CNS infections Flashcards
What is meningitis
Infection of meninges and cerebrospinal fluid space
What is encephalitis
Infection of brain parenchyma
What is meningoencephalitis
Infection of the brain and Meninges
Main route of infection of the meninges and csf
Hematogenous most common
Direct in plantation from trauma lumbar puncture corneal transplant etc.
Local extension from sinuses
Peripheral and cranial nerves from viruses
Classification of meningitis
Acute pyogenic meningitis - bacterial purulent
acute aseptic meningitis- viral lymphocytes
chronic meningitis- bacterial , fungal
Main part of the brain affected by pachymeningitis
Dura
Main cause of acute pyigenic meningitis in each age group
Neonates E. coli Group B streptococcus
Infant and young children influenza
Older children and adolescents and young adults and meningitidis
Elderly network pneumococci
Route of transmission of a cute pyogenic meningitis
Hematogenous
bacteria from airways
Direct trauma
Basal fracture or brain surgery
Macro Morphology of acute pyogenic meningitis
Brain swollen congested Meninges clouded meninges Purulent exudate accumulation on convexity’s or basal Ventriculitis
Micro morphology of acute pyogenic meningitis
Acute inflammatory exhibit exudatein subarachnoid space and within Pia and arachnoid matter
Lumbar puncture findings in acute pyogenic meningitis
Cerebrospinal fluid cloudy increased pressure increased cell polymorphs increaesed protein Decreased glucose
Symptoms and signs of a cute pyogenic meningitis
General malaise Fever meningeal irritation agitation irritability headaches clouded sensorium photophobia stiff neck Kernig’s sign
Complication of a cute pyogenic meningitis
Adhesion from fibroblastic proliferation -> constrict cranial nerves , obliterates subarachnoid space -> cause hydrocephalus, deafness ,blindness
Arteritis and pheblitis -> thrombosis and micro infarct-> intracerebral abscess and convulsions
Main causes of aseptic meningitis
Viral 70%
Viruses types involved in aseptic meningitis
Enteroviruses -echo ,Coxsackie
EBV
herpes simplex
mumps
Cerebrospinal fluid findings in viral aseptic meningitis
Increased lymphocytes
increased protein
sugar content normal
negative culture bacteria and fungi
Findings of chemical aseptic meningitis
Increased polymorphs
increased Protein
normal sugar
no organism
Morphology of aseptic meningitis
Swollen brain
moderate to mild lymphocytic infiltration of meninges
Main causes of brain abscess
Direct implantation of organism during trauma surgery ,needle biopsy ,
local extension from Adjacent Foli like sinusitis, otitis
hematogenous from heart valve septic emboli from endocarditis like abscesses
Organisms involved in brain abscess
staphylococcus
Streptococcus
Anaerobes
Symptoms and signs of brain abscess
Progressive focal deficits
raised intracranial pressure
CSF findings of brain abscess
Increased pressure leukocyte pleocytosis
increased protein
normal sugar
MacroMorphology of Brain abscess
Discrete lesions
central liqueFactive necrosis surrounded by fibrous and edema
Complication of brain abscess
Rupture
Increased intracranial pressure causing herniation
What is subdural empyema
Collection of pus in the subdural space from spread of bacterial or fungal infection of skull, bones or air sinuses
Complication in subdural empyema
Space occupying lesion _> thrombophlebitis of bridging veins crossing subdural space -> venous occlusion ->infarction of brain
Clinical symptoms of subdural empyema
Fever
headache
neck stiffness
focal neurologic deficit’s
Csf findings in subDural empyema
cerebrospinal fluid under pressure
increase White cell
increased proteins
normal glucose
Main association to extradural abscess
Osteomyelitis of skull bones after otitis ,sinusitis ,trauma ,surgery
Form of chronic meningoencephalitis seen in adults with HIV
Tuberculous meningitis
How does tuberculous get to the brain
hematogenously spread from primary focus usually in the lung
Microscopic presentation of tuberculous meningitis
Granuloma that gets in sub arachnoid space
Shaggy necrotic yellowish exudate at the base of the brain
Arachnoid fibrosis
Why is there a cranial nerve palsies in tuberculous meningitis
Arachnoid fibrosis and compression of cranial nerves and brainstem
Why is there a Hydrocephalus in tuberculous meningitis
Due to obliteration of subarachnoid space
Presentation of tuberculosis meningitis
cranial nerve palsies Hydrocephalus obstructive hydrocephalus vasculitis parenchymal granulomas tuberculosis abscesses tuberculosis cerebritis Pachymeningitis spinal cord infection
Clinical presentation of tuberculous meningitis
Malaise
headache
mental confusion
vomiting
CSF findings of tuberculosis meningitis
Pleocytosis - mononuclear or mixture of mononuclear and polymorphs
increased protein levels
glucose is reduced or normal
Micro morphology of tuberculous meningitis
Subarachnoid space gelatinous or fibrous exudates
discrete whitish granules scattered over meninges
tuberculosis granulomas with central caseation
What is tuberculoma
Well circumscribe intraparenchymal mess associated with meningitis
central caseation necrosis surrounded by granuloma
sometimes calcification
Percentage of cases of syphilis leading to neurosyphilis
30%
Route of spread of syphilis
Hematogenous
Stage of syphilis with neurosyphilis
Second stage
Stage of syphilis in meningovascular syphilis or parenchymal syphilis
3 stage
Meningovascular syphilis micro morphology
Lymphocytes and Plasma cell infiltration in meninges
Complications of Meningovascular
Scarring leading to nerve compression and hydrocephalus
Obliterative endarteritis-> parenchymal infarction -> stroke
Tissue invaded in paretic neuro syphilis
Parenchyma
Morphology of paretic neuro syphilis
Loss of neurons
Hyperplastic neuroglia
Peribascular inflammatory infiltrate
Clinical presentation 15years after trepanoma infection
Progressive dementia
Mood alteration
Delusion
General paresis of insane
What’s tabes dorsalis
Locomotor ataxia from spinal corD involvement in infection with syphylis
Damage occurring in tabes dorsalis
Dorsal root damage
Loss of myelin axon
Clinical presentation of tabes dorsalis
Ataxia - Impaired joint position Loss of pain sensation Lightening pains in limbs Loss of deep tendon reflexes Urinary retention Argyll Robertson pupils
Most common fungal infection of brain in ´HIV
Cryptococcus
Cryptococcus Brain morphology
Soap bubble appearance
no inflammation
In which patient do you have brain fungal infection called mucormycosis
Diabetics with dka
Immunocompromised
Common parasitic infection of brain
Toxoplasmosis
Plasmodium
Cysticercosis - tænia solium
Route of spread of viral encephalitis
Hematogenous
Peripheral nervesn
Types of p primary enceophalitis
Acute viral infections
Persistent viral infections
Slow viral infections
Why is there CNS damage in encephalitis due to virus
Direct destruction of tissues ( slow viruses. )
Cell lysis by immune rxns
Immune complex in vessel walls
autoimmunity to myelin
Csf finding in viral encephalitis
Increased mononuclear cells
Normal glucose
Raised or normal protein
What is tropism in viral encephalitis
The fact that many viruses are site specific so infect specific part of brisn
Area of Brain infected by heroes zoster
Dorsal root ganglion
Area of Brain infected by polio
Anterior horn cell
Area of Brain infected by papova virus
Oligodendrocytes
Area of Brain infected by rabies
Neurones
Area of Brain infected by hsv2
All cells
Inferior frontal m temporal lobe
Virus infection that can lead to post encephalitic Parkinsonism
Influenza
Virus infection that can lead to congenital malformations
Rubella
Histology of viral infections
Peri vascular mononuclear infiltrate
Glial nodules with microglial and lymphocytes
Neuronophagia - macrophages cluster around dead neurons
Intranuclear and intracytoplasmic inclusions
Cowdry A - intranuclear eosinophilic inclusion with hyaline of granular appearance with halo
Cowdry B - small round indistinct intranuclear inclusion
Virus that cause the most encephalitis and spread to spread person
Enteroviruses
Polio manifestation in CNS
Large motor neurones in spinal cord and brainstem -> Lower motor neurons paralysis
Polio micro morphology
neurones loss
Gliosis loss
AStrocytes loss
Neurogenic atrophy of muscle
Causes of death in polio I
Respiratory muscle paralysis
Myocarditis
Coxsackie virus presentation in the CNS
Meningoencephalitis
myocarditis
Mumps CNS presentation
Mild transient meningitis
Ganglion affected by herpes type one
Trigeminal ganglion
CNS Presentation of herpes virus 1
Focal neurologic deficit bizarre behavior seizures impaired sensorium coma
Microscopy morphology of herpes virus one
hemorrhaging necrosis l
edema
Cowdry a inclusions
Effective treatment of herpes virus one
Acyclovir
Ganglia with herpesvirus 2
Sacral ganglia
CNS presentation of herpes virus 2
Necrotizing encephalitis in AIDS patients
encephalitis in 50% newborns
severe meningitis ,necrotizing encephalitis
Ganglia with varicella zoster
Dorsal root ganglia
Can can you have encephalitis with varicella zoster
Rarely
Presentation of CMV
Syndrome of microcephaly Periventricular calcification hepatosplenomegaly Purpura Pneumonitis choroidoretinitis
Animals involved in rabies bite
Animal like dog cat fox bat
Incubation period of rabies
1-3 months
symptoms of rabies
Headache fever malaise
Progression to profound sensitivity , pain, convulsions photophobia ,coma and death
Rabies morphology
Edematous brain
congested brain with neuronal degeneration especially in basal ganglia ,midbrain ,and the floor of the fourth ventricle
What is the diagnostic criteria in micro morphology of rabies
Negri bodies(70% cases) - Intracytoplasmic multiple rounds to oval eosinophilic inclusions
What can cause persistent viral encephalitis
Chronic viral infection like in measles
CNS presentation of measles
Intellectual deterioration personality change involuntary movements gait disturbances eventual death in months to 2 to 3 years
Immunoglobin presents highly in measles
IgG
Morphology of measles
Granular firm brain
perivascular and parenchymal infiltration by inflammatory cells
inclusion bodies mostly in oligodendrocytes but also neurons and astrocytes
neuronophagia
Nerve cell loss
Dense fibrillary gliosis
Why can’t measles virus be cleared and therefore spreads in the brain
Because csf do not have M proteins antibodies so produce defective virus
Type of encephalitis in in persistent viral encephalitis
Sub acute sclerosing panencephalitis
Virus involved in slow virus infection causing progressive multifocal leukoencephalopathy
JC virus of Popovaviruses
JC virus infect which cell of the CNS
Oligodendrocytes
Patience affected by JC virus
Immuno compromised patients
Morphology of JC virus
Multifocal lesions in cerebrum cerebellum and spinal cord white matter
foci of demyelination
lipid laden macrophages
cystic areas sometimes in progression
enlarged oligodendrocyte nuclei with glassy amphophilic viral inclusions
bizarre giant astrocytes
Percentage of patients with eight presenting with CNS involvement
60
Syndromes CNS in HIV
Acute aseptic meningitis and encephalitis
subacute encephalitis
Vacuolar myelopathy
peripheral neuropathy
Percentage of HIV patients with aseptic meningitis
10
What is the cause of 2/3 of aids patients developing dementia
Subacute encephalitis also Cold aids dementia
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