NB2 8+9+DLAs Flashcards
Meroencephaly /Anencephaly
The cranial neuropore fails to fuse in week 4
skull is not formed
Brain tissue (if present) is disorganized and exposed to the amniotic fluid which causes necrosis /degeneration
Rudimentary brain stem is usually present
Elevated alpha fetoprotein; polyhydramnios
Holoprosencephaly
no cleavage of prosencephalon
small undivided forebrain and a large single fused ventricle
can have craniofacial anomalies
can be due to environmental or genetic (SHH) factors
microcephaly
Abnormally small calvaria and brain but normal sized face
reduction in brain growth
neurological deficits
can be due to genetic or environmental factors
(virus, ionizing radiation, FAS)
development of the skull
the skull develops from mesenchyme and the brain
Craniosynostosis
One or more of the fibrous sutures in an infant skull fuses prematurely thereby changing the growth pattern of the skull
Trigonocephaly
early closure of the frontal (metopic) suture
the forehead has a triangular shape
can have developmental delay, behavioral issues, vision defects
Scaphocephaly
Most frequent type of craniosynostosis
caused by the premature closure of the sagittal suture
Enlargement of the cranium in the anterior/ posterior dimensions
CT scan shows long narrow shape of the head with bossing of the frontal and occipital regions
Brachycephaly
Craniosynostosis due to the premature closure of the coronal sutures
On physical exam there might be flattening of the frontal and occipital regions
Plagiocephaly
Missing, full, or bulging “soft spot” (fontanel) on the newborn’s skull
Facial abnormalities including bulging forehead and brow on one side, uneven cheekbones, eye sockets, or lower jaw
Prominent blood vessels in the scalp
Poor feeding or projectile vomiting and Seizures
Cranium Bifidum
Defect in the formation of cranial vault usually in the midline
often in the occipital bone (foramen magnum)
Leads to encephalocele - herniation of intracranial contents
Cranium Bifidum with Meningocoele
defect in the formation of the cranial vault
usually foramen magnum
swelling will contain meninges and CSF
Cranium Bifida with Meningoencephalocoele
defect in the formation of the cranial vault usually at foramen magnum
Swelling contains meninges, CSF & brain
Cranium Bifidum with Meningohydroencephalocoele
defect at the posterior fontanelle of cranium
Swelling contains extensions of meninges, CSF, brain and ventricle
Arnold -Chiari Malformation
Most common anomaly of the cerebellum
Inferior displacement of the vermis of the cerebellum and medulla through the foramen magnum into the vertebral canal
can be associated with obstructive hydrocephalus
CN’s IX, X, and XII might be stretched causing difficulty in speech, swallowing and absent or diminished gag reflex
Arnold-Chiari Malformation symptoms and imaging
symptoms: Headaches, nausea and vomiting due to raised intracranial pressure Muscle weakness in the head and face Difficulty swallowing Impaired coordination In severe cases paralysis
imaging:
Downward displacement of cerebellar tonsils through
foramen magnum in imaging
Compression of the brain stem
Dilation of the ventricular system due to non communicating hydrocephalus
Orexigenic vs anorexigenic neuron
orexigenic:
increases hunger
stimulates ghrelin and inhibits insulin
Anorexigenic:
decrease hunger
stimulate insulin
found in the arcuate nucleus then goes to the paraventricular nuclei
NTS - found in brainstem.. goes to these two nuclei
lateral vs ventromedial nuclei (feeding)
lateral = increase in feeding
ventromedial = decrease in feeding
Ventromedial Hypothalamic Syndrome (Fröhlich syndrome)
a disorder of caloric balance characterized by obesity
(besides other symptoms). The obesity results from damage to the ventromedial nucleus of the hypothalamus
major want to eat
anterior vs posterior hypothalamus (body temp)
anterior: temp decrease
dilation of skin vessels
sweating
remove clothes
cooler environment
posterior: temp increase
constriction of skin vessels
shivering
warmer environment
add clothes
hypothermia
the body cant increase body temp
hyperthermia
body cant decrease body temp
Automatic Bladder
lesion above S2-S4 will lead to a spastic or autonomic bladder.
The patient will have reflexive emptying of the bladder once it fills and once there is threshold volume
Atonic Bladder
A lesion at S2-S4
the spinal cord cannot process the incoming filling signals of the urinary bladder and would not be able to direct a reflex voiding response via the parasympathetic fibers. So, here the bladder will just fill to the brim and the urine will overflow
pontine micturition center
facilitation of urinary discharge through activation of the parasympathetic and inhibition of the sympathetic innervation, with additional information reaching higher centers, contributing to urinary urges
