Pt is euvolemic. [Na⁺] < 135 mmol/L - DDx?

- rapid correction =>?

- slow correction =>

SIADH ([Na]_urine>20mol/L), drugs (¹ADH-like)

- CPM

- Cerebral edema

¹desmopressin,SSRI, TCA, ecstasy

[Na⁺] < 135 mmol/L

Osmolarity_serum > 280

Dx - causes?

Pt is hypovolemic

[Na⁺]_serum < 135 mmol/L , [Na⁺]_urine > 30mmol/L 

Dx? 

Hyponatremia-Renal losses

<-- diuretics, medullary renal disease, Addison,RTA I

Pt is hypovolemic

[Na⁺]_serum < 135 mmol/L , [Na⁺]_urine < 30mmol/L 

Dx? 

Hyponatremia- Extrarenal loss

<-- GI, 3^rd spacing

Hypernatremia

DDx

Na⁺ administration <-- IV, sodium bicarbonate, high-dose Na⁺ -Antibiotics

Dehydration <-- DI, DM, diarrhea, sweating, osmotic diuretics

Pt: elevated [K⁺]_serum, no in vitro hemolysis

no clinical evidence of hyperkalemia

DDx?Causes?

Pseudohyperkalemia--> no Rx required

thrombocytosis/leukocytosis --> ¹passive transm K⁺leak

familial --> ¹RBC , autos. dom. chrom 16

Acidosis and hypokalemia

DDx

Increased Ca⁺⁺, Cl^-, nephrogenous cAMP

decreased PO₄^-2   -- Dx? Most common cause?

1^o hyperparathyroidism

1.Adenoma(90%), 4-gland hyperplasia, carcinoma

Hypercalcemia, increased nephrogenous cAMP, nml PTH

Cause?

Humoral hypercalcemia of malignancy-->PTHrP

RCC, SCC of lung/head&Neck/ skin/esophagus/cervix, breast ca, Islet cell tm, paraganglioma, TCL

clear cell ca (ovary)

Granulomatous disease and hypercalcemia

Dx?

Sarcoidosis

histiocytes of granulomas -->⁺ VitD-->1,25(OH)₂VitD

Pruritus, "metastatic" calcification of vessel walls and soft tissue (GI/skin bx's)

Dx?

s/p renal transplant and hyperparathyroidism

Dx?

Tertiary hyperparathyroidism

parathyroid -->autonomous => 1^o hyperparathyroidism

Acidosis--> increases free Ca⁺⁺

Alkalosis--> decreases free Ca⁺⁺

"Loses Calcium, Ads Calcium"

free Ca⁺⁺

50% --> protein bound (mainly albumin)

Arterial blood, no exposure to air / EDTA/Citrate

avoid fist clenching & prolonged tourniquet application

rapid delivery , keep cool

0.8mg/dL Ca⁺⁺ per 1g/dL protein lost

Avoid if: Acid-base disturbances, neonates, renal insufficiency, liver disease

PTHrP secreted by which normal epithelia?

compare with PTH?

Sqaumous and lactating breast epithelium

PTHrP ~ N-terminal PTH --> biologic activity , short t_1/2

--> can be specifically assayed

Low PTH/Calcium, Increased Phosphate,

Low 1,25(OH)₂D levels

Dx

Hypoparathyroidism

acquired-->most common

hereditary--> isolated / a/w DiGeorge syndrome

Low Calcium, PTH = nml-high

tissue deposition of calcium salts,brown tm's of bone¹

Dx?Causes?

2^o hyperparathyroidism (pseudohypoparathyroidism)

<--peripheral resistance to PTH -->⁺ osteoclasts¹

Chronic renal failure, VitD deficiency

Magnesium and PTH secretion

- mild transient decrease of Mg⁺⁺

- persistent/ marked decrease of Mg⁺⁺

- increased PTH-->balance of divalent cations

- inhibition of PTH secretion