• CNS => first observable structure
• Neural tube => central axis of development
• development can be interrupted at any point and then continue normally
• 2/1000 live births have some defect

1. Spina bifida

• A general term referring to problems in the caudal neural tube.
• spina bifida occulta
• least serious
• minor vertebral arch defect
• chronic back pain, cold feet, enuresis

1. Meningocele

• equal incidence at cervical, lumbar and thoracic vertebral regions
• protrusion of a sas with CSF, lined with meninges and usually covered with intact skin.
• no neurological deficit
• Increased risk for infection and trauma
• surgical correction

1. Meningomyelocele

• similar protrusion as meningocele but contains spinal nerves and spinal cord as well as meninges and CSF.
• spina bifida cystica
• fully normal neurological function is rare
• increased loss of CSF and infections
• usually lumbar and lumbosacral regions
• neurological function below site altered (paralysis, sensory loss, loss of control of bowel & bladder)
• kidney infections

1. Anencephaly

• most common neural tube defect (2/1000)
• arise with a failure of the development of the cranial neural tube
• roof of cranium missing
• brain stem develop and function can be normal (swallowing, breathing)
• survival => few hours or days
• may be an enviromental factor (Ireland/Wales => 8/1000)
• genetic link? (more females than males)

2. CNS Infections

• any interruption of vascular, meningeal and bony protection of the CNS
• relatively rare
• infection is isolated from access/attack by immune systems
• AIDS, transplant recipients at a higher risk
• Terms:

1. Acute bacterial meningitis

• TRUE medical emergency
• 60% fatality is untreated
• 10% fatality even with aggressive treatment
• CSF has fewer lymphocytes, Ab’s and complement but does have an abundance of glucose and electrolytes.
• little host defense
• Symptoms:

• Nisseria, Phsumococcus, Hemophilus
• From upper respiratory tract infection, otitis media or pneumonia

1. Viral Meningitis

• self-limiting
• Symptoms:

• Treatment:

1. Creutzfeldt-Jacob Disease

• rapidly progressive
• fatal
• caused by an abnormal form of a normal brain protein => PRION
• disrupt brain structure and function
• long incubation period
• rapidly progressive dementia (less than 12 months)
• Infection risk (corneal transplants, growth hormone preparation, blood transfusion?)
• age of onset => mid-50’s
• may be a genetic link??

1. Reyes Syndrom

• potentially fatal post-viral condition
• link to the administration of aspirin in children (6-15 months) for the flu
• Symptoms:

3. Nervous System Tumors

1. CNS Tumors

• 2% of cancer in adults
• neurons excluded
• cell types involved:

• Brain makes up 80% of the tumors
• age of onset 40 and up
• most are from metastasis
• Symptoms:

headaches, GI symptoms, change in mood or personality, seizures

increased intracranial pressure, infiltration, cerebral edema

Tumor growth in skull

Impaired Increased Focal Compression Increased

CSF flow osteoclast brain of nerves intracranial

activity damage pressure

Hydrocephalus Thinning Alteration of

of skull CNS function

EEG abnormalities

1. PNS Tumors

1. Neurofibromatosis

• NF-1 and NF-2
• Tumor Suppressors
• SEE HANDOUT

3. Sensory, Motor and Degenerative Disorders

1. Sensory Disorders

1. Meniere’s Syndrome

• Cause is unknown
• Increased fluid in the inner ear
• age of onset is 40-70
• Symptoms:

• Treatment:

1. Motor Disorders

1. Myasthenia Gravis

• autoimmune disorder
• Ab’s produced to ACh receptor at neuromuscular junction
• Ab’s are not stimulatory but result in degradation of the receptors
• course is variable

• Symptoms:

• Therapy:

1. Duchenne’s Muscular Dystrophy

• X-linked
• affect males almost exclusively
• apparent by age 2
• rapidly progressive
• death by 25
• defective membrane protein => dystrophin
• multiple mutations
• Symptoms:

• Treatment:

1. Saran Gas poisoning

• Nerve Gas
• Destroys acetylcholinesterase
• constant state of muscle contraction
• Therapy:

1. Cerebral Palsy

1. Degenerative Disorders

1. Multiple Sclerosis

• focal, chronic, progressive and usually exacerbating and remitting demyelination of CNS tracts.
• lesions can occur over a wide range of locations
• include cerebrum, brain stem, cerebellum and spinal cord
• periods of remission
• onset is 20-40
• clinical presentation depends on type of MS, location, extent and pattern of development of the plaques
• increased incidence in colder climates
• some evidence of a viral infection and genetic predisposition
• Symptoms:

• Treatment:

1. Parkinson’s

• slow, reduced movement and restless tremoring
• degenerative CNS disorder
• middle age onset
• principal lesion => substantia nigra
• decreased dopamine output
• idiopathic
• did see some cases from viral encephalopathy
• Symptoms:

• decreased life expectancy
• Therapies:

1. Huntington’s Disease

• affect 1/10,000
• produce rapid, writhing, flicklike contortions of the hands, arms and face as well as a profound dementia
• genetic defect of chromosome 4
• autosomal dominant inheritance
• onset 35-45
• if inherited from father, show disease earlier than if inherit from mother
• prenatal testing available
• massive cell loss from caudate and putamen as well as dilation of the ventricles
• course of disease is about 15 years
• some experimental drugs are being tried to slow the progress of the disease

1. Alzheimers Disease

• slow progressive dementia in the following order:

• can appear in patients as young as 50
• pathology restricted to cerebral cortex, hippocampus and amygdala
• microscopic findings include neurofibillary tangles and amyloid plaques
• gene responsible is on chromosome 21
• treatment is supportive care.