Pathophysiology: Ca and PTH Flashcards
What are the fast PTH responses? Slow?
Fast: bone and renal resorption
Slow: Intestinal Vit D, renal effect takes time
What senses Ca in the Parathyroid?
CaSR
What are the top three causes of HyperPTH?
PT Adenoma
Familial HypocalURIA HypercalcEMIA
Lithium or HCTZ meds
<1% PT carcinoma
What are the PTH dependent causes of high Ca?
HyperPTH, Familial HH, Li/HCTZ
What are the PTH independent causes of high Ca?
Tumor
Granulomatous disease
Multiple myeloma
Waht is the treatment of acute high Ca?
Saline (to correct polyuria)
Furosemide (to draw off Ca)
What is the presentation of PT Adenoma? What do you to?
Stones: pain while peeing
Groans: constipation/GI pain
Bones: fractures?
Measure albumin, PTH
What do you do to differentiate FHH and PT adenoma?
24 hour urine:
PTadenoma: high Ca
FHH: low Ca
What is the defect in FHH?
CaSR, AD mutation
decreased Ca sensation removes negative feedback of PTH increasing Ca
What is typical 24 hr urine in FHH?
<50-100
What is 3* HyperPTH?
End stage renal disease, post kidney transplant causes Ca wasting in urine
What cancers make Ca higher?
Small cell lung
Breast
*Mets, cytokines, multiple myeloma
What do labs for cancer high Ca look like?
HIGH Ca, low PTH (PTHrelated peptide is made, NOT PTH!)
What causes increased Ca in granulomatous disease?
1a Hydroxylase–>increased VitD3
How do you tell difference between gland hyperplasia and adenoma?
Adenoma: one site
Hyperplasia: whole gland
What is 2* hyperPTH?
Renal disease: HIGH PTH! but it doesnt work…
low Ca, high PO4, low VitD3
What are causes of low Ca?
Albrights hereditary osteodystrophy
MEN syndromes
*acute pancreatitis, transfusion, tumor lysis, rhabdomyolysis, sepsis, bisphosphonates, hungry bone syndrome
DDx for low Ca?
PTH low? HypoPTH, Mg deficiency, PO4 excess
PTH high? Vit deficiency, renal failure, PTH/VitD resistance
How does low Ca present?
Agitation Hyperreflexia Convulsions QT prolongation Hyperextension
Tx for acute low Ca?
Correct Mg
Calcium gluconate
Tx for chronic low Ca?
Oral Ca
Vit D if PTH still present
HCTZ
What is defect in PseudohypoPTH? What do they look like?
Gsa subunit mutation, cannot stimulate PTH via cAMP pathway
*Short stature, round face, “short 5th metacarpal”, obesity
MEN definition?
Multiple Endocrine Neoplasia:
Multiple tumors, 1 patient
When do MEN 1 patients get pancreatic cancer?
25-35, pituitary by 38, 1* HPT by 40
MEN 1 includes?
Defect in MENIN: TSG MEN1 Chromosome 11 "PPP" Pancreas: hypoglycemia Parathyroid: high Ca, stones Pituitary: galactorea, weight gain, diarrhea
Patient presents with polyuria, pain in peeing and lethargy, found passing out and says to have grown breasts and gained weight:
MEN1: PPP
MEN 2a?
RET : RTK oncogene Chromosome 10 "TPP" Thyroid: medulary Pheochromocytoma Parathyroid
MEN 2b?
RET/Cr.10-single AA! TPMM Thyroid: medulary Pheochromocytoma Marfan-looking Mucosal Neuromas
Especially tall patient has lump in throat and bumps on tongue?
MEN2b
Large round patient has kidney stones and is bugging out eyes….
MEN2a (terrible presentation… sorry)
What branchial pouch do top 2 parathyroids develop from?
4th
What branchial pouch do bottom 2 parathyroids develop from?
3rd (with Thymus!)
