Feedback Loop: Thyroid Stimulating Hormone (TSH)
Authors: Josh Kariath Reviewers: Andrea Kuczynski Bernard Corenblum* * MD at time of publication
Stress
Excess: heat intolerance, tremor, proximal muscle weakness, palpitations, systolic HTN, brisk reflexes, weight loss, ↑ appetite, ↑ bowel movements
Deficiency: cold intolerance, firm gland of any size, fatigue, depression, weight gain, constipation, delayed relaxation of DTRs, diastolic HTN
Cortisol
–
+ +
Cold
Hypothalamus
TRH
TRH travels down
hypophyseal stalk through portal vessels
Anterior Pituitary Gland –
TSH
TSH travels through the blood
Thyroid Gland (Follicle) +
T3 T4
Converted into T3 in all target tissues
↑ BMR
–
Abbreviations:
TRH: Thyrotropin Releasing Hormone HTN: Hypertension
DTRs: Deep Tendon Reflexes
TSH: Thyroid Stimulating Hormone I2: iodine
CO: Cardiac Output
T3: Triiodothyronine
T4: Thyroxine
CNS: Central Nervous System
SNS: Sympathetic Nervous System BMR: Basal Metabolic Rate
–
Diet
I2
Excess: no real disorders
Deficiency: goiter
↑ CO, ↑ contractility, ↓ resistance
Hormone metabolism, bilirubin metabolism
Heart Liver
Bone growth Bone
↑ SNS activation, temperature homeostasis
CNS
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published October 2, 2018 on www.thecalgaryguide.com