Neuropathology Flashcards
CNS is normally sterile.
How can microorganisms gain entry? list 3 possible routes;
- Direct spread – e.g. middle ear infection, base of skull fracture
- Blood-borne – sepsis, infective endocarditis, bronchiectasis
- Iatrogenic (by us)– V-P shunt, surgery, lumbar puncture
what is leptomeninges ?
Bacterial meningitis
- causative organisms in different age groups?
- symptoms?
- complications?
- occurs secondary to?
- Diagnosis?
inflammation in the subarachnoid space involving the arachnoid and pia mater, (leptomeningitis)
The WORRY IS>> Can occur With or without septicaemia > causes death!
u can someone w/ not much meningitis but they SEPSIS
must treat quickly even if u dont know the organism!
Causative Organisms
- Neonates: E.coli, Strep. agalactiae, Listeria monocytogenes
- 2–18 years: N. meningitidis , H Influenza
- over 30 years: Strep pneumoniae .
Complications
- DEATH>> Raised ICP
- cause precocious puberty & ADH deficiency
- Waterhouse–Friderichsen syndrome
- cerebral infarction
- obstructive hydrocephalus
- cerebral abscess
- subdural empyema
- epilepsy.
secondary to
- Mastoiditis
- acute otitis media
Diagnosis
- Examination of the CSF in lumbar puncture
- Waterhouse–Friderichsen syndrome (WFS): is defined as bilayeral adrenal gland failure due to bleeding into the adrenal glandsing lumbar puncture (adrenal hemmorhage)*
describe this
Bacterial meningitis: basal exudate.
example of pyogenic meningitis, acute inflammatory exudate is present around the brainstem, cerebellum and adjacent structures at the base of the brain.
Obstruction of the fourth ventricle exit foramina resulted in acute hydrocephalus in this case.
Chronic Meningitis
common cause
Slow nonpurulent infection, dont get the typical symptoms of meningitis
TB infects the meninges caused by> M. tuberculosis
- Granulomatous inflammation
- Fibrosis of meninges
- traps cranial nerve> cranial nerve palsy’s
- scar tissue
doesnt present the same way as bacterial meningitis
Leptomeningitis vs Pachymeningitis
Pachymeningitis is usually a consequence of direct spread of infection from the bones of the skull following otitis media or mastoiditis, and is a well-recognised complication of skull fracture
Leptomeningitis (‘meningitis’) frequently results from blood-borne spread of infection, particularly in children, but many cases arise from direct spread of infection from the skull bones
what is this? how did it ccur?
Cerebral abscess
Abscess formation occurs when pus is accompanied by local tissue destruction, pyogenic membrane is formed and the abscess develops a capsule composed of granulation tissue
- condition?
- causes?
- main areas of brain affected?
- symptoms?
Encephalitis
Infection of the brain parenchyma itself
microscopy
Inclusion bodies
Causes
- viral not bacterial! virus takes over cell & cell death!
Symptoms
- mild flu-like signs and symptoms — such as a fever or headache — or no symptoms at all
microscopy
Cytomegalovirus (CMV)
Causes encephalitis
abnormal inclusions>> looks like “owls eyes”
eventually leads to cell death
what r Prion-related diseases?
group of rare transmissible neurodegenerative disorders
Prions: normal proteins present in the synapses of all of us, important for normal synaptic function
In prion diseases, these proteins become mutated or abnormal:
- theyre either produced abnormally (genetic)
- INHERIT genetic mutation
- or u ingest it
what r prions? how do u develop prion diseases?
In prion diseases, these proteins become mutated or abnormal.
- They’re either produced abnormally (genetic)
- INHERIT genetic mutation
- or u ingest it
Mutated PrP interacts with normal PrP to undergo a post translational conformational change >> aggregates>> NEURONAL CELL DEATH
what r prion diseases also called? why?
PrPSC aggregates >> Neuronal death>> “holes” in grey matter (as ur neurons drop out)
Spongiform encephalopathies > cuz brain looked like sponges
Creutzfeldt–Jakob disease (CJD)
microscopy
Creutzfeldt–Jakob disease (CJD) usually presents in late adult life as a rapidly progressive dementia accompanied by myoclonus, visual abnormalities and ataxia
The brain in CJD often shows no macroscopic abnormalities, the cerebral cortex shows a characteristic spongiform vacuolation ( arrows ) accompanied by neuronal loss and reactive astrocytosis.
how is vCJD (Variant Creutzfeldt–Jakob disease) linked to butchery?
A new variant form of CJD was identified in the UK in 1996, affecting young patients (average age 28 years). This disease results from oral infection by the bovine spongiform encephalopathy (‘mad cow’ disease)
the brain and spinal cord were found in the animal meat,animal was butchered w/ the brain & spinal cord insitu>> which caused the infected nervous system to become contaminated>humans eat it> infected
has a long incubation period
Dementia
Dementia:
is an umbrella term used to describe an aquired range of progressive neurological disorders, that is, conditions affecting the brain
Acquired global impairment of intellect, reason and personality without impairment of consciousness
common type of Dementia?
others?
– Alzheimer’s (50%) >> Sporadic (just get it, no fam history) or Familial, Early 50-60 age/Late 70 onwards
– Vascular dementia (20%)
– Lewy body
– Picks disease
what type of Alzheimer’s disease is common?
Sporadic Late!
Vascular Dementia (explain)
insufficient blood supply to brain> neurons ischemic> dementia
types of brain hernia’s
defiine hernia
Hernia: A protrusion of an organ or part of an organ through wall that normally contains it
what is the most common brain hernia?
Subfalcine Herniation
type of hernia? symptoms? what parts of brain can be affected & why?
Subfalcine Herniation
- Same side as mass
- Cingulate gyrus pushed under the free edge of the falx cerebri
- Ischaemia of medial parts of the frontal and parietal lobe and corpus callosum due to compression of ACA >> Infarction
Can be asymptomatic or headache & contralateral leg weakness if ACA affected
What is a Transtentorial Herniation? What is an alternate name? What can be compressed & how is it manifested?
Uncus gyri hippocampi is herniated underneath the free edge of the Tentorium notch
- Alternate = Uncinate Hernia
- compresses MIDBRAIN
- Occlusion of BF in PCA and superior cerebellar arteries
Symptoms> think of where it is compressing!
- oculomotor N. = dilation of the Ipsilateral dialted Pupil + abnormal eye movement on the same side (dilation bc u have parasympathetic hitch-hiking on oculomotor)
- Compression of cerebral peduncle – contralateral leg weakness
- compressing on arousal centres> Decreased level of consciousness
- FATAL BC OF SECONDARY HEMMORHAGE IN BRAINSTEM
what do u see? complication of what?
Duret Haemorrhage into Midbrain and Pons
- due to pressure from tentorial Herniation
- many pathways run here>> patients get neurological problems
- Duret haemorrhages: r small lineal areas of bleeding in the midbrain and upper pons of the brainstem*
Tonsilar herniation
Cerebellar tonsils herniate through foramen magnum compressing the:
◦ medulla & upper spinal cord
◦ Brain stem affected>> cardiac & respiratory dysfunction
◦ Decreased level of consciousness
whats this? effects and symptoms?
Not really a brain tumor
Benign Meningioma
squashes onto brain!>> may causes headache, epilepsy too
- Meningiomas are smooth lobulated masses, which are broadly adherent to the dura*
- easy to get meningioma out via surgery*
what is this?
Malignant Astrocytomas
Astrocyte origin
Spread along nerve tracts and through sub arachnoid space often presents with a spinal secondary
benign and maliganat
can kill patient lana itll grow and grow and push brain, does not have well demarcated edges so its hard to remove it via surgery
how r tumors classified? most common location?
tumours of the CNS are classified according to their cellular differentiation and presumed cell of origin:
They don’t metastasize like regular tumors into lymph node, rather they metastasize to near by cns structures
Tend to be MIDLINE or POSTERIOR region
- ◦ Raised ICP*
- ◦ Hydrocephalus*
Causes of raised ICP
Cushings reflex
is a physiological nervous system response to increased (ICP) that results in Cushing’s triad of :
- increased BP >>
- Low breathing >> Ischemia at pons/medulla at respiratory centres
- Bradycardia >> Ischemia at medulla –> sympathetic activation –> Rise in blood pressure + tachycardia. Baroreceptors react –> bradycardia
so if u see increased BP and bradycardia in a patient w/ head injury…that bad knews mate)
is is the exact opposite of symptoms u see in a septic patient!
Pathophysiology of brain injury (cellular level)
why is headache worse when ur asleep (2) ? and when u cough?
rememebr… when ur standing up, venous pressure in legs is more than neck.
- when u lie flat, u increase the VR to neck and head.
- in sleep> hyperventilate>> u breath slower >> get rid of less co2, accumalation of co2 > chemoregulation> vasodilation> more volume in head>> gets worse
- Cough> increased intrathoracic p. >compress SVC > u stagnate the return of VR from ur heart to ur head .
why do u get papilledema? what causes it?
optic disc swelling that is caused by increased ICP
it is NOT an acute sign!! happens gradually w/ time
what is meant by “false localising sign”
what is a false localising sign found it? in ICP?
a sign that u think will point u to an area of patholgoy, but… madry
it is false localizing> bc u would have thought “ surely the tumor should be a lower pons tumor” but in reality…… it doesnt have to be that, it could be a tumor somewhere else in ur brain thats compressing ur whole brain.
what is shunt surgery?
(this is for u lalls for interest)
a thin tube called a shunt is implanted in the brain. The excess cerebrospinal fluid (CSF) in the brain flows through the shunt to another part of the body, usually the tummy. From here, it’s absorbed into your bloodstream.
Inside the shunt there’s a valve that controls the flow of CSF and ensures it doesn’t drain too quickly. You can feel the valve as a lump under the skin of your scalp.
Principles of management of raised ICP
Acute management of raised ICP
Idiopathic intracranial hypertension
- most common in?
- treatment?
Raised intracranial p. w/out evidence of hydrocephalus or mass lesion
- Obese young women after weight gain
- weight loss, drugs ex: CA inhibitors, CSF drainage and shunts
