77 Questions
What is the primary cause of hypernatremia from osmotic diuresis in diabetes?
Hyperglycemia
What is the result of extrarenal losses of hypotonic fluids in hypernatremia?
Decreased total body water
Which of the following is a risk factor for hypernatremia?
Excessive sweating
What is the primary goal of treatment for hypernatremia?
Water replacement
What is the cause of hyponatremia in patients with congestive heart failure?
Increased total body water
Which of the following is a cause of euvolemic hyponatremia?
Addison's disease
What is the result of hypernatremia on the brain?
Brain shrinkage
Which of the following is a common cause of hypernatremia in the elderly?
All of the above
What is the term for the inappropriate secretion of antidiuretic hormone?
SIADH
What is the result of diabetes insipidus on urine production?
Dilute urine
What is the basis for deciding for or against surgery in an asymptomatic patient with hypercalcemia?
Complicating problems
What is the typical response to mild hypercalcemia in postmenopausal women?
Estrogen therapy
What is the goal of IV fluid administration in the treatment of hypercalcemia?
To expand ECF and increase renal excretion of calcium
What is the treatment of choice for symptomatic and progressive hyperparathyroidism?
Surgery
What is used to 'map' a tumor prior to surgery in hyperparathyroidism?
99m Tc Sestamibi
What is one of the guidelines for surgery in hypercalcemia?
Calcium > 12 mg/dL
What is the effect of angiotensin II on thirst and GFR?
Increased thirst and decreased GFR
What is the difference in brain H2O content between acute and chronic hyponatremia?
Brain H2O content is less in chronic hyponatremia than expected
What is the characteristic of hyponatremia with hypovolemia?
Decreased total body Na+ and TBW
What is the effect of Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) on urine?
Less than maximally dilute urine
What is the cause of SIADH?
All of the above
What is the diagnostic criterion for SIADH?
Plasma osmolality less than 270 mOsm/kg
What is the characteristic of primary hyperparathyroidism?
Increased serum Ca+, normal PO4-
What is the diagnostic test for hyperparathyroidism?
Parathyroid Hormone Assays by IRMA
What is the treatment approach for mild hypercalcemia?
Conservative approach
What are the symptoms of the so-called asymptomatic patient?
Anxiety, nervousness, daytime sleepiness, and loss of energy
What is the primary consideration for deciding for or against surgery in an asymptomatic patient with hypercalcemia?
Complicating problems
What is the typical treatment for mild hypercalcemia in postmenopausal women?
Estrogens
What is the goal of IV fluid administration in the treatment of hypercalcemia?
To expand the ECF volume and increase renal excretion of calcium
What is the treatment of choice for symptomatic and progressive hyperparathyroidism?
Surgery
What is used to 'map' a tumor prior to surgery in hyperparathyroidism?
99m Tc Sestamibi
What is one of the guidelines for surgery in hypercalcemia?
Calcium > 12 mg
What is the effect of angiotensin II on GFR and thirst?
Decreased GFR and increased thirst
What is the characteristic of hyponatremia with euvolemia?
Near normal total body water and sodium
What is the effect of SIADH on urine concentration?
Urine concentration is less than maximally dilute
What is the underlying mechanism of SIADH?
All of the above
What is the diagnostic criterion for SIADH?
Plasma osmolality less than 275 mmol/L
What is the characteristic of primary hyperparathyroidism?
Increased serum calcium and decreased phosphate
What is the treatment approach for mild hypercalcemia?
Conservative approach
What is the characteristic of the so-called asymptomatic patient with hypercalcemia?
Presence of prominent psychiatric and neuromuscular symptoms
What is the effect of hypothyroidism on sodium levels?
Decreased sodium levels
What is the effect of glucocorticoid deficiency on sodium levels?
Decreased sodium levels
What is the underlying mechanism by which hypernatremia occurs in a patient with diabetes insipidus?
Inability to secrete a concentrated urine due to a defect in ADH production or release
What is the primary cause of hypernatremia in patients who are unable to access water, especially in the elderly?
All of the above
What is the characteristic of hypernatremia with hypovolemia?
Decreased total body water and decreased total body sodium
What is the effect of hypernatremia on the brain?
Brain shrinkage due to water movement out of intracellular spaces
What is the primary cause of euvolemic hyponatremia?
H2O retention by kidneys due to release of ADH
What is the characteristic of hypervolemic hyponatremia?
Increased total body water and increased total body sodium
What is the effect of hypernatremia on mortality?
Mortality of 40-60%
What is the primary goal of treatment for hypernatremia?
Replacement of water deficit
What is the characteristic of hypernatremia with euvolemia?
Increased total body water and near normal total body sodium
What is the effect of excessive sweating on the development of hypernatremia?
Excessive sweating leads to hypotonic fluid loss, which can cause hypernatremia
What is the primary consideration for deciding for or against surgery in an asymptomatic patient with hypercalcemia?
Complicating problems
What is the goal of IV fluid administration in the treatment of hypercalcemia?
to expand ECF and increase renal excretion of Ca+
What is the treatment of choice for symptomatic and progressive hyperparathyroidism?
Surgery
What is used to 'map' a tumor prior to surgery in hyperparathyroidism?
99m Tc Sestamibi
What is the response to mild hypercalcemia in postmenopausal women?
Estrogens
What is the rate of complications in an asymptomatic patient with hypercalcemia?
Low
What is the underlying mechanism by which hypernatremia occurs in a patient with central diabetes insipidus?
Inability to secrete a concentrated urine due to ADH deficiency
What is the characteristic of hypernatremia with hypervolemia?
Increased total body sodium content and normal total body water
What is the primary cause of hypernatremia in patients who are unable to access water, especially in the elderly?
Inability to access water due to physical or mental impairment
What is the effect of hypernatremia on the brain?
Brain stem shrinkage and neuromuscular irritability
What is the characteristic of euvolemic hyponatremia?
Normal total body water and decreased sodium content
What is the primary cause of hyponatremia in patients with congestive heart failure?
Water retention in response to decreased effective circulating volume
What is the underlying mechanism of SIADH?
Inappropriate secretion of antidiuretic hormone
What is the effect of hypernatremia on mortality?
Mortality rate of 40-60%
What is the characteristic of hypervolemic hyponatremia?
Increased total body water and sodium content
What is the effect of angiotensin II on thirst and GFR?
Decreased GFR and stimulation of thirst
What is the characteristic of hyponatremia with hypovolemia?
Decreased total body Na+ and decreased total body water
What is the underlying mechanism of SIADH?
Sustained ADH release with a subnormally low osmostat
What is the diagnostic criterion for SIADH?
Less than maximally dilute urine in the presence of plasma hypoosmolality
What is the characteristic of primary hyperparathyroidism?
Increased serum Ca+, normal PO4-
What is the treatment approach for mild hypercalcemia?
Conservative approach with fluid management
What is the characteristic of the so-called asymptomatic patient with hypercalcemia?
No symptoms, but neuromuscular disturbances
What is the effect of hypothyroidism on sodium levels?
Decreased sodium levels
What is the characteristic of hyponatremia with euvolemia?
Near normal total body Na+ and increased total body water
What is the effect of glucocorticoid deficiency on sodium levels?
Decreased sodium levels
Study Notes
Disorders of Sodium
Hypernatremia
- Definition: Plasma Na+ >145 mEq/L, caused by a deficit of H2O relative to solute
- Mortality: 40-60%
- Pathogenesis: Usually caused by excess loss of H2O from body that is not adequately replaced
- Risk Factors: Vomiting, Diarrhea, Renal disease, Taking loop diuretics, Burns, Excessive sweating
- Pathogenesis (continued): Osmotic diuresis, Renal insufficiency, Diabetes insipidus, Inability to access H2O
- Symptoms: Thirst, CNS Symptoms (Brain stem shrinkage, Confusion, Neuromuscular irritability, Seizures, Coma)
- Treatment: H2O replacement is primary goal, IV with D5W if patient cannot drink
Principle Causes of Hypernatremia
- Hypernatremia with Hypovolemia (Extrarenal losses, Renal losses, Intrinsic renal disease, Osmotic diuresis)
- Hypernatremia with Euvolemia (Inability to access H2O, Primary hypodipsia, Reset osmostat)
- Hypernatremia with Hypervolemia (Hyper-tonic IV fluids, Hypertonic Saline, NaHCO3, TPN)
Disorders of Sodium (continued)
Hyponatremia
- Definition: Plasma Na+ <135 mEq/L, caused by Na+ loss than H2O
- Pathogenesis: Significant ECF loss results in release of ADH, causing H2O retention by kidneys and hyponatremia
- Euvolemic Hyponatremia: Dilutional hyponatremia, Renal failure, Addison's disease, Myxedema, or nonosmotic ADH secretion
- Hypervolemic Hyponatremia: Increase in TBW and total body Na+ content, CHF and Liver Failure
- Symptoms: Effects on CNS, Brain cellular H2O increases in acute and chronic hyponatremia
Principle Causes of Hyponatremia
- Hyponatremia with Hypovolemia (GI, Syndrome of Inappropriate ADH secretion, Congestive Heart Failure, 3rd spacing)
- Hyponatremia with Euvolemia (Diuretics, Osmotic diuresis, Mineralocorticoid deficiency, Salt-losing nephropathies)
- Hyponatremia with Hypervolemia (Congestive Heart Failure, Liver Failure, Renal disease)
Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)
- Definition: Less than maximally dilute urine in presence of plasma hypoosmolality and hyponatremia
- Pathogenesis: Sustained ADH release, Osmotic threshold for ADH release is subnormally low, In some, ADH is not suppressed in presence of low plasma osmolality
- Diagnosing SIADH: Symptoms of hyponatremia, Low PO4- indicates some form of hyperparathyroidism
Disorders of Calcium
- Hypercalcemia: Parathyroid Hormone Assays, PTH by IRMA, Diagnosis is usually made by presence of PTH-related peptide
- Diagnostic Tests: PTH Assays, Check urinary excretion of calcium
- Treatment: If symptoms are mild and Ca+ <15 mg/dL, conservative approach is appropriate, Prominent symptoms include anxiety, nervousness, daytime sleepiness, loss of energy, crying easily, excessive worry, irritability, lack of interest
- Therapy: Rate of complications is low in the asymptomatic patient, Decision for or against surgery is based on complicating problems, Mild hypercalcemia in postmenopausal women may respond to estrogens, For Vitamin D excess, Prednisone usually controls the Ca+
- Treatment (continued): With normal renal function, IV of 0.9% NS with KCL and Lasix, In patients with malignancy, bisphosphonates plus NS and Lasix, If hyperparathyroidism is symptomatic and progressive, surgery is treatment of choice
Disorders of Sodium
Hypernatremia
- Definition: Plasma Na+ >145 mEq/L, caused by a deficit of H2O relative to solute
- Mortality: 40-60%
- Pathogenesis: Usually caused by excess loss of H2O from body that is not adequately replaced
- Risk Factors: Vomiting, Diarrhea, Renal disease, Taking loop diuretics, Burns, Excessive sweating
- Pathogenesis (continued): Osmotic diuresis, Renal insufficiency, Diabetes insipidus, Inability to access H2O
- Symptoms: Thirst, CNS Symptoms (Brain stem shrinkage, Confusion, Neuromuscular irritability, Seizures, Coma)
- Treatment: H2O replacement is primary goal, IV with D5W if patient cannot drink
Principle Causes of Hypernatremia
- Hypernatremia with Hypovolemia (Extrarenal losses, Renal losses, Intrinsic renal disease, Osmotic diuresis)
- Hypernatremia with Euvolemia (Inability to access H2O, Primary hypodipsia, Reset osmostat)
- Hypernatremia with Hypervolemia (Hyper-tonic IV fluids, Hypertonic Saline, NaHCO3, TPN)
Disorders of Sodium (continued)
Hyponatremia
- Definition: Plasma Na+ <135 mEq/L, caused by Na+ loss than H2O
- Pathogenesis: Significant ECF loss results in release of ADH, causing H2O retention by kidneys and hyponatremia
- Euvolemic Hyponatremia: Dilutional hyponatremia, Renal failure, Addison's disease, Myxedema, or nonosmotic ADH secretion
- Hypervolemic Hyponatremia: Increase in TBW and total body Na+ content, CHF and Liver Failure
- Symptoms: Effects on CNS, Brain cellular H2O increases in acute and chronic hyponatremia
Principle Causes of Hyponatremia
- Hyponatremia with Hypovolemia (GI, Syndrome of Inappropriate ADH secretion, Congestive Heart Failure, 3rd spacing)
- Hyponatremia with Euvolemia (Diuretics, Osmotic diuresis, Mineralocorticoid deficiency, Salt-losing nephropathies)
- Hyponatremia with Hypervolemia (Congestive Heart Failure, Liver Failure, Renal disease)
Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)
- Definition: Less than maximally dilute urine in presence of plasma hypoosmolality and hyponatremia
- Pathogenesis: Sustained ADH release, Osmotic threshold for ADH release is subnormally low, In some, ADH is not suppressed in presence of low plasma osmolality
- Diagnosing SIADH: Symptoms of hyponatremia, Low PO4- indicates some form of hyperparathyroidism
Disorders of Calcium
- Hypercalcemia: Parathyroid Hormone Assays, PTH by IRMA, Diagnosis is usually made by presence of PTH-related peptide
- Diagnostic Tests: PTH Assays, Check urinary excretion of calcium
- Treatment: If symptoms are mild and Ca+ <15 mg/dL, conservative approach is appropriate, Prominent symptoms include anxiety, nervousness, daytime sleepiness, loss of energy, crying easily, excessive worry, irritability, lack of interest
- Therapy: Rate of complications is low in the asymptomatic patient, Decision for or against surgery is based on complicating problems, Mild hypercalcemia in postmenopausal women may respond to estrogens, For Vitamin D excess, Prednisone usually controls the Ca+
- Treatment (continued): With normal renal function, IV of 0.9% NS with KCL and Lasix, In patients with malignancy, bisphosphonates plus NS and Lasix, If hyperparathyroidism is symptomatic and progressive, surgery is treatment of choice
Disorders of Sodium
Hypernatremia
- Definition: Plasma Na+ >145 mEq/L, caused by a deficit of H2O relative to solute
- Mortality: 40-60%
- Pathogenesis: Usually caused by excess loss of H2O from body that is not adequately replaced
- Risk Factors: Vomiting, Diarrhea, Renal disease, Taking loop diuretics, Burns, Excessive sweating
- Pathogenesis (continued): Osmotic diuresis, Renal insufficiency, Diabetes insipidus, Inability to access H2O
- Symptoms: Thirst, CNS Symptoms (Brain stem shrinkage, Confusion, Neuromuscular irritability, Seizures, Coma)
- Treatment: H2O replacement is primary goal, IV with D5W if patient cannot drink
Principle Causes of Hypernatremia
- Hypernatremia with Hypovolemia (Extrarenal losses, Renal losses, Intrinsic renal disease, Osmotic diuresis)
- Hypernatremia with Euvolemia (Inability to access H2O, Primary hypodipsia, Reset osmostat)
- Hypernatremia with Hypervolemia (Hyper-tonic IV fluids, Hypertonic Saline, NaHCO3, TPN)
Disorders of Sodium (continued)
Hyponatremia
- Definition: Plasma Na+ <135 mEq/L, caused by Na+ loss than H2O
- Pathogenesis: Significant ECF loss results in release of ADH, causing H2O retention by kidneys and hyponatremia
- Euvolemic Hyponatremia: Dilutional hyponatremia, Renal failure, Addison's disease, Myxedema, or nonosmotic ADH secretion
- Hypervolemic Hyponatremia: Increase in TBW and total body Na+ content, CHF and Liver Failure
- Symptoms: Effects on CNS, Brain cellular H2O increases in acute and chronic hyponatremia
Principle Causes of Hyponatremia
- Hyponatremia with Hypovolemia (GI, Syndrome of Inappropriate ADH secretion, Congestive Heart Failure, 3rd spacing)
- Hyponatremia with Euvolemia (Diuretics, Osmotic diuresis, Mineralocorticoid deficiency, Salt-losing nephropathies)
- Hyponatremia with Hypervolemia (Congestive Heart Failure, Liver Failure, Renal disease)
Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)
- Definition: Less than maximally dilute urine in presence of plasma hypoosmolality and hyponatremia
- Pathogenesis: Sustained ADH release, Osmotic threshold for ADH release is subnormally low, In some, ADH is not suppressed in presence of low plasma osmolality
- Diagnosing SIADH: Symptoms of hyponatremia, Low PO4- indicates some form of hyperparathyroidism
Disorders of Calcium
- Hypercalcemia: Parathyroid Hormone Assays, PTH by IRMA, Diagnosis is usually made by presence of PTH-related peptide
- Diagnostic Tests: PTH Assays, Check urinary excretion of calcium
- Treatment: If symptoms are mild and Ca+ <15 mg/dL, conservative approach is appropriate, Prominent symptoms include anxiety, nervousness, daytime sleepiness, loss of energy, crying easily, excessive worry, irritability, lack of interest
- Therapy: Rate of complications is low in the asymptomatic patient, Decision for or against surgery is based on complicating problems, Mild hypercalcemia in postmenopausal women may respond to estrogens, For Vitamin D excess, Prednisone usually controls the Ca+
- Treatment (continued): With normal renal function, IV of 0.9% NS with KCL and Lasix, In patients with malignancy, bisphosphonates plus NS and Lasix, If hyperparathyroidism is symptomatic and progressive, surgery is treatment of choice
This quiz covers various disorders related to electrolytes such as sodium, calcium, phosphorus, and magnesium, as well as protein disorders in serum and urine. It also touches on uncommon anemias and advanced laboratory tests.
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