Exam 5: Calcium Disorders

what are the other terms for parturient paresis in cows

• milk fever [hypocalcemia

• paresis puerperalis

• parturient apoplexy

describe the calcium shift to milk

• calcium excretion goes from 10g to 30g per day

• normal blood total calcium 8.5mg/dL, milk fever cows generally drop below 5.5

what animals are at risk of milk fever

• periparturient cows

• all ages, though greater incidence in high producting cows in their 3rd or more lactation

• jersy and guernsey more predisposed

• usually seen within 3 days post calving → initial excitability, then weakness/inability to stand

what is stage 1 of milk fever

• hyperexcitability

• standing/ambulatory

• hypersensitive and excited

• mild ataxia, fine tremors

• ear twitching,, head bobbing

what is stage 2 of milk fever

• recumbent

• able to remain sternal

• obtunded, anorectic, dry muzzle

• hypothermic and cool extremities

• tachycardic, weak heart sounds and weak pulses

• ileus, bloat, possible inability to urinate

what is stage 3 of milk fever

comatose → may only have hours to live

what are other signs of milk fever

• dystocia

• uterine prolapse

• retained fetal membranes

• metritis

• abomasal displacement

• mastitis

what are differentials for milk fever

• toxic mastitis/mtritis/ect

• trauma

• calving paralysis syndrome

• compartment syndrome

how is the timing for milk fever different in small ruminants

• 6 weeks before to 10 weeks after

• most commonly 1-3 weeks pre-partum

what is hypocalcemic tetany in horses

• severe sweating causing loss or cantharadin toxicity

• dx ith history, physical exam (sweat, ulcerations, thumps/hiccups), severe hypocalcemia on bloodwork

what are thumps or hiccups in horses?

• synchronous diaphragmatic flutter

• severe hypocalcemia leading to decreased neuroprotection of nerve fibers

• synchronous firing of phrenic nerve with heart

what are the functions of calcium

• membrane stabilization for nerve impulses, bouncer that decreases influx of Na+ and depolarizatoon

• muscle contraction via release of AcCh at NMJ, skeletal, smooth, cardiac, coag

what is ionized calcium

• not protein bound

• active form of calcium

• better indication of true -calcemia

what are the clinical signs of hypocalcemia

• anorexia

• anxiety

• tremors

• tetanic contraction

• seizures

• paw chewing

• facial rubbin

• aggression

• cataracts

what are the most common causes of hypocalcemia

• eclampsia

• prtein losing enteropathy

• primary hypoparathyroidism

• nutritional secondary hyperparathyroidism

• renal secondary hyperparathyroidism

what is eclampsa or puerperal tetany

• females, small dogs

• 1st 28 days of nursing

• pathophysiology poorly understood

• check for concurrent hypoglycemia

what is primary hypoparathyroidism

• rare and immune mediated

• dogs = middle aged, female toy poodles and schnauzers

• young to middle age cats

how is primary hypoparathyroidism

• more progressive history with clinical signs that may be severe

• CBC/Chem/UA to rule out renal disease, CK may be high, consistent with lack of PTH

• lack of PTH = low Ca, high P

• PTH panel

how is nutritional secondary hyperparathyroidism described

• becoming more common

• all meat diets

• low dietary Ca:P

• hypicalcemia → hyperparathyroidism → bone resorption

how does renal disease cause hypocalcemia

• ionized hypocalcemia due to

• decreased calcitriol production

• resistance to PTH

• hyperphosphatemia

what are the clinical signs of hypercalcemia in dogs

• disease dependent

• lethargy/anorexia

• PU/PD

• vomiting, constipation

• muscle weakness, tremors

• may not have clinical signs

what are the clinical signs of hypercalcemia in cats

• lethargy and anorexia

• urolithiasis

• OU/PD but much less common than dogs

• vomiting

what are the most common causes of hypercalcemia in dogs

• neoplasia

• renal disease

• hyperparathyroidism

• hypoadrenocorticism

what are the most common etiologies of hypercalcemia in cats

• idiopathic

• renal disease

• neoplasia

• primary hyperparathyroidism

what is Hogs in yard in regards to hypercalcemia rule outs

• hyperparathyroidism

• osteolytic

• granulomatous

• spurious

• idiopathic or iatrogenic

• neoplasia

• youth

• addisons

• renal

• D (vitamin) toxicosis

what are causes of hyperparathyroidism in dogs

• neoplasia → benign functional adenomas

• hyperplasia

what is the signalment associated with hyperparathyroidism

• older of any sex

• keeshonds predisposed due to autosomal dominant trait

what are the clinical signs of primary hyperparathyroidism

• often none

• urolithiasis, UTI

• PU/PD

• weakness, decreased activity

• decreased appetite

• weight loss, vomiting

what are the diagnostic abnormalities of primary hyperparathyroidism

• increased tCa and iCa

• low BUN/creat

• low to normal P

• low USG

• UTI

• urinary calculi

how can testing the parathyroid hormone directly give info about hyperPTH

• if a dog is hypercalcemic, PTH should be suppressed

• high calcium with normal PTH is abnormal

what are Osteolytic causes of hypercalcemia

• osteomyelitis

• osteosarcoma (poor prognosis)

• usually obvious on PE

what are granulomaous causes of hypercalcemia

• fungal

• schistosomiasis

what are spurious causes of hypercalcemia

• aka lab error

• lipemia

• hemolysis

• recheck

what is idiopathic hypercalcemia

• seen in cats, most common cause

• older animials of any sex

• may be due to increased Ca":P in diet in some cases

what are the clinical signs of idiopathic hypercalcemia in cats

• none in 50%

• weight loss

• IBD

• constipation

• vomiting

• anorexia

• uroliths

what are the mechanisms of neoplastic hypercalcemia

• hymoral hypercalcemia of malignancy, circulating factors cause bone resorption

• osteolytic metastatic lesions such as carcinomas

• local osteolytic effect of tumor on bone such as hematopoietic tumors

what are the typical neoplasias that cause hypercalcemia

• lymphoma

• apocrine gland adenocarcinoma

• multiple myeloma

• mammary adenocarcinoma

• thymoma

how does addisons disease cause hypercalemia

• rare primary reason for presentation but always a rule out

  • increased renal tubular absorption/decreased excretion?

how does renal disease cause hypercalcemia

is actually usually low to normal but can be higgh

what are sources of vitamin D toxicosis

• iatrogenic

• rat killer

• psoriasis cream