3/25/99

Pathology II

Amytrophic lateral sclerosis—Lou Gehrig's disease

· Progressive degeneration disorder involving upper and lower motor neurons of pyramidal system, with progressive muscle, atrophy, and spasticity

· Most cases are sporadic, some are familial

· Cause is unknown

· Some may be genetic

· Loss of motor neurons in anterior horns of spinal cord, brain stem, motor nuclei, and 1° motor cortex of cerebrum

· Peripheral nerves carrying motor fibers are depopulated

· Affected skeletal muscles show denervation atrophy

· Insidious onset, marked by weakness, clumsiness, and speech difficulties

· Muscle weakness accompanied by atrophy and fasciculations

· Spasticity (upper)—hyperactive DTR, +Babinski reflex

· Median survival is 5 yrs after symptom onset

· Death from respiratory insufficiency and infections

Werdnig-Hoffman Disease

· Infantile spinal muscular atrophy ("floppy infant" syndrome)

· Loss of motor neurons in anterior horns—atrophy of anterior spinal roots, peripheral motor nerves, and denervation of skeletal muscle

· Most die w/in 1^st yr of life

Diseases of Peripheral Nervous System

Peripheral Neuropathies

· Wallerian degeneration-degeneration of axon distal to transection i.e. nerve cut by knife. Disintegrates to form coarse globules, myelin ovoids. Some axonal regeneration w/some recovery of function (usually incomplete). Ischemic injury an important cause of wallerian degeneration

· 1° axonal degeneration—most common type of peripheral atrophy. Caused by nutritional deficiencies and intoxications

· segmental demyelination—myelin sheath affected. Leukodystrophies, acute inflammatory demyelinating neuropathy (Guillain-Bare), some forms of diabetic neuropathy

· Clinically—some combination of motor, sensory, and occasionally autonomic deficits. Most neuropathies, particularly axonal disorders, present w/slowly evolving symmetric sensory loss, often in a "glove-and-stocking" distribution, reflecting injury of distal axonal processes

· Gullain-Barre syndrome

Neoplasms

· Schwannomas—well circumscribed mass attached to peripheral nerves, cranial nerve VIII

Chapter 15—GI

Esophageal Disease

· Dyphagia—difficulty in swallowing. Due to motor dysfunction or narrowing or obstruction

· Heartburn—retrosternal burning pain. Regurgitation of gastric contents into lower esophagus

· Hematemesis—vomiting of blood. Massive with varices—severe inflammation, ulceration or laceration of mucosa

· Melena—blood in the stools

· Hiatal Hernia

paraesophageal (rolling)

· surgical situation

· rolling up the side of the esophagus

· can strangulate the venous return

· less common

sliding (axial)

· more common—95%

· shortening of the esophagus

· when it relaxes, the stomach goes back down

· not necessarily symptomatic

· Achalais

· Incomplete relaxation of lower esophageal sphincter in response to swallowing

· Produces fxnal obstruction

· Muscles are normal—problem is sphincter innervation

· Clinically—progressive dysphagia—nocturnal regurgitation and aspiration

· Mallory-Weiss Syndrome

· Longitudinal tears at esophagogastric junction

· Preceded by bouts of severe retching or vomiting

· Chronic alcoholics—bulimics

· Inadequate relaxation of musculature w/stretching and tearing during expulsion

· Varices

· Portal hypertension induces collateral bypass channels through esophageal veins, axygos veins and into SVC

· Increased pressure produces dilated tortuous vessels

· Occurs in about 2/3^rd of all cirrhotic patients and most commonly w/alcoholic cirrhosis

· Asymptomatic until rupture produces massive hemorrhage into lumen

· Rarely subsides spontaneously—40% die in first episode

· Tx—endoscopic injection of thrombotic agents and balloon tamponade