Hemolytic uremic syndrome in children in northern India

Post-Diarrheal Acute Kidney Injury During an Epidemic in Monsoon - A Retrospective Study from a Tertiary Care Hospital

Background

Acute kidney injury (AKI) is a severe complication of acute diarrheal diseases; however, there is limited data on post-diarrheal AKI (PD-AKI) epidemiology and outcomes. This study aimed to investigate the clinicodemographic profile and outcomes of PD-AKI in our hospital.

Materials and Methods

We retrospectively analyzed data from 93 patients admitted with PD-AKI during a diarrheal illness epidemic. Patients were stratified based on the Kidney Disease: Improving Global Outcomes (KDIGO) AKI stage and quick Sequential Organ Failure Assessment (qSOFA) score. Clinicodemographic data and outcomes were recorded and analyzed.

Results

The mean age of the patients was 45.7 ± 11.9 years, with a majority being men (n = 55, 59%). All patients presented with watery diarrhea, 85% (n = 79) had vomiting, and 66% (n = 61) presented in shock. At presentation, 59% were oliguric, while 32% were anuric. KDIGO stage 3 AKI was observed in 71% (n = 66) of patients. Dialytic support was required in 29% (n = 27) of cases. The mortality rate was 6.5% (n = 6), mostly due to refractory shock, while the remaining patients recovered. Risk factor analysis demonstrated a higher qSOFA score, and peak serum creatinine levels were associated with an increased likelihood of requiring renal replacement therapy and delayed renal recovery.

Conclusion

This study provides valuable insights into the clinicodemographic characteristics and outcomes of PD-AKI. The high prevalence of severe AKI emphasizes the importance of early recognition and appropriate management strategies for these patients.

A Systemic Review on Fitness and Survival of Salmonella in Dynamic Environment and Conceivable Ways of Its Mitigation

Gastroenteritis caused by non-typhoidal Salmonella still prevails resulting in several recent outbreaks affecting many people worldwide. The presence of invasive non-typhoidal Salmonella is exemplified by several characteristic symptoms and their severity relies on prominent risk factors. The persistence of this pathogen can be attributed to its broad host range, complex pathogenicity and virulence and adeptness in survival under challenging conditions inside the host. Moreover, a peculiar aid of the ever-changing climatic conditions grants this organism with remarkable potential to survive within the environment. Abusive use of antibiotics for the treatment of gastroenteritis has led to the emergence of multiple drug resistance, making the infections difficult to treat. This review emphasizes the importance of early detection of Salmonella, along with strategies for accomplishing it, as well as exploring alternative treatment approaches. The exceptional characteristics exhibited by Salmonella, like strategies of infection, persistence, and survival parallelly with multiple drug resistance, make this pathogen a prominent concern to human health.

Postdiarrheal hemolytic uremic syndrome in Egyptian children: An 11-year single-center experience

Hemolytic-uremic syndrome (HUS) is a leading cause of childhood acute kidney injury (AKI) worldwide, with its postdiarrheal (D+HUS) form being the most common. Scarce data are available regarding D+HUS epidemiology from developing countries. This study aims to reveal the characterization of D+ HUS in Egyptian children. This is a retrospective study of all children with D+HUS admitted to a tertiary pediatric hospital in Egypt between 2007 and 2017. The study included epidemiological, clinical and laboratory data; management details; and outcomes. A cohort of 132 children aged 4months to 12 years was analyzed. Yearly incidence peaked in 2017, and spring showed the highest peak. All cases had a diarrheal prodrome that was bloody in 83% of the cases. Edema and decreased urine output were the most frequent presentations (50.3% and 42.4%, respectively). Escherichia coli was detected in 56 cases. Dialysis was performed in 102 cases. Eight patients died during acute illness, while five patients experienced long-term sequels. Lactate dehydrogenase (LDH) positively correlated with serum creatinine and negatively correlated with reticulocytic count. Univariate analysis showed that longer anuria duration, short duration between diarrheal illness and development of AKI (P = 0.001), leukocyte count above 20 × 10⁹ cells/L (P ≤ 0.001), platelet count below 30 × 10⁹ cells/L (P = 0.02), high LDH levels (P = 0.02) and hematocrit above 30% (P = 0.0001), need for dialysis (P = 0.03), and neurological involvement (P ≤ 0.001) were associated with unfavorable outcomes. This is the first report with a detailed insight into the epidemiology of D+HUS in Egyptian children. The incidence of D+HUS is increasing in our country due to increased awareness of the disease and the poor public health measures. Anuria duration, leukocyte count, and neurological involvement are predictors of poor outcome in the current work, and LDH is introduced as a marker of disease severity.

Hemolytic uremic syndrome in a developing country: Consensus guidelines

BACKGROUND

Hemolytic uremic syndrome (HUS) is a leading cause of acute kidney injury in children. Although international guidelines emphasize comprehensive evaluation and treatment with eculizumab, access to diagnostic and therapeutic facilities is limited in most developing countries. The burden of Shiga toxin-associated HUS in India is unclear; school-going children show high prevalence of anti-factor H (FH) antibodies. The aim of the consensus meeting was to formulate guidelines for the diagnosis and management of HUS in children, specific to the needs of the country.

METHODS

Four workgroups performed literature review and graded research studies addressing (i) investigations, biopsy, genetics, and differential diagnosis; (ii) Shiga toxin, pneumococcal, and infection-associated HUS; (iii) atypical HUS; and (iv) complement blockade. Consensus statements developed by the workgroups were discussed during a consensus meeting in March 2017.

RESULTS

An algorithm for classification and evaluation was developed. The management of Shiga toxin-associated HUS is supportive; prompt plasma exchanges (PEX) is the chief therapy in patients with atypical HUS. Experts recommend that patients with anti-FH-associated HUS be managed with a combination of PEX and immunosuppressive medications. Indications for eculizumab include incomplete remission with plasma therapy, life-threatening features, complications of PEX or vascular access, inherited defects in complement regulation, and recurrence of HUS in allografts. Priorities for capacity building in regional and national laboratories are highlighted.

CONCLUSIONS

Limited diagnostic capabilities and lack of access to eculizumab prevent the implementation of international guidelines for HUS in most developing countries. We propose practice guidelines for India, which will perhaps be applicable to other developing countries.

Hemolytic Uremic Syndrome Associated With Non-Shigatoxin-producing Infectious Agents: Expanding the Shigatoxin Theory

Diarrhea-associated hemolytic uremic syndrome (HUS) is usually associated with shigatoxin-producing Escherichia coli or shigella infections. We report 2 cases of HUS, respectively, caused by salmonella and Campylobacter jejuni infections. None of these bacteria produce shigatoxins, and the underlying mechanism of HUS development remains unknown. In streptococcus pneumoniae-associated HUS, bacterial neuraminidase cleaves neuraminic acid and causes exposure of Thomsen-Friedenreich cryptantigen on the cell surface of, for example, erythrocytes, which induces an inflammatory response caused by binding of preformed IgM. Both campylobacter and salmonella bacteria also produce neuraminidase, and HUS development could be explained by a similar mechanism.

Characteristics and outcome of hemolytic uremic syndrome in Sudanese children in a single Centre in Khartoum State

Hemolytic uremic syndrome (HUS) is one of the important causes of acute kidney injury (AKI) and chronic kidney disease (CKD) in children. Proposed prognostic features are controversial. We reviewed, retrospectively, the records of children with HUS seen at Soba hospital, Khartoum (2004-2012). We aimed to study demographics, clinical/ laboratory features, outcome and prognostic risk factors. Thirty-nine children with HUS were recorded; 59% had diarrhoea positive (D+) and 41% diarrhoea negative (D-) HUS. The mean age was 65.4 months and males were 61.5%. At the acute phase seizures, coma, anuria/oliguria and hypertension were present in 25%, 17.9%, 51.3% and 53.8% respectively. Severe anaemia, thrombocytopenia, and leukocytosis were present in 71.8%, 97.4%, and 28.2% respectively. On discharge, hypertension was detected in 23.1%. Clinical and laboratory features were not significantly different in D+ and D- cases (P > 0.05 for all parameters). Dialysis was undertaken in 84.6% and acute mortality was 12.8% being significantly higher in D+ (P = 0.002). Demographic, clinical and laboratory features, late referral or need for dialysis were not significantly associated with higher risk of acute mortality (p > 0.05 for all). At short-term follow up (mean period ± SD of 18.54 ± 13.21 months), 51.3% had complete renal recovery, 15.4% CKD 3-4, 12.8% CKD 5 requiring renal replacement therapy (RRT), and 20.5% died. Higher mean serum creatinine and hypertension on discharge were risk factors for adverse outcome (CKD5 requiring RRT or death), P = 0.011 and 0.00 respectively. In spite of institution of RRT and supportive therapy, our data showed less favourable outcome of HUS.

Postinfectious Hemolytic Uremic Syndrome

Post-infectious hemolytic uremic syndrome (HUS) is caused by specific pathogens in patients with no identifiable HUS-associated genetic mutation or autoantibody. The majority of episodes is due to infections by Shiga toxin (Stx) producing Escherichia coli (STEC). This chapter reviews the epidemiology and pathogenesis of STEC-HUS, including bacterial-derived factors and host responses. STEC disease is characterized by hematological (microangiopathic hemolytic anemia), renal (acute kidney injury) and extrarenal organ involvement. Clinicians should always strive for an etiological diagnosis through the microbiological or molecular identification of Stx-producing bacteria and Stx or, if negative, serological assays. Treatment of STEC-HUS is supportive; more investigations are needed to evaluate the efficacy of putative preventive and therapeutic measures, such as non-phage-inducing antibiotics, volume expansion and anti-complement agents. The outcome of STEC-HUS is generally favorable, but chronic kidney disease, permanent extrarenal, mainly cerebral complication and death (in less than 5 %) occur and long-term follow-up is recommended. The remainder of this chapter highlights rarer forms of (post-infectious) HUS due to S. dysenteriae, S. pneumoniae, influenza A and HIV and discusses potential interactions between these pathogens and the complement system.

Early erythropoietin in post-diarrheal hemolytic uremic syndrome: a case-control study

BACKGROUND

Although erythropoietin (EPO) deficiency has been reported in children with post-diarrheal hemolytic uremic syndrome (D + HUS), very limited clinical data on EPO use in this disease are currently available. In this case-control study we examined whether EPO administration would reduce the number of red blood cell (RBC) transfusions in D + HUS patients under our care.

METHODS

Data from children treated exclusively with RBC transfusions (controls; n = 21) were retrospectively compared with data on those who also received EPO for the treatment of anemia (cases; n = 21).

RESULTS

Both patient groups were similar in age (p = 0.9), gender (p = 0.12), weight (p = 1.00) and height (p = 0.66). Acute phase severity was also comparable, as inferred by the need for dialysis (p = 0.74), the duration of dialysis (p = 0.3), length of hospitalization (p = 0.81), presence of severe bowel (p = 1.00) or neurological injury (p = 0.69), arterial hypertension (p = 1.00) and death (p = 1.00). No differences in the hemoglobin level at admission (p = 0.51) and discharge (p = 0.28) were noted. Three children treated with EPO and two controls did not require any RBC transfusion (p = 1.00). Median number of RBC transfusions needed by cases and controls was 2 (p = 0.52).

CONCLUSION

Treatment with EPO did not reduce the number of RBC transfusions in D + HUS children. Assessment of EPO efficacy in D + HUS merits further studies.

Prompt plasma exchanges and immunosuppressive treatment improves the outcomes of anti-factor H autoantibody-associated hemolytic uremic syndrome in children

Antibodies to complement factor H are an uncommon cause of hemolytic uremic syndrome (HUS). Information on clinical features and outcomes in children is limited. In order to explore this we studied a multicenter cohort of 138 Indian children with anti-complement factor H antibody associated HUS, constituting 56% of patients with HUS. Antibody titers were high (mean 7054 AU/ml) and correlated inversely with levels of complement C3, but not complement factor H. Homozygous deletion of the CFHR1 gene was found in 60 of 68 patients. Therapies included dialysis in 119 children, 105 receiving plasma exchanges and 26 intravenous immunoglobulin. Induction immunosuppression consisted of 87 children receiving prednisolone with or without intravenous cyclophosphamide or rituximab. Antibody titers fell significantly following plasma exchanges and increased during relapses. Adverse outcome (stage 4-5 CKD or death) was seen in 36 at 3 months and 41 by last follow up, with relapse in 14 of 122 available children. Significant independent risk factors for adverse outcome were an antibody titer over 8000 AU/ml, low C3 and delay in plasma exchange. Combined plasma exchanges and induction immunosuppression resulted in significantly improved renal survival: one adverse outcome prevented for every 2.6 patients treated. Maintenance immunosuppressive therapy, of prednisolone with either mycophenolate mofetil or azathioprine, significantly reduced the risk of relapses. Thus, prompt use of immunosuppressive agents and plasma exchanges are useful for improving outcomes in pediatric patients with anti-complement factor H-associated HUS.

Raising awareness of acute kidney injury: a global perspective of a silent killer

Worldwide, acute kidney injury (AKI) is associated with poor patient outcomes. Over the last few years, collaborative efforts, enabled by a common definition of AKI, have provided a description of the epidemiology, natural history, and outcomes of this disease and improved our understanding of the pathophysiology. There is increased recognition that AKI is encountered in multiple settings and in all age groups, and that its course and outcomes are influenced by the severity and duration of the event. The effect of AKI on an individual patient and the resulting societal burden that ensues from the long-term effects of the disease, including development of chronic kidney disease (CKD) and end-stage renal disease (ESRD), is attracting increasing scrutiny. There is evidence of marked variation in the management of AKI, which is, to a large extent, due to a lack of awareness and an absence of standards for prevention, early recognition, and intervention. These emerging data point to an urgent need for a global effort to highlight that AKI is preventable, its course is modifiable, and its treatment can improve outcomes. In this article, we provide a framework of reference and propose specific strategies to raise awareness of AKI globally, with the goal to ultimately improve outcomes from this devastating disease.

Long-term consequences of foodborne infections

Foodborne infections with Campylobacter, E. coli O157:H7, Listeria monocytogenes, Salmonella, Shigella, Toxoplasma gondii, and other pathogens can result in long-term sequelae to numerous organ systems. These include irritable bowel syndrome, inflammatory bowel disease, reactive arthritis, hemolytic uremic syndrome, chronic kidney disease, Guillain-Barré Syndrome, neurological disorders from acquired and congenital listeriosis and toxoplasmosis, and cognitive and developmental deficits due to diarrheal malnutrition or severe acute illness. A full understanding of the long-term sequelae of foodborne infection is important both for individual patient management by clinicians, as well as to inform food safety and public health decision making.

Haemolytic uraemic syndrome in India due to Shiga toxigenic Escherichia coli

The emergence of Shiga toxigenic Escherichia coli (STEC) as a causative agent of diarrhoea, haemorrhagic colitis and haemolytic uraemic syndrome (HUS) in humans is a significant public health concern worldwide. Here we describe a case of HUS following dysentery due to STEC. Though STEC is not a major cause of diarrhoea in India, we recommend that STEC should be looked for in all cases of bloody diarrhoea. To our knowledge, this is the first case of HUS caused by STEC in India.

The contrasting characteristics of acute kidney injury in developed and developing countries

Acute kidney injury (AKI) has become increasingly prevalent in both developed and developing countries, and is associated with severe morbidity and mortality, especially in children. Uncertainty regarding the true incidence of AKI limits awareness of the problem, thereby reducing political visibility of the disorder and hampering efforts to prevent its occurrence. In developed countries, AKI occurs predominantly in urban intensive care units and is associated with multiorgan failure and sepsis, high mortality, and occurrence in older populations. While cases of AKI in urban areas of the developing world have similar characteristics to those in the developed world, AKI in rural regions commonly develops in response to a single disease and specific conditions (e.g. gastroenteritis) or infections (e.g. severe malaria, leptospirosis, or hemolytic-uremic syndrome) and in younger otherwise healthy individuals. Many causes of AKI in rural settings, such as diarrhea, poisoning, malaria, or septic abortion, can be prevented by interventions at the individual, community, and regional levels. Treatment with dialysis is often unavailable or too costly in developing regions, so there must be community-wide efforts to eradicate causes of AKI, expedite diagnosis, and aggressively manage prerenal conditions and specific infections. We have reviewed recent literature on AKI, identified differences and similarities in the condition between developed and developing areas, analyzed the practical implications of the identified differences, and made evidence-based recommendations for study and management.

Haemolytic uraemic syndrome: an overview

Haemolytic uraemic syndrome (HUS) is the most common cause of acute renal failure in children. The syndrome is defined by triad of microangiopathic haemolytic anaemia, thrombocytopenia and acute renal failure (ARF). Incomplete HUS is ARF with either haemolytic anaemia or thrombocytopenia. HUS is classified into two subgroups. Typical HUS usually occurs after a prodrome of diarrhoea (D+HUS), and atypical (sporadic) HUS (aHUS), which is not associated with diarrhoea (D-HUS). The majority of D+HUS worldwide is caused by Shiga toxin-producing Esherichia coli (STEC), type O157:H7, transmitted to humans via different vehicles. Currently there are no specific therapies preventing or ameliorating the disease course. Although there are new therapeutic modalities in the horizon for D+HUS, present recommended therapy is merely symptomatic. Parenteral volume expansion may counteract the effect of thrombotic process before development of HUS and attenuate renal injury. Use of antibiotics, antimotility agents, narcotics and non-steroidal anti-inflammatory drugs should be avoided during the acute phase. Prevention is best done by preventing primary STEC infection. Underlying aetiology in many cases of aHUS is unknown. A significant number may result from underlying infectious diseases, namely Streptococcus pneumoniae and human immunedeficiency virus. Variety of genetic forms include HUS due to deficiencies of factor H, membrane cofactor protein, Von Willebrand factor-cleaving protease (ADAMTS 13) and intracellular defect in vitamin B12 metabolism. There are cases of aHUS with autosomal recessive and dominant modes of inheritance. Drug-induced aHUS in post-transplantation is due to calcineurin-inhibitors. Systemic lupus erythematosus and catastrophic antiphospholipid syndrome may also present with aHUS. Therapy is directed mainly towards underlying cause.

Overview of tropical nephrology

Tropical nephrology covers renal diseases commonly seen in the tropics and elsewhere and specific tropical renal diseases seen mostly or only in the tropical area. Emphasis in this article is placed on the latter category, which includes renal involvement in tropical infectious diseases, natural toxin poisoning, and environmental renal problems. Pathologically, all renal structures can be affected. There is, therefore, a broad spectrum of pathologic changes, and clinical renal manifestations vary from mild urinary sediment changes to acute renal failure. Inflammatory processes plays an essential role in the pathogenesis of renal involvement in infection and toxin groups. Both models share the same inflammatory pathways through cytokines, chemokines, and mediators. Hemodynamic alterations, immune response, and direct nephrotoxicity are involved in the development of renal lesions.

Management of acute renal failure

Acute renal failure (ARF) is defined as an abrupt decline in the renal regulation of water, electrolytes, and acid-base balance. It continues to be an important factor contributing to the morbidity and mortality of critically ill infants and children. The frequency of specific diseases that result in ARF differs among different age-groups and geographical areas. The common causes in Indian children include hemolytic uremic syndrome, acute tubular necrosis, glomerulonephritis and urinary tract obstruction. Though the hallmark of renal failure is oliguria, there is increasing recognition of non-oliguric ARF often associated with the use of nephrotoxic drugs. The basic principles of management are avoidance of life-threatening complications, maintenance of fluid and electrolyte balance and nutritional support. Specific management of the underlying disorder is possible only in a minority of cases. All the major dialysis modalities--peritoneal dialysis (PD), hemodialysis (HD) and continuous hemofiltration--can be used to provide equivalent solute clearance and ultrafiltration. Peritoneal dialysis requires minimal equipment and infrastructure, and is easy to perform; this makes it the favoured modality in developing countries where resources for HD or continuous therapies may not be accessible. However, continuous hemofiltration is an excellent alternative to PD in patients with ARF and severe fluid overload. The prognosis of children with renal failure depends on the underlying condition and associated medical complications.

Hemolytic uremic syndrome in Belgium: incidence and association with verocytotoxin-producing Escherichia coli infection

OBJECTIVE: To evaluate the incidence of hemolytic uremic syndrome (HUS) in Belgium and to determine the role of verocytotoxin-producing Escherichia coli O157:H7 and other serotypes (non-O157 VTEC). METHODS: Twenty-two centers, including the seven university hospitals, registered prospectively all cases of HUS; they collected clinical samples for isolation of VTEC strains and serum for detection of specific O-lipopolysaccharide antibodies. RESULTS: Forty-seven cases of HUS (including five incomplete cases) were recorded. Three cases were seen in non-residents. The incidence of complete HUS in Belgian residents was 4.3 cases/100 000 in children <5 years old, 1.8 cases/100 000 when all children <15 years were considered, and 0.42/100 000 when patients of all ages were taken into account. By combining bacteriologic and serologic results, evidence of VTEC infection was obtained in 64% of the patients, mainly but not exclusively in children with prodromal diarrhea. The 13 VTEC isolates belonged to serotypes O157:H7 (nine isolates), O26:H11, O121:H---, O145:H--- and O172:H--- (one each) and all produced VT2 (+VT2vh-a in three O157 strains) and were positive for the eaeA gene. CONCLUSIONS: The incidence rate found in this study and the high mortality and morbidity linked with this syndrome warrant further registration of pediatric and post-diarrheic adult HUS cases and also examination of stools for both O157 and non-O157 VTEC strains. For effective prevention of this disease, further study of the serotypes and accessory virulence factors associated with HUS is needed.

Hemolytic uremic syndrome - clinical aspects and outcome of an outbreak: Report of 28 cases

Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. There are two main subgroups: the typical form of HUS follows a diarrheal prodrome (D+HUS) and the atypical form is without the diarrheal prodrome (D-HUS). We have studied 28 children with HUS over a period of 15 months between 1992 and 1993. The median age was 2.2 years (range from six months to six years). All children had prodromal diarrhea. Hypertension was present in 71% and neurological complications in 39%. All the patients had oliguria or anuria (16 oliguric and 12 anuric). The mean duration of anuria was 16 days (range seven to 42 days). Serum creatinine on admission ranged between 112 and 1064 Amicromol/L (mean 453 Amicromol/L). The lowest hemoglobin level and platelet count during hospitalization ranged between 38 and 87 g/L and 7 to 147x109/L respectively. Leukocytosis on admission was present in 22 patients, low C3 was documented in 11 patients (34%), and four patients had low C4. All patients received fresh frozen plasma transfusion, a total of 25 patients received dialysis therapy, 19 patients were treated with peritoneal dialysis (PD), one patient had hemodialysis (HD), and five patients had both HD and PD. The mean duration of dialysis was 18 days (range three to 56 days). Only one patient died (mortality rate 3%). The median duration of hospital stay was 28 days (range eight to 90 days). We conclude that HUS is emerging as an important clinical and public health problem and that early comprehensive management including dialysis therapy, aggressive management of hypertension, fresh frozen plasma transfusion, and nutritional support all improve the outcome and decrease the mortality and morbidity in patients with HUS.

Daily peritoneal dialysis using a surgically placed Tenckhoff catheter for acute renal failure in children

Thirty-one infants and children with acute failure were treated with peritoneal dialysis using a surgically placed Tenckhoff catheter. In 10 patients a peritoneal dialysis cycler was used, and 21 were dialyzed by the manual method. Initially, hourly exchanges were given for 24 to 48 h and, as the patients stabilized, 10 exchanges per day at 1-h intervals were given. The mean stabilization period was 36 +/- 8 h. The predialysis mean serum creatinine was 5.8 +/- 1.8 mg% and the serum creatinine while on daily dialysis was 2.8 +/- 1.1 mg%. Peritoneal dialysis succeeded in controlling metabolic abnormalities and improving fluid balance. All the catheters except one functioned immediately following insertion. Median duration of catheter placement for dialysis was 18 days (range 2 to 90). The incidence of peritonitis was 12.8%, and exit site infection was 6.4%. The infection rate was decreased when a cycler was used compared with the manual method (23.8% vs. 10.0%), though not statistically significant. Two patients developed hypothermia while being dialyzed via the manual method. To conclude, 10 daily peritoneal dialysis exchanges performed at 1-h intervals after initial stabilization using a surgically placed Tenckhoff catheter is an effective and safe mode of dialytic therapy for children with acute renal failure. Complications (infection and hypothermia) are reduced with the use of a cycler.

Salmonella, Shigella, and Campylobacter: common bacterial causes of infectious diarrhea

Salmonella, Shigella, and Campylobacter species are the most common causes of acute bacterial enteritis in the United States. These pathogens should be considered seriously in children who progress rapidly from secretory to inflammatory diarrhea syndrome or in whom diarrhea persists beyond 5 to 6 days. Furthermore, children who appear more toxic than their state of dehydration would suggest should be suspected of having an acute bacterial etiology for their diarrhea. Systemic, extraintestinal dissemination of these organisms is uncommon, with the exception of salmonella infection during the first year of life and in immunocompromised hosts. In this latter situation, culture of blood and other appropriate body fluids should be considered, along with empiric systemic antibiotic therapy. When antibiotics are warranted in patients with shigella or campylobacter infection, oral therapy is usually sufficient. Careful attention to handwashing and personal hygiene is always appropriate to prevent further spread of these organisms. The very low infectious dose of shigella infection mandates an even more compulsive attention to these latter recommendations when this organism is implicated.

Hemolytic-uremic syndrome

HUS is one of the most common causes of acute renal failure in childhood. D+ HUS is the most common form and usually follows an episode of hemorrhagic colitis due to VTEC or S. dysenteriae type 1. The SLT elaborated by these organisms is responsible for the endothelial damage that is the initial insult in the pathogenesis of the acute renal failure. Excellent supportive care is necessary to reduce the mortality and morbidity due to HUS.