Haemolytic Uraemic Syndrome Flashcards
(18 cards)
What is haemolytic uraemic syndrome caused by?
Shiga toxin producing E.coli
What is the triad in HUS?
AKI with oliguria and oedema
Thrombocytopenia
Microangiopathic haemolytic anaemia
Which demographic is commonly affected?
Young children
Risk factors with contact with farm animals or faeces
Summer months swimming in or drinking contaminated water
Immunosuppression
What is the pathophysiology of haemolytic uraemic syndrome?
Profuse diarrhoea that becomes bloody is the classic presenting feature
The Shiga toxin triggers inflammatory cytokine release, activates the complement system and is directly toxic to the endothelium, resulting in microvascular thrombosis which consumes platelets, causing thrombocytopenia
Red blood cells are sheared as they pass through thrombosed vessels, leading to intravascular haemolysis
What causes atypical HUS?
Other infections (e.g. Streptococcus pneumonia, HIV)
Pregnancy
Medications (cisplatin, quinine, tacrolimus)
Illicit drugs (e.g. cocaine, heroin)
Autoimmune conditions (e.g. systemic lupus erythematosus)
Malignancy
-> treated with plasma exchange.
What are the diagnostics for HUS?
STOOL culture or PCR
Blood gas for acidosis and hyperkalemia in AKI
Urinalysis
Urine microscopy and culture
Blood fil will show schistosities
What are the systemic effects of HUS?
PULMONARY OEDEMA causing tachypnea
Dehydration leading to AKI
Microangiopathic thrombosis causing petechia
Oliguria
Fatigue
What is the management of HUS?
Fluid resuscitation
Blood transfusion for active bleeding
Correction of hyperkalemia wih calcium gluconate
Which antibiotics are given for HUS
ANTIBIOTICS are not indicated
What is a cause of haemolytic uraemic syndrome other than E.Coli?
Streptococcus pneumonia
Shigella
What is used for acute treatment of atypical HUS other than supportive management?
Calcium gluconate with insulin dextrose for hyperkalemia
Eculizumab, monoclonal antibody targeting complement C5
How is E.coli contracted other than food intake?
Petting farms
Which type of anaemia is present in HUS?
Normocytic
What are the non E. coli causes of haemolytic uraemia?
pneumococcal infection
HIV
rare: systemic lupus erythematosus, drugs, cancer
What is the cause of primary HUS?
Complement dysregulation
What is the most important intiial diagnostic test for HUS?
Blood film with Haemolysis that is Coomb’s negative
What cultures can be done for HUS?
Stool culture for shigella E. coli
PCR for shiga toxins
