1. Nervous System Diseases & Disorders
Introduction to Human Diseases
Chapter 13

2. Nervous System Anatomy
Divisions of the nervous system:
Central Nervous System
Brain and spinal cord
Peripheral Nervous System
Peripheral nerves
Autonomic Nervous System
Symphathetic nervous system
Parasympathetic nervous system

3. CNS anatomy Major parts of the brain Cerebrum Cerebellum Brain stem
Cognitive center (thought, memory)
Level of consciousness
Cerebellum
Center of balance & coordination
Brain stem
Center of automatic functions
Blood pressure, respiration, etc.

4. Meninges Dura Arachnoid Pia Outermost layer Thick, fibrous
Thin, filmy like a spiderweb
Pia
Thin, vascular layer of loose connective tissue, inseparable from the outer brain surface

5. Headaches Any pain occurring in the head Acute or chronic
Numerous etiologies
Very common condition
May be a symptom of other diseases
Infections, neoplasms, inflammatory diseases, etc.

6. Headaches
Due to irritation, inflammation of any pain-sensitive structure
Brain itself is not a source of headache
Diagnostic procedures and testing:
Physical exam (PE), CT scan, LP (lumbar puncture or spinal tap), EEG, routine x-rays, MRA, MRI and more

7. Migraine Headache
Recurrent, usually severe headache of vascular origin
More common in females (3 to 1)
Family history in 70-80%
Onset common in adolescence or early adulthood
80% have first migraine by 30YOA
Usually become less frequent with age

8. Migraine Headache 10-20% US population have migraines
2nd most common cause of HA in US
Muscle tension HA is #1
S/S:
Intense throbbing headache, uni-or bilateral
Nausea, vomiting, dizziness, tinnitus
Visual disturbances
With or without aura (classical vs. common)
Duration from 4-72 hours

9. Migraine Headache Etiology:
Vasoactive chemicals (peptides) in brain (serotonin and dopamine)
Stimulate inflammatory cascade
This causes vasodilation
Serotonin appears to be most important factor

10. Subarachnoid Headache
Due to a subarachnoid hemorrhage
80% SAH due to ruptured intracranial aneurysm
Berry aneurysm, saccular, acquired due to hemodynamic stress at bifurcations
About 28,000 SAH/yr in US
Mean age is 50 YOA
Accounts for 6-8% strokes in US

11. Subarachnoid Headache
Most common etiology of non-traumatic intracranial hemorrhages
S/S: “worst headache of my life”
Rapid onset, neck stiffness (nuchal rigidity), low back pain, photophobia, nausea & vomiting, seizures in 10-25%
10% mortality immediately
Up to 60% mortality in 1st month

12. Head Trauma #1 cause of trauma deaths in US
Many possible mechanisms of injury:
Falls
Motor vehicle crashes
Assaults

13. Shaken Baby Syndrome
Vigorous episode of shaking the baby by the arms, torso, or chest
Most victims less than 3 years of age
Produces characteristic injury pattern:
Neurological injury
Mental retardation, seizures, hearing loss
Intracranial hemorrhage or edema, coma
Retinal hemorrhages

14. Shaken Baby Syndrome One version of child abuse
First described in 1946
Part of overall pattern of child abuse:
Multiple fractures
Bruises in all stages of healing, often axial
Often abuse from non-biological parent or caregiver

15. Shaken Baby Syndrome Brain injuries: Prognosis: Hemorrhage (SDH)
Cerebral edema & raised pressure
More common
Prognosis:
1/3rd mortality
1/3rd with permanent neurological disabilities

16. Epidural and Subdural Hematomas
Epidural Hematoma
Hemorrhage above the dura layer
Arterial bleeding
Parietal skull fx, middle meningeal artery
“lucid” interval
Subdural Hematoma
Below the dura
Venous bleeding
More common

17. EDH & SDH S/S: Treatment:
Altered level of consciousness (coma or lethargy), headache
Hemiparesis (right or left)
Unilateral dilated pupil
Treatment:
Neurosurgical drainage of the hematoma

18. Cerebral Concussion
Disruption of brain function without actual physical brain injury
Typically follows a blow to the head
Often, not always, has loss of consciousness
S/S: headache, nausea, dizziness, amnesias, disorientation, vertigo, photophobia

19. Concussion Testing is done to rule out other injuries
Treatment: supportive, observation

20. Cerebral Contusion Bruising of the brain tissue
Cerebral edema around the contusion is common
Mechanism: a blow to the head, usually localized force
S/S: headache, variable loss of consciousness, variation from concussion-like symptoms to coma with hemiparesis

21. Cerebral Contusion
Testing: CT scan to examine extent of brain injury & possible brain herniation
Treatment: variable
Monitoring of ICP, meds to decrease brain swelling, usually surgery is not helpful, other supportive care in ICU

22. Disorders that cause paralysis
Hemiplegia
Loss of muscle control & sensation on one side of the body (L or R)
Paraplegia
Loss of muscle control & sensation on the lower part of the trunk and lower extremities
Quadriplegia
Paralysis of all four extremities

23. Hemiplegia Etiology: most frequently stroke
Also intracranial tumor or hemorrhage
Other S/S: weakness of half of the face, aphasia, agnosia, apraxia, agraphia, alexia, etc.

24. Paraplegia & Quadriplegia
Etiology: most commonly spinal cord injuries due to trauma
Other S/S: loss of bowel & bladder control, sexual dysfunction
S/S of quadriplegia also include:
Low blood pressure and pulse
Variable loss of respiratory control

25. CNS Infections Acute Bacterial Meningitis
Acute inflammation & infection of the CSF & the meninges
Etiology: bacterial, viral, or fungal
Source may be spread from blood or nasopharynx
Most severe type = bacterial
Most common bacteria involved are Strep pneumoniae & Neisseria meningitidis

26. Acute Bacterial Meningitis
S/S: Headache, nausea, vomiting, fever, seizure, nuchal rigidity, drowsiness, coma
Testing: lumbar puncture makes the diagnosis
Characteristic rash with Neisseria m.
Treatment: antibiotics or antifungals and supportive care

27. Brain Abscesses Localized collection of pus Most commonly in:
Cerebellum
Frontal or temporal lobes of cerebrum
Etiology: spread from some other nearby or distant infection

28. Brain abscesses
S/S: depending on location, may resemble hemorrhage or CVA
Treatment:
Antibiotics
Surgical drainage of the abscess

29. Peripheral Nerve Diseases
Peripheral neuritis (peripheral neuropathy)
Noninflammatory degenerative disease of nerve supplying the distal extremities
Commonly males, YOA
Etiology: numerous, including alcohol, heavy metal, drug, poisons, TB & infections, diabetes, lupus, nutritional, etc

30. Peripheral neuropathy
S/S: muscle weakness, paresthesias, pain, tenderness, atrophy, loss of reflexes
Gradual in onset usually
Diagnostics: EMG
Treatment: varies with cause

31. Bell’s Palsy Disorder of the facial nerve (cranial nerve VII)
Unilateral paralysis/paresis of the facial muscles
Usually transient
Typically in patients YOA

32. Bell’s Palsy Etiology: idiopathic technically
Viral etiology is strongly suspected
Autoimmune, ischemic, etc
S/S: facial asymmetry, drooping mouth, drooling, incomplete closure of eye (Bell’s phenomenon)
Treatment: antiviral drugs and steroids usually

33. Cerebrovascular Accident (CVA)
Focal neurological impairment due to lack of blood supply to an area of the brain lasting more than 24 hours
Clinical condition is called stroke
2 types of stroke:
Ischemic: embolic or thrombotic, 75% CVA’s
Hemorrhagic: 25% CVA’s

34. CVA
Risk factors: same as for cardiovascular disease, smoking, HTN, hyperlipidemia, diabetes, etc. TIA’s, oral contraceptives
S/S: hemiplegia or hemiparesis, dysphagia, speech impairment, diplopia & loss of visual fields, lack of coordination, confusion, sensory impairment

35. CVA Diagnostics: CT scan to rule out hemorrhage or tumor Treatment:
Thrombolytic medicines “Clot busters” if stroke symptoms of 3 hrs or less
Supportive care, nutritional, PT & OT

36. Transient Ischemic Attacks (TIA)
Focal neurological impairment due to transient lack of blood supply to an area of the brain, lasting less than 24 hrs.
TIA’s indicate increased risk of CVA in the future
Resolve completely
Often minutes in duration

37. Transient Ischemic Attacks
Symptoms: most commonly upper extremity clumsiness, weakness, paresthesias, visual field cuts (curtain-like)
Treatment: surgery for carotid plaque, anticoagulants

38. Epilepsy
Chronic brain disorder characterized by seizures (abnormal, rapid, intense neuronal discharge)
Types of seizures:
Generalized (gran mal)
Involve entire body, unconscious
Partial: part of the body is involve, conscious
Petit mal: momentary, frequent unconscious episodes

39. Epilepsy Etiology: mostly idiopathic
Trauma, tumors, CNS infection, drugs & toxins, etc
S/S: in classic generalized seizure
Aura, tonic, clonic, post-ictal phases
Respiratory insufficiency & cyanosis
Incontinence of bowel & bladder

40. Epilepsy
Treatment: acute and long-term anticonvulsant meds

41. Degenerative Neurological Diseases
Alzheimer’s Disease
Fatal, long-term disease of the brain
Characterized by neurofibrillary tangles and senile “plaques”
Gradual & permanent deterioration of memory, judgment, cognitive and verbal skills
Geriatric disorder in general

42. Alzheimer’s Disease Etiology: unknown
S/S: previous section, end-stage is complete inattention to self
Diagnosis of exclusion
Treatment: some meds slow progression, supportive care of patient and family

43. Parkinson’s Disease
Movement disorder characterized by muscle rigidity & tremors
Usually males over 65 YOA
Etiology: unknown, related to dopamine deficiency in brain

44. Parkinson’s Disease
S/S: bradykinesia, involuntary tremors, muscular rigidity
Treatment: dopamine replacement meds, PT, supportive

45. Multiple Sclerosis (MS)
Chronic, progressive, demyelinating autoimmune disorder
Makes antibodies to myelin
Females (2:1)
Occurs during adult years, not geriatric
About 25,000 new cases/yr in US

46. MS S/S: variable, may last hours to weeks
Classically: eye symptoms, paresthesias, paralysis, mood swings, balance problems, often sudden onset with relapses
Treatment: beta-interferon products, corticosteroids, glatiramen acetate (synthetic myelin protein)
Usual cause of death is due to chronic disability issues

47. Amyotrophic Lateral Sclerosis (ALS)
Adult-onset motor neuron disease
Progressive degeneration & loss of motor function
Called Lou Gehrig’s Disease (1941)
Males between YOA
About 6/100,000 adult population in US
25,000-30,000 cases total in US

48. ALS
S/S: progressive muscle weakness, atrophy, and fasciculations (twitching)
Eventual involvement of mouth, respiratory muscles, end-stage is complete paralysis
75-80% begin with limb involvement
Slurred speech, hoarseness, dysphagia, tripping & stumbling, trouble with usual daily activities

49. ALS Sporadic form (nonhereditary) 90-95% cases
Inherited version is autosomal dominant
Mean time till ventilator dependent or death: 2-4 years
May survive 5-10 years on ventilator

50. Cancers of the CNS Primary brain tumors Secondary brain tumors
Benign or malignant
Most pediatric brain tumors are primary
Examples are astrocytoma, glioblastoma
Secondary brain tumors
Metastases from other sites
Most common tumors of the brain