Moschowitz

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Moschowitz Disease

• Galila Zaher
• MRCPath

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Case Presentation

• 20 years old Saudi patient
• Easy fatigability
• Easy bruising
• Afebrile
• Systemic examination normal
• Anaemia thrombocytopenia
• Blood film
• High urea creatinin

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Clinical course

• Abdominal US
• Auto-immune profile
• Seizures
• Plasma pharesis
• Normal platelets count
• Renal dialysis
• Relapse

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Thrombotic Thrombocytopenic Purpura

• Thrombotic thrombocytopenic purpura (TTP) is
  characterized by
• Microangiopathic hemolytic anemia
• Thrombocytopenia
• Microvascular thrombosis causes variable degrees
  of tissue ischemia and infarction

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VWF Biochemistry

• VWF monomers synthesized in EC
• Monomers linked into multimers
• Multimers constructed in megacaryocytes EC
• Stored in alpha granules weibel-palade bodies
• ULVWF entangled to sub-endothelial collagen
• Bind to platelets GP1b-IX V and activated plt
  GPIIb-IIIa ? adhesion and aggregation
  
• 
  Moake et al 1982

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VWF Biochemistry

• Activation, immobilization and spreading
• Recruit more VWF and more platelets
• A disintegrin and metalloprotease with eight
  thrombospondin -1-like domain ADAMTS
• Metalloprotease cleaves ULVWF in A2 domain
• Impaired degradation of VWF by deficiency of
  metalloprotease Tsai 1996
• Characterization of ADAMTS and elicidation of its
  cDNA and gene structure 2001

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ADAMTS 13

• Encoded on chromosome 9q34
• Produced mainly in liver
• Activator Zn and Ca requiring protein
• Inhibitors metal chelators EDTA
• Substrate VWF
• Plasma activity 50-178
• Half-life 2-3 days

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Patho-physiology

• TTP favored by conditions that combine
• Increased VWF level (late pregnancy)
• Decreased ADAMTS13 activity
• Two-hit model could explain substantial variation
  in age at which patients with inherited TTP
  develop symptoms.

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Platelet-rich Microvascular Thrombi

• Wide spread of intravascular thrombosis
• Organ ischemia Renal, Cerebral
• Blood flows through turbulent area of partially
  occluded by platelet aggergates
• Schistocytes
• High LDH correlates with severity of ischemia

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Clinical Presentation

• Pentad
• Thrombocytopenia (increased marrow
  megakaryocytes)
• Microangiopathic hemolytic anemia (MAHA)
• Renal failure (50)
• Neurologic abnormality (25)
• Fever
• Thrombocytopenia , schistocytes elevated LDH
• Nonspecific symptoms weakness, abdominal pain,
  nausea, vomiting, and diarrhea
• Median duration of symptoms prior to diagnosis
  was 6 days
• 
  Oklahoma TTP-HUS
  Registry

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Types Of TTP

• Congenital TTP
• Acquired idiopathic TTP
• Secondary TTP

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Congenital Familial TTP

• Moschowitz Disease
• Rare Autosomal recessive
• Homozygous mutations in both ADAMTS13 alleles
• Both parents showing 50 of activity
• Infancy or childhood
• Severe ischemic brain lesions by MRI
• ADAMTS13 lt 5 of normal plasma
• Almost always have ULVWF multimers
• Response to FFP infusion is rapid Prophylactic
  FFP q2-3 weeks avoid relapses

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Conditions Associated

• Bone marrow transplantation
• Pregnancy Postpartum
• Drugs
• Autoimmune disorders
• TBI
• Kidney, liver, heart, or lung transplant

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Drug-associated TTP

• Acute immune-mediated or dose-related toxic
• Most common cause of immune-mediated TTP
• Quinine ( isolated thrombocytopenia)
• Ticlopidine (TTP and HUS)
• Clopidogrel (TTP and HUS)
• Mitomycin C- Cyclosporine
• Tacrolimus (FK506)
• Discontinuation or dose adjustment is sufficient
  
• Trial of plasma exchange efficacy is uncertain

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Acquired idiopathic

• Adults and older children
• Sever ADAMTS 13 deficiency acute episodes
• IgG autoantibody produced transiently
• Return to normal upon recovery
• Mortality rate 13
• Worse prognosis Prolonged courses more
  frequent complications

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HUS

• Children, usually gt5 years old
• Bloody diarrhea
• E.coli O157H7
• Shiga toxin
• Acute renal failure
• Thrombocytopenia and MAHA
• Mortality is 3-5
• Normal plasma ADAMTS13 activity
• Plasma exchange treatment is rarely considered

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Laboratory Tests

• Anemia
• Thrombocytopenia
• Blood film (Schistocytes gt 1 of total RBCs)
• High LDH (hemolysis and leakage from ischemic
  tissue)
• High bilirubin
• DCT negative
• High urea and ceriatnin
• PT , APTT, fibrinogen D-dimers normal

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Diagnosis

• No gold standard for diagnosis
• ADAMTS13 activity
• Auto-antibodies against ADAMTS13

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Clinical Applications

• Diagnosis
• Discrimination of TTP from HUS
• Discrimination of congenital and acquired
• Estimating risk of relapse
• Monitoring therapeutic efficacy of plasma
  exchange or plasma infusion.

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Furlan

• NP VWF as substrate
• Test plasma is activated by barium chloride
• Mix over night in presence of 1.5M urea
• Separated by SDS agarose gel electophoresis
• Followed by immunoblotting.
• Excellent resolution leader
• Very sensitive
• Reproducible
• Requires several days

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Bohm et al

• Test plasma is incubated with recombinant
  substrate
• Separated by SDS polyacrelamide gel
• Quantitate residual VWF using RIPA
• Short incubation

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Immunoassay Assay

• Residual VWF binding to collagen after its
  degradation
• ELISA simple
• Fast few hours
• Less sensitive and less precise
• Problems with reproducibility

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Low Levels Of ADAMTS

• PLiver disease
• DIC
• Chronic metabolic conditions inflammatory
  conditions
• Uremia
• HIT
• Pregnancy third trimesters
• Newborn
• Healthy controls levels 20-50 and none lt 10

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Management

• Untreated almost always fatal (90)
• FFP Byrnes and Khurana 1977
• Cryo-supernatant contain ADAMTS
  
• 
  Tsai 1998
• Solvent/detergent-treated plasma contain ADAMTS
  
• Tsai and Lian and
  Furlan 1998

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Plasma pheresis

• Plasma exchange reduced MR from 90- 25
• Remove circulating ULVWF multimer-platelet
  strings
• Remove circulating auto-antibodies against
  ADAMTS13
• Infusion of FFP or cryosupernatant , SD or
  methylene blue/light-treated plasma
• Response rate 8090
• T1/2 of infused ADAMTS13 activity is 2 days
• Prompt and complete response no further therapy

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Risk For Relapse

• Severe ADAMTS13 deficiency
• Idiopathic TTP auto-Abs
• Non following SCT
• No relapse following drug toxicity
• No relapse who had a prodrome of bloody diarrhea
• Oklahoma TTP-HUS
  Registry

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Management Of Relapse

• Most relapses occur within the first year
• Suboptimal response or relapse steroids
• Sever neurologic defect immunosuppressive
  treatment
• Spleenectomy eliminates autoantibody-producing B
  cells

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Acquired idiopathic TTP

• Lower titers better responses
• High titer inhibitor wore prognosis
• Inconsistent response to steroids and other
  immunosuppressive agents
• Rituximab or cyclophosphamide
• Removal of autoantibody-producing cells by
  splenectomy.

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Pregnancy And TTP

• During pregnancy ,postpartum 70 around time of
  delivery
• Pre-eclampsia/HELLP 3rd trimester or following
  delivery, HT , protinurea Spontaneous
  postpartum recovery
• Observation for several days after delivery
• Acute, severe multi-organ failure prompt plasma
  exchange

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TTP Following BMT

• Post allogeneic 2-76
• Post autologous 0-27
• Mortality rate 0-93
• DD Renal and neurotoxicities of GVHD
• Cyclosporine and Tacrolimus
• Clinically suspected TTP efforts to diagnose
  treat GVHD and sepsis delay a decision for
  plasma exchange
• ADAMTS13 activity normal
• No response to plasma exchange

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HIV

• Typical TTP
• Acquired autoantibody to ADAMTS13
• Rapidly fatal course
• Plasma exchange one plasma volume once daily
• Glucocorticoids auto-antibodies to ADAMTS13

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• Thank you

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Central Venous Catheter Insertion

• Deaths
• Cardiac arrest with near-death
• Hemorrhage
• Pneumothrax
• Pericardial tamponade
• Allergic reactions
• Severe hypotension and hypoxia
• Fatal sepsis

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ADAMTS13 Absent Clinical Presentation
Familial TTP chronic relapsing TTP ADAMTS13 mutations Presentation in infancy/childhood Disease presentation delayed
Acquired idiopathic TTP Single episode Recurrent (intermittent) TTP Ticlopidine/clopidogrel-TTP Autoantibodies against ADAMTS13 Transient Recurrent Thienopyridine-associated
Acquired idiopathic TTP (?) ADAMTS13 transient production or survival (?) defect
Pregnancy-associated TTP Pregnancy
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• Tsai
• Plasma samples incubated with guanidine
  HCl-treated VWF X1hr
• Products separated by SDSpolyacrylamide gel
  electrophoresis
• Immunoblotting
• Obert et al
• Plasma samples incubated with recombinant VWF
  overnight
• Degraded VWF fragments detected by two-site
  immunoradiometric assay
• Performed in hospital laboratory
• High-throughput method
• Gerritsen et al Functional assay
• Preferential binding of HMWt forms of VWF to
  collagen.
• Plasma treated with EDTA to abolishes the
  VWF-cleaving activity.
• Dialyzed against the buffer and used as
  substrate.

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• Recombinant protein as ADAMTS13 substrate E coli
  culture
• Direct assay for measuring ADAMTS13 product
  generation
• More accurate
• Protease-free VWF.
• Substrate tagged with two different molecules
  makes it easy to modify the detection of product.
  
• One potential disadvantage GST-VWF73-H is not a
  natural substrate

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Sensitivity And Specificity

• Specificity Severe deficiency (lt5 ) is specific
  
• Sensitivity remains questionable 66- 100 Tsai
  and Lian.
• Levy et al identified 12 gene mutations

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Parameter Finding Points
Neurologic findings None 0
Confusion, lethargy, behavioral changes 1
Focal neurologic deficits, convulsions, stupor, coma 2
Renal function impairment None 0
BUN gt 30 and lt 70 mg/dL and/or creatinine ? 1.5 mg/dL and lt 2.5 mg/dL, and/or proteinuria gt 2 g per day and/or hematuria 1
BUN gt 70 mg/dL and/or creatinine gt 2.5 mg/dL and/or dialysis 2
Platelet count at presentation gt 100,000 per L 0
20,000 100,000 per L 1
lt 20,000 per L 2
Hemoglobin level at presentation gt 12 g/dL 0
9-12 g/dL 1
lt 9 g/dL 2
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Differential Diagnosis

• Thrombotic thrombocytopenic purpura (TTP)
• Immune thrombocytopenia purpura (ITP)
• Autoimmune hemolytic anemia
• Hemolytic uremic syndrome (HUS)
• Pregnancy, eclampsia
• Disseminated intravascular coagulation (DIC)
• Septicemia with DIC
• Systemic lupus erythematosus (SLE)
• Scleroderma
• Paroxysmal nocturnal hemoglobinuria (PNH)

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Comparison of the features of TTP and hemolytic
uremic syndrome (HUS)
Feature TTP HUS
Age Peak incidence at 40 years Childhood
Gender Female Equal
Epidemic No Yes
Re-occurrence Common Rare
Link to E. coli 0157H7 Occasional Yes
Renal failure Uncommon Common
Neurologic Common Uncommon
Thrombocytopenia Severe Moderate to severe
Organ involvement Multiple Limited to kidney