Page 1047 - Cote clinical veterinary advisor dogs and cats 4th

Hypoparathyroidism, Primary 519

hyponatremia. For animals with normal or Classification of Hyponatremia According to Plasma Tonicity and Volume
excessive volume status, minimal parenteral Status
VetBooks.ir Acute Treatment + Plasma Tonicity Pseudohyponatremia: hyperlipidemia, hyperproteinemia Water and Na Status Diseases and Disorders
fluids should be administered.
+
Example
+
Isotonic
Water normal, Na normal
1
• Monitoring the rate of change in [Na ]
+
during correction is crucial. 2 Hypertonic Extreme hyperglycemia, mannitol infusion Various effects; Na can
• Direct treatment of the underlying disease is increase, or water can
decrease
always in order. Sometimes, this may be the +
only treatment required for hyponatremia 3 Hypotonic a Hypovolemic (overt volume contraction): GI loss, Water and Na depleted
(e.g., furosemide to address CHF helps hemorrhage, Addison’s disease, third spacing
+
eliminate excess water and correct hypo- b Hypervolemic (overtly edematous): CHF, cirrhosis, Water and Na excess
natremia; dosoxycorticosterone [DOCP] nephrotic syndrome
to address hypoadrenocorticism increases c Euvolemic (volume status grossly clinically normal Water excess, Na normal
+
+
[Na ], although hypovolemia is likely to but mildly hypervolemic): SIADH, myxedema
require crystalloid fluids).
+
• For animals that are not responsive to these CHF, Congestive heart failure; GI, gastrointestinal; Na , sodium ion; SIADH, syndrome of inappropriate antidiuretic hormone. Isotonic
+
treatments, calculate the Na deficit. = normosmolar; hypertonic = hyperosmolar; hypotonic = hypoosmolar.
+
○ Deficit = BW (kg) × 0.6 × (normal [Na ]
+
− patient [Na ]) Possible Complications develops sudden-onset ataxia and abnormal
• If hyponatremia is of short duration • Osmotic demyelination syndrome with too mentation).
(<24 hours), rapid correction with isotonic rapid correction • In humans, there are many reported causes
(0.9%) or hypertonic (3% or even 7.5%) • Hypervolemia and cardiopulmonary over- of SIADH. Causes described in veterinary
saline is acceptable. Multiple formulas exist load when fluids are given to hypervolemic medicine include drugs, neoplasia, central
to determine infusion rate. patient nervous system disease, lung disease, and
○ Administer the 3% saline at a rate of others.
0.5-2 mL/kg body weight (BW) per Recommended Monitoring • Hypoadrenocorticism is an important
+
hour to increase the serum sodium level During correction of hyponatremia of > 24 cause of low serum Na with high potas-
by 1-2 mEq/L/h. hours’ duration, monitor serum sodium q 2-4h sium, but other causes include enterocolitis
○ For animals with hyponatremia-induced to avoid too rapid increase. Repeat neurologic (e.g., whipworms), diabetes mellitus, renal
coma or seizures, can increase rate to 2-4 mL/ evaluations several times each day. disease, pregnancy, or effusive disease (e.g.,
+
kg/h until Na is raised by 5-6 mEq/L (not chylothorax)
to exceed 8-12 mEq/L/day). PROGNOSIS & OUTCOME
○ Can give furosemide with saline to Prevention
promote free-water excretion and prevent Depend on underlying cause and ability to Be alert to electrolyte abnormalities in any ill
+
extracellular volume expansion, especially correctly restore serum Na > 130 mEq/L in animal.
if the animal is not volume depleted (e.g., the absence of iatrogenic complications
water intoxication). Technician Tips
• If hyponatremia has been present > 24 hours, PEARLS & CONSIDERATIONS Carefully monitor fluid rates during treatment
gradual correction is essential. Rates should of hyponatremia.
not exceed 0.5 mEq/L/h. Comments
+
○ If the Na is < 120 mEq/L, a maximum • If slow-onset hyponatremia, correct slowly. SUGGESTED READING
of only 10-12 mEq/L of sodium increase If rapid-onset hyponatremia, correct rapidly. Guillaumin J, et al: Disorders of sodium and water
is recommended during the first 24-hour • Osmotic demyelination syndrome may not homeostasis. Vet Clin Small Anim 47:293-312,
period and by no more than 18 mEq/L be evident for up to 2 weeks after overly 2017.
by 48 hours. rapid correction of hyponatremia.
○ Rate (mL/h) = (0.6 × BW (kg) × (desired • Water intoxication is uncommon but often AUTHOR: Michael Schaer, DVM, DACVIM, DACVECC
EDITOR: Leah A. Cohn, DVM, PhD, DACVIM
+
+
[Na ] − measured [Na ]) × 1000)/(fluid is suggested by history (e.g., previously
+
[Na ] × hours) to target gradual correction. healthy dog on a recreational lake outing that
Hypoparathyroidism, Primary Client Education
Sheet
Epidemiology Clinical Presentation
BASIC INFORMATION
SPECIES, AGE, SEX HISTORY, CHIEF COMPLAINT
Definition • Uncommon disorder of dogs; rare in cats Sporadic or episodic signs related to hypocal-
Absolute or relative deficiency of parathyroid • Dogs: any age, either sex may be affected cemia (p. 515)
hormone (PTH) due to parathyroid gland • Cats: young to middle-aged, male pre- • Most common
destruction or atrophy, causing hypocalcemia dominance ○ Focal or diffuse muscle tremors or
twitching that may worsen with exercise
Synonyms GENETICS, BREED PREDISPOSITION or excitement
Vitamin D 2 : ergocalciferol; vitamin D 3 : cholecal- Toy poodles, miniature schnauzers, Saint ○ Seizures
ciferol; calcitriol: 1,25-dihydroxycholecalciferol, Bernards (in Australia) ○ Stiff gait, muscle pain/cramping
1,25-dihydroxyvitamin D, activated vitamin D 3
www.ExpertConsult.com