Transient Thyrotoxicosis Post Parathyroidectomy With Primary Hyperparathyroidism Trisha Patel, Kunjal Shah and Tahira Yasmeen

Department of Internal Medicine, University of Illinois at Chicago/Advocate Christ Medical Center

Background Discussion• Transient hyperthyroidism after parathyroidectomy for hyperparathyroidism is a rare phenomenon that has been thought to be seen in 30% of cases.

• Majority of the scenarios described are related to secondary and tertiary hyperparathyroidism.

• Symptoms arise quickly, within 1 week of surgery and is due to palpation of the gland itself along with calcium disorders.

• Severity can range from mild tremors or palpitations to symptoms mimicking myocardial infarction.

• We present a rare case of an individual with primary hyperparathyroidism who subsequently presented with both features of hypocalcemia and thyrotoxicosis.

A 47-­year-­old female with primary hyperparathyroidism without history of hyperthyroidism presented to the emergency department complaining of perioral numbness and hand tremors.

She underwent parathyroidectomy 7 days prior to presenting to ER. The patient had correlated her symptoms with hypocalcemia and took a total of 4500 mg of calcium and presented to the hospital as symptoms did not abate. She also reported anxiety, restlessness and neck pain at the incision site for which she was taking ibuprofen. She denied family history of thyroid disease.

Preoperatively her thyroid tests were normal and thyroid ultrasound had shown a 0.6 cm anterior, inferior right thyroid nodule. Her vitals and physical exam revealed the following: temperature of 36.9 F, heart rate > 90 bpm, (sinus), blood pressure within normal limits and hand tremors. Lab tests were pertinent for suppressed thyroid stimulating hormone (TSH) at 0.047, elevated free triiodothyronine (FT3) at 6.5 and elevated free thyroxine (FT4) at 4 1.8.

Patient received one dose of propranolol and prochlorperazine with improvement of symptoms. She was subsequently discharged home with nonsteroidal anti-­inflammatory drugs. Her heart rate was normal, she did not require any more doses of propranolol.

She was advised to repeat TSH, FT3 and FT4 in 5 days as an outpatient. Two weeks after her visit to ER, her repeat lab showed improvement in TSH 0.092, T4 1.2, T3 3.7 and normal corrected serum calcium level of 9.2 mg/dl

References:

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Kauffels, A., et al. “Thyrotoxicosis after Parathyroidectomy Mimicking Myocardial Infarction: a Case Report and Review of theLiterature.” Clinical Research in Cardiology, vol. 101, no. 8, 2012, pp. 687–690., doi:10.1007/s00392-­012-­0446-­0.

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“Why Propranolol Is Preferred to Other Beta-­Blockers in Thyrotoxicosis or Thyroid Storm.” EBM Consult, Oct. 2015, www.ebmconsult.com/articles/propranolol-­preferred-­thyroid-­storm-­thyrotoxicosis.

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Yatavelli, R. K., & Levine, S. N. (2018). Transient Hyperthyroidism Induced by Thyroid Ultrasound. Annals of Otology, Rhinology & Laryngology, 127(8), 558–562. https://doi.org/10.1177/0003489418781169

Case

Thyroid and Parathyroid AnatomyCourtesy of Austin Thyroid and Parathyroid Surgeons, https://www.austinthyroidsurgeons.com/anatomy-­gallery/.

• Patients who undergo parathyroidectomy are at risk for hyperthyroidism due to physical manipulation of their thyroid gland.

• Symptoms can range from mild tremors, tachycardia, anxiety to severe like atrial fibrillation or thyroid storm.

• Our patient presented with symptoms of hypocalcemia, such as perioral numbness/tingling. After performing a review of systems, she endorsed anxiety, tremors and restlessness.

• Management is largely supportive, if patients present with palpitations and tachycardia, beta blockers can be administered. Beta blockers can not only provide symptomatic relief, but they can also prevent further progression as it decreases peripheral conversion of inactive T4 to active T3.

• There are no clear guidelines in management of post parathyroidectomy patients and suggestions on how frequently thyroid studies should be performed after.

• It is evident that close monitoring is required with frequent thyroid function tests. The purpose of this case report is to shed light on an exceedingly rare complication and allow clinicians to keep it in their differential when tending to post parathyroidectomy patients.

• Counseling patients regarding warning symptoms may also be warranted for early detection and intervention if need be.

Depiction of how propranolol blocks peripheral conversion of T4, image provided by EBM Consult“Why Propranolol Is Preferred to Other Beta-­Blockers in Thyrotoxicosis or Thyroid Storm.” EBM Consult, Oct. 2015, www.ebmconsult.com/articles/propranolol-­preferred-­thyroid-­storm-­thyrotoxicosis.