Notes on Environmental Pathology

Rahul's Noteblog Notes on Pathology Notes on Environmental Pathology

Leading causes of disease:

• Alcohol and tobacco.

Tobacco use causes:

• CV disease, lung cancer, stroke.

• Nicotine is the most addictive substance in tobacco.

• This also includes chewing tobacco and second-hand (passive) smoke.

Alcohol use:

• Stomach absorption.

• Metabolism in liver and stomach.

• Alcohol dehydrogenase is the rate-limiting metabolism enzyme.

Products of alcohol metabolism:

• Reduced NADH.

• Acetyl CoA.

• Alcohol induction of cytochrome P-450 increases alcohol metabolism, increasing tolerance.

• Females have less gastric alcohol dehydrogenase.

Lab findings in alcohol abuse:

• Fasting hypoglycemia: pyruvate, which is a substrate for gluconeogenesis, is converted to lactate.

• Increased anion gap metabolic acidosis.

• Other findings: Hyperuricemia, hypertriglyceridemia, AST greater than ALT, increased GGT.

Other drugs:

Cocaine:

• Stimulant; mydriasis, tachycardia, hypertension, AMI, CNS infarction.

Heroin:

• Opiate; miotic pupils, frothing at mouth, nephrotic syndrome.

Marijuana:

• Stimulant; red conjunctiva, euphoria, delayed reaction time.

Complications of IV drug abuse:

• Hepatitis B, HIV, tetanus, infective endocarditis.

Overall effects of drugs:

• Cerebral atrophy; damaged neurotransmitter sites.

Adverse effects of certain medications:

Acetaminophen:

• Damage to liver and kidneys; production of free radicals.

Aspirin (also known as acetylsalicylic acid or salicylate) overdose:

• Tinnitus, vertigo, altered mental status, tachypnea, respiratory alkalosis, metabolic acidosis with increased anion gap, hyperthermia, hemorrhagic gastritis, fulminant hepatitis.

Exogenous use of estrogen without progesterone:

• Cancer, venous thromboembolism, intrahepatic cholestasis with jaundice, myocardial infarction, stroke.

Use of oral contraceptives:

• Cancer, venous thromboembolism, folate deficiency, hypertension, hepatic adenoma, intrahepatic cholestasis with jaundice, cholesterol gallstones.

Types of wounds:

• Contusion, abrasion, laceration, incision.

Thermal injury:

First-degree:

• Eg., sunburn; heal without scarring.

Second-degree:

• Blister formation; usually heal without scarring.

Third-degree:

• Painless; full thickness burns.

• Scarring is inevitable.

• Keloids and potential for developing squamous cell carcinoma.

P. aeruginosa

• Infection is common in burn victims.

Frostbite:

• Damage by ice crystallization in cells.

• Loss of pain; waxy appearance.

Electrical shock injury:

• Alternating current is more damaging than direct current.

• AC produces tetanic contractions and DC produces a single shock.

High-altitude injury:

• Respiratory alkalosis activates glycolysis.

• Increased 2,3-BPG synthesis.

• Right-shifts O2 binding curve; more oxygen dumped in tissues.

Acute mountain sickness:

• Headache, fatigue, dizziness, anorexia, insomnia; pulmonary and cerebral edema.

Drowning:

Wet:

• Initial laryngospasm, hypoxemia, damage to pneumocytes.

Dry:

• Asphyxia.

Pathphysiology:

• Hypoxemia with damage to heart, CNS, kidneys, lungs.

Diving reflex activated in cold water drowning:

• Blood shunted from periphery to central core.

Ionizing radiation injury:

• DNA damage and formation of hydroxyl free radicals.

• Most sensitive tissues: lymphoid, bone marrow, mucosa of GI tract; germinal tissue.

• Least sensitive tissues: bone, brain, muscle, skin.

Radiation has effects in the areas of:

• Hematopoietic, vascular, epidermal, and GI.

• Susceptibility to cancers.

Non-ionizing radiation:

Ultraviolet light B:

• Pyrimidine dimers.

• TP53 inactivation and RAS activation.

• Sunburn.