaria, small foci of necrosis surrounded by glia that dot the brain
Organism that causes cerebral malaria
Plasmodium falciparum
Amebic meningoencephalitis is practically always fatal and treatment with usual antiprotozoal agents is ineffective. What medication/s may be given instead?
Amphotericin B (same sched as for cryptococcal meningitis) + Rifampin
A dependable sign of severe malaria
Retinopathy - macular whitening, orange or white discoloration of retinal vessels, and intra-retinal blot-type hemorrhages
What is the Winterbottom sign, to which infection is it associated?
Posterior cervival adenopathy in trypanosomiasis
What is Kerandel hyperesthesia?
In African Sleeping Sickness type of trypanosomiasis, pronounced pain at sites of minor injury
Match virus with certain neuron/ NS component it has affinity to:
- Polio virus
- VZV
- Rabies virus
- JC virus
A. Brainstem neurons
B. Motor neurons
C. Peripheral Sensory neurons
D. Supporting glial cells
1B
2C
3A
4D
Most common viral cause of acute aseptic meningitis
Enterovirus: echovirus and Coxsackie virus
Followed by the ff
- HSV2
- Varicella, HIV, mumps in children, lymphocytic choriomeningitis, HSV1 & adenovirus
- EBV, CMV, leptospira, HSV1, (Mycoplasma pneumoniae), tick-borne encephalitis virus, Borrelia, arboviruses
Other viruses that can cause orchitis other than Mumps
Group B Coxsackie virus
Infectious mononucleosis
Lymphocytic choriomeningitis
Natural host of the Lymphocytic Choriomeningitis (LCM) virus
Common house mouse (Mus musculus)
Neurologic manifestations of Parvovirus in the adult esp when contracted from a child
Brachial neuritis
Encephalitis and Meningitis (B-19 strain)
Some can have strokes
In chronic persistent and recurrent meningitis, when is biopsy of the meninges suggested?
If dx not clarified in 6-12mos OR if febrile Meningitis persists for several weeks
What is Vogt-Koyanagi-Harada syndrome
Iridocyclitis Depigmentation of a thick swath of hair (poliosis circumscripta) and skin Vitiligo around eyes Loss of eyelashes Dysacusis Deafness Chronic or acute recurrent meningitis
Characterized by episodes of acute Meningitis with severe headache, low grade fever lasting about 2 weeks and recurring over several months or years.
Have been associated with HSV1 and HSV2 infection
Mollaret recurrent meningitis
Viral meningitis causes ONLY these 4 symptoms, if any other symptoms are added, the condition is called a meningoencephalitis.
Fever, headache, stiff neck and photophobia
What are the histopathologic hallmarks of viral encephalitis?
Perivascular cuffing by lymphocytes and other mononuclear leukocytes and plasma cells; patchy infiltration of the meninges with similar cells
Areas of predilection of HSV Encephalitis
Inferomedial or Lateral portions of the frontal and temporal lobes and the insula
False negative HSV PCR tests are most likely to occur during which period of the infection?
First 48 hours of febrile infection
True or False
In cases of HSV Encephalitis, coma and pupillary changes is most probably due to mass effect from the hemorrhagic necrosis and edema of the temporal lobes, regardless of whether compression is evident on imaging.
False.
The infection is capable of spreading to the mesencephalon from the contiguous deep temporal lobe and may cause coma through a direct destructive effect. Do not attribute this to mass effect unless evident on imaging.
Survival from HSV Encephalitis if treatment is begun within 4 days of illness onset in an awake patient
Greater than 90%
Virus that causes a medial temporal lobe limbic encephalitis n adult patients following allogeneic hematopoietic stem cell bone marrow transplant
Mainly HHV-6
Also the cause of roseola or exanthema subitum
Others
Adenoviruses
What are the pathologic features of Rabies?
Negri bodies - cytoplasmic eosinophilic inclusions most prominent in pyramidal cells of the hippocampus and Purkinje cells
Babes nodules - focal collections of microglia
Inflam most intense at brainstem
On top of those seen in viral encephalitis.
Post-exposure prophylaxis for rabies
Human rabies immune globulin 20U/kg
1/2 infiltrated around the wound
1/2 IM
- provides passive immunization x 10-20days
Specific zoster to which Cerebral Angiitis is most closely associated
Ophthalmic Zoster
Disseminated Herpes Zoster
Lesions in more than 3 dermatomes
First proven viral polyneuritis in humans
HIV peripheral polyneuropathy
What are the opportunistic infections and neoplasms of the CNS in AIDS?
In Approx this order of frequency: Toxoplasmosis CMV infection Primary B-cell lymphoma Cryptococcosis Progressive Multifocal Leukoencephalopathy
Two particular types of mycobacterial infection that tend to complicate AIDS
Mycobacterium tuberculosis
Mycobacterium avium - intracellulare
Organism that causes cat scratch fever
Bartonella henselae
What is quaternary syphilis
Seen among patients with HIV, Aggressive and rapidly progressive necrotizing process that causes strokes and dementia as a result of involvement of brain parenchyma and vessels.
Viruses other than the polio virus that causes an acute anterior poliomyelitis
Enteroviruses such as Coxsackie groups A and B
Japanese encephalitis
West Nile virus
Of the viruses other than polio virus that causes an acute anterior poliomyelitis, which is associated with a severe and persistent asymmetrical flaccid poliomyelitis?
West Nile Virus
Atrophy in poliomyelitis can be detected as early as A and is maximal at B?
A. within 3 weeks
B. 12-15 weeks
Earliest histopathologic changes in the anterior horn in acute poliomyelitis
Central chromatolysis of the nerve cells, along with an inflammatory reaction
Diagnosis of SSPE
Presumptive clinical case
Periodic complexes on EEG
Elevated gamma globulin and oligoclonal bands in CSF
Elevated measles titers in serum and CSF
Histopathologic hallmark of SSPE
Eosinophilic inclusions in the cytoplasm of neurons and glia
This part of the brain is usu spared in SSPE
Cerebellum
Characteristic EEG abnormality in SSPE
Periodic (every 5-8sec) bursts of 2-3/s high voltage waves, followed by a relatively flat pattern
Antibodies to the JC virus is present in approximately what percent of the normal adult population?
70%
In the non-AIDS patient PML from JC virus is untreatable. In AIDS patients however, what is the treatment that slows down progression of PML and leads to remission in almost half of patients for a year?
Aggressive treatment with anti-retroviral drug combinations, including protease inhibitors.
A poor prognostic sign for recovery in PML
CD4 count below 100cells/uL
Main pathologic findings in Encephalitis Lethargica or von economo Disease
Depigmentation of the substantia nigra and locus ceruleus because of nerve cell destruction
Neurofibrillary changes in the surviving nerve cells of the Substantia nigra and Oculomotor nuclei
Location primarily in the midbrain, subthalamus and hypothalamus
What is a prion
A proteinaceous infectious particle devoid of nucleic acid, resists actions of enzymes that destroy RNA nd DNA, fails to produce an immune response, and electron microscopically does not have the structure of a virus
In humans the prion protein (PrP) is normally encoded by a gene on which chromosome?
Short arm of Chromosome 20
Spongiform encephalopathy is associated with the conversion of a normal cellular protein PrPc to an abnormal isoform. This conversion involves ____
Change in confirmation of the protein in which the helical proportion diminishes and the proportion of B pleated sheet increases
Mechanism of infectivity of prions
Susceptibility of native PrP to alter its shape as a result of physical exposure to the abnormal protein
Most common variant of CJD? least common?
Most common is MM type 1
Least common is VV
Brownell-Oppenheimer variant
Variant of CJD that presents with cerebellar ataxia
Heidenhain variant
Variant of CJD that presents with visual disturbances preceding the mental changes
Confirmatory test for CJD and its Sn Sp
14-3-3
Sn 92%
Sp 80%
Pathology of CJD
Degeneration and disappearance of nerve cells associated with extensive astroglial proliferation;
Microscopic vacuoles within the cytoplasmic processes of glia cells and dendrites of nerve cells
Differential diagnoses for CJD that may mimic it in the early weeks of illness
Lithium intoxication Hashimoto encephalopathy Whipple disease Intravascular lymphoma Carcinomatous Meningitis Also CBD LBD SSPE limbic-brainstem-cerebellar encephalitis
The transmissible agent in CJD is resistant to boiling, formalin, alvohol and UV radiation but can be activated via any of the ff
- Autoclaving (132C at 15lbs/in2 x 1hr)
2. Immersion in 5% Sodium hypochlorite (bleach) x 1hr
Like CJD, Fatal insomnia is characterized by a methionine at codon 129 on chromosome 20 but with the addition of what other mutation?
Mutation in the prion gene at codon 178
- protease resistant form of the gene
Kuru plaques
Periodic acid-Schiff- positive stellate plaques of amyloid-like material
