Clinical Case: Sick euthyroid syndrome

A 57 yo female was admitted to the hospital with multilobar pneumonia.

On hospital day 2, thyroid function tests showed low levels of TSH, T4 and T3.

What is the most likely diagnosis?

Read more in Sick euthyroid syndrome in a patient with multilobar pneumonia on

Image source: Thyroid histology, Wikipedia, public domain.


  1. Secondary hypothyroidism

  2. Lisa,

    It is not secondary hypothyroidism. The repeated TFTs a week later were completely normal after the resolution of acute illness.