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Symptoms and Signs – Differential Diagnosis of Hyponatremia
HYPOTONIC HYPONATREMIA
Isovolemic Hyponatremia
• Syndrome of inappropriate antidiuretic hormone (SIADH)
• Water intoxication (e.g., schizophrenic patients, primary polydipsia, sodium-free irrigant solutions, multiple tap-water enemas, dilute infant formulas). These entities are rare and often associated with a deranged antidiuretic hormone (ADH) axis.
• Renal failure
• Reset osmostat (e.g., chronic active TB, carcinomatosis)
• Glucocorticoid deficiency (hypopituitarism)
• Hypothyroidism
• Thiazide diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), carbamazepine, amitriptyline, thioridazine, vincristine, cyclophosphamide, colchicine, tolbutamide, chlorpropamide, angiotensin-converting enzyme (ACE) inhibitors, clofibrate, oxytocin, selective serotonin reuptake inhibitors (SSRIs), amiodarone. With these medications, various drug-induced mechanisms are involved.
Hypovolemic Hyponatremia
• Renal losses (diuretics, partial urinary tract obstruction, salt-losing renal disease)
• Extrarenal losses: GI (vomiting, diarrhea), extensive burns, third spacing (peritonitis, pancreatitis)
• Adrenal insufficiency
Hypervolemic Hyponatremia
• Congestive heart failure (CHF)
• Nephrotic syndrome
• Cirrhosis
• Pregnancy
ISOTONIC HYPONATREMIA
Normal Serum Osmolality
• Pseudohyponatremia (increased serum lipids and serum proteins). Newer sodium assays eliminate this problem.
• Isotonic infusion (e.g., glucose, mannitol)
HYPERTONIC HYPONATREMIA
Increased Serum Osmolality
• Hyperglycemia: each 100 mg/dL increment in blood glucose level above normal decreases plasma sodium concentration by 1.6 mEq/L
• Hypertonic infusions (e.g., glucose, mannitol)
HYPOTONIC HYPONATREMIA
Isovolemic Hyponatremia
• Syndrome of inappropriate antidiuretic hormone (SIADH)
• Water intoxication (e.g., schizophrenic patients, primary polydipsia, sodium-free irrigant solutions, multiple tap-water enemas, dilute infant formulas). These entities are rare and often associated with a deranged antidiuretic hormone (ADH) axis.
• Renal failure
• Reset osmostat (e.g., chronic active TB, carcinomatosis)
• Glucocorticoid deficiency (hypopituitarism)
• Hypothyroidism
• Thiazide diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), carbamazepine, amitriptyline, thioridazine, vincristine, cyclophosphamide, colchicine, tolbutamide, chlorpropamide, angiotensin-converting enzyme (ACE) inhibitors, clofibrate, oxytocin, selective serotonin reuptake inhibitors (SSRIs), amiodarone. With these medications, various drug-induced mechanisms are involved.
Hypovolemic Hyponatremia
• Renal losses (diuretics, partial urinary tract obstruction, salt-losing renal disease)
• Extrarenal losses: GI (vomiting, diarrhea), extensive burns, third spacing (peritonitis, pancreatitis)
• Adrenal insufficiency
Hypervolemic Hyponatremia
• Congestive heart failure (CHF)
• Nephrotic syndrome
• Cirrhosis
• Pregnancy
ISOTONIC HYPONATREMIA
Normal Serum Osmolality
• Pseudohyponatremia (increased serum lipids and serum proteins). Newer sodium assays eliminate this problem.
• Isotonic infusion (e.g., glucose, mannitol)
HYPERTONIC HYPONATREMIA
Increased Serum Osmolality
• Hyperglycemia: each 100 mg/dL increment in blood glucose level above normal decreases plasma sodium concentration by 1.6 mEq/L
• Hypertonic infusions (e.g., glucose, mannitol)
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Symptoms and Signs – Differential Diagnosis of Serum Hypo-osmolality
• Syndrome of inappropriate antidiuretic hormone (SIADH)
• Overhydration
• Hypothyroidism
• Hyponatremia
• Addison’s disease
• Syndrome of inappropriate antidiuretic hormone (SIADH)
• Overhydration
• Hypothyroidism
• Hyponatremia
• Addison’s disease
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Symptoms and Signs – Differential Diagnosis of Urine Hypo-osmolality
• IV hydration with D5W
• Glomerulonephritis
• Excessive water intake
• Diabetes insipidus (DI)
• Acute renal insufficiency
• IV hydration with D5W
• Glomerulonephritis
• Excessive water intake
• Diabetes insipidus (DI)
• Acute renal insufficiency
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Symptoms and Signs – Differential Diagnosis of Hypophosphatemia
• Decreased intake (prolonged starvation, hyperalimentation, or IV infusion without phosphate)
• Malabsorption
• Phosphate-binding antacids
• Renal loss: renal tubular acidosis (RTA), Fanconi’s syndrome, vitamin D–resistant rickets, tyrosinase-negative oculocutaneous albinism (ATN) (diuretic phase), hyperparathyroidism (primary or secondary), familial hypophosphatemia, hypokalemia, hypomagnesemia, acute volume expansion, glycosuria, idiopathic hypercalciuria, acetazolamide
• Transcellular shift into cells: alcohol withdrawal, diabetic ketoacidosis (DKA) (recovery phase), glucose-insulin or catecholamine infusion, anabolic steroids, total parenteral nutrition, theophylline overdose, severe hyperthermia, recovery from hypothermia, “hungry bones” syndrome
• Decreased intake (prolonged starvation, hyperalimentation, or IV infusion without phosphate)
• Malabsorption
• Phosphate-binding antacids
• Renal loss: renal tubular acidosis (RTA), Fanconi’s syndrome, vitamin D–resistant rickets, tyrosinase-negative oculocutaneous albinism (ATN) (diuretic phase), hyperparathyroidism (primary or secondary), familial hypophosphatemia, hypokalemia, hypomagnesemia, acute volume expansion, glycosuria, idiopathic hypercalciuria, acetazolamide
• Transcellular shift into cells: alcohol withdrawal, diabetic ketoacidosis (DKA) (recovery phase), glucose-insulin or catecholamine infusion, anabolic steroids, total parenteral nutrition, theophylline overdose, severe hyperthermia, recovery from hypothermia, “hungry bones” syndrome
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Symptoms and Signs – Differential Diagnosis of Hypopigmentation
• Atopic dermatitis
• Chemical leukoderma
• Idiopathic hypomelanosis
• Nevoid hypopigmentation
• Oculocutaneous albinism
• Phenylketonuria (PKU)
• Sarcoidosis
• Scleroderma
• Systemic lupus erythematosus (SLE)
• Tinea versicolor
• Vitiligo
• Atopic dermatitis
• Chemical leukoderma
• Idiopathic hypomelanosis
• Nevoid hypopigmentation
• Oculocutaneous albinism
• Phenylketonuria (PKU)
• Sarcoidosis
• Scleroderma
• Systemic lupus erythematosus (SLE)
• Tinea versicolor
• Vitiligo
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Symptoms and Signs – Differential Diagnosis of Hypopituitarism
• Acquired: the result of destruction of pituitary cells caused by
• Congenital: mutations in transcription factors produce multiple hormonal deficiencies. Mutations in genes produce single hormonal deficiency.
• Infiltrative disease, including sarcoidosis, hemochromatosis, histiocytosis X, Wegener’s granulomatosis, lymphocytic hypophysitis, and infection of the pituitary (tuberculosis,
• Pituitary apoplexy: hemorrhage or infarction of the pituitary gland. Predisposing factors include diabetes mellitus, anticoagulation therapy, head trauma, and radiation therapy. Sheehan’s syndrome: postpartum necrosis, a rare complication after pregnancy.
• Pituitary tumors: classified by size (microadenomas, <10 mm; macroadenomas, >10 mm) and function. Prolactin-secreting tumors and nonfunctioning tumors account for the majority of pituitary adenomas.
• Primary empty sella syndrome: flattening of the pituitary gland caused by extension of the subarachnoid space and filling of cerebrospinal fluid into the sella turcica
• Suprasellar tumors: craniopharyngiomas are the most common.
mycosis, syphilis)
• Acquired: the result of destruction of pituitary cells caused by
• Congenital: mutations in transcription factors produce multiple hormonal deficiencies. Mutations in genes produce single hormonal deficiency.
• Infiltrative disease, including sarcoidosis, hemochromatosis, histiocytosis X, Wegener’s granulomatosis, lymphocytic hypophysitis, and infection of the pituitary (tuberculosis,
• Pituitary apoplexy: hemorrhage or infarction of the pituitary gland. Predisposing factors include diabetes mellitus, anticoagulation therapy, head trauma, and radiation therapy. Sheehan’s syndrome: postpartum necrosis, a rare complication after pregnancy.
• Pituitary tumors: classified by size (microadenomas, <10 mm; macroadenomas, >10 mm) and function. Prolactin-secreting tumors and nonfunctioning tumors account for the majority of pituitary adenomas.
• Primary empty sella syndrome: flattening of the pituitary gland caused by extension of the subarachnoid space and filling of cerebrospinal fluid into the sella turcica
• Suprasellar tumors: craniopharyngiomas are the most common.
mycosis, syphilis)
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Symptoms and Signs – Differential Diagnosis of Hypoproteinemia
• Chronic diseases
• Cirrhosis
• Low-protein diet
• Malabsorption
• Malnutrition
• Neoplasms
• Nephrosis
• Overhydration
• Pregnancy
• Severe burns
• Chronic diseases
• Cirrhosis
• Low-protein diet
• Malabsorption
• Malnutrition
• Neoplasms
• Nephrosis
• Overhydration
• Pregnancy
• Severe burns
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Symptoms and Signs – Differential Diagnosis of Postural Hypotension
• Adrenal insufficiency
• Antihypertensive medications (especially α-blockers, diuretics, angiotensin-converting enzyme [ACE] inhibitors)
• Central autonomic dysfunction (Shy-Drager syndrome)
• Idiopathic orthostatic hypotension
• Impaired cardiac output (constrictive pericarditis, aortic stenosis)
• Peripheral autonomic dysfunction (diabetes mellitus [DM], Guillain-Barré)
• Peripheral venous disease
• Volume depletion (hemorrhage, dehydration)
• Adrenal insufficiency
• Antihypertensive medications (especially α-blockers, diuretics, angiotensin-converting enzyme [ACE] inhibitors)
• Central autonomic dysfunction (Shy-Drager syndrome)
• Idiopathic orthostatic hypotension
• Impaired cardiac output (constrictive pericarditis, aortic stenosis)
• Peripheral autonomic dysfunction (diabetes mellitus [DM], Guillain-Barré)
• Peripheral venous disease
• Volume depletion (hemorrhage, dehydration)
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Symptoms and Signs – Differential Diagnosis of Hypothermia
• Cerebrovascular accident (CVA)
• Drug intoxication
• Hypoglycemia
• Myxedema coma
• Cerebrovascular accident (CVA)
• Drug intoxication
• Hypoglycemia
• Myxedema coma
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Symptoms and Signs – Differential Diagnosis of Hypothyroidism
• Chronic fatigue syndrome
• Dementia from other causes
• Depression
• Systemic disorders (e.g., nephrotic syndrome, congestive heart
failure [CHF], amyloidosis)
• Chronic fatigue syndrome
• Dementia from other causes
• Depression
• Systemic disorders (e.g., nephrotic syndrome, congestive heart
failure [CHF], amyloidosis)
