Haemolytic uraemic syndrome: 17 years' experience in a Scottish paediatric renal unit

Protection against Shiga Toxins

Shiga toxins consist of an A-moiety and five B-moieties able to bind the neutral glycosphingolipid globotriaosylceramide (Gb3) on the cell surface. To intoxicate cells efficiently, the toxin A-moiety has to be cleaved by furin and transported retrogradely to the Golgi apparatus and to the endoplasmic reticulum. The enzymatically active part of the A-moiety is then translocated to the cytosol, where it inhibits protein synthesis and in some cell types induces apoptosis. Protection of cells can be provided either by inhibiting binding of the toxin to cells or by interfering with any of the subsequent steps required for its toxic effect. In this article we provide a brief overview of the interaction of Shiga toxins with cells, describe some compounds and conditions found to protect cells against Shiga toxins, and discuss whether they might also provide protection in animals and humans.

Symptoms and clinical course of EHEC O104 infection in hospitalized patients: a prospective single center study

OBJECTIVES

Shiga-toxin producing O157:H7 Entero Haemorrhagic E. coli (STEC/EHEC) is one of the most common causes of Haemolytic Uraemic Syndrome (HUS) related to infectious haemorrhagic colitis. Nearly all recommendations on clinical management of EHEC infections refer to this strain. The 2011 outbreak in Northern Europe was the first to be caused by the serotype O104:H4. This EHEC strain was found to carry genetic features of Entero Aggregative E. coli (EAEC) and extended spectrum β lactamase (ESBL). We report symptoms and complications in patients at one of the most affected centres of the 2011 EHEC O104 outbreak in Northern Germany.

METHODS

The courses of patients admitted to our hospital due to bloody diarrhoea with suspected EHEC O104 infection were recorded prospectively. These data include the patients' histories, clinical findings, and complications.

RESULTS

EHEC O104 infection was confirmed in 61 patients (female = 37; mean age: 44±2 years). The frequency of HUS was 59% (36/61) in our cohort. An enteric colonisation with co-pathogens was found in 57%. Thirty-one (51%) patients were treated with plasma-separation/plasmapheresis, 16 (26%) with haemodialysis, and 7 (11%) with Eculizumab. Patients receiving antibiotic treatment (n = 37; 61%) experienced no apparent change in their clinical course. Twenty-six (43%) patients suffered from neurological symptoms. One 83-year-old patient died due to comorbidities after HUS was successfully treated.

CONCLUSIONS

EHEC O104:H4 infections differ markedly from earlier reports on O157:H7 induced enterocolitis in regard to epidemiology, symptomatology, and frequency of complications. We recommend a standard of practice for clinical monitoring and support the renaming of EHEC O104:H4 syndrome as "EAHEC disease".

Distinct physiologic and inflammatory responses elicited in baboons after challenge with Shiga toxin type 1 or 2 from enterohemorrhagic Escherichia coli

Shiga toxin-producing Escherichia coli is a principal source of regional outbreaks of bloody diarrhea and hemolytic-uremic syndrome in the United States and worldwide. Primary bacterial virulence factors are Shiga toxin types 1 and 2 (Stx1 and Stx2), and we performed parallel analyses of the pathophysiologies elicited by the toxins in nonhuman primate models to identify shared and unique consequences of the toxemias. After a single intravenous challenge with purified Stx1 or Stx2, baboons (Papio) developed thrombocytopenia, anemia, and acute renal failure with loss of glomerular function, in a dose-dependent manner. Differences in the timing and magnitude of physiologic responses were observed between the toxins. The animals were more sensitive to Stx2, with mortality at lower doses, but Stx2-induced renal injury and mortality were delayed 2 to 3 days compared to those after Stx1 challenge. Multiplex analyses of plasma inflammatory cytokines revealed similarities (macrophage chemoattractant protein 1 [MCP-1] and tumor necrosis factor alpha [TNF-alpha]) and differences (interleukin-6 [IL-6] and granulocyte colony-stimulating factor [G-CSF]) elicited by the toxins with respect to the mediator induced and timing of the responses. Neither toxin induced detectable levels of plasma TNF-alpha. To our knowledge, this is the first time that the in vivo consequences of the toxins have been compared in a parallel and reproducible manner in nonhuman primates, and the data show similarities to patient observations. The availability of experimental nonhuman primate models for Stx toxemias provides a reproducible platform for testing antitoxin compounds and immunotherapeutics with outcome criteria that have clinical meaning.

Shiga toxin 2 affects the central nervous system through receptor globotriaosylceramide localized to neurons

Affinity-purified Shiga toxin (Stx) 2 given intraperitoneally to mice caused weight loss and hind-limb paralysis followed by death. Globotriaosylceramide (Gb(3)), the receptor for Stx2, was localized to neurons of the central nervous system (CNS) of normal mice. Gb3 was not found in astrocytes or endothelial cells of the CNS. In human cadaver CNS, we found Gb(3) in neurons and endothelial cells. Mouse Gb(3) localization was confirmed by immunoelectron microscopy. In Stx2-exposed mice, anti-Stx2-gold immunoreaction was positive in neurons. During paralysis, after Stx2 injection, multiple glial nuclei were observed surrounding motoneurons by electron microscopy. Also revealed was a lamellipodia-like process physically inhibiting the synaptic connection of motoneurons. Ca2+ imaging of cerebral astrocytic end-feet in Stx2-treated mouse brains suggested that the toxin increased neurotransmitter release from neurons. In this article, we propose that the neuron is a primary target of Stx2, affecting neuronal function and leading to paralysis.

Diabetes during diarrhea-associated hemolytic uremic syndrome: a systematic review and meta-analysis

OBJECTIVE

To quantify the incidence of diabetes during the acute phase of diarrhea-associated hemolytic uremic syndrome (D + HUS) and to identify features associated with its development.

RESEARCH DESIGN AND METHODS

A systematic review and meta-analysis of articles assessing diabetes during D + HUS was conducted. Relevant citations were identified from Medline, Embase, and Institute for Scientific Information Citation Index databases. Bibliographies of relevant articles were hand searched. All articles were independently reviewed for inclusion and data abstraction by two authors.

RESULTS

Twenty-one studies from six countries were included. Only 2 studies reported a standard definition of diabetes; 14 defined diabetes as hyperglycemia requiring insulin. The incidence of diabetes during the acute phase of D + HUS could be quantified in a subset of 1,139 children from 13 studies (1966-1998, age 0.2-16 years) and ranged from 0 to 15%, with a pooled incidence of 3.2% (95% CI 1.3-5.1, random-effects model, significant heterogeneity among studies, P = 0.007). Children who developed diabetes were more likely to have severe disease (e.g., presence of coma or seizures, need for dialysis) and had higher mortality than those without diabetes. Twenty-three percent of those who developed diabetes acutely died, and 38% of survivors required long-term insulin (median follow-up 12 months). Recurrence of diabetes was possible up to 60 months after initial recovery.

CONCLUSIONS

Children with D + HUS should be observed for diabetes during their acute illness. Consideration should be given to long-term screening of D + HUS survivors for diabetes.

Shiga-toxin-producing Escherichia coli and haemolytic uraemic syndrome

Most cases of diarrhoea-associated haemolytic uraemic syndrome (HUS) are caused by Shiga-toxin-producing bacteria; the pathophysiology differs from that of thrombotic thrombocytopenic purpura. Among Shiga-toxin-producing Escherichia coli (STEC), O157:H7 has the strongest association worldwide with HUS. Many different vehicles, in addition to the commonly suspected ground (minced) beef, can transmit this pathogen to people. Antibiotics, antimotility agents, narcotics, and non-steroidal anti-inflammatory drugs should not be given to acutely infected patients, and we advise hospital admission and administration of intravenous fluids. Management of HUS remains supportive; there are no specific therapies to ameliorate the course. The vascular injury leading to HUS is likely to be well under way by the time infected patients seek medical attention for diarrhoea. The best way to prevent HUS is to prevent primary infection with Shiga-toxin-producing bacteria.

Clostridium difficile colitis associated with hemolytic-uremic syndrome

The authors report the case of a 46-year-old woman who presented with vomiting and profuse bloody diarrhea. Laboratory studies were significant for a hematocrit of 27% and lactate dehydrogenase of 5,394 U/L (5,394 U/L). Her renal function deteriorated rapidly with a peak creatinine of 12.4 mg/dL (1,096.4 micromol/L), and platelet count dropped simultaneously to a nadir of 123,000/microL (123 x 10(9)/L]. Schistocytes were observed in peripheral blood smear. Stool was positive for Clostridium difficile toxin A by enzyme immunoassay (EIA). Stool assay for Shiga-like toxin was negative by EIA, and stool cultures returned negative for Escherichia coli O157:H7 and other enteric pathogens. A diagnosis of C difficile colitis associated with hemolytic-uremic syndrome was made; the patient received plasmapheresis and recovered with no relapse after 10 months of follow-up. This is the second reported case of C difficile colitis associated with hemolytic-uremic syndrome in an adult.

Effectiveness of therapeutic plasma exchange in the 1996 Lanarkshire Escherichia coli O157:H7 outbreak

BACKGROUND

The largest number of adult cases of haemolytic uraemic syndrome (HUS)/thrombotic thrombocytopenic purpura (TTP) during an Escherichia coli O157 outbreak occurred in 1996 in central Scotland. Adults who develop HUS/TTP induced by E. coli O157 tend to be elderly and have a historical mortality rate of almost 90% when treated conservatively. Therefore the decision was made to treat adults who developed HUS/TTP during this outbreak with therapeutic plasma exchange (TPE). We report our outcome with this controversial treatment.

METHODS

A case definition for HUS/TTP was developed at the beginning of the outbreak. All cases meeting this definition were considered for TPE. Information on demographics, clinical features, treatment and outcome of patients was obtained by retrospective case note review.

FINDINGS

22 adults developed HUS/TTP. They had a mean age of 71 years. 16 cases received TPE. Six cases had contraindications to TPE or died before the procedure could be done. Ten of the 22 (45%) adults with HUS/TTP died. Five of the 16 (31%) TPE-treated cases died, four of eight aged over 70 years compared with one of eight aged less than 70 years. Premorbid illness, neurological features, treatment with ciprofloxacin or prostacyclin, and the laboratory severity of HUS/TTP were not associated with death; the number of cases, however, was too small to allow statistical conclusion.

INTERPRETATION

The mortality rate is high in adults who develop HUS/TTP induced by E. coli O157. TPE appears to be a promising treatment that was well tolerated in our elderly patients. A national register of adult cases of HUS/TTP induced by E. coli O157 should be established.

Cyclosporine-associated thrombotic microangiopathy/hemolytic uremic syndrome following kidney and kidney-pancreas transplantation

Cyclosporine-associated thrombotic microangiopathy (CsA-TMA) is characterized by anemia, acute renal failure, and renal TMA. We report a case-control study of 13 patients (seven kidney-alone transplant recipients and six kidney-pancreas transplant recipients) who developed TMA (12 CsA, 1 FK506). Once CsA-TMA was identified, CsA or FK506 was discontinued and isradipine, aspirin, and pentoxifylline were started. Cyclosporine was reinstituted in all patients once serum creatinine reached the previous baseline value. Patients developing further decreases in renal function on rechallenge with CsA were converted to FK506 (n = 3). Rechallenge with CsA was successful in nine of the 13 patients (69%), with three (23%) converted to FK506 for a total salvage rate of 92%. The creatinine clearance at 6 months, 1 year, and 2 years following transplantation was 73.2 +/- 25.7 mL/min, 54.7 +/- 18.8 mL/min, and 57.0 +/- 32.0 mL/min, respectively, for patients successfully rechallenged with CsA compared with 67 +/- 17 mg/min, 71.8 +/- 21.2 mL/min, and 69 +/- 19 mg/min, respectively, for controls (P = NS). The average creatine clearance for patients converted to FK506 was 44.7 +/- 31.2 mL/min at 6 months following transplantation (n = 3) and 27.0 +/- 11.3 mL/min at 1 year. In this case-controlled retrospective series of renal transplant patients with documented CsA-TMA, the triple-drug combination of isradipine, aspirin, and pentoxifylline allowed for the successful reinstitution of CsA or conversion to FK506 in the setting of TMA, and resulted in increased transplant survival compared with previous reports.