Extra Topic 2.5 -- Pituitary Tumor

Question 1

What information would you like to know pre-operatively?

(A 41-year-old female is scheduled for transphenoidal resection of a pituitary tumor.)

Answer 1

In addition to a thorough history and physical exam, I would want to know –

• the size of the tumor,
• if there were any suprasellar extension,
• if there were any neurological deficits,
• if the tumor was secreting hormones, or
• if there were any associated syndromes such as Cushing’s or acromegaly.

I would also assess the airway, IV access, and the severity of any co-existing disease.

Based on this information, I would order the appropriate lab work and formulate a plan for intubation and post-operative hormone replacement.

Question 2

What are the systemic effects of a growth hormone secreting tumor?

(A 41-year-old female is scheduled for transphenoidal resection of a pituitary tumor.)

Answer 2

Excessive excretion of growth hormone results in gigantism in prepubertal patients, and acromegaly in adults.

Acromegalic patients experience skeletal and soft tissue overgrowth, which results in large hands, feet, nose, mandible, tongue, soft palate, tonsils, and epiglottis.

This condition is also associated with –

HTN, accelerated atherosclerosis, osteoarthritis, skeletal muscle weakness, cardiomyopathy, vocal cord palsy, obstructive sleep apnea, arthritis, insulin resistance, and glottic stenosis.

Question 3

During infiltration of local anesthesia, you notice multiple premature ventricular contractions (PVCs). What would you do?

(A 41-year-old female is scheduled for transphenoidal resection of a pituitary tumor.)

Answer 3

The PVCs are likely to be the result of the injection of epinephrine-containing local anesthetic or the use of cocaine pledgets.

With this in mind, I would alert the surgeon to stop the infiltration, ensure adequate ventilation with 100% oxygen, check blood pressure, and examine the EKG for signs of myocardial ischemia.

I would then be prepared to treat any hypertension and/or significant arrhythmias that may occur.

Question 4

During infiltration of local anesthesia, you notice multiple PVCs.

What do you think was the cause?

(A 41-year-old female is scheduled for transphenoidal resection of a pituitary tumor.)

Answer 4

As I mentioned, the most likely cause is systemic uptake of epinephrine contained in the local anesthetic.

However, other potential causes include, –

hypoxia, cardiac ischemia, air embolism, electrolyte abnormalities, or anesthetic induced cardiac depression.