FA Q4, Endocrine II
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FA Q4, Endocrine II
FA Q4 Endocrine II
FA Q4, Endocrine II
what is the most common cause of hypoP?
complication of *periparturient hypocalcemia* - fails to respond to conventional therapy/relapses - alert but unable to stand (creeper cow)
how is hypoP treated?
IV phosphorous = sodium monophosphate
Fleet enema diluted in sterile water IV
oral therapy via stomach tube for 5 days
how does prolonged hypoP affect RBCs?
depletes RBC 2,3DPG - friable - intravascular hemolysis = *postparturient hemoglobinuria*
who is most commonly affected by postparturient hemoglobinuria? how is it treated?
oral and IV sodium monophosphate
grain/P-rich and dicalcium phosphate feed to follow up
blood transfusion if PCV <10% or severe signs
what is seen on CBC with postparturient hemoglobinuria? what other deficiencies are usually concurrent?
anemia with Heinz bodies (kidney values affected from pigment nephropathy)
copper and selenium deficiency (so low antioxidants)
What is cause of spontaneous fractures, lameness, and enlarged epiphysis in young, growing animals?
rickets due to *chronic dietary deficiency* of P and vit. D
what is string of pearls lesion? how is it prevented?
costochondral junction enlargement seen w/deficiency in vit D and P
adequate diet and exposure to UV light
where is phosphorous absorbed?
(low levels stim. vit.D for increased absorption of Ca/P)
what is effect of PTH on phosphorous levels?
increases P loss through saliva/feces and urine
what are main losses/drains for P?
fetal skeleton, formation of milk
what is normal phosphorous level in adults?
4-8mg/dl (slightly higher in young)
what is serum P level with rickets (chronic dietary deficiency)?
what is serum P with postparturient hemoglobinuria? what about with severe acute hypoP (milk fever)?
severe, acute <1
what are functions of Mg?
cofactor for enzymes (ATPase, kinases)
bone mineral (released w/Ca)
needed for PTH synthesis/release
opposes Ca at neuromuscular jx
what is role of Mg at neuromuscular jx? what is result of hypoMg here? what is hyperMg?
cofactor for acetylcholinesterase
inhibits Ach release from axon (opposite Ca)
hypoMg: build up of Ach/incr. Ach release - prolonged contraction/spasm
hyperMg: neuromusc. blockade - weakness
what is main condition seen with hypoMg? Who is commonly effected?
beef cattle grazing rapidly growing pastures in spring/fall
where is Mg absorbed? where is it lost?
absorbed from GI but not efficiently (excess = laxative)
modest loss in milk, deposited in fetal bone/soft tissue
excreted via kidney
what are two compounds that impair GI absorption of Mg? When are these elements higher in soil?
nitrogen and potassium
-heavily fertilized and rapidly growing
cereal grains also low in Mg
(add P to soil helps mg uptake)
what is mechanism for Mg homeostasis?
NO hormone mechanisms
must ingest/absorb (GIT tract main source - rumen for adults; small intestine for young)
what happens to Mg levels with renal failure or impaired renal perfusion? what will be signs in patient as a result?
hyperMg (fails to excrete) - somnolence
what are early signs of grass tetany? what are Ca levels?
: spasms, goose stepping, nervous, aggressive
without Mg - impaired PTH so Ca drops (stage 1)
what are late signs of grass tetany?
: recumbency, convulsions, paddling
"dirt angel" from repetitive mm. contractions
low CSF concentration of Mg
what is cause of transport tetany?
low Mg due to stress - catecholemines move Mg into cells; worsened by low Mg diet
what is cause of milk tetany?
low Mg because milk low in Mg already, growing calf outgrows the Mg supply by 4-6wks
what is cause of winter tetany?
low Mg in late gestation when inadequate crops available (eating mostly corn stalks/straw)
what is cause of wheat pasture tetany?
cereal forage so naturally low in Mg
(concurrently hypoCa so resembles milk fever)
how is hypoMg reliably diagnosed postmortem?
low Mg in vitreous humor for 24-48hrs
low Mg in CSF
(serum levels not reliable)
how is hypoMg treated?
immediately minimize stress (AceP) + IV Ca/Mg salts
relapse common - follow up w/oral or SQ
can do Mg enema as well (careful rectal slough)
how is diet managed to prevent hypoMg?
feed legumes (good source of Mg/Ca) and cool season grasses - avoid rapid growing grass
salt/molasses blocks, supplement drinking water
what is main function of K?
maintenance of resting membrane potential
what were 3 factors in common with all cows reported to have hypoK syndrome?
hx of mod-severe ketosis
parturition w/in 30 days
isoflupredone acetate given
what are clinical signs seen w/HypoK?
muscle fasciculations and profound flaccidity
recumbent, unable to hold up head
cardiac arrhythmias, atrial fibrillation, Vtach
what clinical pathology is consistent with hypoK syndrome?
mild elevation in CPK
what are causes of hypoK?
incr. urination of K from steroids/mineralcorticoids like isoflupredone
alkalosis - drives K into cell for H
insulin/glucose tx drive K intracellular
how is hypoK treated?
*IV + oral* K (IV alone not effective)
do not excede 0.5mEq/kg/hr IV