196 results
Hypercalcemia of Malignancy - Pathophysiology
PTH-mediated
 • Parathyroid cancer
 • Ectopic production: Small cell lung cancer, ovarian
intestinal calcium absorption ... and stimulates resorption ... Stimulate calcium reabsorption ... kidney, Stimulates resorption
Parathyroid Hormone (PTH) Effect in Calcium and Phosphorus
Calcium - Net Effect Hypercalcemia:
   ↑ intestinal
↑ intestinal absorption ... ↑ bone reabsorption ... ↑ tubular reabsorption ... Hypophosphatemia: ↑ bone reabsorption ... ↓↓ tubular reabsorption
Workup for Hyperphosphatemia - Differential Diagnosis Framework
Rule out spurious hyperphosphatemia: paraproteinemia, hyperlipidemia, hemolysis, hyperbilirubinemia, liposomal amphotericin
heparin Acute Phosphate ... Exogenous: Excessive phosphate ... intake, Phosphate ... Increased Renal Phosphate ... Absorption:
Hypercalcemia - Hormones and Pathophysiology  
Calcitriol:
 • Bones: Enhances mineralization
 • GI Tract: ↑ Ca2+
Kidneys: ↑ Ca2+ reabsorption ... , ↑ PO4- reabsorption ... , ↓ PO4- reabsorption ... Kidneys: ↑ Ca2+ reabsorption ... , PO4- reabsorption
Hypophosphatemia - Differential Diagnosis Algorithm
 • Decreased intake/absorption: Starvation, Alcoholism, Malabsorption, Phosphate binder use
 • Redistribution/
Decreased intake/absorption ... Malabsorption, Phosphate ... causes #nephrology #phosphate
Hyperphosphatemia - Differential Diagnosis Algorithm
Transcellular Shift:
 • Rhabdomyolysis
 • Tumor Lysis
 • Metabolic or Respiratory Acidosis
Increased Intake / Absorption ... Hypervitaminosis D • Phosphate ... Supplementation • Phosphate
Hypophosphatemia - Differential Diagnosis Algorithm
Appropriately Low Kidney Phosphate Excretion:
 • Decreased GI Absorption: Chronic Diarrhea, Antacids,
Appropriately Low Kidney Phosphate ... • Decreased GI Absorption ... Diarrhea, Antacids, Phosphate ... Inappropriately High Kidney Phosphate
Hypercalcemia - Differential Diagnosis Algorithm
Elevated PTH (High or normal):
 • Primary Hyperparathyroidism
 • Familial Hypocalciuric Hypercalcemia
Low
Miscellaneous - Bone Resorption ... - Calcium Reabsorption
Workup for Hypophosphatemia - Differential Diagnosis Framework
Rule out spurious hypophosphatemia: paraproteinemia, acute leukemia
Measure Urine Fractional Excretion
Fractional Excretion of Phosphate ... diarrhea, Poor absorption ... Framework #Workup #phosphate
Proximal Renal Tubular Acidosis (RTA) Ttype 2 Overview

HCO3 reabsorptive failure
Lowering of threshold for HCO3 absorption in
Overview HCO3 reabsorptive ... threshold for HCO3 absorption