Constipation and coloured urine: the diagnostic challenge of acute intermittent porphyria
Leenen, C.H.M., Westerman, M., Siegert, C.E.H., Veenstra, J.
Voorzitter(s): dr. B.J. Looij, Geleen & dr. Y.W.J. Sijpkens, Den Haag
Locatie(s): Zaal 2.1
Categorie(ën):
Introduction: acute intermittent porphyria (AIP) is one of a cluster of rare metabolic disorders. It is an autosomal dominant condition, characterized by a reduced activity of one of the enzymes in the heme biosynthetic pathway resulting into an array of symptoms characterized by autonomous dysfunction.
Case: a 23-year old woman with an unremarkable medical history was admitted to our hospital with complaints of two weeks duration of abdominal pain and constipation. Prior to admission she visited four medical doctors, including three general practitioners and the emergency department. However, the initiated treatment consisting of laxatives and analgesics was ineffective. Upon admission vital signs and temperature were normal. On abdominal examination normal bowel sounds were heard and palpation was not painful. Laboratory tests revealed an acute kidney injury (creatinine 111 μmol/l, GFR using MDRD 53 ml/min), low sodium (sodium 131 mmol/l), increased creatinine kinase (CK 1200 U/l) and a microcytic anemia (hemoglobin 6,5 mmol/l). Abdominal ultrasound was normal. During admission the striking discovery was done that her urine was dark-red coloured. Additional urine analysis showed increased levels of porphyrines, especially a high delta-aminolevulinic acid level (336,3 umol/l) and porphobilinogen level (500,0 umol/l), suggestive for AIP. Furthermore, it appeared she had a positive family history for AIP. In two affected sisters of her father a mutation in the HMBS gene was detected. Her father had never experienced any attacks and had therefore never been tested. Treatment with glucose (10%) intravenously and morphine was immediately started after which the patient fully recovered. This first episode of AIP was probably initiated by an urinary tract infection for which she received intravenously ceftriaxone. In literature, five other cases of rhabdomyolisis and AIP have been reported.
Conclusion: In case of unexplained abdominal pain with constipation and unexpected biochemical changes including low sodium levels, rhabdomyolysis and/or microcytic anemia, AIP should be considered.Family history is of great importance.