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Sindrome hemolítico urêmica
1. Sindrome
hemolítico-urêmica
Antonio Souto
acasouto@bol.com.br
Médico coordenador
Unidade de Medicina Intensiva Pediátrica
Unidade de Medicina Intensiva Neonatal
Hospital Padre Albino
Professor de Pediatria nível II
Faculdades Integradas Padre Albino
Catanduva / SP
2011
2. H emolytic uremic syndrome is
the most common cause of acute
renal failure in children,
and the incidence of this syndrome in
children is increasing worldwide.
3.
4. Epidemiology
•Primarily occurs in children one to 10 years of age
•Annual incidence: 1-3/100,000
•Survival rate of nearly 90 percent
•Rural populations are more at risk
•Incidence is higher in warmer months
•Three to 15 percent of persons who have STEC with
diarrhea
E. coli O157:H7 strains could survive for as long as
one year
Am Fam Physician 2006;74:991-6, 998.
8. Etiology
Two types (diarrheal prodrome)
•Diarrhea-positive
Shiga toxin–producing Escherichia
coli
E. coli O157:H7 other strains also have been
implicated
Diarrhea-negative in adults can have a genetic cause
and generally has a poor prognosis
9.
10. Etiology
E. coli O157:H7 is believed to cause more than 80
percent of the STEC infections that lead to
hemolytic uremic syndrome.
Form of transmission to children
•ingestion of undercooked beef containing E. coli
•by contact with persons who inadequately wash
their hands, resulting in fecal and oral
contamination and transmission
13. There is increasing awareness that
other organisms, drugs, and conditions
can also initiate the triad of
microangiopathic hemolytic anemia,
thrombocytopenia, and acute
nephropathy that defines HUS.
Current Opinion in Pediatrics 2005, 17:200–204
14. . Distribution of hemolytic uremic syndrome cases associated with Shiga toxin–producing
Escherichia coli O157, 026, O111, and O145, by year
15.
16. Shiga Toxin
Toxin is almost identical to Stx from Shigella
dysenteriae
Stx cause different degrees and types of tissue
damage
Higher pathogenicity of strains that produce only
Stx-2, most commonly associated with HUS
17. •Oral ingestion
• Stx-E. coli reaches the gut and closely adheres to
the epithelial cells
• Stx then translocate into the circulation
•Transport of Stx from the intestine to the kidney,
consistently, Stx bound to circulating PMN
•In vitro, PMN loaded with Stx transfer the ligand to
glomerular endothelial cells
18. •The findings indicate that Stx favor leukocyte-
dependent inflammation.
•Activates endothelial cells that leads to
microvascular thrombosis.
•In vivo evidence of coagulation disturbances has
been found in children who developed HUS upon E.
coli O157:H7 infection.
•Recent work indicating that fibrinolysis is
substantially inhibited.
19.
20. Clinical Characteristics
The classic triad:
•Microangiopathic hemolytic anemia
•Thrombocytopenia
•Acute renal failure
Typical hemolytic uremic syndrome usually develops
after a prodrome of diarrhea.
21. Clinical Characteristics
•Clinical features are vague and may mimic common
gastroenteritis
•Bloody diarrhea three days to more than two
weeks before HUS
•Additional symptoms:
•Nonbloody diarrhea, abdominal cramping and
nausea or vomiting.
•Fever low grade or absent.
•Ten percent of cases rectal prolapse with colitis
22.
23. HUS cannot be diagnosed
without evidence of hemolytic
anemia.
Hematologic findings:
•Destruction and fragmentation of erythrocytes
•Microangiopathic hemolytic anemia
•92% develop thrombocytopenia
•Clotting times are normal
•Petechiae and purpura are uncommon
27. Microvascular
•`The lesion is mainly confined to the glomerular tuft
and is noted in an early phase of the disease.
•Biopsies showed that most glomeruli are normal,
whereas 15 to 20% eventually became sclerotic.
31. Management
Is There Any Effective Treatment for
Stx-HUS?
There is no treatment of proven
value, and care during the acute
phase of the illness is still merely
supportive
32.
33. Management
HUS is a selflimiting disease
•Close monitoring and treatment of symptoms are
essential
•Wide spectrum of presentations
•Supportive therapy
•Close monitoring of fluid and electrolyte status
The amount of parenteral hydration before the
development of HUS, is crucial in preventing anuria
and, ultimately, dialysis.
34. Management
Detecting early renal failure
•Should be handled aggressively
•Renal replacement therapy (peritoneal dialysis)
•Hypertension is treated traditionally
Antibiotics and antimotility agents are not
recommended as treatments for hemolytic uremic
syndrome during the diarrheal stage of the disease.
35. Management
Studies of antibiotic usage in children with E. coli
O157:H7 infections show an increased risk of
complications from HUS
36. Management
On the basis of available data, we
suggest that in patients with Stx-E.
coli gastrointestinal infection,
antibiotics should be avoided unless
in cases with sepsis.
37. Management
Serial monitoring of the hematocrit and platelet
count is important
•Platelet transfusion can worsen the thrombotic
process
•Transfusion of red blood cells may be needed
•Transfusion can deteriorate the patient’s
condition
38. Management
Renin-angiotensin system blockade may be
particularly beneficial
•Early restriction of proteins and use of angiotensin-
converting enzyme inhibitors may have a beneficial
effect
•Treatment with angiotensin-converting enzyme
inhibitors normalized BP, reduced proteinuria, and
improved GFR.
41. Complications
10% of patients
Central nervous system
problems
coma, hemiparesis, or stroke
3,476 patients with diarrhea-positive hemolytic
uremic syndrome, 313 (9%) died, 104 (3%)
developed end-stage renal disease, and 869 (25%)
exhibited renal sequelae
Neurologic involvement correlates highly with a
fatal outcome
