31
Table 4. Endocrine Toxicities
Additional considerations:
• Thyroiditis is self-limited and the initial hyperthyroidism generally resolves in weeks
with supportive care; most often to primary hypothyroidism or occasionally to
normal. Persistent or symptomatic hypothyroidism developing after hyperthyroidism
should be treated as above (see section 4.1).
• Graves' disease has not been reported with ICPi specifically, but sporadic cases could
occur. GD is generally persistent and is treated with anti-thyroid medical therapy,
radioactive iodine, or surgery. Endocrine consultation is recommended if suspected.
• Physical exam findings of ophthalmopathy or thyroid bruit are diagnostic of Graves'
disease and should prompt early endocrine referral.
4.2 Adrenal — Primary adrenal insufficiency (AI)
Workup/Evaluation:
• Evaluate AM levels of ACTH (if >2× ULN) and cortisol level (if <3 ug/dL).
• Basic Metabolic Panel (Na, K, CO
2
, Glucose).
• Renin and aldosterone.
• Consider standard dose ACTH stimulation test for indeterminate results (AM
cortisol >3 ug/dL and <15 ug/dL).
• Evaluate for precipitating cause of crisis such as infection.
• Adrenal CT for metastasis or hemorrhage (most common causes of primary AI).
Grading Management
All Grades • Referral to endocrinolog y.
• Education on steroid stress dosing, emergency
injections, and a medical alert bracelet/necklace,
accessory, or system.
G1: Asymptomatic or mild
symptoms
• Consider holding ICPi until patient is stabilized on
replacement hormone.
• Endocrine consultation.
• Initiate replacement therapy with hydrocortisone
(15–20 mg in divided doses — see additional
considerations).
• Titrate hydrocortisone to maximum of 30 mg daily
total dose for residual symptoms of AI.
• Reduce maintenance dosing for symptoms of
iatrogenic Cushing's syndrome (e.g., bruising,
thin skin, edema, weight gain, hypertension,
hyperglycemia).
• Most primary AI will also require fludrocortisone
(starting dose 0.5–0.1 mg/day). Adjust based on
volume status, sodium level, and renin response
(target upper half of the reference range).
(cont'd)
