pathology of nervous system Flashcards
what is anencephaly
birth defect characterized by failure of formation of upper part of neural tube
what are the risk factors for anencephaly
- folate deficiency: insufficient intake of folic acid before and during pregnancy
- maternal diabetes
- alcohol/ substance abuse
what is spina bifida
type of neural tube defect that occurs during early fetal development
- failure of posterior part of neural tube to fuse
3 main types of spina bifida
- spina bifida occulta; mildest form - small gap in one/ more vertebrae bones of spine (can appear as back dimples)
- meningocele; protrusion of membranes that cover spinal cord through vertabrae gap
- myelomeningocele; most severe/ common - when meninges and spinal cord protrude through vertebrae gap
spina bifida sagittal U/S
- break in skin - occulta
- gap in vertebrae located in midline/ posterior of spine - sagittal view in ultrasound
what is hydrocephalus
- build up of cerebrospinal fluid (CSF) in brains ventricles –> enlargement of skull and increases pressure
what are the 2 types of hydrocephalus
- congenital hydrocephalus - obstruction to flow + reabsorption
- acquired hydrocephalus - due to disease eg tumors or brain bleeds (brain doesnt enlarge)
what is communicating hydrocephalus
- ventricles + subarachnoid space freely communicating
- problem caused by lack of reabsorption of CSF/ blockage of lower subarachnoid space
what is non-communicating hydrocephalus
- blockage of flow within ventricles
- one lateral ventricle
- bilateral
by-pass procedures of hydrocephalus
- lateral ventricle into cisterna magna
- lateral ventricle into jugular vein
lumbar puncture
- method of sampling CSF
- insert fine needle between two lumbar vertabrae in lower back in subarachnoid space that contains CSF
cisternal puncture
- where lumbar puncture cannot be performed
- insert needle through back of head into cisterna magna (space at base of skull where CSF accumulates)
CSF examination
- presence of blood always abnormal
- changes in iconic concentration
- changes in protein conc
- presence of infective organisms
what can pressure be measured with for CSF examination
- measured with manometer
- increase CSF pressure –> ICP also increased
why does increase in CSF pressure increase (intracranial pressure) ICP pressure
- exist within closed fixed space of skull
- limited space in brain to accommodate excess fluid
increase in ICP effects
- papilloedema
- cerebellum may be forced through foramen magnum
- coning
- death
infections in utero
- rubella
- toxoplasmosis
- may lead to abnormalities
- may lead to mental retardation
what is meningitis
inflammation of meninges surrounding brain and spinal cord caused by infection
space occupying lesions (SOL)
- neoplasms
- subdural haematomas
- abscesses
- cysts
- aneurysms
signs and symptoms of SOL
- raised ICP
- vomiting
- headaches
- papilloedema
- sudden onset epilepsy
gilomas
- brain tumours that start in glial cells
what is an aneurysm
- distension/ enlargement of blood vessel caused by weakness in blood vessel wall
- common at branches
what is parkinsons disease
- severe loss of dopamine neurones + transporter
- SPECT binds to dopamine transporter
- helps differentiate between essential tremor and parkinsons
what is epilepsy
- sudden spread of electrical activity in brain
- commonly associated with repeated seizures
grande mal - generalized seizure
petit mal - one region of brain - can result from trauma
