Acute Hepatic Porphyria and Systemic Lupus Erythematosus: coincidence or clinical connection

Abstract

Porphyrias are a group of disorders caused by deficiencies of the enzymes involved in the production of heme.¹ They are each caused by a specific abnormality in the heme biosynthesis process.² They can result in neurovisceral manifestations (e.g. abdominal pain, motor, and sensory peripheral neuropathy, neuropsychiatric manifestations) and/or cutaneous photosensitivity (either chronic and blistering or acute and mostly non-blistering).³ The diagnosis of porphyrias can be challenging because they are rare and their symptoms sometimes non-specific.³ Porphyrias can be classified into hepatic or erythropoietic, depending on whether pathway intermediates first accumulate in the liver or the bone marrow, respectively.³ The hepatic porphyrias can present as acute hepatic porphyrias (AHP) and include Acute intermittent porphyria (AIP), Aminolevulinic acid dehydratase porphyria (ALAD), Hereditary coproporphyria (HCP) and Variegate porphyria (VP).^3,4

In contrast, systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with a variable clinical course.⁵ Coexistence of an AHP and SLE is rare but has been described. As of June 2023, only 16 cases had been described and documented in literature.⁶ No case in South Africa has previously been documented. The overlap of symptoms makes diagnosis difficult and a delay in diagnosis and treatment may result in significant morbidity and/or mortality. The question is whether coexistence is mere coincidence or if there is  causal bi-directional unmasking relationship? Simply put, does SLE pre-dispose to an acute porphyria flare presentation or does an acute porphyria flare evoke an SLE presentation? If so, what would putatively explain the relationship?