Elevated anti-Thyroglobulin Antibodies

HOSP # WARD Oudtshoorn Clinic
CONSULTANT George van der Watt & David Marais DOB/AGE 66y Male

Abnormal Result

Presenting Complaint

Mr. X, a 66 year old male, complained of chest pain, was seen at the Oudtshoorn Emergency department and a myocardial infarction was excluded by three serial point-of-care (POC) Troponin I results.

History

  • Known with hypothyroidism, but the cause was not defined yet.
  • On Eltroxin 150 ug daily PO
  • No other treatment.
  • Various stool analyses had been sent in for culture, with no definitive result.

Examination

Unfortunately not known.

Laboratory Investigations

Free T4: 24.6 pmol/L (7.6 – 16.1 pmol/L)

Anti-Thyroglobulin Antibody levels were elevated at 1944 U/mL (ref. <115 U/mL).

Other Investigations

Later, by retrospective viewing of the patient’s results it was revealed:

Total Cholesterol (TC) was elevated at 7.6 mmol/L. Hypothyroidism is associated with hypercholesterolemia. It can be concluded by the retrospective overview of results that upon an episode of hypothyroidism, the patient had hypercholesterolemia. This was most likely due to cessation of Thyroxine treatment, to whatever reason.

Index sample marked by the yellow shade. TC result which is raised (upper left corner) corresponds to the severely hypothyroid episode as revealed by the low T4 on that same sample.

Investigations also confirmatory for auto-immune hypothyroidism are:

  • Anti-Thyroid peroxidase antibodies
  • Anti-TSH receptor antibodies

Final Diagnosis

Auto-immune hypothyroidism

Take Home Messages

Interestingly, numerous patients with hypothyroidism is diagnosed at our Lipid Clinic at Groote Schuur Hospital. Patients are being referred for hypercholesterolaemia. Generally referral to this clinic happens when TC > 7.5 mmol/L. These patients are referred as presumed to have familial hypercholesterolaemia, but upon further work-up it is found that many of these patients have long-standing untreated hypothyroidism.

Prevalences of antithyroid antibodies as summarized by Up-to-date:

Image result for auto-immune hypothyroidism antibodies"