HypophosphatemiaFrom Wikipedia, the free encyclopedia

Jump to: navigation, search This article needs additional citations for verification.Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (March 2008)

Hypophosphatemia

Classification and external resources

Phosphate group chemical structure

ICD-10 E 83.3

ICD-9 275.3

DiseasesDB 6503

MedlinePlus 000307

eMedicine med/1135

MeSH D017674

Hypophosphatemia is an electrolyte disturbance in which there is an abnormally low level of phosphate in the blood. The condition has many causes, but is most commonly seen when malnourished patients (especially chronic alcoholics) are given large amounts of carbohydrates, which creates a high phosphorus demand by cells, removing phosphate from the blood (refeeding syndrome).

Because a decrease in phosphate in the blood is sometimes associated with an increase in phosphate in the urine, the terms hypophosphatemia and "phosphaturia" are occasionally used interchangeably; however, this is improper since there exist many causes of hypophosphatemia besides overexcretion and phosphaturia, and in fact the most common causes of hypophosphatemia are not associated with phosphaturia.

Contents

[hide]

1 Common causes of hypophosphatemia 2 Pathophysiology 3 Major signs and symptoms 4 Treatment 5 See also 6 External links 7 References

[edit] Common causes of hypophosphatemia

Refeeding syndrome This causes a demand for phosphate in cells due to the action of phosphofructokinase, an enzyme that attaches phosphate to glucose to begin metabolism of this. Also, production of ATP when cells are fed and recharge their energy supplies, requires phosphate.

Respiratory alkalosis Any alkalemic condition moves phosphate out of the blood into cells. This includes most common respiratory alkalemia (a higher than normal blood pH from low carbon dioxide levels in the blood), which in turn is caused by any hyperventilation (such as may result from sepsis, fever, pain, anxiety, drug withdrawal, and many other causes).

Alcohol abuse Alcohol impairs phosphate absorption. Alcoholics are usually also malnourished with regard to minerals. In addition, alcohol treatment is associated with refeeding, and the stress of alcohol withdrawal may create respiratory alkalosis, which exacerbates hypophosphatemia (see above).

Malabsorption This includes GI damage, and also failure to absorb phosphate due to lack of vitamin D, or chronic use of phosphate binders such as sucralfate, aluminum-containing antacids, and (more rarely) calcium-containing antacids.

Phosphaturia or hyperexcretion of phosphate in the urine. This condition is divided into primary and secondary types. Primary hypophosphatemia is characterized by direct excess excretion of phosphate by the kidneys, as from primary renal dysfunction, and also the direct action of many classes of diuretics on the kidneys. Additionally, secondary causes, including both types of hyperparathyroidism cause hyperexcretion of phosphate in the urine.

Primary hypophosphatemia is the most common cause of nonnutritional 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.[1]

Other rarer causes include

Certain blood cancers such as lymphoma or leukemia hereditary causes hepatic failure Tumor-induced osteomalacia

[edit] Pathophysiology

Hypophosphatemia is caused by the following three mechanisms:

Inadequate intake (often unmasked in refeeding after long-term low phosphate intake) Increased excretion (e.g. in hyperparathyroidism) Shift from extracellular to intracellular space (seen in treatment of diabetic ketoacidosis,

refeeding, short-term increases in cellular demand (e.g., hungry bones syndrome) and acute respiratory alkalosis)

[edit] Major signs and symptoms

Muscle dysfunction and weakness. This occurs in major muscles, but also may manifest as: diplopia, low cardiac output, dysphagia, and respiratory depression due to respiratory muscle weakness.

Mental status changes. This may range from irritability to gross confusion, delirium, and coma.

White cell dysfunction, causing worsening of infections Instability of cell membranes due to low ATP levels: this may cause rhabdomyolysis with

increased CPK, and also hemolytic anemia.

[edit] Treatment

Standard intravenous preparations of potassium phosphate are available and are routinely used in malnourished patients and alcoholics. Oral supplementation also is useful where no intravenous treatment is available. Historically one of the first demonstrations of this was in concentration camp victims 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.

[edit] See also

Hyperphosphatemia Hypophosphatasia

[edit] External links

eMedicine review Tutorial - complications Refeeding Syndrome

[edit] References

1. ̂ Toy, Girardet, Hormann, Lahoti, McNeese, Sanders, and Yetman. Case Files: Pediatrics, Second Edition. 2007. McGraw Hill.

[hide] v • d • e

Inborn error of metal metabolism (E83, 275)

Transition metal

Cuhigh: Copper toxicity · Wilson's disease

deficiency: Copper deficiency · Menkes disease/Occipital horn syndrome

Fe

high: Primary iron overload disorder: Hemochromatosis/HFE1 · Juvenile/HFE2 · HFE3 · African iron overload/HFE4 · Aceruloplasminemia · Atransferrinemia · Hemosiderosis

deficiency: Iron deficiency

Znhigh: Zinc toxicity

deficiency: Acrodermatitis enteropathica

Electrolyte

PO43−

high: Hyperphosphatemia

deficiency: Hypophosphatemia · alkaline phosphatase (Hypophosphatasia)

Mg 2+ high: Hypermagnesemia

deficiency: Hypomagnesemia

Ca 2+

high: Hypercalcaemia · Milk-alkali syndrome (Burnett's) · Calcinosis (Calciphylaxis, Calcinosis cutis) · Calcification (Metastatic calcification, Dystrophic calcification)

deficiency: Hypocalcaemia · Osteomalacia · Pseudohypoparathyroidism (Albright's hereditary osteodystrophy) · Pseudopseudohypoparathyroidism

M: MET mt, a/u/y/n/h, r/g/c/p/i, f/s/l/o, m

au/y/n/h, rgcp/i, f/s/l/o, m, epon

meds(A16, C10),intm(a/u/y/n/h,

r/g/c/p/i, f/s/o)Retrieved from "http://en.wikipedia.org/wiki/Hypophosphatemia"Categories: Metabolic disorders | Electrolyte disturbances

Hyperphosphatemia

From Wikipedia, the free encyclopedia

Jump to: navigation, search This article needs additional citations for verification.Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (December 2008)

Hyperphosphatemia

Classification and external resources

Phosphate group chemical structure

ICD-9 275.3

DiseasesDB 20722

eMedicine med/1097

MeSH D054559

Hyperphosphatemia is an electrolyte disturbance in which there is an abnormally elevated level of phosphate in the blood.[1] Often, calcium levels are lowered (hypocalcemia) due to precipitation of phosphate with the calcium in tissues.

Contents

[hide]

1 Causes 2 Treatment 3 Signs and symptoms 4 References

[edit] Causes

Hypoparathyroidism: In this situation, there are low levels of Parathyroid hormone (PTH). PTH normally inhibits renal reabsorption of phosphate, and so without enough PTH there is more reabsorption of the phosphate.

Chronic renal failure: When the kidneys aren't working well, there will be increased phosphate retention.

Drugs: hyperphosphatemia can also be caused by taking oral sodium phosphate solutions prescribed for bowel preparation for colonoscopy in children.

[edit] Treatment

High phosphate levels can be avoided with phosphate binders and dietary restriction of phosphate.

[edit] Signs and symptoms

Signs and symptoms include ectopic calcification, secondary hyperparathyroidism, and renal osteodystrophy.

[edit] References

1. ̂ hyperphosphatemia at Dorland's Medical Dictionary

[hide] v • d • e

Inborn error of metal metabolism (E83, 275)

Transition metal

Cuhigh: Copper toxicity · Wilson's disease

deficiency: Copper deficiency · Menkes disease/Occipital horn syndrome

Fe

high: Primary iron overload disorder: Hemochromatosis/HFE1 · Juvenile/HFE2 · HFE3 · African iron overload/HFE4 · Aceruloplasminemia · Atransferrinemia · Hemosiderosis

deficiency: Iron deficiency

Znhigh: Zinc toxicity

deficiency: Acrodermatitis enteropathica

Electrolyte

PO43−

high: Hyperphosphatemia

deficiency: Hypophosphatemia · alkaline phosphatase (Hypophosphatasia)

Mg 2+ high: Hypermagnesemia

deficiency: Hypomagnesemia

Ca 2+

high: Hypercalcaemia · Milk-alkali syndrome (Burnett's) · Calcinosis (Calciphylaxis, Calcinosis cutis) · Calcification (Metastatic calcification, Dystrophic calcification)

deficiency: Hypocalcaemia · Osteomalacia · Pseudohypoparathyroidism

M: MET mt, a/u/y/n/h, r/g/c/p/i, f/s/l/o, m

au/y/n/h, rgcp/i, f/s/l/o, m, epon

meds(A16, C10),intm(a/u/y/n/h,

r/g/c/p/i, f/s/o)

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Retrieved from "http://en.wikipedia.org/wiki/Hyperphosphatemia"Categories: Metabolic disorders | Electrolyte disturbances | Medicine stubs