Thrombotic Microangiopathies Flashcards
How can you clinically differentiate TTP from HUS?
True or false: The treatment of choice for TTP is plasma exchange.
True
True or false: Platelet transfusion is the treatment of choice for TTP.
False
What type of anaemia is the hallmark in TMA?
MAHA
True or false: Iron deficiency anaemia is the hallmark in TMA.
False
What is the most correct statement regarding TTP and HUS?
HUS is a more common cause of ARF than TTP
What are the classic pentad features of TTP?
- Microangiopathic haemolytic anaemia
- Thrombocytopenia
- Renal insufficiency or abnormalities
- Neurologic abnormalities
- Fever
What accounts for >99% of adolescent and adult cases of TTP?
Acquired TTP
What autoimmune condition is associated with TTP?
Anti-ADAMTS-13 antibodies
What does decreased ADAMTS13 activity lead to?
Accumulation of UL vWF multimers
TTP is a _______ diagnosis.
clinicopathological
What is considered pathologic in terms of schistocytes on a blood film?
More than two schistocytes per high-power field or > 1.0% schistocytes
What is the cornerstone of current management of TTP?
Therapeutic Plasma Exchange (TPE)
What is the recommended dosage of prednisone for TTP treatment?
1 mg/kg/day orally followed by a rapid taper
Without therapy, the mortality rate of TTP exceeds _____%.
90
What should be assayed before beginning therapy for TTP?
ADAMTS13 activity
What laboratory features are indicative of TTP?
- Anaemia
- Thrombocytopenia
- Schistocytes
- Elevated LDH
- Unconjugated hyperbilirubinaemia
- Reduced haptoglobin
What is the major component of the hemostatic system?
- Vascular endothelium
- Platelets
- Coagulation and fibrinolytic systems
What is the incidence of TTP in adults?
About 3 per 1,000,000
TTP has a higher incidence in which gender?
Female
What is the primary cause of ADAMTS13 deficiency in acquired TTP?
Autoantibodies to ADAMTS13
What is the role of ADAMTS13?
Cleaves vWF
What is a common feature of obstetric TTP?
Occurs during the second half of pregnancy
True or false: HIV infection alters the prognosis of TTP.
False
What characterizes HUS?
MAHA and thrombocytopenia
What is the major clinical manifestation of HUS?
Renal disease
What is the most common cause of acute renal failure in children?
HUS
What is the inheritance pattern of aHUS?
Autosomal dominant
What is the typical treatment for STEC-HUS?
Supportive care
What is iculocytosis?
A clinical term related to the presence of schistiocytes in a peripheral blood smear
Schistiocytes are fragmented red blood cells often seen in conditions of hemolysis.
What are elevated LDH levels indicative of?
Tissue damage, commonly associated with hemolytic conditions
LDH (lactate dehydrogenase) is an enzyme released during tissue injury.
What clinical findings are associated with hemolytic uremic syndrome (HUS)?
Triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal damage
What is the primary treatment for STEC-HUS?
Supportive care
Volume expansion within the first 4 days is crucial.
What should be avoided in the management of STEC-HUS?
Antimotility agents
These can worsen the condition.
True or False: Antibiotics are routinely recommended for STEC-HUS.
False
Use is controversial and only indicated for suspected sepsis or S. dysenteriae infection.
What characterizes thrombotic microangiopathies (TMAs)?
MAHA, thrombocytopenia, and microthrombi leading to ischemic tissue injury
What is the hallmark of thrombotic microangiopathy?
Microangiopathic hemolytic anemia (MAHA)
What is the typical prognosis for patients with STEC-HUS?
Generally favorable, but chronic renal insufficiency may develop over time
What is the incidence of atypical HUS (aHUS) in the USA?
Estimated at 2 per million
What is a common cause of typical HUS?
Shiga toxin-producing E. coli (STEC)
Responsible for 90% of childhood HUS cases.
Fill in the blank: The most common serotype associated with STEC-HUS is _______.
E. coli O157:H7
What are some potential triggers for atypical HUS?
Varicella, H1N1 influenza
What is the primary clinical feature of hemolytic uremic syndrome?
Thrombotic microangiopathy (TMA)
What are the main pathological lesions in HUS?
Thickening of arterioles, endothelial swelling, and detachment
What is the typical age of onset for pediatric TTP?
Typically occurs during infancy or early childhood (<10 years)
What is the role of Eculizumab in aHUS management?
Inhibits C5 activation and prevents TMA process
What percentage of children with STEC-HUS require dialysis during the acute phase?
Up to 60%
What are alloantibodies?
Antibodies produced against transfused blood cells from another individual
What conditions can cause alloantibodies?
- Hemolytic disease of the newborn
- Incompatible blood transfusion
What distinguishes autoantibodies from alloantibodies?
Autoantibodies are directed against one’s own RBCs
What are some common causes of autoimmune hemolytic anemia?
- Systemic lupus erythematosus (SLE)
- Other autoimmune diseases
What is the usual outcome for D(+) HUS?
Self-limiting, but residual renal dysfunction is common
What is the significance of DAT in hemolytic anemia?
Direct Antiglobulin Test (DAT) indicates the presence of autoantibodies
