Phosphate Balance Flashcards
What is the normal phosphate level?
The normal range for phosphorus is 2.7 to 4.5 mg/dL. The
symptoms of paresthesias, myopathy, delirium, seizures, and
coma correspond to hypophosphatemia.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 355.
How does respiratory alkalosis affect the renal
excretion of phosphate?
Respiratory alkalosis decreases the renal excretion of
phosphate.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 355.
How does fluid volume expansion affect the renal
excretion of phosphate?
Volume expansion increases the renal excretion of phosphate.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 355.
What are the three primary factors that influence the
renal reabsorption of phosphate by the kidneys?
Dietary intake, parathyroid hormone, and insulin-like growth
factor.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 355.
Where is the majority of the body’s phosphorus
located?
About 90% of the body’s phosphorus is found in bone. Almost
10% is located in the intracellular fluid. The <1% remaining is
found in the extracellular fluid.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 355.
What is a potential effect of administering phosphate
to patients who are hypocalcemic?
The administration of phosphate to hypocalcemic patients could
exacerbate the hypocalcemia.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 356.
How does hyperventilation affect the phosphate
level?
Respiratory alkalosis from hyperventilation decreases
phosphate levels. Respiratory alkalosis is also presumed to be
the cause of hypophosphatemia associated with gram-negative
sepsis and salicylate poisoning.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 355-356.
What is ‘refeeding syndrome’?
Carbohydrate loading can induce hypophosphatemia via an
insulin-mediated uptake of phosphorus. This is the most
common form of hypophosphatemia seen in hospitalized
patients.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 356.
How does hypophosphatemia affect hematologic
function?
Hypophosphatemia results in dysfunction of red and white blood
cells as well as platelets. Because the phagocytic, chemotaxic,
and bactericidal activity of the white blood cells is diminished,
hypophosphatemia can contribute to a patient’s susceptibility to
sepsis.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 356.
What are the neurologic symptoms of
hypophosphatemia?
Paresthesias, myopathy and, encephalopathy.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 1134-1135.
How is hyperphosphatemia treated in patients with
renal failure?
Limited phosphate intake and aluminum hydroxide ingestion
can help ameliorate hyperphosphatemia, but dialysis is the
most effective method for treating it quickly.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 356.
How is hyperphosphatemia treated in patients
without renal failure?
The cause of the elevated phosphate level should be eliminated
(if possible) and any associated hypocalcemia should be
corrected. Phosphate excretion in the urine should be
encouraged with saline and acetazolamide. Gastrointestinal
losses of phosphate can be increased by administering
aluminum hydroxide.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 356.
What is the most common cause of
hyperphosphatemia?
Renal failure
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 356.
What are the three basic mechanisms by which
hyperphosphatemia occurs?
- Inadequate renal excretion of phosphate, 2. the movement of
phosphate from inside the cells to outside the cell, and 3.
increased phosphate or vitamin D intake.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 356.