Ca and P Homeostasis- Heemer

Things that are bolded I think are super important.

Functions of Calcium:

Functions of Calcium:

• neuromuscular/ muscle cell function

• platelet aggregation/coagulation

• bone metabolism

Where is a majority of Calcium found in our body?

Bone (99%)

What is the range of Calcium in our serum? (mg/dL)

8.5-10.5 mg/dL

What is the equation for corrected calcium?

MEMORIZE

Corrected Calcium = Serum Ca + (0.8 (4- albumin))

Hypercalcemia occurs due to these 3 mechanisms:

• ↑ bone resorption

• ↑ GI absorption

• ↓ renal excretion

2 most common causes of hypercalcemia:

• CANCER

• Primary Hyperparathyroidism

Symptoms of mild (Serum <13) and severe (Serum >13) hypercalcemia:

mild- asymptomatic

severe- usually seen in cancer pts. weakness, depression, anorexia, N/V, etc. (Think: picture a cancer pt in your head and just think of those symptoms)

Signs/ Symptoms of a hypercalcemic crisis (Serum >15)

• acute renal insufficiency

  • think your kidneys are shutting down

• coma, death, arrythmias are all possible

• YOU DYING

Signs/Symptoms of Chronic Hypercalcemia

• calcifications

• kidney stones

• chronic renal failure

Nonpharm treatment of Hypercalcemia

• hemodialysis

• surgery

  • remove thyroid (hyperparathyroidism)

  • remove tumor (cancer)

• discontinue any drugs that cause high Ca

Hemodialysis is the treatment of choice in what situation?

• life threatening hypercalcemia

  • Ex: hypercalcemic crisis (Serum >15)

Volume Expansion pharm treatment of hypercalcemia uses what fluid?

NS

What are the pharmacologic treatments of hypercalcemia?

• loop diuretics

• calcitonin

• bisphosphonates

• denosumab

• glucocorticoids

• cinacalcet

Loop diuretics words by ______________ urinary Ca excretion.

a. increase

b. decrease

a- increase

Calcitonin inhibits what?

bone resorption of Calcium

ADRs of Calcitonin

• facial flushing

• N/V

• TACHYPHYLAXIS (stops working after awhile)

What is 1st line for cancer associated hypercalcemia?

(SUPER IMPORTANT***********)

bisphosphonates

Bisphosphonates:

• MOA

• CI

• Drugs that belong to this class

• ROA

MOA- block resorption and prevent osteoclast maturation

CI- renal insufficiency

Drugs- Pamidronate, Etidronate, Zoledronate, Ibandronate

ROA- IV

Denosumab is typically in what patients?

for pts. that haven’t used bisphosphonates or in patients where bisphosphonates didn’t work. (Useful in cancer pts.)

Glucocorticoids

• ADRs

• CI

ADRs- DM, Osteoporosis, infection

CI- Serious infections

Cinacalcet (Sensipar) is used to treat what? What 2 conditions is it approved for?

• CHRONIC hypercalcemia

• Approved for:

  • hyperparathyroidism due to CKD

  • parathyroid carcinoma (CANCER)

Cinacalcet:

• MOA

• 2 most common ADRs

MOA- calcimimetic (reduce PTH, and Ca)

ADRs- N/V and diarrhea

Primary causes of hypocalcemia:

1. hypoparathyroidism

2. Vit D deficiency

What are some medications that may cause low calcium?

• loop diuretics- furosemide

• calcitonin

• bisphosphonates

• drugs that cause low Mg

What is the hallmark symptom of acute hypocalcemia?

tetany

Signs/Symptoms of Hypocalcemia:

• Neuromuscular

  • tetany, spasms, cramps

• CNS

  • depression, anxiety, confusion, etc.

• Cardiac

  • CHF, arrythmias, hypotension, bradycardia

• Derm

  • skin changes (dry, coarse)

What is the treatment for Acute Symptomatic hypocalcemia?

IV Calcium Salts

Which IV Calcium Salt is preferred for Peripheral Administration?

Calcium Gluconate (burns less)

Chronic Hypocalcemia due to hypoparathyroidism or Vit D deficiency can be treated with…

• Calcium/ Vit D supplements

Functions of Phosphorous:

• makes up phospholipids/nucleic acids

• mitochondrial fxn

• regulates metabolism and enzyme rxns

• ATP

Normal level of Phosphorus in the serum:

2.5-2.5 mg/dL

Is phosphorus mainly found in the ECF or ICF?

ICF

Our phosphorus levels can vary daily because of our _____.

diet

What increases phosphorous absorption?

• PTH

• Active form of Vit D

• low P diet

What decreases phosphorous absorption?

• high P or Mg diet

• glucocorticoids

• hypothyroidism

3 Causes of Hyperphosphatemia:

• ↓ urinary excretion

• exogenous administration

  • TPN, PPN, hypercalcemia treatments

• endogenous intracellular release

  • anything that causes cells to release their P

  • Ex: rhabdomyolysis, hyperthermia, tumor lysis

Signs/Symptoms of Hyperphosphatemia

• related to hypocalcemia

• deposition of Ca-P crystals

  • these crystals cause damage to organs and tissues

To treat severe symptomatic hyperphosphatemia that’s associated w/ hypocalcemia what treatment is used?

IV calcium salts

Treatment of chronic symptomatic hyperphosphatemia

• limit P in diet

• use a phosphate binding agent

Examples of phosphate binding agents

• Calcium

• Aluminum

• Magnesium

• Sevelamer

• Lanthanum Carbonate

3 Causes of Hypophosphatemia:

• ↑ urinary excretion

• ↓ GI absorption

• Extracellular to intracellular redistribution

Signs/Symptoms of Hypophosphatemia:

Think: things to do with the brain

• irritability

• weakness

• numb

• confused

• seizures

• coma

long term consequences of hypophosphatemia:

• osteopenia, osteomalacia

• cardiomyopathy, CHF

Treatment of severe or symptomatic hypophosphatemia:

• IV Phosphorous replacement

  • Sodium Phosphate or Potassium Phosphate

Treatment of mild-moderate asymptomatic hypophosphatemia:

• Oral P replacement

  • Ex: Nuertra-Phos, Nutra-Phos-K, K-Phos Neutral, Uro-KP-Neutral