Hyperphosphatemia: Symptoms, Diagnosis and Treatment

Index

Definition:

Hyperphosphatemia are abnormally high levels of phosphate in the blood, may be the result of increased phosphate intake, decreased phosphate excretion, or a disorder that shifts intracellular phosphate to the extracellular space.

However, severe hyperphosphatemia is for the most part clinically asymptomatic. Morbidity in patients with this condition is associated more frequently with an underlying disease than with increased phosphate values.

Signs and symptoms

Although the majority of patients with Hyperphosphatemia are asymptomatic, they sometimes report symptoms of hypocalcemia, such as: muscle cramps, tetany, and perioral or tingling numbness. Other symptoms include bone and joint pain, pruritus and rash.

More commonly, patients report symptoms related to the underlying cause of Hyperphosphatemia. These are usually uraemic symptoms, such as the following:

  • Fatigue.
  • Difficulty breathing.
  • Anorexia.
  • Nausea.
  • Vomiting
  • Sleep disorders

In acute hyperphosphatemia, especially that caused by the administration of parenteral phosphate, the patient may be hypotensive or show signs of hypocalcemia, such as the following:

  • Positive Trousseau or Chvostek sign.
  • Hyperreflexia.
  • Carpopedal spasm.
  • Seizure

Diagnosis

The results of a complete chemical profile can be used to determine the cause of Hyperphosphatemia:

Low levels of calcium along with high levels of phosphate: observed with renal failure, hypoparathyroidism. Blood urea nitrogen and creatinine: helps determine if renal failure is the cause of Hyperphosphatemia.

High levels of intact parathyroid hormone (HPI): higher probability in patients with renal failure. Relatively low levels of intact HPI and normal renal function: have been found in patients with primary or acquired hypoparathyroidism.

Serum Calcium and Phosphate elevated in levels observed with: vitamin D intoxication and milk and alkaline syndrome.

Relatively low levels of HPI and high 25 and vitamin D: 1.25 It is also observed in vitamin D intoxication.

Low levels of HPI and vitamin D: seen in milk and alkaline syndrome.

There are other more unusual disorders, such as the following, which may also be considered as the cause:

  • Vitamin D poisoning
  • Laxative abuse (phosphodate).
  • Tumor lysis
  • Rhabdomyolitis
  • Hypoparathyroidism isolated.
  • Pseudohypoparathyroidism

Rarely, if the cause of Hyperphosphatemia is not clear, a measurement of the urinary phosphate can be made within 24 hours. If the results indicate the following:

Fractional renal excretion greater than 15%: suggests either massive ingestion of phosphate (eg, laxative abuse [Fosfosoda] or lysis of tissues and the subsequent release of intracellular phosphate.

Fractional renal excretion not exceeding 15%: suggests that renal excretion deteriorates due to either renal failure or hypoparathyroidism.

Treatment

The main strategies for the treatment of Hyperphosphatemia are the following:

Diagnose and treat the cause: for example, Hyperphosphatemia due to tumor lysis responds to forced saline diuresis to improve urinary losses

Limit phosphate intake: renal failure is the clinical condition that most often require restriction of phosphate ingestion; Patients with advanced renal failure or complete renal failure also require phosphate binders, to inhibit gastrointestinal absorption of phosphate

Improve renal excretion: it is used in patients with normal renal function and Hyperphosphatemia; It can be carried out more effectively by the use of volume replacement with saline solution together with forced diuresis and a loop diuretic such as Furosemide or Bumetanide.