Hypophosphatemia | |
---|---|
Other names | Low blood phosphate, phosphate deficiency, hypophosphataemia |
Phosphate group chemical structure | |
Specialty | Endocrinology |
Symptoms | Weakness, trouble breathing, loss of appetite[1] |
Complications | Seizures, coma, rhabdomyolysis, softening of the bones[1] |
Causes | Alcohol use disorder, refeeding in those with malnutrition, hyperventilation, diabetic ketoacidosis, burns, certain medications[1] |
Diagnostic method | Blood phosphate < 0.81 mmol/L (2.5 mg/dL)[1] |
Treatment | Based on the underlying cause, phosphate[1][2] |
Frequency | 2% (people in hospital)[1] |
Hypophosphatemia is an electrolyte disorder in which there is a low level of phosphate in the blood.[1] Symptoms may include weakness, trouble breathing, and loss of appetite.[1] Complications may include seizures, coma, rhabdomyolysis, or softening of the bones.[1]
Causes include alcohol use disorder, refeeding in those with malnutrition, recovery from diabetic ketoacidosis, burns, hyperventilation, and certain medications.[1] It may also occur in the setting of hyperparathyroidism, hypothyroidism, and Cushing syndrome.[1] It is diagnosed based on a blood phosphate concentration of less than 0.81 mmol/L (2.5 mg/dL).[1] When levels are below 0.32 mmol/L (1.0 mg/dL) it is deemed to be severe.[2]
Treatment depends on the underlying cause.[1] Phosphate may be given by mouth or by injection into a vein.[1] Hypophosphatemia occurs in about 2% of people within hospital and 70% of people in the intensive care unit (ICU).[1][3]
Primary hypophosphatemia is the most common cause of non-nutritional rickets. Laboratory findings include low-normal serum calcium, moderately low serum phosphate, elevated serum alkaline phosphatase, and low serum 1,25 dihydroxy-vitamin D levels, hyperphosphaturia, and no evidence of hyperparathyroidism.[8]
Hypophosphatemia decreases 2,3-bisphosphoglycerate (2,3-BPG) causing a left shift in the oxyhemoglobin curve.[citation needed]
Other rarer causes include:
Hypophosphatemia is caused by the following three mechanisms:
Hypophosphatemia is diagnosed by measuring the concentration of phosphate in the blood. Concentrations of phosphate less than 0.81 mmol/L (2.5 mg/dL) are considered diagnostic of hypophosphatemia, though additional tests may be needed to identify the underlying cause of the disorder.[9]
Standard intravenous preparations of potassium phosphate are available and are routinely used in malnourished people and people who consume excessive amounts of alcohol. Supplementation by mouth is also useful where no intravenous treatment are available. Historically one of the first demonstrations of this was in people in concentration camp who died soon after being re-fed: it was observed that those given milk (high in phosphate) had a higher survival rate than those who did not get milk.[citation needed]
Monitoring parameters during correction with IV phosphate[10]