Endocrine Abstracts

A 24-year-old lady was initially presented with vomiting due to gastroenteritis and muscle cramps in 1993. Investigations revealed corrected calcium 1.65 mmol/l (range 2.2–2.6), phosphate 1.21 mmol/l (range 1.4–2.2) with intact Parathyroid hormone (PTH) 11 pmol/l (range 1.3–8.1) and potassium 3.1 mmol/l (range 3.5–5). She was found to have hypertension but no somatic signs. Ellsworth Howard test displayed a blunted response of cAMP and a normal phosphaturic response to PTH infusion: Urinary cAMP/Creatinine: 0.5 (30 min), 0.49 (60 min), 1.05 (90 min), 0.84 (120 min), 0.47 (180 min), 0.44 (210 min), Urine Phosphate 2.47 mmol/l, consistent with a diagnosis of Pseudohypoparathyroidism (PHP).

Despite stopping her oral contraceptive pills, she remained hypertensive, requiring 3 antihypertensives. Other endocrine and renal causes of hypertension were excluded.

In 2003, she developed severe Osteoarthritis (OA) affecting both hands confirmed by X-rays changes with negative immunology. This affects her quality of life. She has no family history of OA and works as a teacher.

PHP is a heterogeneous disease characterized by PTH resistance and classified as types Ia, Ib, Ic and II, according to its different pathogenesis and phenotype. Because of her absent somatic features with abnormal biochemistry, the diagnosis of PHP-Ib was made. Her offspring are unaffected.

Hypertension is found in 53% of patients with PHP and strongly linked to severe obesity. Surprisingly, our patient who is severely hypertensive has a normal body mass index. It is rather unusual to see severe OA at her age without any risk factors. Association between PHP and OA changes has not been reported so far yet.