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Immune-Related Adverse Events for Endocrine Toxicities - Hypothyroidism
CTCAE-based severity grade for hypothyroidism from checkpoint inhibitor therapy.
Immune-Related Adverse Events for Endocrine Toxicities - Hypothyroidism
Clinical picture
ResultNo hypothyroidism
No evidence of hypothyroidism.
When to use
- Grading hypothyroidism (primary or secondary to hypophysitis) that develops during or after immune checkpoint inhibitor therapy.
Formula
CTCAE v5.0 general endocrine-toxicity grading applied to ICPi-related hypothyroidism: Grade 1, asymptomatic; Grade 2, symptomatic and thyroid hormone replacement indicated; Grade 3, severe symptoms limiting self-care, hospitalization indicated; Grade 4, life-threatening (e.g., myxedema coma).
Pearls and pitfalls
- Check TSH and free T4 at baseline and periodically during ICPi therapy; a low TSH with low free T4 suggests hypophysitis rather than primary thyroiditis and warrants pituitary-axis work-up and imaging.
- ICPi therapy can usually continue through grade 1-2 hypothyroidism once levothyroxine replacement is started.