HomeAnswersEndocrinologyhypothyroidismWhy hypothyroidism causes fast heartbeat and jaw lock?

Can hypothyroidism be the cause of a fast heartbeat, milk ejaculation, and the locking of the left jaw while eating?


The following is an actual conversation between an iCliniq user and a doctor that has been reviewed and published as a Premium Q&A.

Medically reviewed by

iCliniq medical review team

Published At March 30, 2023
Reviewed AtOctober 6, 2023

Patient's Query

Hi doctor,

I have been diagnosed with hypothyroidism at the age of 17. The doctor gave me a prescription and he told to come for a review. I finished the prescribed medicine and did not go back to the doctor since my mother told me I was fine already. Now at the age of 21, I am suffering from a fast heartbeat, my left jaw is always locking while eating, I always feel tired and milk comes into my left breast but I am not pregnant.


Welcome to icliniq.com.

I have gone through your complaints and understand your concern.

Hypothyroidism is associated with problems with the temporomandibular joint (the joint which connects the two jaws). It is also associated with milk secretion from the breast without pregnancy and tiredness. However, it is not associated fast beat rather it is associated with a slow heartbeat. I would recommend you to get a serum TSH (thyroid stimulating hormone), free T3 and free T4, and complete blood count with ESR (erythrocyte sedimentation rate) done. A thyroid profile will help in ruling or confirming hypothyroidism.

Investigations to be done

The investigations include serum TSH (thyroid stimulating hormone), free T4, and free T3, and complete blood count with ESR (erythrocyte sedimentation rate).

Differential diagnosis

The differential diagnosis includes anemia.

Probable diagnosis

The probable diagnosis includes hypothyroidism.

Regarding follow up

Follow-up after test results.

Same symptoms don't mean you have the same problem. Consult a doctor now!

Dr. Dhananjay Tiwari
Dr. Dhananjay Tiwari

General Practitioner

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