Patho Exam 1

What are electrolytes?

Substances that dissociate in solution into ions (charged particles).

What is the difference between cations and anions?

Cations are positively charged ions, while anions are negatively charged ions.

What are non-electrolytes involved with fluid balance?

Glucose and urea.

What are the main compartments of body fluids?

Intracellular and extracellular compartments.

What regulates intracellular fluid?

Proteins and organic compounds within cells.

What are the components of extracellular fluid?

Vascular (blood and plasma), interstitial (fluid between cells), and transcellular (fluid in epithelial-lined spaces).

What is oncotic pressure?

The pressure exerted by albumin in the bloodstream that helps keep fluid in the vessels.

What is the normal range for total albumin in the blood?

3.5-5 g/dL.

What is tonicity?

The effect of osmotic pressure of a solution containing impermeable solutes on water movement across a cell membrane.

What is the difference between osmolality and osmolarity?

Osmolality refers to the concentration of solutes per kg of solvent, while osmolarity refers to the concentration of solutes per liter of solution.

What is the normal range for osmolality in the body?

275-295 milliosmoles/kg of water.

What is the main determinant of osmolarity?

Sodium (Na+).

What is edema?

The movement of vascular fluid into the interstitial space, resulting in swelling.

What are the two types of edema?

Localized and generalized edema.

What causes dependent edema?

Increased capillary pressure in lower areas of the body due to gravity.

How does low albumin contribute to edema?

Decreased colloidal pressure inside capillaries leads to fluid leakage into interstitial spaces.

What are some examples of conditions that can cause low albumin?

Liver disease, starvation/malnutrition, burns, or kidney disease.

What can increase capillary pressure leading to edema?

Increased vascular volume (e.g., heart failure, pregnancy) or venous obstruction (e.g., portal vein obstruction).

What is the goal of diffusion?

To achieve equilibrium by moving charged particles along a concentration gradient from higher to lower concentration.

What is osmosis?

The movement of water across a semipermeable membrane due to osmotic pressure.

What is the normal serum range for osmolarity of blood?

270-300 mOsm/L.

What is the significance of measuring osmolarity?

It helps evaluate hydration status and body fluid balance.

What medication caused bilateral leg swelling in the patient's father?

Nifedipine

What condition is characterized by increased capillary permeability?

Conditions such as inflammation, allergic reactions, malignancy, burns, and tissue injury.

What is lymphedema?

A collection of protein-rich fluid in tissues due to obstructed lymph flow.

What are some causes of obstructed lymph flow?

Cancers, surgical removal of lymph nodes, parasites, infections, trauma, or improper development of the lymphatic system.

What are the life-threatening locations for edema?

Brain, larynx, and lungs.

How does edema impair function in extremities and joints?

It increases the distance for oxygen, nutrients, and waste to diffuse, making tissues susceptible to injury.

What is pitting edema?

When tissue is compressed with a finger, it leaves an imprint due to fluid accumulation exceeding the absorptive capacity of tissue gel.

What is non-pitting edema?

A condition where plasma proteins accumulate in interstitial spaces, often seen in lymphedema.

What is 'third spacing'?

The accumulation of fluid in the transcellular compartment, such as serous cavities like the pericardial sac, peritoneal cavity, and pleural cavity.

What contributes to weight gain in the context of fluid accumulation?

Fluid in the third space contributes to weight gain, not vascular volume.

What is hydrothorax?

Excessive fluid in the pleural cavity.

What is ascites?

Fluid accumulation within the peritoneal cavity.

What regulates extracellular fluid volume?

Sodium (Na+) regulates extracellular fluid volume.

How does the body respond to low extracellular fluid volume?

It increases renal sodium and water retention.

What role do baroreceptors play in fluid balance?

They monitor volume by detecting vessel wall stretching.

What is the primary regulator of water intake?

Thirst, controlled by the hypothalamus.

What triggers the sensation of thirst?

Changes in extracellular fluid osmolality, specifically a 1-2% change.

What is hypodipsia?

A decreased ability to sense thirst, often due to hypothalamus lesions or age.

What is polydipsia?

Excessive thirst that can be symptomatic or inappropriate despite adequate hydration.

What are some causes of excessive thirst?

Conditions like congestive heart failure, diabetes mellitus, chronic kidney disease, and dry mouth.

What is the role of antidiuretic hormone (ADH) in fluid balance?

ADH regulates water output through the kidneys.

What are the two stimuli for true thirst?

Cellular dehydration and a decrease in blood volume.

What is the primary issue in Diabetes Insipidus (DI)?

A deficiency or decreased response to ADH (vasopressin) affecting water reabsorption.

What are the main symptoms of Diabetes Insipidus?

Excessive thirst and excretion of large amounts of urine (3-20 L/day).

What is Neurogenic Diabetes Insipidus?

A condition caused by a defect in ADH synthesis or release, leading to partial ability to concentrate urine.

What can cause temporary Neurogenic DI?

Brain surgery or head injury.

What characterizes Nephrogenic Diabetes Insipidus?

Kidneys are unresponsive to ADH, impairing urine concentration and free water conservation.

What are some causes of Nephrogenic DI?

Drugs (like lithium), genetic factors, and electrolyte disorders (hypokalemia, chronic hypercalcemia).

What diagnostic tests are used for Diabetes Insipidus?

24-hour urine collection, hypothalamus scan, and ADH challenge.

What is the main issue in the Syndrome of Inappropriate Antidiuretic Hormone (SIADH)?

Failure of the negative feedback loop to turn off ADH, leading to inappropriate secretion.

What are the clinical manifestations of SIADH?

Similar to hyponatremia, including water retention and dilutional hyponatremia.

What are the five cardinal features used to diagnose SIADH?

Hypotonic hyponatremia, natriuresis (Na+ in urine > 20 mEq/L), urine osmolality > plasma osmolality, absence of edema, and normal renal, thyroid, adrenal function.

What is isotonic volume deficit?

A condition where water and sodium are lost together, leading to hypovolemia.

What are some causes of isotonic volume deficit?

Body fluid loss (vomiting, diarrhea), decreased intake, kidney disease, diuretic therapy, and excess sweating.

What are the manifestations of isotonic volume deficit?

Thirst, weight loss, low blood pressure, thready pulse, postural hypotension, decreased urine output, and increased urine osmolality.

What is isotonic volume excess?

An expansion of extracellular fluid (ECF) leading to increased interstitial and vascular volumes.

What are common causes of isotonic volume excess?

Renal disease, heart failure, liver failure, and corticosteroid excess.

What are the manifestations of isotonic volume excess?

Weight gain, edema, increased central venous pressure, and respiratory symptoms like shortness of breath.

What is the significance of weight gain in fluid volume excess?

Weight gain can indicate the severity of volume excess: mild (2%), moderate (5%), severe (8%).

What is the relationship between sodium and water in isotonic volume deficit?

Proportional losses of sodium and water occur, leading to a decrease in extracellular fluid.

What can cause dilutional decrease in BUN and HCT in isotonic volume excess?

Increased fluid volume leading to dilution of blood components.

What is the role of ADH in the body?

ADH regulates water reabsorption in the kidneys, affecting urine concentration.

How does SIADH affect serum osmolality?

ADH is secreted in the absence of decreased serum osmolality, leading to water retention.

What are some transient stimuli that can cause SIADH?

Surgery, pain, stress, and temperature changes.

What plasma sodium level is classified as low sodium (hyponatremia)?

Plasma Na+ < 135 mEq/L

What are the three classifications of hyponatremia based on volume status?

Hypovolemic, Normovolemic, Hypervolemic

What causes hypovolemic hyponatremia?

Loss of both water and sodium, such as through excessive sweating, GI losses (vomiting, diarrhea), or dilute formula in infants.

What is the primary mechanism behind normovolemic hyponatremia?

Retention of water that dilutes sodium levels, often due to conditions like SIADH or excessive water intake.

What conditions are associated with hypervolemic hyponatremia?

Fluid overload conditions such as edema-associated disorders, decompensated heart failure, advanced liver disease, and renal disease.

What are some clinical manifestations of hyponatremia?

Decreased serum osmolality, cellular swelling, muscle cramps, weakness, fatigue, nausea, vomiting, and in severe cases, stupor or coma.

What is the treatment for hyponatremia?

Fix the underlying cause of the sodium imbalance.

What plasma sodium level is classified as hypernatremia?

Na+ > 145 mEq/L.

What are the common causes of hypernatremia?

Net water loss through GI, kidneys, lungs, skin, or rapid ingestion of sodium without water replacement.

What are the clinical manifestations of hypernatremia?

ECF loss, cellular dehydration, weight loss, increased blood cell concentration, thirst, decreased urine output, and CNS symptoms like agitation and headache.

What is the treatment for hypernatremia?

Fix the underlying cause and replace fluids.

What is the normal range for serum potassium levels?

3.5-5.5 mEq/L.

What is the primary role of potassium in the body?

It is crucial for osmotic cell integrity, acid-base balance, nerve impulse conduction, and muscle excitability.

What are the causes of hypokalemia?

Inadequate intake, excessive renal loss (e.g., diuretics), excessive GI losses (vomiting, diarrhea), and transcellular shifts.

What are the clinical manifestations of hypokalemia?

Serum K+ < 3.5 mEq/L, impaired urine concentration, GI symptoms (anorexia, nausea, constipation), neuromuscular weakness, and cardiovascular issues.

What is the most serious effect of hypokalemia?

Cardiovascular function impairment.

What are some treatment options for hypokalemia?

Increase dietary potassium intake, oral potassium supplements, and controlled IV potassium replacement.

What role does aldosterone play in potassium balance?

Aldosterone regulates the elimination of potassium by the kidneys.

What is the significance of potassium in metabolic activities?

It is involved in converting glucose to glycogen and maintaining resting membrane potential.

What are the early signs of hyponatremia related to the musculoskeletal system?

Muscle cramps, weakness, and fatigue.

What is a sign of excess intracellular water in hyponatremia?

Fingerprint edema, where pressing on the sternum leaves an indentation.

What can extremely low sodium levels lead to?

Feelings of impending doom, depression, lethargy, stupor, or coma.

What is hyperkalemia and what are its causes?

Hyperkalemia is an elevated serum potassium level (> 5 mEq/L) caused by excessive intake, release from intracellular compartments (tissue trauma, burns, extreme exercise), or inadequate renal elimination (renal failure, adrenal insufficiency, K+ sparing diuretics).

What are the manifestations of hyperkalemia?

Manifestations include GI symptoms (nausea, vomiting, intestinal cramps, diarrhea), neuromuscular symptoms (paresthesias, weakness, dizziness, muscle cramps), and cardiovascular issues (ECG changes, risk of cardiac arrest).

What is the most serious effect of hyperkalemia?

The most serious effect is cardiac conduction issues leading to ventricular fibrillation and cardiac arrest.

What treatments are used for hyperkalemia?

Treatments include moving potassium out of the extracellular fluid using sodium bicarbonate, IV insulin, and glucose.

What is hypocalcemia and what are its causes?

Hypocalcemia is a low serum calcium level (< 8.5 mg/dL) caused by abnormal renal losses, impaired mobilization from bone, decreased intake/absorption, and increased protein binding.

What are the manifestations of hypocalcemia?

Manifestations include cardiovascular symptoms (hypotension, prolonged QT interval), neuromuscular excitability (paresthesias, muscle cramps, tetany), and chronic skeletal problems (osteomalacia, fractures).

What are Chvostek and Trousseau signs?

Chvostek sign is facial spasm upon tapping the facial nerve below the temple. Trousseau sign is the contraction of fingers and hand when a BP cuff is inflated above systolic for 3 minutes, indicating tetany.

What is hypercalcemia and what are its causes?

Hypercalcemia is an elevated serum calcium level (> 10.5 mg/dL) caused by increased intestinal absorption (excessive Vitamin D), increased bone resorption (parathyroid hormone, malignancies), and decreased elimination (thiazide diuretics).

What are the manifestations of hypercalcemia?

Manifestations include impaired urine concentration, gastrointestinal symptoms (anorexia, nausea, constipation), neuromuscular symptoms (muscle weakness, atrophy), and CNS effects (lethargy, stupor).

What is hypophosphatemia and what are its causes?

Hypophosphatemia is a low serum phosphorus level (< 2.5 mg/dL) caused by decreased intestinal absorption, increased renal elimination, and malnutrition.

What are the manifestations of hypophosphatemia?

Manifestations include neurological symptoms (tremors, confusion, seizures), musculoskeletal symptoms (muscle weakness, bone pain), and impaired RBC metabolism.

What is hyperphosphatemia and what are its causes?

Hyperphosphatemia is an elevated serum phosphorus level (> 4.5 mg/dL) commonly caused by impaired renal function, acute phosphate overload, and intracellular-to-extracellular shifts.