Secondary haemophagocytic lymphohistiocytosis in a patient with new-onset systemic lupus erythematosus: the challenges of timely diagnosis and successful treatment.

Haemophagocytic lymphohistiocytosis (HLH) is an immune-mediated disease driven by abnormal macrophage activation and regulatory cell dysfunction. HLH can be primary due to genetic mutations or secondary due to infection, malignancy or autoimmune conditions. We describe a woman in her early 30s who developed HLH while being treated for newly diagnosed systemic lupus erythematosus (SLE) complicated by lupus nephritis as well as concomitant cytomegalovirus (CMV) reactivation from a dormant infection. The trigger for this secondary form of HLH may have been either aggressive SLE and/or CMV reactivation. Despite prompt treatment with immunosuppressive therapies for SLE consisting of high-dose corticosteroids, mycophenolate mofetil, tacrolimus, etoposide for HLH and ganciclovir for CMV infection, the patient developed multiorgan failure and passed away. We demonstrate the difficulty in identifying a specific cause for secondary HLH when multiple conditions are present (SLE and CMV) and the fact that, despite aggressive treatment for both conditions, the mortality for HLH remains high.

Obesity-related glomerulopathy in the presence of APOL1 risk alleles.

Nephropathic apolipoprotein L1 (APOL1) risk alleles (G1/G2) have been associated with focal segmental glomerulosclerosis, HIV-associated nephropathy, Systemic lupus erythematosus (SLE)-associated collapsing glomerulopathy and other glomerulonephritides. These alleles confer protection from Trypanosoma brucei infections which are enriched in sub-Saharan African populations. We present a young woman with obesity, hypertension, subnephrotic range proteinuria who was found to have obesity-related glomerulopathy on kidney biopsy while harbouring two high-risk APOL1 alleles (G1/G2). Given the potential effects on lipid metabolism and their association with obesity, the presence of APOL1 risk alleles may impact cardiovascular health in addition to renal disease in these patients.

Atypical presentation of allergic interstitial nephritis likely induced by ciprofloxacin.

Though the prevalence of drug induced allergic interstitial nephritis (AIN) appears to be increasing, the diagnostic and treatment strategies still remain vague. We present a 56-year-old man with a history of hypertension, chronic kidney disease stage IIIa, recent exposure to ciprofloxacin who presented with acute kidney injury. Though the suspicion of AIN was high, his urinary sediment was bland, that is, no leucocytes or leucocyte casts. A renal biopsy subsequently showed features of AIN correlating with a resolving phase of inflammation. Given the resolving nature of the pathology, we chose not to complete a course of corticosteroids despite his need for temporary haemodialysis. He was able to fully recover his renal function. In this report, we emphasise the unreliable nature of the urinary sediment in the diagnosis of AIN, the utility of a renal biopsy in helping to guide treatment, and the controversial data in corticosteroid treatment.