Med Neuro Diseases

Front 1

Rachischisis

Back 1

Developmental malformations of the spinal cord that arise due to failure of neural tube closure

Front 2

Anencephaly

Back 2

failure of rostral neuropore to close- rarely survive and frequently terminated which makes incidence hard to calculate

Front 3

Spina Bifida

Back 3

Refers to developmental defects in caudal vertebral column, meninges, and/or spinal cord. Two types: spina bifida occulta and open spina bifida

Front 4

Spina Bifida Occulta

Back 4

Vertebral defect can only be seen on x-ray or MRI. There may be however dimpling of the skin or a hairy patch at the base of the spine

Front 5

Open Spina Bifida

Back 5

meninges, spinal nerves, and spinal cord connected to the overlying skin of the back

Front 6

Meningocele

Back 6

Meninges are fused with overlying skin in pouch containing CSF

Front 7

Myelomeningocele

Back 7

Meninges fused with overlying skin in pouch containing CSF and the pouch also contains spinal nerves or in the most severe form includes spinal cord in contact with skin as caudal neural tube has not closed

Front 8

Causes of Neural Tube Defects

Back 8

Mothers of one infant have 10x the background risk for another, but often born into families with no history suggesting an environmental factor w/in the first 16 weeks of pregnancy

Front 9

Holoprosencephaly

Back 9

Failure of the prosencephalon to differentiate into forebrain and diencephalon during the 2nd gestational month

Front 10

Microcephaly

Back 10

Brain is small in size due to a defect in neuronal prolferation. Because of the small size of the brain, the skull is also small

Front 11

Lissencephaly

Back 11

"Smooth Brain", rare, gene-linked brain malformation characterized by the absence of normal convolutions in the cerebral cortex and an abnormally small head. It is caused during embryonic development by defective neuronal migration

Front 12

Pachygyri

Back 12

In this condition the gyri of the brain surface are broad, shallow, and reduced in number also as a result of a defect in neuronal migration

Front 13

Polymicrogyria

Back 13

Characterized by numerous small gyri due to interference in neuronal migration

Front 14

Cortical Heterotopias

Back 14

Characterized by islands of neurons in abnormal location along their migration route due to arrest in their migration process. The extent of heterotopias determines the degree of neurological impairment and seizures

Front 15

Fetal Alcohol Syndrome

Back 15

Widespread apoptosis during the last months of gestation caused by NMDA antagonization and GABA (A) agonism. Other drugs can cause this as well (ketamine, PCP, anxiolytics, etc.). Absent corpus callosum

Front 16

Structural Imaging of the BBB

Back 16

Contrast dyes (gadolinium) that only enter the brain at sites of BBB compromise

Front 17

Functional Imaging of the BBB

Back 17

Radioactive compounds to study transport, blood cell movement.

Front 18

Cloudy CSF

Back 18

May indicate presence of leukocytes, RBCs or elevated proteins

Front 19

Normal Protein Content Levels of CSF

Back 19

Normal-15-45mg/dL

Levels above 150mg/dL is indicative of CSF bacterial or viral infection or breach of the BBB

Front 20

Blood Cell Count in CSF

Back 20

Neither red nor white blood cells are characteristic of CSF. A white blood cell count greater than 3 per CC is indicative of inflammation. In bacterial meningitis, white count may be 1,000-fold higher than normal

Front 21

Hyperkalemic Periodic Paralysis

Back 21

Periodic paralysis brought on by heavy physical work and associated with raised plasma potassium concentrations (from diet, bananas). During attack muscle fibers with abnormal Na+ channels are depolarized and unable to fire AP. Voltage gated sodium channels are not fully inactivating after a depolarization so there is a constant Na+ current and therefore a slight depolarization which leads to muscle fibers being in-excitable for a period of minutes or hours and probably leads to paralysis

Front 22

Myotonia

Back 22

Mutation in Cl- Channel. Muscles of patient take an unusually long time to relax following contractions. Mutated channel increases resistance and muscle fibers take longer to repolarize. Resting membrane potential becomes dominated by K+ concentration so that small changes in extracellular K+ concentration cause more depolarization than normal. Now, a stimulus that would cause a single AP now causes multiple AP which is why the contraction lasts longer

Front 23

Hypokalemic Periodic Paralysis

Back 23

Autosomal dominant disorder. Mutation in the voltage gated calcium channel. Patients have episodes of muscle weakness and this usually appears in their teen years. Their muscles have low resting potentials and action potentials with little overshoot. Patients have Ca currents with enhanced inactivation

Front 24

Episodic Ataxia

Back 24

channelopathy in which a single AA mutation in potassium channels causes generalized ataxia during emotional or physical stress

Front 25

Multiple Sclerosis

Back 25

Symptoms: sensory and motor issues. Visual problems, fatigue or chronic pain, changes in sensation, muscle weakness, difficulties with coordination and balance, cognitive impairment.
Diagnosis: MRI shows demyelinated areas. CSF analysis shows evidence of chronic inflammation, and evoked potentials
Possible causes: Specific genes have been linked. Hygiene hypothesis- exposure to several infections agents early in life is protective against MS. Decreased vitamin D. Severe Stress

Front 26

Guillain-Barre Syndrome

Back 26

Inflammatory process that usually begins a week or so after a viral infection. Infection triggers an immune response that causes macrophages to attack PNS myelin. Patients may become progressively weaker and eventually fully paralyzed.
Diagnosis: rapid development of muscle paralysis, areflexia, absence of fever, and a likely inciting event. CSF is used to verify symptoms

Front 27

Wallerian Degeneration

Back 27

the axonal degeneration that occurs in the axon segment distal to the axotomy. The target neurons may also degenerate

Front 28

Retrograde Chromatolysis

Back 28

reaction of the cell body to axotomy. Inhibitors of protein synthesis can block axotomy-induced apoptotic cell death

Front 29

Factors affecting the response to axotomy

Back 29

Site of axotomy (closer to cell body = bad)
Age- embryonic and neonatal (less likely to survive)
Sustaining collaterals- other collaterals may be receiving trophic factors retrogradely

Front 30

Axon compression or crush

Back 30

i.e. due to a tumor, ventricular swelling

can elicit a similar response at the cell body as axotomy

Front 31

Deafferentation vs Denervation

Back 31

Deafferentation refers to the removal of the electrical and/or physical input to another neuron

Denervation refers to the removal of the electrical and/or physical input to a non-neural