hyperphosphatemia Flashcards
Q: What does hyperphosphatemia mean?
A: Hyperphosphatemia means having a high phosphate level in the blood, typically above 4.5 mg/dL.
Q: What is the chemical structure and charge of phosphate?
A: Phosphate consists of one phosphorus atom surrounded by four oxygen atoms in a tetrahedral arrangement, with a charge of minus 3, written as PO43-.
Q: Where is most of the phosphate in the body stored?
A: About 85% of the phosphate in the body is stored in the bones.
Q: What role does phosphate play in the body?
A: Phosphate is involved in phosphorylation, forms high energy bonds in ATP, is part of DNA and RNA backbones, and is involved in cellular signaling molecules like cAMP.
Q: How is phosphate related to calcium levels in the body?
A: Phosphate levels are tied to calcium levels; if calcium levels fall, parathyroid hormone releases calcium and phosphate from bones, but parathyroid hormone also causes phosphate to be excreted while keeping calcium in the blood.
Q: How does kidney disease lead to hyperphosphatemia?
A: In kidney disease, the glomerular filtration rate (GFR) decreases, reducing phosphate excretion, leading to phosphate accumulation in the blood.
Q: What is secondary hyperparathyroidism and how is it related to hyperphosphatemia?
A: Secondary hyperparathyroidism occurs when low calcium levels due to kidney disease lead to continuous parathyroid hormone release, causing calcium and phosphate to be released from bones, with phosphate building up in the blood.
Q: What is pseudohypoparathyroidism?
A: Pseudohypoparathyroidism is a genetic defect where kidneys do not respond to parathyroid hormone, leading to calcium loss and phosphate buildup in the blood.
Q: What happens in hypoparathyroidism related to hyperphosphatemia?
A: In hypoparathyroidism, insufficient parathyroid hormone production leads to increased phosphate reabsorption and decreased calcium reabsorption, causing hyperphosphatemia.
Q: What is DiGeorge syndrome and how does it relate to hyperphosphatemia?
A: DiGeorge syndrome is a genetic disorder where individuals are born with underdeveloped parathyroid glands, leading to insufficient parathyroid hormone and hyperphosphatemia.
Q: How can excessive intake cause hyperphosphatemia?
A: Excessive intake of phosphate through phosphate-based laxatives or intravenous fluids can rapidly increase blood phosphate levels.
Q: What is tumor lysis syndrome?
A: Tumor lysis syndrome is a condition where rapid cancer cell death releases intracellular phosphate into the bloodstream, causing hyperphosphatemia.
Q: What conditions can cause cell phosphate to spill into the bloodstream?
A: Conditions like crush injuries, rhabdomyolysis, respiratory acidosis, and diabetic ketoacidosis can cause cell phosphate to spill into the bloodstream, leading to hyperphosphatemia.
Q: What symptoms can severe hyperphosphatemia cause?
A: Severe hyperphosphatemia can cause neuron excitability, tetany, muscle spasms, Chvostek’s sign, Trousseau’s sign, seizures, and bone pain.
Q: What complications arise from high phosphate levels binding with calcium?
A: High phosphate levels can bind with calcium to form crystals, leading to metastatic calcification, kidney stones, and nephrocalcinosis.
