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hemolytic uremic syndrome (HUS)

Microangiopathic hemolytic anemia & thrombocytopenia sharing many of the properties of thrombotic thrombocytopenic purpura (TTP). Both have a tendency to affect the kidneys. Also see TTP. Etiology: 1) unlike TTP, HUS is not caused by a deficiency or an inhibitor of vWF-cleaving protease 2) verotoxin or shiga toxin-producing Escherichia coli or Shigella [2] (enterohemorrhagic Escherichia coli) - antibiotic treatment may increase risk [3] 3) may be associated with certain pharmaceutical agents a) mitomycin C (generally weeks to months after therapy) b) cyclosporine c) oral contraceptives d) moxetumomab 4) associated disorders a) postpartum renal failure b) malignant hypertension c) scleroderma d) systemic lupus erythematosus 5) atypical HUS is a congenital syndrome caused by overwelming complement activation, not preceded by diarrhea [2] Pathology: 1) small renal arteries & afferent arterioles are affected in a patchy, focal pattern 2) variable findings a) intimal hyperplasia b) fibrin deposition c) microaneurysms d) interstitial edema e) glomerular infarction f) tubular necrosis Genetics: - atypical form associated with defects in CD46 Clinical manifestations: 1) fever 2) renal disease a) oliguria b) renal failure is common 3) fluctuating neurologic signs a) confusion b) focal neurologic signs 4) Patients with HUS have more severe renal failure & less severe CNS symptoms than patients with TTP 5) bloody diarrhea if due to enterohemorrhagic Escherichia coli Laboratory: 1) renal function tests a) serum urea nitrogen: azotemia (uremia) b) serum creatinine is be elevated 2) urinalysis a) proteinuria b) hematuria 3) complete blood count: - anemia - thrombocytopenia 4) peripheral smear a) erythrocyte fragments b) diminished platelets 5) also see TTP Management: 1) similar for HUS & TTP, but generally managed with supportive therapy [2] 2) high dose glucocorticoids should be initiated as early as possible 3) plasmapheresis a) indicated for TTP, but is less well established as a treatment of HUS b) over a column of Staphylococcal protein A 4) atypical HUS may be treated with infusions of eculizumab [2,7] 5) prognosis is better for children than for adults. 6) antibiotics not helpful [2] 7) *** also see TTP ***

Related

thrombotic thrombocytopenic purpura (TTP)

Specific

postpartum hemolytic uremic syndrome (HUS)

General

thrombotic microangiopathy syndrome hemolytic anemia arterial disease kidney disease; renal disease

Database Correlations

OMIM 235400

References

  1. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 1320
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 18, 19. American College of Physicians, Philadelphia 1998, 2012, 2015, 2018, 2021. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  3. Wong CS et al. Risk factors for the hemolytic uremic syndrome in children infected with Escherichia coli O157:H7: A multivariable analysis. Clin Infect Dis 2012 Jul 1; 55:33. PMID: 22431799
  4. Zipfel PF, Heinen S, Skerka C. Thrombotic microangiopathies: new insights and new challenges. Curr Opin Nephrol Hypertens. 2010 Jul;19(4):372-8. PMID: 20539230
  5. George JN, Al-Nouri ZL. Diagnostic and therapeutic challenges in the thrombotic thrombocytopenic purpura and hemolytic uremic syndromes. Hematology Am Soc Hematol Educ Program. 2012;2012:604-9 PMID: 23233641
  6. Page AV, Liles WC. Enterohemorrhagic Escherichia coli Infections and the Hemolytic-Uremic Syndrome. Med Clin North Am. 2013 Jul;97(4):681-95, xi. Review. PMID: 23809720
  7. Kao AY, Sagar P, Klig JE et al Case 19-2018: A 15-Year-Old Girl with Acute Kidney Injury. N Engl J Med 2018; 378:2421-2429. June 21, 2018 PMID: 29924949 https://www.nejm.org/doi/full/10.1056/NEJMcpc1802827
  8. Mele C, Remuzzi G, Noris M. Hemolytic uremic syndrome. Semin Immunopathol. 2014 Jul;36(4):399-420. Review. PMID: 24526222
  9. Hemolytic Uremic Syndrome http://kidney.niddk.nih.gov/kudiseases/pubs/hemolyticuremic/index.htm