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Haemolytic uremic syndrome
Hemolytic Uremic Syndrome (HUS) is a clinical syndrome characterized by microangiopathic hemolytic anemia, acute kidney injury, and thrombocytopenia. It is caused by Shiga toxin-producing bacteria like E. coli O157:H7 or by complement dysregulation. Treatment involves supportive care and addressing the underlying cause, such as antibiotics for bacterial infections or plasma therapy for complement abnormalities. With proper management, the prognosis is generally good, though permanent kidney damage can occur without timely treatment.
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Introduction of Dr. Virendra Kumar Gupta on HUS affecting children, its definition, and relevance.
HUS defined as a syndrome leading to acute kidney failure in children characterized by MAHA, thrombocytopenia, and AKI.
Categories of HUS based on etiology: Stx-associated and non-Stx-associated HUS, including infection-related causes.
Detailed differentiation between Stx-HUS and non-Stx-HUS, with common pathogens in developed and developing countries.
Feco-oral transmission and contamination sources such as undercooked food and contaminated water.
Mechanism of action of Shiga toxin impacting kidney endothelial cells, resulting in RN and hematological syndromes.
Thrombotic microangiopathy as a key histopathological characteristic demonstrating capillary damage.
Differentiation between familial and acquired ADAMTS-13 deficiency, related to TTP in adults.
Typical presentation including signs such as pallor, oliguria, diarrhea, hematuria, and neurological symptoms.
Lab investigations like CBC, stool cultures, and urine analysis to confirm HUS and its causative agents.
Diagnostic challenges, comparing HUS with TTP based on clinical and laboratory findings.
Approaches including supportive care, plasma therapy, and specific treatments for underlying causes.
Importance of prevention, prognosis with a low mortality rate, and the need for careful management.
Prognostic indicators and potential complications affecting gastrointestinal, neurological, and renal function.
Overview of conditions to consider when diagnosing HUS, including GI and systemic disorders.
Summary reiterating critical aspects of HUS, including treatment insights and etiological differentiation.
Essential takeaways for prevention, supportive care, and the need for rapid diagnosis and treatment.
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Haemolytic uremic syndrome
- 1. Haemolytic Uremic Syndrome (HUS) Dr.Virendra Kumar Gupta Assistant Professor Department Of Pediatric Gastroentero-hepatology & Liver Transplantation NIMS Medical College & Hospital , Jaipur
- 2. DEFINITION • HUS isa clinical syndrome that destroys red blood cells, is the most common cause of sudden, short-term acute kidney failure in children. It is a triad of: • Micro-angiopathic hemolytic anemia (MAHA) • Thrombocytopenia. • Acute kidney injury (acute renal failure) • A clinical syndrome
- 3. • Most commoncause of acute renal failure in children and is increasingly recognized in adults. • First described by Gasser et al in 1955.
- 4. CLASSIFICATION OF HUS/ TTP ACCORDING TO ETIOPATHOGENESIS Type of HUS / TTP Specific Cause • Infection related Shiga toxin producing E.coli/Shigella Pneumococcal infection HIV Typical Other viral or bacterial infections • Complement factor abnormality Factor H deficiency CTD Factor I deficiency • Miscellaneous Drugs Atypical Malignancy
- 5. Two main categoriesof HUS • Shiga-like toxin associated HUS (Stx-HUS) • Non-shiga-like toxin associated HUS (non-Stx-HUS)
- 6. • Stx-HUS: (tHUS) D+HUS D- HUS • Non-StxHUS: (aHUS) Sporadic Familial
- 7. Stx-associated HUS In developedcountries: • Escherichia coli serotype O157:H7 (EHEC) most common. In developing countries: • Shigella dysenteriae serotype 1.
- 9. Source of infection •Human feco-oral transmission. • Milk and animal products (incompletely cooked) • Veges, salads,drinking water contaminated by bacteria shed in animal wastes.
- 10. Pathogenesis Shiga-like toxin affectsendothelial cells and initiates intravascular thrombo-genesis. After entering the circulation via the gastrointestinal mucosa, the toxin preferentially localizes to the kidneys, inhibiting protein synthesis and eventually leading to cell necrosis or apoptosis. Endothelial cell damage subsequently potentiates renal microvascular thrombosis by promoting activation of the blood coagulation cascade. Platelet aggregation results in a consumptive thrombocytopenia. Microangiopathic hemolytic anemia results from mechanical damage to red blood cells circulating through partially occluded microcirculation.
- 12. Histopathological hallmark ofHUS • Thrombotic microangiopathy (TMA) Characterized by: • Capillary endothelial damage. • Microvascular formation of platelet/fibrin plugs. • This induces tissue ischemia • Damage to erythrocytes • Consumptive thrombocytopenia.
- 13. ADAMTS-13 deficiency Familial: • usuallyin children. • rare. Acquired: • more common in adults and older children. • Associated with presence of anti-ADAMTS13 antibodies. • Manifestation classically of frank TTP.
- 14. CLINICAL FEATURES • Thecommonest clinical presentation of HUS is : Acute pallor Oliguria Diarrhea or dysentery • It occurs commonly in children between 1-5 years of age • HUS develops about 5-10 days after onset of diarrhea
- 15. CONTI.. • Hematuria andhypertension are common. • Complications of fluid overload may present with: Pulmonary edema Hypertensive encephalopathy • Despite thrombocytopenia, bleeding manifestations are rare • Neurological symptoms like: Irritability Encephalopathy Seizures
- 16. INVESTIGATIONS • CBC • Peripheralblood smears • Reticulocyte count • LDH • Bili unconjigated • Cr & BUN • Urine analysis Hemoglobinuria Hematuria Proteinuria
- 17.
- 18. Investigations to IdentifyCause • In patients with dirrhea, the identification of pathogenic EHEC or Shigella is performed by: Stool culture Further serotyping by agglutination or enzyme immunoassay • Rarely HUS can occur with E. coli UTI: Urine cultures are indicated in non-diarrheal patients
- 19. Conti.. • Bacteriological culturesof body fluids are indicated in suspected pneumococcal disease. Sputum CSF Blood Pus
- 20. Diagnosis • Clinically, HUScan be very hard to distinguish from TTP • The laboratory features are almost identical, and not every case of HUS is preceded by diarrhea • HUS is characterized by the triad of: Hemolytic anemia Thrombocytopenia Acute renal failure
- 21. Cont… – The onlydistinguishing feature is that in TTP fever and neurological symptoms are often present, but this is not always the case – A pericardial friction rub can also sometimes be heard on auscultation – The two conditions are sometimes treated as a single entity called TTP/HUS.
- 22. MANAGEMENT • Supportive Therapy •Antibiotics • Plasma Therapy • Miscellaneous
- 23. Supportive Therapy • Inall patients, supportive treatment is primary. • Close clinical monitoring of : Fluid status Blood pressure Neurological Ventilatory parameters • Blood levels of glucose, electrolytes, creatinine and hemogram need frequent monitoring
- 24. CONTI.. • The useof antimotility therapy for diarrhea has been associated with a higher risk of developing HUS • With the onset of acute renal failure : Fluid restriction Diuretics
- 25. Antibiotics • E. coli •Shigellosis • pneumococcal HUS
- 26. Plasma Therapy • InaHUS due to : complement factor abnormality ADAMTS13 deficiency • The replacement of the deficient factor with FFP • Daily plasma infusions (10 to 20 mL/kg/day) • Exchange of 1.5 times plasma volume ( 60 to 75 mL/kg/day) using FFP
- 27. Miscellaneous • In infantswith HUS associated with cobalamin abnormalities: Treatment with hydroxycobalamin Oral betaine Folic acid • Normalizes the metabolic abnormalities can help to prevent further episodes.
- 28. CONTI.. • In patientswith persistent ADAMTS13 antibodies and poor response to plasma exchange: Immunosuppressive therapy with high dose steroids/cyclophosphamide/ cyclosporin/rituximab Splenectomy
- 29. Prevention • Once patientinfected with EHEC, attempts to prevent progression from bloody diarrheal phase to postdiarrheal phase of HUS have been unsuccessful. • Antibiotics and anti-motility drugs not recommended. • Vigorous fluid repletion during diarrheal phase of illness is associated with less severe renal involvement.
- 30. Prognosis • Hematologic manifestationresolve usually within one to two weeks. • Mortality rate <5%. • Causes of death include hyperkalemia, CHF, pulmonary hemorrhage.
- 31. Markers of poorprognosis • WCC>20 on presentation • Persistent oliguria/anuria. • Renal histology showing a glomerular microangiopathy affecting >50% of glomeruli, arterial microangiopathy +/- cortical necrosis.
- 32. Complications GASTROINTESTINAL NEUROLOGIC RENAL •Intestinal strictures/perforations • Intussusception • Pancreatitis • Severe colitis • Altered mental status • Focal neurologic signs • Seizures • Chronic renal failure • Hematuria • Hypertension • Proteinuria
- 33. DIFFERNTIAL DIAGNOSIS • Acuteabdomen • Acute gastroenteritis • Appendicitis • Colitis • Disseminated intravascular coagulation • Inflammatory bowel disease • Lupus • Thrombotic thrombocytopenia
- 34. summary • HUS isa clinical syndrome characterized by MAHA, ARF and Thrombocytopenia. • Thrombotic Microangiopathy (TMA) is the hallmark of disease pathogenesis. • Stx or Non-Stx associated HUS. • E.coli O157:H7 most common cause for Stx HUS. • Strep pneumoniae for non-STx HUS. • Familial form of HUS usually associated with complement dysregulation. • Treatment of StxHUS mainly supportive with a good prognosis.
- 35. KEY MESSAGES • Goodsanitation and maintenance of food hygiene can prevent diarrhea associated HUS. • Supportive care with early dialysis support remains the cornerstone of management. • Non-infective atypical HUS should be treated rapidly with plasma therapy. • Efforts should be made to make an etiological diagnosis in cases of atypical HUS as treatment and prognosis is affected.