Disorders of Calciume and phosphorus and Mg Flashcards
what are the mechanisms for calcium and phosphorus maintained by?
Vit D, the small intestine, renal tubles, PTH, and bone
what cells secrete PTH in the PT?
Chief Cells
what does PTH do to the bone?
stimulates osteoclasts and osteoblasts (bone resorbed and Ca released into blood stream)
renal actions of PTH?
increases reabsorption of Ca
- passively in the proximal tubule
- actively transported in cortical TAL of LOH and DCT
2) Inhibits reabsorption of phosphate: Occurs in the proximal tubule
3) Synthesis of calcitriol: Stimulates synthesis of 1-alpha hydroxylase to convert calcidiol to calcitriol
Intestinal Actions of PTH?
ntestinal Actions
Increases the intestinal absorption of calcium by calcitriol
what does increased levls of PTH cause?
increased serum calcium and decreased Ph
what does decreased levels of PTH cause?
decreased serum Ca and increased Ph
what are he most common causes of disorders of Ca and phosphorus?
parathyroid disorders, renal failure, malignancy
what is one of the most common disorders of calcium and phosphorus in hospitalized pts w/ malignancies?
hypercalcemia
what tpes of maligancies might pts get hypercalcemia w/
lung cancer, SCC of head, neck, and esophagus, femal genital tract carcinoma, multiple myeloma, lymphoma, renal cell carcinoam
what are some other causes of hyperca
vit D intoxication
hyperparathyroidims
sarcoidosis
CF of hyperca
anorexia, N, constipation, polyuria, polydipsia, dehydration, change in levelof consciousness
-volume depletion: orthostatic hypotension, tachycardia
what dx studies need to be done in a hyper cc workup
corrected calcium (albumin)
- CXR: pulmonary mass
- UA for hematuria (early sign of RCC)
- ESR: monoclonal gammopathy
- vita D
- 24 hours urine collection
what does an elevated urine clacium suggest?
malignant neoplastic or paraneoplastic process or hyperparathyroidims
what does an decreased uring Ca suggest?
primary hyperparathyroidms
tx of hyperCa
isotonic saline for volume repletion,
- loop diuretics if pt is hypervolemic after volume repletion
- bisphosphonates in severy hyperca
what is the more common disorder? hyper Ca or hypoCa?
hypoCa!
critically ill ps
what does hypoCa commonly result from
CKD or hypoparathyroidism
what can sever hyopcalcemia cause?
compmelete cardiovascular collaps
what are clinical features of hypocalemia?
dry skin, brittle nails, pruritis, muscle cramping, SOB, numbness and tinglin in the extremeites
what are some sever cardiovasuble manifestation of hypoca
syncope and angina
what are some dlinical signs of hypocalcemia?
psroiasis, dry skin, perioral numbness,
-wheezing, bradycardia, crackles, 3rd heart sound
what are classic neurologic findings in hyopca?
trousseau sign, chvostek sign (facial nerve),
irritabilyt, confusion, dementaion, sz
what dx studies need to be done?
Ca < 8.5
ionized Ca, Mg, Ph albumine, LFts,
BUN and creatinine
tx of hypocalemia
tx any emergent CV states
-severe hypoca; I V calcium gluconate or Ca Cl
hyperphosatemia is most common secondary to what disorder?
CKD or excessiv euse of phosphate-containing laxitives or enemas
what is hypophosphatemia secondary to?
deminished supply or absorption, increased urinary loss,
-vit D deviciency,
-respiratory alkalosis
burns
-hyperparathyroidism
how is hypoPh classifed?
based on serum level
- moderate: 1-2.5 and is usually ax
- severe: 1 or less
what can severe hypoPh lead to?
rhabdomyolysis, paresthesia, encephalopathy
tx of hyperphopahtemia
if secondary to CKD- dietary phophorous restriction and oral phosphate binders
-calcium carb tablest
hypomagensemia
denfined as plasma Mg levels of les than 1.8 mEq/L
*plasma levels do not reflect total storage
when does hypoMg usually prsent?
when totat body stors are severly depleted- results from diminished intake and imparied absorbtion
what are some common causes of hypoMg?
chronic alcoholism, chronic D, hypopartathyroidism, hyperaldosteronis, diuretic therapy, osmotic diureses, and nutritional deficiencies
what OTC drug can cause hypomg?
PPI (greater than 5 yrs)
what are clinical features of hypomag?
lethargy, anorexia, N, V, wkns, tetany, seizure
what lab test should be checked along side HyopMg?
K, Ca, urine calcium
hypoaK, hyopCa, and hypocalciuria sheen w.hypoMg
what might an EKG show with hypoMg?
polonged PR and QT intervals, or widening of the QRS
how do you tx hypomg?
oral mg oxide
in severe- Mg sulfate solution via IV, can used IM
hyper mg?
> 2.2
Mg stored in bones and muscles
CFof hypermg
sx are rare- except in pts w/ CKD who are given Mg containing products such as laxatives or antacids
what conditions can iatrogenically induce hypermg?
eclampsia or preterm labor
what are sgns and symptoms of hyperMg?
impaired neruomuscular transmission
- reduced deep tendon reflexes
- muscle weaknessm hypotenson
- respiratory depression- cardiac arrest
- N,V, flusing
what may been seen on an EKG w/ hypermg?
widened QRs, prolonged PR, prolonged QT
lab studies of hypermg?
bleeding and clotting times are incraeased
tx of hypermg?
calcium gluconate IV
=saline diuresis and IV furosemide
-dialysis
