Phys: Electrolyte Disturbance: Ca, Mg, Phosphate Flashcards
Calcium normal range
8.5-10
50% of calcium is bound to ______
Albumin
Majority of calcium is stored in the __________
Bones
Roles of Calcium
Coagulation, cell signaling, muscle contraction, neuromuscular transmission
Endocrine regulation of Calcium done by these 2 things
Calcitriol and PTH
Hypocalcemia
Causes: eating disorders, chelation therapy, low PTH, low vitamin D, tumor lysis
Clinical presentation: NM irritability, parasthesis (oral, perioral, a real) tingling or pin and needles, tenany, hyperreflexia, laryngospasm
ECG: prolonged QT interval
Hypercalcemia
Causes: Excess PTH, excess Vit D, Malignancy
Clinical presentation: constipation, fatigue, lethargy, depression, bone pain, kidney stones, anorexia, nausea, vomiting, pancreatitis
Psychiatric: Depression and confusion
EKG: Short QT interval, widened T wave
Renal regulation of Calcium
Kidneys excrete Ca in urine and kidneys are involved in forming Vit D
99% of filtered Ca is reabsorbed
Reabsorption of Ca is tightly coupled to Na
What is the major controller of GI calcium absorption?
Vitamin D
Ca++ reabsorption is tightly coupled to _______
Na+ reabsorption in the PCT and TALH
Only in the distal tubule is the reabsorption of the two ions dissociated
Magnesium normal range
1.5-2.0
Mg is a necessary __________ for many enzymed
Cofactor
Hypomagnesemia
Caused by: alcoholism, malnutrition, Chron’s disease, Whipple’s disease, celiac sprue
Renal Loss: Bartter’s syndrome, Gitelman syndrome, Loop and thiazide diuretics side effect
Clinical presentation: weakness and muscle cramps, CNS-irritability, hallucinations, depression
EKG: Prolonged PR, QRS, and QT. Tornadoes de pointes, complete heart block and cardiac arrest, Cardiac arrythmias
Hypermagnesemia
Causes: cell lysis, hemolysis, tumor cell lysis, renal insufficiency
Clinical presentation: weakness, nausea, vomiting (4.0 mEq/L hyporeflexia)
EKG: arrhythmia and asystole
>5 : prolonged AV conduction
>10: complete heart block
>13 Cardiac arrest
Prolonged PR interval, shortened QT
Renal Regulation of Mg
Free component is freely filtered and then handled by the nephron almost identically to Calcium