A 66-year-old man with abnormal thyroid function tests

Cleveland Clinic Journal of Medicine. 2019 October;86(10):666-675 | 10.3949/ccjm.86a.19024
October 1, 2019|Cleveland Clinic Journal of Medicine
Yazan N. Alhalaseh, MD;Zaid A. Abdulelah, MD;Ahmad O. Armouti, MD;Ayman A. Zayed, MD, MSc, FACE, FACP
Author and Disclosure Information

Yazan N. Alhalaseh, MD
Department of Internal Medicine, King Hussein Cancer Center, Amman, Jordan

Zaid A. Abdulelah, MD
Istishari Hospital, Amman, Jordan

Ahmad O. Armouti, MD
King Hussein Medical Center, Amman, Jordan

Ayman A. Zayed, MD, MSc, FACE, FACP
Professor of Medicine and Chief, Division of Endocrinology, Diabetes, and Metabolism, Department of Internal Medicine, Jordan University Hospital, Amman, Jordan

Address: Ayman A. Zayed, MD, MSc, FACE, FACP, Department of Internal Medicine, Jordan University Hospital, Queen Rania Street, Amman, Jordan, 11942; baraaayman@gmail.com

Release date: October 1, 2019
Expiration date: September 30, 2020
Estimated time of completion: 1 hour

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CASE CONTINUED

The patient continued to improve. On hospital day 6, he was feeling better but still had mild respiratory distress. There had been no further episodes of arrhythmia since day 4. His blood pressure was 136/86 mm Hg, heart rate 88 beats per minute and regular, respiratory rate 18 breaths per minute, and oral temperature 37.1°C. His oxygen saturation was 92% on room air.

Before discharge, he was encouraged to quit smoking. He was offered behavioral counseling and medication therapy, but he only said that he would think about it. He was discharged on oral cefixime for 4 more days and was instructed to switch to a long-acting bronchodilator along with his other home medications and to return in 1 week to have his thyroid hormones checked.

One week later, his laboratory results were:

,
  • TSH 11.2 mU/L (reference range 0.5–5.0)
  • Free T4 1.2 ng/dL (0.9–2.4)
  • Total T3 92 ng/dL (80–180).

Clinically, the patient was euthyroid, and examination of his thyroid was unremarkable.

4. Based on these last test results, which statement is correct?

  • Levothyroxine therapy should be started
  • His serum TSH elevation is most likely transient
  • Thyroid ultrasonography is strongly indicated
  • A radioactive iodine uptake study should be performed
  • Measurement of thyroid-stimulating immunoglobulins is indicated

During recovery from nonthyroidal illness, some patients may have elevated serum TSH levels that are usually transient and modest (< 20 mU/L).48 Normalization of the thyroid function tests including serum TSH may take several weeks49 or months.50 However, a systematic review found that the likelihood of permanent primary hypothyroidism is high in patients with serum TSH levels higher than 20 mU/L during the recovery phase of their nonthyroidal illness.51

Ultrasonography is useful for evaluating patients with thyroid nodules or goiter but is of little benefit for patients like ours, in whom the thyroid is normal on examination.

Similarly, a radioactive iodine uptake study is not indicated, as it is principally used to help differentiate between types of thyrotoxicosis. (Radioactive iodine is also used to treat differentiated thyroid cancer.)

Thyroid-stimulating immunoglobins are TSH receptor-stimulating antibodies that cause Graves disease. Nevertheless, measuring them is not routinely indicated for its diagnosis. However, their measurement is of significant help in the diagnosis of Graves disease if a radioactive iodine uptake study cannot be performed (as in pregnancy) and in atypical presentations such as euthyroid Graves ophthalmopathy.52 Other indications for thyroid-stimulating immunoglobin measurement are beyond the scope of the article. Our patient’s test results are not consistent with hyperthyroidism, so measuring thyroid-stimulating immunoglobins is not indicated.

CASE CONCLUSION: BETTER, BUT STILL SMOKING

The patient missed his 1-month clinic follow-up, but he visited the clinic for follow-up 3 months later. He was feeling well with no complaints. Test results including serum TSH, free T4, and total T3 were within normal ranges. His COPD was under control, with an FEV1 88% of predicted.

He was again encouraged to quit smoking and was offered drug therapy and behavioral counseling, but he declined. In addition, he was instructed to adhere to his annual influenza vaccination.

KEY POINTS

  • In patients with acute illness, it is recommended that thyroid function not be assessed unless there is a strong indication.
  • If thyroid function assessment is indicated for critically ill patients, serum TSH and free T4 concentrations should be measured. Some clinicians also measure serum total T3 level.
  • Thyroid function testing in critically ill patients usually shows low serum total T3, normal or low serum TSH, and normal or low serum free T4.
  • Many drugs can alter thyroid hormone levels.
  • Thyroid hormone therapy is not recommended for critically ill patients with low T3, low T4, or both.
  • During recovery from nonthyroidal illness, some patients may have mild elevation in serum TSH levels (< 20 mU/L).
  • Thyroid hormone levels may take several weeks or months to return to normal after the acute illness.
  • Patients with serum TSH levels higher than 20 mU/L during the recovery phase of their nonthyroidal illness are more likely to have permanent primary hypothyroidism.