Endocrine Abstracts

Thyroid hormone exerts direct effects on almost every body organ or tissue, and thyroid deficiency produces a wide range of metabolic disturbances. Hypothyroidism is readily recognized in an individual presenting with characteristic clinical signs and symptoms. However involvement of the haematologic and renal systems is less commonly acknowledged making the diagnosis less apparent and, therefore, the initial focus of attention is on a diagnosis other than hypothyroidism.

Case report: A 64-year-old woman presented with bilateral ankle oedema and dry skin. Initial investigation revealed heavy proteinuria (4+ on urinalysis), full blood count revealed pancytopenia (Hb – 10.2, WBC – 2.9 and platelets – 127); impaired renal function – serum creatinine 129 μmol/l and eGFR – 38. She was investigated by nephrology services and no primary renal pathology was identified. Subsequently primary autoimmune hypothyroidism was diagnosed and thyroid hormone replacement commenced. This led to complete recovery of the pancytopenia, renal function and resolution of proteinuria.

Discussion: In hypothyroidism, mild degree of anaemia is common and seen in about 30% cases. It is associated with reduced plasma volume, RBC mass and plasma erythropoietin levels. However white blood cells and platelets are usually unaffected in hypothyroidism. Besides involvement of haematologic system, hypothyroidism can cause significant changes in kidney function with reduction in glomerular filtration rate and renal plasma flow, leading to rise in serum creatinine and glomerular involvement causing mild proteinuria.

Pancytopenia has been reported in patients with hypopituitarism however we are not aware of any report of pancytopenia associated with primary hypothyroidism.

Conclusion: This case highlights two rare complications of hypothyroidism – nephrotic syndrome and pancytopenia. It is important to recognize that other organ systems may be involved and that the resulting disease states can dominate the clinical picture. As with the classic manifestations of hypothyroidism, these unusual manifestations respond to thyroid hormone replacement therapy.