Diagnostic and Therapeutic Challenges in an Acute Variegate Porphyric Crisis Complicated by Anuric Renal Failure and Multiorgan Dysfunction: A Case Report

Abstract

BACKGROUND Acute porphyrias arise from genetic defects in heme synthesis. Significant increases in urine porphobilinogen (PBG) levels are diagnostic, enabling further testing and the commencement of targeted therapies. We report a rare case of an elderly woman with a delayed diagnosis of acute variegate porphyria (VP) neurovisceral crisis, anuria, and multiorgan failure precipitated by methicillin-sensitive Staphylococcus aureus (MSSA) sepsis. Diagnostic and therapeutic difficulties confirming an acute VP crisis in the anuric patient are explored. CASE REPORT A 77-year-old South African woman presented with undifferentiated MSSA sepsis. Despite escalation to intensive care and treatment of her infection, she developed encephalopathy, tetraparesis, autonomic dysfunction, and anuric renal failure, requiring renal replacement therapy. Given her anuric state, novel assays of the dialysate effluent were performed and revealed elevated PBG levels. Xanthochromic cerebrospinal fluid was also obtained. Taken together with confirmatory plasma porphyrin spectrography, an acute VP neurovisceral crisis with multiorgan failure was established. Intravenous heme-arginate combined with extracorporeal filtration via continuous renal replacement therapy and therapeutic plasma exchange were initiated. Inappropriate blood leak detector clamping occurred during extracorporeal filtration due to the presence of porphyrins in the effluent. Despite these aggressive measures, the patient died due to her illness. CONCLUSIONS Progressive neurological compromise, coupled with undifferentiated multiorgan failure, should prompt consideration of an underlying acute porphyric crisis. In anuric porphyria patients, PBG assays of extracorporeal circuit effluents may be of diagnostic value. Effluent PBGs can interfere with the extracorporeal circuit blood leak detector, thereby offering further clinical suspicion of an underlying acute porphyric crisis.

Figure 1.

(A) Markedly xanthochromic cerebrospinal fluid obtained from the patient, suggestive of neurovisceral involvement by a variegate porphyria (VP) crisis. (B) Yellow-orange discoloration of the post-continuous renal replacement therapy (CRRT) dialysate effluent obtained from this patient.

Figure 2.

(A) Prismaflex continuous renal replacement therapy (CRRT) circuit control unit utilized for the treatment of this patient. (B) The connection of two 3-mL syringes infusing 0.9% normal saline via a plastic connector (red arrows) are shown, which bypasses the infrared blood leak detector. This enabled therapeutic plasma exchange (TPE) and CRRT to proceed without repeated activation of the blood leak detector alarm.