Hemolytic uremic syndrome

Question 1

Triad of HUS

Answer 1

1) Non-immune microangiopathic hemolytic anemia
2) Thrombocytopenia
3) Acute renal failure

Question 2

Most common cause of acute renal failure in children

Answer 2

HUS

Question 3

Most common causative agent in HUS

Answer 3

Diarrhea

EHEC, O157:H7 shiga toxin

Question 4

Pathophysiology

Answer 4

Toixin enters->damages endothelium of colon->bloody diarrhea
Enters blood stream->damage to endothelium= +release of prothrombic/endothelial agents
Platelets aggregate-form thrombi, thrombocytopenia
RBCs forced through vessels occluded by thrombus= fragmented

Question 5

Important history

Answer 5

Abdominal pain, diarrhoea, especially bloody diarrhoea (common)
childhood, especially age

Question 6

Risk factors for HUS

Answer 6

Strong
ingestion of contaminated food or water
known community outbreak of toxogenic E coli
exposure to infected individuals in institutional settings
genetic predisposition

Weak
bone marrow transplant
exposure to ciclosporin, some chemotherapy agents, targeted cancer agents, and quinine
pregnancy- or postpartum-related

Question 7

Investigations

Answer 7

CBC (anemia, thrombocytopenia), blood smear (schistocytes), electrolytes, renal function (+creatinine),
urinalysis (microscopic hematuria), stool cultures and verotoxin/shigella toxin assay

Question 8

Prognosis

Answer 8

Mortality

Renal failure

Question 9

Are antibiotics useful in EHEC

Answer 9

No

+Risk of developing HUS

Question 10

Management

Answer 10

• mainly supportive: nutrition, hydration, ventilation (if necessary), blood transfusion for
symptomatic anemia
• monitor electrolytes and renal function: dialysis if electrolyte abnormality cannot be corrected,
fluid overload, or uremia
• steroids are NOT helpful
• antibiotics are contraindicated because death of bacteria leads to increased toxin release and
worse clinical course
Calcium channel blockers if hypertonic
Plasma exchange can be trialled in adults