Endocrine Abstracts

Case History: We report the case of a 25-year-old Asian male who presented to our hospital with recurrent episodes of abdominal pain complicated by significant Hyponatremia. Initial admission was in November 2021 followed by March, 2022 with similar symptoms. He remained under surgical care during both admissions. For his severe hyponatremia, an urgent Endocrine input was sought. The patient was not on any medications that could be implicated in his biochemical picture and his past medical history was unremarkable except for appendicectomy. During his stay, he also had recurrent episodes of fluctuating confusion associated with severe hypertension.

Investigations: Biochemistry during both admissions revealed severe Hyponatremia with nadir sodium 103 mmol/l. Hyponatremia work up was consistent with SIADH without any obvious cause. Extended biochemistry confirmed normal Lipid profile, Thyroid functions, and re-assuring Cortisol levels. Computerised Tomography (CT) imaging on both occasions ruled out any evidence of obvious surgical pathology. Due to lack of any obvious explanation to his symptoms, Porphyria screen was requested to exclude Acute Intermittent Porphyria (AIP).

Results and treatment: During the first admission, his symptoms were managed by analgesia and anti-emetics. He required exploratory laparotomy for suspected intestinal obstruction, given his previous history of appendicectomy. His sodium levels improved well with Fluid restriction and Urea tablets. To ensure strict electrolyte monitoring, he was transferred to the High Dependency Unit on both occasions. His stay in HDU was complicated by recurrent episodes confusion and severe hypertension consistent with sympathetic overactivity. Following discharge after his first admission, he was due to be followed up in the Endocrine outpatient clinic, however, unfortunately did not attend respective appointments. During the second admission of a similar nature, given lack of obvious explanation to his symptoms, Porphyria screen was requested as one of the rarer medical causes of abdominal pain and severe hyponatremia. This revealed significantly elevated random PBG excretion - 91(high) and total porphyrin levels PBG- 310(high). He has now been referred to the regional Tertiary Porphyria Centre for management.

Conclusions and points for discussion: AIP is one of several disorders that arise from enzymatic derangements in the biosynthetic pathway of the heme molecule. AIP is the most common of the acute porphyrias worldwide, with an estimated prevalence of approximately 5 per 100,000 people This case highlights the importance of considering the diagnosis of AIP in patients presenting with recurrent abdominal pain and Hyponatremia, where in surgical causes have been excluded.