Streptococcus pneumoniae-Associated Hemolytic and Uremic Syndrome With Cholestasis: A Case Report and Brief Literature Review

Streptococcus Pneumoniae-Associated Hemolytic Uremic Syndrome in the Era of Pneumococcal Vaccine

Streptococcus pneumoniae-associated hemolytic uremic syndrome (Sp-HUS) is a serious complication of invasive pneumococcal disease that is associated with increased mortality in the acute phase and morbidity in the long term. Recently, Sp-HUS definition has undergone revision and cases are categorized as definite, probable, and possible, based on less invasive serological investigations that evaluate Thomsen-Friedenreich crypt antigen (T-antigen) activation. In comparison to the pre-vaccine era, Sp-HUS incidence seems to be decreasing after the introduction of 7-serotype valence and 13-serotype valence pneumococcal vaccines in 2000 and 2010, respectively. However, Sp-HUS cases continue to occur secondary to vaccine failure and emergence of non-vaccine/replacement serotypes. No single hypothesis elucidates the molecular basis for Sp-HUS occurrence, although pneumococcal neuraminidase production and formation of T-antigen antibody complexes on susceptible endothelial and red blood cells continues to remain the most acceptable explanation. Management of Sp-HUS patients remains supportive in nature and better outcomes are being reported secondary to earlier recognition, better diagnostic tools and improved medical care. Recently, the addition of eculizumab therapy in the management of Sp-HUS for control of dysregulated complement activity has demonstrated good outcomes, although randomized clinical trials are awaited. A sustained pneumococcal vaccination program and vigilance for replacement serotypes will be the key for persistent reduction in Sp-HUS cases worldwide.

New insights into the pathogenesis of Streptococcus pneumoniae-associated hemolytic uremic syndrome

The purpose of this review is to describe Streptococcus pneumoniae-associated hemolytic uremic syndrome (P-HUS) with emphasis on new insights into the pathophysiology and management over the past 10 years. Even though awareness of this clinico-pathological entity has increased, it likely remains under-recognized. Recent observations indicate that although neuraminidase activity and exposure of the T-antigen are necessary for development of P-HUS, they are not sufficient; activation of the alternate pathway of complement may also contribute. It is unclear, however, whether or not eculizumab and/or plasmapheresis are of value.

Typical and Atypical Hemolytic Uremic Syndrome in the Critically Ill

Hemolytic uremic syndrome is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, and hemolytic uremic syndrome have a similar clinical presentation. Diagnostic needs to be prompt to decrease mortality, because identifying the different disorders can help to tailor specific, effective therapies. However, diagnosis is challenging and morbidity and mortality remain high, especially in the critically ill population. Development of clinical prediction scores and rapid diagnostic tests for hemolytic uremic syndrome based on mechanistic knowledge are needed to facilitate early diagnosis and assign timely specific treatments to patients with hemolytic uremic syndrome variants.

Escherichia coli-associated hemolytic uremic syndrome and severe chronic hepatocellular cholestasis: complication or side effect of eculizumab?

BACKGROUND

Liver lesions of hemolytic uremic syndrome due to Shiga-toxin-producing Escherichia coli (STEC-HUS) are uncommon.

CASE-DIAGNOSIS/TREATMENT

We report three observations of severe STEC-HUS with delayed hepatic involvement. They presented with multiple organ failure and received eculizumab; 15 days after the onset of STEC-HUS, cholestasis appeared and cytolysis worsened. Abdominal ultrasonography showed vesicular sludge. Liver biopsy performed 3 to 6 months after the STEC-HUS found cholangiolar proliferation and inflammatory portal fibrosis. Despite renal recovery, cholestasis persisted and worsened in two cases, leading to biliary cirrhosis and subsequent liver transplantation. Pathological examination of one native liver found thrombotic microangiopathy.

CONCLUSIONS

Even though the pathological examination performed on one native liver demonstrated areas of thrombotic microangiopathy, we cannot completely rule out that eculizumab may have worsened the liver lesions. Before the efficacy of eculizumab in STEC-HUS is formally demonstrated, physicians should stay cautious in its use.