Case 28 - Parathyroidectomy Flashcards
What is the physiology of calcium regulation?
Vitamin D
- absorption of Ca2+ from GI
PTH
- absorption of Ca2+ from bone, intestines, vit D production, decrease renal excretion
Calcitonin (produced by thyroid)
- decrease Ca2+ plasma concentrations
Ca2+
- ionized Ca = active and free form
- alkalosis –> increases binding of Ca2+ to albumin –> decrease ionized plasma conc
clinical features of hypercalcemia?
Bones, stones, groans, and psych overtones
Muscukloskeletal (bones)
- weak/atrophy
- bone fx
Renal (stones)
- kidney stones / polyuria
GI (Groans)
- n/v
- abd pain / stomach ulcer
- pancreatitis
- constipation
CNS (psych overtones)
- seizures
- disorientation
- altered mental status
- lethardy/sedation
Cards
- htn
- conduction abnormalities / arrhythmias
how do you treat hypercalcemia?
- stop administration of calcium (limit intake)
- 0.9% NS administration
- diuresis with furosemide
- do not give thiazide diuretics –> they save calcium in renal tubules –> increase levels
- consider dialysis (if patient has pre-existing renal failure or CHF)
- CHF can be exacerbated with fluid administration
-
bisphosphonates (pamidronate)
- tx for life threatening hpercalcemia
what are pre-op anesthetic considerations for parathyroidectomy?
- fluid management
- life threatening hypercalemia requires fluid admin
- at risk for hypervolemia, CHF**
- life threatening hypercalemia requires fluid admin
- diuretic use
- risk of hypokalemia
- muscle relaxation
- hypercalcemia antagonizes muscle relaxation (need frequent dosing)
- conduction abnormal / arrhythmias
- parathyroid hyperplasia assoc with MEN (MEN 2 involves pheochromocytoma)
are there important aspects to consider during anesthetic managment for a patient undergoing parathyroidectomy?
general anes straightforward
1) muscle relaxation vs intraop nerve monitoring
- consider opioid infusions to maintain relaxation
- benefits of opioids: provides deeper anesthesia, depress laryngeal reflexes –> avoid coughing during surgery and emergence
- coughing can cause neck hematoma
2) frequent lab draw for PTH levels
- PTH half life of 5 minutes
- frequent intraop lab draws to assess surgical success (low PTH = successful surgery, correct gland excised)
What regional anesthesia technique could you use for parathyoridectomy?
superficial and deep cervical plexus block
- superficial = sensory to surgical site
- deep = motor to surgical site
- risks: vertebral A. injection, phrenic nerve paralysis, neck hematoma, epidural or subdural block
what are the complications of parathyroidecotmy?
similar to thyroidectomy - complications resulting in respiratory distress
Resp Distress
- recurrently laryngel N. injury (uni vs b/l)
- neck hematoma
- tracheomalacia
-
Hypocalacemia - laryngeal muscle tetany
- occurs 24-72 hours after surgery
Other complications
- coagulopathy
- neuromuscular irritability
- muscle cramps
- chvostek’s sign (facial n irritability) /trousseau’s sign (carpal spasm)
- paresthesia
- CNS
- psychosis
- seziures
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