Neurological Disorders Dr. Kline FSU-PC
I. Neurological Disorders • The normal functioning of the CNS can be affected by a number of disorders, the most common of which are headaches, tumors, vascular problems, infections, epilepsy, head trauma, demyelinating diseases, and metabolic & nutritional diseases.
A. Vascular Diseases in the brain: • Minor to total reduction in blood flow to the neurons deprives the cells of oxygen & glucose, resulting in interference with cellular metabolism. • Disruption of cellular metabolism, caused by reduced blood flow, lasting longer than 10 min. , results in cell death for neurons in that brain region. • These disorders account for most common causes of death & chronic disability in the Western world.
1. Stroke (Cerebral vascular accident) • Results from severe severe interruption of blood flow to the brain (usually affecting arteries). • The onset of a stroke may span days to years, often with little-to-no warning. • A stroke produces an infarct (area of dead or dying tissue resulting from obstruction of blood vessels normally supplying area).
What factors influence the severity of deficits resulting from a stroke? • Location of the blockage • Size of the blood vessels • --prognosis is better if blockage occurred in small vessels rather than larger vessels. • Relative health of surrounding vessels • Age of patient (younger has better chance of recovery) • How quickly patient is seen following stroke
2. Cerebral Ischemia- insufficient supply of blood to brain, are like mini-strokes. • Decreases in blood flow result of 3 causes: • A. Thrombosis-a plug or clot in a blood vessel that remains at its point of formation. • B. Embolism -moving (clot, bubble of air, sack of cells, or fat deposit) from larger vessel into a smaller vessel. • --often effect middle cerebral artery of left side of brain which is near speech comprehension for many. • C. Cerebral arteriosclerosis-thickening & hardening of arteries that reduces blood flow.
3. Migraine Stroke • People with classic migraines often experience a transient ischemic attack with some neurological symptoms. These include: • Impaired sensory functioning (vision) • Numbness of skin • Difficulties in moving & aphasia (Language Disorder) • *Account for a significant proportion of strokes in young people under 40. • *Occurs more in females than males. *Cause is unknown (may be vasospasm).
4. Cerebral Hemorrahage • Massive bleeding in the brain. Onset is abrupt & may be quickly fatal. Prognosis often poor. • Causes: • Hypertension • Congenital defects of cerebral arteries • Leukemia & other blood disorders • Toxic chemicals
5. Aneurysms • Vascular dilations resulting from localized defects in the elasticity of the vessel. • The vessels distend like a “balloon” until they are vulnerable to rupture. • Most common symptom is severe headache, often present for many months to years.
Treatment for vascular disorders: • Drug therapy (anticoagulants to dissolve clots or prevent clotting) • Vasodilators to dilate vessels • Drugs used to treat hypertension • Salty solutions to reduce edema in brain • Surgery to repair damaged vessels; total removal of aneurysm.
B. Head Trauma Injuries • Brain injury from head trauma is most common form of brain damage in people under 40. • There are two types of Head Trauma Injuries: • Open-head & closed-head injuries.
Ways in which Head trauma may damage the brain: • 1. By directly damaging neurons & support cells (e.g., gunshot wound). • 2. By causing blood flow disruption leading to a stroke (closed-head injury). • 3. By causing bleeding in the brain which causes the brain to swell. • 4. By making the brain vulnerable to infection (open-head injuries).
1. Open-Head Injuries: • Results from injury to brain in which the skull is penetrated either by projectiles (gunshots/missile wounds) or other moving objects. • Most people with open-head injuries do not lose consciousness & produce distinctive symptoms that may undergo rapid & spontaneous recovery. • Deficits are specialized & often resemble those of surgical excisions.
2. Closed-Head Injuries • Caused by a blow to the head (car accident, blunt instrument swung at head). Damage may be three-fold: • A. Damage at site of blow is called a coup. • B. The brain may shift & hit the opposite side of the skull producing an additional bruise (contusion) known as a countercoup.
Closed-Head Injuries (Contd.) • C. The brain may suffer additional damage, resulting from shearing of nerve fibers which produce microscopic lesions. • Frontal & temporal areas are most likely to be damaged in closed-head injuries. • These injuries are commonly accompanied by loss of consciousness (from damage to brainstem fibers), edema (swelling), & hemorrhaging. • Length of coma often is positively correlated with severity of damage.
Behavioral impairments resulting from closed-head injuries: • 1. Discrete impairment of functions mediated by brain regions that sustained direct impact (coup & countercoup). • 2. Microscopic lesions caused by shearing of neurons results in widespread damage.
Mental recovery from Closed-Head Injury: • Most mental recovery occurs rapidly in the first 6-9 months following injury. • Memory functions recover more slowly than general intellectual functions. Depending on length of coma & amnesia following injury, prognosis may be very good. • Personality changes may be pronounced; person may be less likely to recover their personality than they are to recover general intellectual functioning.
C. Epilepsy • Results from recurrent seizures (disruptions in neural firing) of various types that disturb consciousness. • Seizures may be classified based on potential cause: • ---Symptomatic seizures-caused by infection, trauma, tumor, toxic chemical, vascular problem, etc. • ----Idiopathic seizures- appear spontaneously; with no apparent cause.
Symptoms of Epilepsy • 1. An aura or warning of a seizure that’s about to occur. • E.g., may be an odor, noise, or visual image • 2. Loss of consciousness (ranges from complete collapse to staring off into space). • 3. Movements (ranging from minor such as small twitching to large convulsions).
Types of Epilepsy • 1. Focal seizures- seizures occur in a locus (particular place in brain) & then spread. E.g., symptoms may start with twitching in one digit of the hand and quickly spread to the other fingers & arm.) 2. Complex partial seizures – usually originate in the temporal lobe (sometimes the frontal lobe).
Stages of Complex partial seizures • 1. Subjective feelings, forced thoughts, alterations in mood, dejavu • 2. Automatisms, which are stereotyped repetitive movements such as lip smacking, chewing, fidgeting. • 3. Postural changes in which person may assume catatonic postures.
3.Generalized seizures • Are bilaterally symmetrical without local onset. • Grand Mal attack is accompanied by loss of consciousness, stereotyped motor behavior. • 4. Petit mal attack- Brief loss of awareness during which there is little motor activity such as blinking, turning the head, rolling the eyes, etc.
Treating Epilepsy • 1. Anticonvulsant drugs are used to treat this. • (E.g., Dilantin, phenobarbital, etc.) • Mode of action is unknown, may work by stabilizing weak neural membrane in abnormal cells. • 2. Surgery to remove focus of epilepsy if known.
D. Brain Tumors • A mass of cells that grow & have no use. • Brain tumors grow from glia & other support cells, not the neurons themselves. • Tumor growth varies depending on type of tumor, where its located, & type of cell that it grows from.
Types of Brain Tumors • 1. Gliomas- tumors that arise from glial cells & infiltrate the brain. May be benign to malignant. • About 45% of all tumors are gliomas. • A. Astrocytomas-result from growth of astrocytes. Usually not malignant & may be treated fairly easily. Prognosis is good. • B. Glioblastomas-highly malignant, rapidly growing.
2. Meningiomas- attached to meninges. Are encapsulated on outside of brain. Usually benign. • 3. Metastatic Tumors- a tumor that results in the brain from tumor cells carried from the body elsewhere (breast, liver, lung, etc.).
Treatment for tumors • Surgery to remove tumors if operable. • Radiation to reduce or shrink tumors.