Electrolyte Disturbances Flashcards
what ECG abnormalities are seen with hyperkalemia?
- peaked T wave
- flat P wave
- prolonged PR interval
- Wide QRS
Hypokalemia and hypomagnesemia can occur together d/t what?
impaired renal absorption
How is hypermagnesemia treated?
- calcium gluconate for cardiac issues
- dialysis if severe
What are the 3 causes of hypovolemic hyponatremia?
- diuretics
- cerebral salt wasting
- Addison’s disease
What medication can be used to reverse the cardiac adverse effects with hyperkalemia?
- calcium gluconate
What are the 3 causes of hypernatremia?
- free water loss
- loss of water > sodium loss
- gain of sodium > water
What are the 2 main causes of hypercalcemia?
- hyperparathyroidism
- malignancy
How is hypovolemic hypernatremia treated?
- volume resuscitation with IVF
- replace free water deficit
What is the effect of hyperkalemia on the heart?
- slows impulse transmission in the heart resulting in possible cardiac arrest
How is hypokalemia treated?
giving back potassium PO or IV
How is hypervolemic hyponatremia treated?
- fluid restriction + diuretics
What is the most common cause of community acquired hypernatremia?
hypovolemic hypernatremia
What is the maximum change of free water deficit that is safe per day?
8-12 mEq/L/hr
How is euvolemic hypernatremia diagnosed?
- failure of urine osm to increase after fluid restriction
What is the treatment for hypervolemic hypernatremia?
- remove source + give diuretics
- AND correct free water deficit
What lab findings are diagnostic for euvolemic hyponatremia?
- high urine Osm and high urine Na
What are the 2 causes of hypovolemic hypernatremia?
- excessive diuresis
- sweating, diarrhea, hypodipsia
What are the 3 causes of hypervolemic hyponatremia?
- Heart failure (low urine Na)
- Cirrhosis (low urine Na)
- Renal failure (high urine Na)
How is refeeding syndrome treated?
electrolyte repletion and careful monitoring
How is euvolemic hypernatremia treated for patients without central DI vs. with central DI?
- no CDI = replace free water deficit
- CDI = replace free water deficit + DDAVP
This is a potentially fatal shift in fluids + electrolytes that may occur in malnourished patients receiving enteral/parenteral feeds.
refeeding syndrome
Encephalopathy, headache, nausea, vomiting, seizures are all consistent with what electrolyte disturbance?
- hyponatremia
What medication can be given to temporarily treat hyperkalemia d/t a transcellular shift?
- insulin
- AND dextrose (to prevent hypoglycemia)
How fast should you treat symptomatic severe hypovolemic hyponatremia?
4-6 mEq/L in the first 1-2 hours to reach 120 mEq/L
What are the 4 causes of hyperkalemia d/t a transcellular shift?
- acidosis
- DKA
- tumor lysis syndrome/rhabdo
- Drugs (e.g. digitalis)
What is the main cause of euvolemic hyponatremia?
SIADH
How is hypocalcemia treated?
- CaCl
- OR calcium gluconate
How do you measure plasma osmolality?
= (2 x Na+) + (Glucose/18) + BUN/2.8)
What is the difference between central vs. nephrogenic DI?
- central DI = no ADH release
- Nephrogenic DI = poor renal response to ADH
What is the normal range for potassium?
3.5-5.0 mEq/L
What is the normal range for sodium?
135-145
What is the main cause of euvolemic hypernatremia?
- diabetes insipidus
The majority of potassium is excreted how?
through urine
Bone pain, kidney stones, constipation, depressed mood are all consistent with what electrolyte abnormality?
- hypercalcemia
What medication blocks aldosterone via competitive binding of receptors?
- spironolactone
What drugs are known to cause hypomagnesemia?
- diuretics
What is the hallmark sign of refeeding syndrome?
hypophosphatemia
What fluid should be used to correct free water deficit? How fast should this be done?
- pure water via gut OR D5W IV
- no faster than 0.5 mEq/L/hr
How is hypomagnesemia treated?
2g MgSO4 IV over 2-5 min
How is hyperphosphatemia treated?
- phosphate binders in GI tract (e.g. sucralfate)
- calcium acetate tablets IF hypocalcemia
- OR dialysis
what ECG abnormalities are seen with hypokalemia?
- U waves
- T wave flattening or TWI
- QT prolongation
What are the 3 causes of hyperkalemia d/t impaired excretion?
- renal failure
- addison’s disease
- HTN drugs/ NSAIDs
First degree AV block can happen with this electrolyte disturbance.
- Hypermagnesemia
If a patient has hypovolemic hyponatremia and is symptomatic ( Na <120) what is the treatment?
- hypertonic saline (3%)
* to reduce cerebral edema
What are the 5 causes of hypokalemia d/t a total body loss?
- diuretics
- hypomagnesemia
- large NG drainage
- diarrhea
- cushing syndrome
What hormone stimulates K+ secretion in distal nephron?
- Aldosterone
Thirst, AMS, seizures, hyperreflexia, lethargy. These clinical features are consistent with what electrolyte disturbance?
- hypernatremia
In what 2 conditions might you see pseudohyperkalemia?
- hemolysis during blood draw
- severe leukocytosis/thrombocytosis
*repeat lab draw!!
What are 4 causes of pseudohyponatremia?
- high triglycerides (>1500 mg/dL)
- high protein level
- profound hyperglycemia
- exogenous osmoles (e.g. mannitol, contrast dye)
What are the 5 indications for renal replacement therapy (RRT)?
- acidosis
- electrolyte imbalances
- intoxicants (lithium, ASA, etc.)
- overload (fluid)
- uremia
What % of patients with acute renal failure in ICU will require RRT?
70%
How is hypercalcemia treated?
- IVF
- AND glucocorticoids/ bisphosphonates
- OR dialysis
How is hypovolemic hyponatremia treated?
- isotonic fluid administration
- IF taking diuretics = STOP
- IF adrenal insufficiency = fludrocortisone
What is the risk of correcting the free water deficit too fast?
- brain swelling
Blood transfusions and Heparin administration can cause this electrolyte disturbance.
- hypocalcemia
What are the 4 causes of hypokalemia d/t a transcellular shift?
- B2 agonism (albuterol)
- Insulin
- Alkalosis
- Hypothermia
How is hypophosphatemia treated?
give back phosphorus (NaPO4 or KPO4)
Chvostek’s and Trousseau’s sign are consistent with this electrolyte disturbance.
- hypocalcemia
How is euvolemic hyponatremia treated?
- fluid restriction and treat underlying cause
What ECG changes are seen with hypocalcemia?
- prolonged QTc interval via ST prolongation
What is the formula to correct hyperosmotic hyponatremia d/t hyperglycemia?
increase Na+ by 1.6 mEq for every 100 mg/dL of glucose over 100 mg/dL
What is the normal range for total calcium on BMP (ionized + bound)?
9-10 mg/dL
Muscle weakness, constipation, palpitations, and fatigue are all clinical symptoms of what electrolyte disturbance?
- hypokalemia
What is the normal level of magnesium?
2.0 mg/dL
What is the most common cause of hypophosphatemia?
- intracellular shift d/t refeeding syndrome
Respiratory muscle weakness, low cardiac output, and hemolytic anemia is consistent with what electrolyte disturbance?
- hypophosphatemia
What are the 3 common causes of hypervolemic hypernatremia?
- Sodium bicarbonate infusions
- aggressive hypertonic saline for high ICP
- excessive salt ingestion
What drugs can be used to remove excess K+ from the body in the setting of hyperkalemia? (2 options)
- Kayexalate
- Veltassa
What is the normal range for phosphorus?
2.5-5 mg/dL
What ECG abnormalities are seen with hypomagnesemia?
- torsades de pointes
What are the 3 goals of hyperkalemia treatment?
- reverse cardiac adverse effects
- transcellular shift into cells
- remove excess K+ from body
