Endocrine Abstracts

Background: A 52-y-old lady (Mrs M) presented with a 10-day history of progressive generalised weakness, dysarthria and un-coordination. 26 y ago, she had cervical carcinoma, requiring a hysterectomy, oophorectomy and radiotherapy. This led to a vesicovaginal fistula, requiring a cystectomy and ureterosigmoidostomy. She is known to have osteoporosis. Medications: calfovit D3 one/d (started 5 days prior to admission), risedronate, lansoprazole. She had HRT until 50 y. Examination: Mrs M was in extremis, with profound tachypnoea, confusion and drowsiness (GCS12/15). FVC was reduced (1.6L). Power was generally reduced throughout (grade 3–4/5). Investigations: ABG showed profound metabolic acidosis: pH 7.13, pO₂ 20.1 kPa, pCO₂ 1.62 kPa, base excess −24.2. Serum biochemistry: Sodium(Na⁺) 145 mmol/l (134–144), Potassium(K⁺) 3.4 mmol/l (3.5–5.1), Bicarbonate(HCO₃¹⁻) 4 mmol/l (23–31), Urea 14.2 mmol/l (2.8–7.6), Creatinine(Cr) 108 μmol/l (55–96), Chloride 125 mmol/l (98–107), Calcium(Ca²⁺) 1.92 mol/l (2.12–2.55), Phosphate (PO₄³⁻) 0.38 mmol/l (0.8–1.4), Magnesium 0.57 mmol/l (0.7–1.0). PTH was raised [136 ng/l (15–65)], 25-OHD level was low-normal [11.5 μg/l (7–40)]. Management: Mrs M went to the intensive care unit, was intubated and given intravenous NaHCO₃, PO₄³⁻, Ca²⁺ and K⁺. Despite 120 mmol/d of K⁺, this remained low (3.0). She was extubated on day 2. By day 4, metabolic derangements were normalising and she was started on oral calcichew and NaHCO₃. By day 6, she felt sufficiently well and self-discharged. Electrolytes on discharge: Na⁺147, K⁺4.2, HCO₃¹⁻ 19, Urea 5.3, Cr 86, Ca²⁺2.06, PO₄³⁻ 0.78.

Discussion: Ureterosigmoidostomies often result in chronic hyperchloraemic metabolic acidosis. Unusually, this patient presented years later, acutely unwell, with generalised weakness, hypokalaemia and osteomalacia. It is unclear what triggered this. Colonic K⁺ reabsorption is poor and together with chronic acidosis, leads to reduced total body K⁺. Chronic acidosis also increases urinary Ca²⁺ and PO₄³⁻ loss, leading to osteomalacia. It is important these patients are maintained on oral sodium bicarbonate to prevent such complications.