renal exam-1-phosphorus

structure of cell membrane, source of high energy bonds in ATP, plays a role in how O2 is released from RBCs

primarily intracellular, critically ill, increased metabolism, increased phosphorus

2.5-4.5 mg/dl, doesn't necessarily reflect total body phosphorus, serum phos varies 2mg/dl over a day due to dietary intake, check serum same time every day

kidney is the major homeostatic regulator, under action of PTH, PTH activiated if increase plasma PO4 or decreased plasma Ca, increased abs if decrease PO4 or serum calc

>4.5 mg/dl

acute renal failure, CKD GFR<=30 ml/min

hypopara, growth hormone excess, hyperthyroidism

phosphate enema(fleet, phospho-soda), phos lax, parenteral/enteral phos admin-can accumulate mostly in mod-severe renal dysfxn, oral phos replacement, vit D toxicity, increase abs of pho

rhabdomyolysis, TLS(malig) hemolysis, other: diabetic ketoacidosis/lactic acidosis(once tx, will shift back)-shifts from intra to extra

hypocalc and tetany(binding of ca and phos)

CaPO$ calcification(once combined, can go to other areas, causes organ damage in soft tissue, eyes, kidneys, vasculature), renal osteodystrophy(renal bond disease)-chronically high PTH levels, risk indicator(higher risk of precipitation): calc phos product >55- serum calcium mg/dl X serum phos mg/dl

treat underlying, saline inf(to expand ECF and dilute pho and incr phos exc at 100-200 ml/hr), dextrose + insulin(rarely used, FYI-less effect on phos than K), hemodialysis(if have access)

dietary restr <=1g/d total of: dairy products, meats, dried beans, nuts, colas, cocoa, choc

decrease phos abs from GI tract, tk with meals, calc carb and calc acetate also used to increase ca, so don't use if increased, sevelamer(renagel), lanthanum(fosrenol), alum hydroxide(amphogel)(caution in pts with renal impairment, long-term, CNS toxicities) are constipatins

check phos level q 24-48 hrs if in hosp, if severe or cont renal replacement therapy/cont dialysis, may monitor more often

<2.5 mg/dl, relatively common in ICU

alcohol related, inadequate int/abs-starvation malabs(diar, vom, phos antacids), phosphate-binding drugs, sucralfate, steroids(impair conver D2-D3)

refeeding syn, rapid tumor growth, resp alkalosis, insulin, gluc, epi admi, hungry bone syn

vol expansion, hyperparathry, acetazolamide, GCs and sodium bicarb

decreased PTH, decreased renal abs, steroid immunosuppressants

weakness, myalgia, resp muscle fat, resp failure, slow weaning from ventilator, osteomala/bone pain, CNS-metabolic encepha

anor/ileus

look at renal fxn <=30ml/min, decrease 50% and consider Ca Phos prod

oral therapy preferred-1.5-2.0 gm (50-60mM) phos qd divided into 3 or 4 doses

milk(1mg/cc, 1g/L), fleet phospho soda, Neutra-phos and neutra-phos k(most common these two)

monitor serum PO4 qd until desired serum level attained, low end of normal 2.5

parenteral-BE CAREFUL, 15-30 mM PO4 in 250cc D5W or NS over 4-6 hours, MD orders can be confusion

• use sodium phosphate if potassium >4
• use potassium phosphate if potassium <4

infuse slowly(ideally with pump) to avoid hypercalc tetany, HOTN, and acute renal failure (secondadry to CaPO4 precipitating out in kidney)

monitor serum PO4 q 2-4 hrs after dose adminsterd and repeat above dose until serum PO4 >2 mg/dl

hypocalc, hyperphos, hyperkale or hypernatre (based on which salt) diarrhea (more with PO) hypomag ( due to intracellular shifting)