Clin Med 2 Mod 7 Electrolytes

Symptoms: Agitation, thirst, weakness, lethargy, hyperthermia, seizure, coma, death

Hypernatremia

Symptoms: Weakness, confusion, seizure, coma, death

Hyponatremia

Symptoms: weakness, decreased refelxes, confusion, respiratory paralysis, cardiac arrest

Hypermagnesemia

Symptoms: weakness, muscle cramps, tremors, jerking, nystagmus, confusion, hypertension, tachycardia, ventricular arrhythmias

Hypomagnesemia

Symptoms: Increases muscle/nerve excitation, spasm, tetany, laryngospasm, hyperreflexia, weak cardiac contractions

Hypocalcemia

Symptoms: painful bones, constipation, n/v, lethargy, depression, renal stones, increased FoC, dysrhythmias

Hypercalcemia

Symptoms: Fatigue, muscle weakness, QT prolongation with flat T wave, rhabdomyolysis, cardic arrest

Hypokalemia

Symptoms: Fatigue, muscle weakness, peaked T wave, nausea, progression to muscle/respiratory paralysis, cardiac arrest

Hyperkalemia

Treatment for hypermagnesemia

IV calcium chloride

Severe kidney disease: dialysis

What does hypermagnesemia do to PTH secretion?

Decreases secretion, can lead to hypocalcemia

Most common cause of hypermagnesemia

Advanced CKD, impaired Mg excretion

Other causes of hypermagnesemia

Tumor lysis syndrome, hypothyroidism, treating HTN in pregnancy w/ IV mg

Treatment of hypomagnesemia

oral mg if mild/moerate

IV mg sulfate is severe

You must correct this electrolyte for pts with hypokalemia/hypocalcemia to respond to treatment

Magnesium

Causes of hypomagnesemia

Diminished absorption: alcoholism, diarrhea due to laxative abuse

Increased renal loss: loop diuretics, hyperthyroidism (decreased reabsorption)

Intracellular ion associated with muscle, nerves, heart, bones/teeth, BP control, blood sugar, enzyme function

Magnesium

Treatment for hypercalcemia

Promote renal excretion via aggressive hydration with saline. Avoid loop diuretics (promotes nephrolithiasis)

Malignancy related: bisphosphonates + calcitonin

Causes of hypercalcemia

Overconsumption of calcium antacids, hyperparathyroidism, acromegaly, neoplasms that produce PTH

Treatment of hypocalcemia

Asymptomatic: oral calcium and Vit D

Severe (tetany): IV calcium gluconate

Increased excitation of facial nerve upon tapping on the zygomatic arch. What electrolyte imbalance is this associated with?

Chvotsek's sign, Hypocalcemia

Spasm of the hand and forearm after BP cuff inflation. What electrolyte imbalance is this associated?

Trousseau's sign, hypocalcemia

Causes of hypocalcemia

malabsorption: decreased calcium/vit D, GI bypass

CKD (less Vit D activation), alcoholism, diuretics, hypoparathyroidism, hypomagnesemia

Extracellular cation used in structure/maintenance of bones, muscle contraction, nerve conduction

Calcium

What three molecules are important in the regulation of calcium in the body?

PTH-releases calcium from bone

VIT D- absorbs caclium from GI

Calcitonin (from thyroid)- inhibits release of calcium from bone

Treatment of hyperkalemia

Severe: IV calcium gluconate to stabilize myocardium, beta agonists & insulin to shift K into cells to manage symptoms. Then treat like mild/moderate

mild/moderate: loop diuretics, hemodialysis if necessary

Causes of hyperkalemia

Excessive intake

Increase K release: tumor lysis, fist clenching, trauma, burns, crush injuries, uncontrolled diabetes

Impaired renal secretion due to kidney disease or hypovolemia from HF

Meds: NSAIDS & heparin (decrease aldosterone, decreases K excretion.

Treatment for hypokalemia

mild/mod: oral potassium

Severe <3mEq/L: IV potassium

Laboratory test to determine if hypokalemia is due to a renal or non-renal source

spot urine ratio of urine K : urine Cr

urine spot ration test

<13mEq/g indicates ________________ hypokalemia, >13mEq/g indicates _______________ hypokalemia

non-renal, renal

Dominant intracellular ion that regulates water balance inside cells and is important for muscle contraction

Potassium

Treatment for hypernatremia

Correct cause of water imbalance and replace fluid w/ hypotonic intake or bolus of 5% dextrose

Causes of hypernatremia

Excess sodium intake via meds, diet, drinks

Hyperaldosteronism

diabetes insipidus

dehydration

Treatment for hyponatremia

Chronic/asymptomatic hyponatremia: correct sodium slowly 4-6mEG/L in 24 hrs to avoid cerebral demyelination syndrome

Loop diuretics w/ w/out salt tablets

3% hypertonic soln

Acute/severe pts with seizure/confusion: Hypertonic 3% NaCL 100mL bolus over 10 mins and admit

Small cell lung cancer causes this condition that results in hyponatremia

SIADH

Hypovolemic hyponatremia

Decrease in total body water and total body sodium

Common causes of hypovolemic hyponatremia

diarrhea/vomiting

pancreatitis

third spacing of fluids

burns

diuretics, osmotic diuretics (glucose, mannitol)

Addison's disease (lack of cortisol and aldosterone)

Most common cause of euvolemic hyponatremia

SIADH (ADH keeps water and dilutes blood sodium)

Causes of hypervolemic hyponatremia

Acute/chronic renal failure

nephrotic syndrome

cirrhosis

cardiac failure

What are the lab values for mild, moderate, and severe hyponatremia?

Mild: 130-134mEq/L

Mod: 125-129mEq/L

Severe: <125

Most common cause of hyponatremia

Excess water due to ingestion, renal failure, or too much ADH (SIADH from cancer, meningitis, opioids)

Most im[portant ion in regulating water balance, nerve signalling, and muscle contractions

What is the osmol gap? What is it primarily used for?

It is an indication of unmeasured solutes in the blood, if there's a gap >10mmol/kg this indicates there are toxins within the blood. Most commonly ethanol (can be methanol, mannitol, isopropanol)

How does the body regulate water?

Thirst mechanism and ADH production

How does the body regulate sodium?

RAAS, ANP/BNP