HUS

Question 1

Triad of HUS

Answer 1

1) Microangiopathic hemolytic anemia 2) Thrombocytopenia 3) Renal insufficiency

Question 2

MC HUS is caused by

Answer 2

Toxin-producing E. coli producing diarrhea-associated HUS

Question 3

MC E. coli serotype that causes HUS in Europe and the Americas

Answer 3

O157:H7

Question 4

Toxin of this organism is causative of HUS in Asia and southern Africa

Answer 4

Shigella dysenteriae type I

Question 5

Toxin of this organism is causative of HUS in Western countries

Answer 5

STEC

Question 6

Reservoir of STEC

Answer 6

Intestinal tract of domestic animals, usually cows

Question 7

HUS is commonly transmitted by

Answer 7

Undercooked meat or unpasteurized (raw) milk and apple cider

Question 8

HUS develops during acute infection with this organism, typically manifesting with pneumonia and empyema

Answer 8

Neuraminidase-producing S. pneumoniae

Question 9

Pathology of HUS nephritis

Answer 9

Capillary and endothelial injury leading to localized thrombosis, particularly in the glomeruli, causing a direct decrease in GFR; consumptive thrombocytopenia; microangiopathic hemolytic anemia from mechanical damage to RBCs as they pass through damaged thrombotic vasculature

Question 10

HUS is MC in what age group

Answer 10

Preschool and school-aged children

Question 11

Timing of nephritis in HUS caused by E. coli

Answer 11

Few days after onset of AGE

Question 12

Diarrhea in HUS is characteristically bloody

Answer 12

F, not necessarily

Question 13

T/F No presenting features reliably predict the severity of HUS in any given patient

Answer 13

T

Question 14

Significant life-threatening electrolyte abnormality in HUS nephritis

Answer 14

Hyperkalemia (from ARF and hemolysis)

Question 15

HUS: CNS involvement occurs in ___% of cases

Answer 15

20

Question 16

T/F Majority of patients with HUS have some CNS involvement

Answer 16

T

Question 17

Severe CNS involvement in HUS results from

Answer 17

Focal ischemia sec to microvascular CNS thrombosis

Question 18

T/F In HUS, large strokes and ICH are common

Answer 18

F, rare

Question 19

Cell type that can be seen on PBS of patients with HUS

Answer 19

Schistocytes from hemolysis

Question 20

T/F PT/PTT in HUS is usually derranged

Answer 20

F, usually normal

Question 21

T/F Coombs’ test in HUS is usually positive

Answer 21

F, usually (-) and T if HUS is pneumococci-induced

Question 22

T/F The presence or absence of toxigenic organisms on stool culture has little role in making the diagnosis of diarrhea-associated, enteropathic HUS

Answer 22

T

Question 23

T/F Stool culture is often negative in patients who have diarrhea-associated HUS

Answer 23

T

Question 24

HUS may take place without diarrheal nor pneumococcal prodrome

Answer 24

T, as in genetic HUS

Question 25

Patients with this type of HUS are more prone to recurrence and has a more severe prognosis

Answer 25

Genetic

Question 26

T/F Most patients with HUS nephritis recover renal function completely

Answer 26

T

Question 27

T/F Prognosis for HUS not associated with diarrhea is more severe

Answer 27

T

Question 28

T/F Early intravenous volume expansion before the onset of oligo anuria may be nephroprotective in diarrhea-associated HUS

Answer 28

T

Question 29

T/F Red cell transfusions are not required in HUS since hemolysis is part of it’s pathophysiology

Answer 29

F, usually required as hemolysis can be brisk and recurrent until the active phase of the disease has resolved

Question 30

Why is it critical that any administered red cells to HUS patients be washed before transfusion?

Answer 30

To remove residual plasma since endogenous IgM directed against revealed T antigen can play a role in accelerating the pathogenesis of the disease.

Question 31

T/F In HUS, platelets should generally not be administered

Answer 31

T, because they are rapidly consumed by the active coagulation and theoretically can worsen the clinical course

Question 32

T/F Despite low platelet counts, serious bleeding is very rare in patients with HUS

Answer 32

T

Question 33

Antibiotic therapy to clear enteric toxigenic organisms (STEC) is not recommended in HUS because

Answer 33

It can result in increased toxin release, potentially exacerbating the disease, specifically in O157-H7-associated HUS

Question 34

T/F Antibiotic therapy against pneumococci -associated HUS is not indicated

Answer 34

F, prompt therapy is important

Question 35

Plasma infusion or plasmapheresis is contraindicated in which type of HUS

Answer 35

Pneumococcal-associated HUS as it could exacerbate the disease

Question 36

Treatment for HUS which is an anti-C5 antibody that inhibits complement activation, a pathway that contributes to active disease in some forms of atypical familial HUS

Answer 36

Eculizumab

Question 37

T/F Most patients with diarrhea-associated HUS recover completely with little risk of long-term sequelae

Answer 37

T