From Textbook (Disease Vocabulary) - Unit 10: The Nervous System

amnesia

Partial or total (global) loss of memory of recent or remote (past) experiences. It is often a consequence of brain injury or a stroke that damages the hippocampus where short-term memories are converted to long-term memories. Treatment: None.

anencephaly

Rare congenital condition in which some or all of the cranium and cerebrum are missing. The newborn breathes because the respiratory centers in the medulla oblongata are present, but only survives a few hours or days. Treatment: None.

aphasia

Loss of the ability to communicate verbally or in writing. Aphasia can occur with head trauma, a stroke, or Alzheimer's disease when there is injury to the areas of the brain that deal with language and the interpretation of sounds and symbols. Patients with aphasia are said to be aphasic. Expressive aphasia is the inability to verbally express thoughts. Receptive aphasia is the inability to understand the spoken or written word. Patients with both types are said to have global aphasia. Limited impairment that involves some difficulty speaking or understanding words is known as dysphasia. Treatment: Correct the underlying cause.

arteriovenous malformation (AVM)

Abnormality in which arteries in the brain connect directly to veins (rather than to capillaries), forming an abnormal twisted nest of blood vessels. An AVM can rupture and cause a stroke. Treatment: Focused beam radiation to destroy the AVM or embolization to block blood flow to the AVM; surgical removal, if needed.

brain tumor

Benign or malignant tumor of any area of the brain. Brain tumors arise from the neuroglia or meninges, rather than from neurons themselves. They are named according to the type of cell from which they originated. Malignant brain tumors can also be secondary tumors that metastasized from a primary malignant tumor elsewhere in the body. Because the cranium is rigid, the enlarging benign or malignant tumor causes increased intracranial pressure (ICP), cerebral edema, and sometimes seizures. The pressure compresses and destroys brain tissue. Treatment: Surgery to remove or debulk the tumor; chemotherapy drugs or radiation therapy for malignant tumors.

cephalalgia

Pain in the head. It is commonly known as a headache. It can be caused by eyestrain, muscle tension in the face or neck, generalized infections such as the flu, migraine headaches, sinus infections, hypertension, or by more serious conditions such as head trauma, meningitis, or brain tumors. Treatment: Correct the underlying cause.

cerebral palsy (CP)

Cerebral palsy is caused by a lack of oxygen to parts of the fetus' brain during birth. The result can include spastic muscles; lack of coordination in walking, eating, and talking; muscle paralysis; seizures; or mental retardation. Treatment: Braces, muscle relaxant drug, physical therapy, speech therapy.

astrocytoma

Malignant brain tumor originating from an astrocyte in the cerebrum.

ependymoma

Benign brain tumor originating from ependymal cells that line the ventricles.

glioblastoma multiforme

Malignant brain tumor originating from an immature astrocyte in the cerebrum.

glioma

Benign or malignant brain tumor originating from any neuroglial cell.

lymphoma

Malignant brain tumor originating from microglia in the cerebrum.

meningioma

Benign brain tumor originating from meninges around the brain or spinal cord.

oligodendroglioma

Malignant brain tumor originating from oligodendroglia in the cerebrum.

schwannoma

Benign brain tumor originating from Schwann cells near the cranial or spinal nerves.

cerebrovascular accident (CVA)

Disruption or blockage of blood flow to the brain, causing tissue death and necrosis (infarct). Caused by an embolus, arteriosclerosis, or hemorrhage. Also known as a stroke or brain attack. Precursors include transient ischemic attack (TIA; effects last 24 hours) and reversible ischemic neurologic deficit (RIND; effects last several days). Left-side brain CVA affects the right side of the body and vice versa. Symptoms include hemiparesis (weakness on one side) or hemiplegia (paralysis on one side), amnesia, aphasia, dysphasia, or dysphagia. Prevention: Carotid endarterectomy, aneurysm clipping, or aneurysmectomy. Treatment: Thrombolytic drugs, physical therapy, speech therapy.

coma

Deep state of unconsciousness and unresponsiveness caused by trauma or disease in the brain, metabolic imbalance (hepatic coma), or hypoglycemia. A coma may be temporary or permanent; a patient is comatose. Brain death is irreversible loss of all brain function confirmed by a flat EEG showing no brain wave activity for 30 minutes. Treatment: Correct the underlying cause.

concussion

Traumatic injury to the brain resulting in immediate loss of consciousness (LOC) for a brief or prolonged time. After consciousness returns, signs of a slowly enlarging brain hemorrhage include sleepiness, irritability, vacant stare, slow response, inability to follow commands, disorientation, slurred speech, or lack of coordination. Contusion is injury with bruising/bleeding in tissues but no LOC. Shaken baby syndrome is caused by vigorous shaking, causing head whipping, contusion, concussion, hemorrhaging, mental retardation, coma, or death.

dementia

Disease of the brain in which many neurons in the cerebrum die, the cerebral cortex shrinks, and progressive deterioration in mental function occurs. Early symptoms include forgetfulness, inability to learn new things, difficulty making decisions, using wrong words, and comprehension issues. Progresses to inability to care for personal needs, failure to recognize family, and complete memory loss. Associated with old age (senile-onset) or multiple small strokes (multi-infarction). Can be caused by trauma, alcoholism, MS, Parkinson's, or Huntington's. Most common cause is Alzheimer's disease (hereditary dementia linked to chromosomes 1, 14, and 21; features neurofibrillary tangles, beta amyloid senile plaques, and decreased acetylcholine). Early middle age onset is early-onset/presenile dementia. Treatment: Drugs to inhibit the enzyme that breaks down acetylcholine.

Down syndrome

Naturally occurring, random error in cell division creating a genetic defect with three copies of chromosome 21. Affects every cell in the body. Characterized by mild-to-severe intellectual disability and physical features like a large, protruding tongue, short fingers, and a single transverse crease on the palm. Prenatal test: Amniocentesis.

dyslexia

Difficulty reading and writing words despite normal visual acuity and intelligence. Tends to run in families; more prevalent in left-handed persons and males. Caused by an abnormality in the occipital lobe of the cerebrum that interprets moving visual images. Treatment: Educational techniques to compensate or overcome.

encephalitis

Inflammation and infection of the brain caused by a virus (Herpes simplex, herpes zoster, West Nile, or cytomegalovirus). Symptoms include fever, headache, stiff neck, lethargy, vomiting, irritability, and photophobia. Treatment: Corticosteroid drugs for inflammation; antiviral drugs specifically for herpes virus. Antibiotics are ineffective.

epilepsy

Recurring condition in which a group of neurons in the brain spontaneously sends out electrical impulses in an abnormal, uncontrolled way. Also known as seizures or convulsions. Can be triggered by flashing lights, stress, lack of sleep, alcohol, or drugs. Some patients experience an aura (visual, olfactory, sensory, or auditory sign) before onset. Postictally, patients experience sleepiness and confusion (postictal state). Chronic seizures can cause memory loss and personality changes. Status epilepticus is a prolonged, continuous seizure or repeated seizures without regaining consciousness. Treatment: Antiepileptic drugs, or surgery if caused by a tumor or localized brain area.

tonic-clonic (grand mal)

Seizure featuring unconsciousness with excessive motor activity. The body alternates between excessive muscle tone with rigidity (tonic) and jerking muscle contractions (clonic) in the extremities, with tongue biting and sometimes incontinence. Lasts 1-2 minutes.

absence (petit mal)

Seizure featuring impaired consciousness with slight or no muscle activity. Muscle tone is retained and the patient does not fall down, but is unable to respond to external stimuli. Features vacant staring, repetitive blinking, or facial tics. Lasts 5-15 seconds.

complex partial (psychomotor)

Seizure featuring some degree of impairment of consciousness and involuntary contractions of one or several muscle groups. Can include automatisms, such as lip smacking or repetitive muscle movements. Lasts 1-2 minutes.

simple partial (focal motor)

Seizure featuring no impairment of consciousness. The patient is aware of the seizure but is unable to stop the involuntary motor activity, such as jerking of one hand or turning of the head. Can also involve sensory hallucinations. Lasts 1-2 minutes.

hematoma

Localized collection of blood that forms in the brain because of trauma to the cranium or the rupture of an intracranial aneurysm or an AVM. An intraventricular hematoma occurs within one of the ventricles. A subdural hematoma forms under the dura mater. Treatment: Surgery to remove the hematoma.

Huntington's chorea

Progressive inherited degenerative disease of the brain that begins in middle age. Characterized by dementia with spasms of the extremities and face (chorea), alternating with slow writhing movements of the hands and feet (athetosis). Treatment: None.

hydrocephalus

Condition in which an excessive amount of cerebrospinal fluid is produced or its flow is blocked. Intracranial pressure increases, distends the ventricles, and compresses brain tissue. Associated with congenital conditions like meningocele or myelomeningocele; can occur in adults if fluid isn't reabsorbed. Causes an enlarged head and intellectual disability; layman's term is "water on the brain." Treatment: Ventriculoperitoneal shunt to move excess fluid to the peritoneal cavity.

meningitis

Inflammation and infection of the meninges of the brain or spinal cord caused by a bacterium or virus. Symptoms include fever, headache, nuchal rigidity (stiff neck with pain and inability to touch chin to chest), lethargy, vomiting, irritability, and photophobia. Prevention: Vaccination. Treatment: Antibiotics for bacterial infection; corticosteroid drugs to decrease inflammation.

migraine headache

Specific type of recurring headache with a sudden onset of severe, throbbing pain, often on just one side of the head. Accompanied by nausea, vomiting, and photophobia. Caused by constriction followed by sudden dilation of arteries in the brain, and the release of neuropeptides by the trigeminal nerve (cranial nerve V). Treatment: Drugs to keep blood vessels from dilating.

narcolepsy

Brief, involuntary episodes of falling asleep during the daytime while engaged in activity. The patient can be aroused but is unable to keep from falling asleep. Linked to a hereditary/autoimmune component and an underlying abnormality of rapid eye movement (REM) sleep. Treatment: Central nervous system stimulant drugs.

Parkinson's disease

Chronic, degenerative disease due to an imbalance in the levels of the neurotransmitters dopamine and acetylcholine in the brain. Characterized by muscle rigidity, tremors, difficulty initiating voluntary movements, a mask-like facial expression, and a shuffling gait (parkinsonism). Treatment: Drugs that increase dopamine or inhibit acetylcholine.

syncope

Temporary loss of consciousness. A syncopal episode involves lightheadedness followed by fainting and brief unconsciousness. Most often caused by carotid artery stenosis and plaque blocking blood flow, or by cardiac arrhythmias that decrease blood flow to the brain. Treatment: Correct the underlying cause.

neural tube defect

Congenital abnormality of the neural tube where the fetus' vertebrae form incompletely (spina bifida), leaving an abnormal opening in the vertebral column covered only by meninges and skin. Includes meningocele (protrusion of meninges through skin) and meningomyelocele (protrusion of meninges and spinal cord through skin).

neural tube defect (continued)

Also known as myelomeningocele. Associated with hydrocephalus. Extent of spinal cord involvement determines muscle control loss in legs, bladder, and bowel. Amniotic fluid sample shows elevated alpha fetoprotein. Prevention: Folic acid supplements during pregnancy. Treatment: Immediate post-birth surgery to close defect and prevent infection; surgery does not restore function.

radiculopathy

Acute or chronic condition occurring from a tumor, arthritis, or a herniated nucleus pulposus (HNP; slipped disk) where intervertebral disk contents press on spinal nerve roots. Usually involves lumbar disk from heavy lifting or poor body mechanics. Also called sciatica when pressing on the sciatic nerve (roots L4-L5), causing pain, tingling (paresthesias), numbness, and muscle weakness. Treatment: Anti-inflammatory drugs, bed rest, traction, physical therapy, corticosteroid nerve root injections, or surgery (rhizotomy, diskectomy, laminectomy).

spinal cord injury (SCI)

Trauma to the spinal cord with partial or complete transection, interrupting nerve impulses to dermatomes and causing anesthesia and paralysis. Lower spinal cord injury causes paraplegia (paralysis of legs); upper injury causes quadriplegia (paralysis of all four extremities). Lack of impulses leads to muscle atrophy (flaccid paralysis). Intact lower reflex arcs responding to pain or a full bladder cause muscle spasms (spastic paralysis) and spontaneous bladder contraction (incontinence). Treatment: Transport on rigid board with cervical collar and taped head, skull traction, vertebra fusion surgery, corticosteroids, passive range-of-motion exercises, splints, muscle relaxants.

amyotrophic lateral sclerosis (ALS)

Chronic, progressive disease of the motor nerves coming from the spinal cord, leading to muscle wasting, spasms, and eventual paralysis of all muscles (including swallowing and respiratory). Sensory nerves and thinking remain completely intact. Also known as Lou Gehrig's disease. Treatment: Supportive care.

anesthesia

Condition in which sensation of any type (touch, pressure, proprioception, or pain) has been lost. Can occur temporarily (compressed nerve), permanently (third-degree burns, spinal cord injury dermatome), or therapeutically via anesthetic drug injection (subcutaneous, nerve root, epidural). Unconsciousness blocks all sensory perception during general anesthesia. Treatment: Correct underlying cause.

Bell's palsy

Weakness, drooping, or actual paralysis of one side of the face caused by inflammation of the facial nerve (cranial nerve VII). Typically caused by a viral infection like herpes virus. The condition usually lasts about a month and then disappears. Treatment: Corticosteroid drug.

carpal tunnel syndrome (CTS)

Chronic condition caused by repetitive motions of the hand and wrist. Inflammation and swelling of tendons compress the median nerve, causing tingling. Aggravated by bending or extending the wrist for 60 seconds (Phalen's maneuver). Treatment: Rest, splinting, split keyboard, physical therapy, corticosteroid injection, surgery.

Guillain-Barré syndrome

Autoimmune disorder where antibodies attack myelin, causing acute inflammation of peripheral nerves, loss of myelin, muscle weakness, and paresthesias. Triggered by infection, stress, or trauma. Weakness begins in legs and rapidly involves the entire body; may require temporary respiratory support. Treatment: Corticosteroid drug.

hyperesthesia

Condition in which there is a heightened awareness and sensitivity to touch and an increased response to painful stimuli. Treatment: Antidepressant drug or tranquilizer drug.

multiple sclerosis (MS)

Chronic, progressive, degenerative autoimmune disorder where antibodies cause demyelination with interruption of nerve conduction in the brain and spinal cord. Demyelination areas turn into hard scar tissue (sclerosis) known as plaque. Symptoms include double vision, nystagmus, uncoordinated gait, spasticity, and paresthesias. Characterized by remissions and flare-ups. Treatment: Corticosteroid drug, muscle relaxant drug.

neuralgia

Pain along the path of a nerve and its branches caused by an injury. Trigeminal neuralgia (tic douloureux) features brief, severe, stabbing pain along the trigeminal nerve (cranial nerve V). Causalgia is severe, burning pain along a nerve. Complex regional pain syndrome (CRPS) consists of causalgia with hyperesthesia, swelling, and skin changes. Treatment: Anti-inflammatory, anticonvulsant, muscle relaxant, nerve block, TENS unit, physical therapy.

neuritis

Inflammation or infection of a nerve. Polyneuritis is a generalized inflammation of many nerves in one part of the body or all the nerves in the body. Treatment: Correct the underlying cause; analgesic drug, anti-inflammatory drug, corticosteroid drug, or antibiotic drug.

neurofibromatosis

Hereditary disease with multiple benign fibrous tumors (neurofibromata) growing on peripheral nerves. Most noticeable on the skin, but can be anywhere (internal organs, eye). Also known as von Recklinghausen's disease. Treatment: Surgical removal of large tumors causing pain or disability.

neuroma

Benign tumor of a nerve or any of the specialized cells of the nervous system. A Morton's neuroma specifically forms from repetitive damage to the nerve near the metatarsophalangeal joints between the ball of the foot and the toes. Treatment: Surgical removal.

neuropathy

General category for any type of disease or injury to a nerve. Treatment: Correct the underlying cause.

paresthesia

Condition in which abnormal sensations, such as tingling, burning, or pinpricks, are felt on the skin. Often the result of chronic nerve damage from a pinched nerve or diabetic neuropathy. Treatment: Correct the underlying cause; anticonvulsant drug, antianxiety drug, or antidepressant drug.