Module 1 Patho Further Explanations

Effects of Hypoxia

Severe consequences of hypoxia can take place in 3-5 minutes. Cells accumulate Na, Ca and K leave the cells. Decreased protein synthesis and cell swelling follows

Once vacuolation occurs along with mitochondrial swelling, it’s completely irreversible

Presentation of Dry Gangrene

• Red lines appear around the affected tissue

• Affected area will eventually become numb and cold

• The area will change from red to brown to black

• Necrotized tissue (dead tissue) shrivels up and falls off

Presentation of Wet Gangrene

• Affected area swells before any tissue dies

• Skill will change from red to brown to black

• There will be pus and foul smell

• Fever

Causes of Edema (FVO)

• Increased capillary hydrostatic pressure

• Venous obstruction

• Hepatic obstruction

• Thrombophlebitis

• Prolonged standing

• CHF

Lowered plasma osmotic pressure in Edema/FVO

Can be caused by loss of plasma albumin

• Wounds

• Hemorrhage

• Burns

• Cirrhosis

Increased capillary membrane permeability in Edema/FVO

Can be caused by inflammation and immune responses

• Trauma

• Cancer

• Allergic reactions

• Burns

Lymphatic channel obstruction in Edema/FVO

• Surgically removed lymph nodes

• Inflammation

• Obstruction

Manifestations of FVO

• Weight gain

• Swelling

• Tight fitting clothes and shoes

• Limited movement of affected area

• Dilute urine (sometimes)

• Increased BP (sometimes)

• Wet lung sounds

• Bounding pulses

FVO also causes…

hemodilution and decreased serum osmolality

Causes of Dehydration/FVD

• Lack of fluid intake

• Vomiting

• Diarrhea

• Fever

• Insensible water losses

• Impaired renal tubular

• Diabetes insipidus

• Fluid loss

Manifestations of FVD

• Thirst

• Dry skin

• Dry mucous membranes

• Elevated temperature

• Weight loss

• Concentrated urine

• Tachycardia

• Postural hypotension

Functions of Sodium

• Principal cation in ECF

• Regulated by kidneys

• Influenced by aldosterone

• Responsible for water retention and osmolarity

• Neuromuscular

• Body fluids

• Cellular

• Acid base balance

Functions of Chloride

• Partially responsible for the acidity of the gastric fluid

• Excreted by the kidneys, GI secretions and sweat

• Anion in ECF

• Regulated by kidneys

• Appears in combination with sodium

Calcium ECF

• Found in ECF and ICF, greater in ECF

In ECF:

• 45% bound to protein

• 40% is free ionized calcium

• 15% is bound to other substances

Functions of Calcium

• Enzyme activation to stimulate many essential chemical reactions

• Needed for skeletal and heart functions

• Nerve impulse transmission

• Regulation of acid base balance

• Role in blood clotting

• Bones and teeth health

• Holds body cells together

High Osmolarity

Solution with high concentration of solutes in proportion to fluid → can lead to cell shrinkage and dehydration

Low Osmolarity

Solution with low concentration of solutes in proportion to fluid → can lead to cell swelling and overhydration

Oncotic Pressure

• Pulls water through capillary wall

• Albumin (produced in the kidneys) will help pull the water

• When patients have low albumin → oncotic pressures decreases (can be due to kidney dysfunction, burns)

• When oncotic pressure is decreased, water will stay stuck in the interstitial space, and swelling will occur

Hydrostatic Pressure

• Pushes water across capillary wall

• Heart contractions create this pressure

• Fluid → Blood (restricted space) → blood vessels

• Highest in arteries, lowest in veins

• Creates filtration → it pushed the solutes out of the capillaries and into the interstitial space

Two main isotonic solutions

1. Normal Saline (0.9% NaCl)

2. Lactated Ringers Solution (Contains NaCl, sodium lactate, KCl, CaCl₂, and water) OR Dextrose (5% in water for fluid loss)

I couldn’t find an exact answer for the 2nd one, but those are the two next common ones

Isotonic

• Equal concentration of solution between inside and outside of cells (normal)

• Isotonic solutions are given to increase ECF volume → could be a result of blood loss, dehydration, surgery

Hypotonic

• Low concentration of solution in ECF (cell swells, too much solution in ICF)

• Hypotonic solutions are given when a patient’s cells are dehydrated

Hypertonic

• High concentration of solution in ECF (cell shrinks, too little solution in ICF)

• Hypertonic solutions are given when a patient’s cells are overhydrated

Take caution when giving these solutions, as they can cause FVO

RAAS Steps (Basic)

1. Bp or blood volume drops, renin is released by kidneys

2. Renin splits angiotensinogen (liver), forms angiotensin I (inactive)

3. Angiotensin further splits by ACE (lungs), forms angiotensin II (active)

4. Angiotensin II increases BP, triggers adrenal glands to release aldosterone and pituitary gland to release ADH

5. Angiotensin II initiates thirst center → end result increased fluid volume

6. Aldosterone and ADH cause kidneys to retain sodium, kidneys also secrete potassium through urine

7. Increase in sodium → water retention → increased BP and blood volume

Causes of Respiratory Acidosis

Hypoventilation caused by conditions such as:

• airway obstruction

• COPD

• pulmonary edema

• chest trauma

• neuromuscular disease

• drug overdose

Causes of Metabolic Acidosis

• diabetic ketoacidosis

• renal failure

• shock

• sepsis

• severe diarrhea

• salicylate OD

Causes of Respiratory Alkalosis

Hyperventilation from conditions such as:

• anxiety

• high altitudes

• pregnancy

• fever

• hypoxia

• initial stages of pulmonary embolism

Causes of Metabolic Alkalosis

• loss of gastric juices

• potassium wasting diuretics

• overuse of antacids