Early Differentiation of Shiga Toxin-Associated Hemolytic Uremic Syndrome in Critically Ill Adults With Thrombotic Microangiopathy Syndromes

Eculizumab in severe Shiga toxin-mediated haemolytic uraemic syndrome

Shiga toxin (Stx)-producing Escherichia coli-mediated haemolytic uraemic syndrome is a primary thrombotic microangiopathy, typified by the development of microangiopathic haemolytic anaemia, thrombocytopaenia and acute renal failure. It is a leading cause of acute renal failure in paediatrics, with a second peak in prevalence in adults over the age of 60. Presentations of Stx-producing E. coli-mediated haemolytic uraemic syndrome in young adults are rare. We present the case of a previously well female in her early 30s presenting with Stx-producing E. coli-mediated haemolytic uraemic syndrome with severe renal and neurological manifestations. Eculizumab was administered due to the severity of presentation and disease trajectory refractory to initial supportive therapy. A significant clinical and biochemical improvement was observed following eculizumab.

HUS and TTP: traversing the disease and the age spectrum

Hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenia purpura (TTP) are rare diseases sharing a common pathological feature, thrombotic microangiopathy (TMA). TMA is characterized by microvascular thrombosis with consequent thrombocytopenia, microangiopathic hemolytic anemia and/or multiorgan dysfunction. In the past, the distinction between HUS and TTP was predominantly based on clinical grounds. However, clinical presentation of the two syndromes often overlaps and, the differential diagnosis is broad. Identification of underlying pathogenic mechanisms has enabled the classification of these syndromes on a molecular basis: typical HUS caused by Shiga toxin-producing Escherichia coli (STEC-HUS); atypical HUS or complement-mediated TMA (aHUS/CM-TMA) associated with genetic or acquired defects leading to dysregulation of the alternative pathway (AP) of complement; and TTP that results from a severe deficiency of the von Willebrand Factor (VWF)-cleaving protease, ADAMTS13. The etiology of TMA differs between pediatric and adult patients. Childhood TMA is chiefly caused by STEC-HUS, followed by CM-TMA and pneumococcal HUS (Sp-HUS). Rare conditions such as congenital TTP (cTTP), vitamin B12 metabolism defects, and coagulation disorders (diacylglycerol epsilon mutation) present as TMA chiefly in children under 2 years of age. In contrast secondary causes and acquired ADAMT13 deficiency are more common in adults. In adults, compared to children, diagnostic delays are more frequent due to the wide range of differential diagnoses. In this review we focus on the three major forms of TMA, STEC-HUS, aHUS and TTP, outlining the clinical presentation, diagnosis and management of the affected patients, to help highlight the salient features and the differences between adult and pediatric patients which are relevant for management.

Treatment of Shiga-Toxin Hus with Severe Neurologic Features with Eculizumab

Hemolytic Uremic Syndrome (HUS) is a constellation of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Shiga toxin-producing Escherichia coli- (STEC-) mediated HUS is a common cause of acute renal failure in children and can rarely result in severe neurological complications such as encephalopathy, seizures, cerebrovascular accidents, and coma. Current literature supports use of eculizumab, a monoclonal antibody that blocks complement activation, in atypical HUS (aHUS). However, those with neurologic complications from STEC-HUS have complement activation and deposition of aggregates in microvasculature and may be treated with eculizumab. In this case report, we describe a 3-year-old boy with diarrhea-positive STEC-HUS who developed severe neurologic involvement in addition to acute renal failure requiring renal replacement therapy. He was initiated on eculizumab therapy, with clinical improvement and organ recovery. This case highlights systemic complications of STEC-HUS in a pediatric patient. The current literature is limited but has suggested a role for complement mediation in cases with severe complications. We review the importance of early recognition of complications, use of eculizumab, and current data available.

Shiga Toxin-Associated Hemolytic Uremic Syndrome in Adults, France, 2009-2017

We conducted a retrospective study on hemolytic uremic syndrome caused by Shiga toxin–producing Escherichia coli (STEC) in 96 adults enrolled in the cohort of the National Reference Center for Thrombotic Microangiopathies network in France during 2009–2017. Most infections were caused by STEC strains not belonging to the O157 or O104 serogroups. Thirty (31.3%) patients had multiple risk factors for thrombotic microangiopathy. In total, 61 (63.5%) patients required dialysis, 50 (52.1%) had a serious neurologic complication, 34 (35.4%) required mechanical ventilation, and 19 (19.8%) died during hospitalization. We used multivariate analysis to determine that the greatest risk factors for death were underlying immunodeficiency (hazard ratio 3.54) and severe neurologic events (hazard ratio 3.40). According to multivariate analysis and propensity score-matching, eculizumab treatment was not associated with survival. We found that underlying conditions, especially immunodeficiency, are strongly associated with decreased survival in adults who have hemolytic uremic syndrome caused by STEC.

Shiga Toxin-Associated Hemolytic Uremic Syndrome: Specificities of Adult Patients and Implications for Critical Care Management

Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (STEC-HUS) is a form of thrombotic microangiopathy secondary to an infection by an enterohemorrhagic E. coli. Historically considered a pediatric disease, its presentation has been described as typical, with bloody diarrhea at the forefront. However, in adults, the clinical presentation is more diverse and makes the early diagnosis hazardous. In this review, we review the epidemiology, most important outbreaks, physiopathology, clinical presentation and prognosis of STEC-HUS, focusing on the differential features between pediatric and adult disease. We show that the clinical presentation of STEC-HUS in adults is far from typical and marked by the prevalence of neurological symptoms and a poorer prognosis. Of note, we highlight knowledge gaps and the need for studies dedicated to adult patients. The differences between pediatric and adult patients have implications for the treatment of this disease, which remains a public health threat and lack a specific treatment.

Shiga Toxin-Associated Hemolytic Uremic Syndrome: A Narrative Review

The severity of human infection by one of the many Shiga toxin-producing Escherichia coli (STEC) is determined by a number of factors: the bacterial genome, the capacity of human societies to prevent foodborne epidemics, the medical condition of infected patients (in particular their hydration status, often compromised by severe diarrhea), and by our capacity to devise new therapeutic approaches, most specifically to combat the bacterial virulence factors, as opposed to our current strategies that essentially aim to palliate organ deficiencies. The last major outbreak in 2011 in Germany, which killed more than 50 people in Europe, was evidence that an effective treatment was still lacking. Herein, we review the current knowledge of STEC virulence, how societies organize the prevention of human disease, and how physicians treat (and, hopefully, will treat) its potentially fatal complications. In particular, we focus on STEC-induced hemolytic and uremic syndrome (HUS), where the intrusion of toxins inside endothelial cells results in massive cell death, activation of the coagulation within capillaries, and eventually organ failure.

Diarrhea-associated Hemolytic Uremic Syndrome in Adults: Two Case Reports and Review of the Literature

Hemolytic uremic syndrome (HUS) is a type of thrombotic microangiopathy syndrome (TMA) defined as a triad of non-immune microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Shiga toxin (Stx) or diarrhea-associated HUS is one of the major categories of secondary HUS, which is seen predominantly in children and is regarded as a rare entity in the adult population. We present two cases of sporadic Stx or diarrhea-associated HUS in adult females. Our first case is a 74-year-old Caucasian woman who presented to the emergency department with nausea, vomiting, and bloody diarrhea for five days. The patient reported a history of consuming meatloaf from a local store three days prior to the onset of symptoms. On presentation, laboratory workup was consistent with hemolytic anemia, thrombocytopenia, and acute kidney injury. Thrombocytopenic purpura was ruled out with normal ADAMTS13 activity. The patient’s kidney function improved and the platelet count recovered to normal with supportive measures and did not require renal replacement therapy. In the second case, we describe a 79-year-old Caucasian woman with a history of metastatic lung cancer who presented with abdominal pain, nausea, vomiting, and bloody diarrhea. History was positive for consuming meat from a local restaurant a day prior to the onset of symptoms. Initial laboratory work showed severe thrombocytopenia, microangiopathic hemolytic process, and acute kidney injury requiring continuous renal replacement therapy. Due to the unfavorable prognosis of her metastatic lung cancer, the patient and the family members decided to opt for hospice care and she was subsequently transferred to the inpatient hospice.

Diarrhea-associated HUS or Stx-HUS is a relatively underreported entity among the adult population. The treatment of typical or Stx-HUS is mainly supportive, but it is critical to rule out other causes of TMAs, especially thrombotic thrombocytopenic purpura (TTP), as it is a medical emergency that requires prompt plasmapheresis.