j. martin johnston, md pediatric project echo 7 december 2018€¦ · pediatric project echo. 7...
TRANSCRIPT
J. Martin Johnston, MD
Pediatric Project ECHO7 December 2018
Objectives
Review history and physical exam as they relate to a potential bleeding disorder
Discuss step-wise laboratory evaluation: screening labs and follow-ups
Review some common congenital and acquired bleeding disorders, and their management
Objectives
Review history and physical exam as they relate to a potential bleeding disorder
Discuss step-wise laboratory evaluation: screening labs and follow-ups
Review some common congenital and acquired bleeding disorders, and their management
Objectives
Review history and physical exam as they relate to a potential bleeding disorder
Discuss step-wise laboratory evaluation: screening labs and follow-ups
Review some common congenital and acquired bleeding disorders, and their management
The chief complaint
“Easy” bruising Nosebleeds Petechiae Menorrhagia Bleeding after
Circumcision Tonsillectomy/adenoidectomy, tooth extraction Mild (head) trauma
• Everyone bleeds.
• All bleeding eventually stops.
The problem….
The bleeding history Birth/neonatal Tooth eruption/shedding Bruising Nosebleeds Surgeries? (don’t forget circumcision!) Orthopedic hx (traumas, joints) Menstruation Family history
How much bleeding is too much? Neonatal
ICH, needle/heel sticks, post-circumcision
How much bleeding is too much? Neonatal
ICH, needle/heel sticks, post-circumcision Infant
Petechiae, chest/back/buttock bruising Consider
NAT
How much bleeding is too much? Neonatal
ICH, needle/heel sticks, post-circumcision Infant
Petechiae, chest/back/buttock bruising Toddler
Soft tissue or joint bleeds, large/palpable bruises
Consider
NAT
How much bleeding is too much? Neonatal
ICH, needle/heel sticks, post-circumcision Infant
Petechiae, chest/back/buttock bruising Toddler
Soft tissue or joint bleeds, large/palpable bruises Older child
Recurrent prolonged nosebleeds (bilateral), joint bleeds, hematomas, menorrhagia
“Easy” bruising Without associated trauma (painless) Unusual locations Palpable (hematomas) “Bigger than a quarter”?
Petechiae Considerations:
Low platelets Dysfunctional platelets Vasculitis○ Viral? HSP?
“Trauma”○ Cough, vomiting, venous stasis (“choking”)
Collagen disorder: ↓ vascular integrity
Menorrhagia Definition:
Excessive but regular menstrual bleeding○ > 80 mL blood loss / cycle
Menorrhagia Definition:
Excessive but regular menstrual bleeding○ > 80 mL blood loss / cycle○ > 7 days of menstruation
Menorrhagia Definition:
Excessive but regular menstrual bleeding○ > 80 mL blood loss / cycle○ > 7 days of menstruation
Passing clots Saturating pad/tampon q 2 hours○ Double barrier○ Replacing overnight
Menorrhagia Definition:
Excessive but regular menstrual bleeding○ > 80 mL blood loss / cycle○ > 7 days of menstruation
Passing clots Saturating pad/tampon q 2 hours○ Double barrier○ Replacing overnight
Not just number of pads/tampons
Pad
Tampon
Clots?
Overflow?
1x25¢
“Bleeding Score” (history) to identify von Willebrand Disease
Rodeghiero F et al. J Thromb Haemost 2005; 3:2619-26
90%
25%90%90%
Putting it all together….
• Everyone bleeds.
The problem….
Family history Known diagnoses?
“Free bleeders” Unexplained death in childhood
Recurrent (prolonged) nosebleeds Menorrhagia Patterns of inheritance:
Dominant: vWD X-linked: hemophilia Recessive: rare factor deficiencies
Platelet disorders
Physical exam Conjunctival/mucosal hemorrhages Petechiae
Distribution Bruises
Age/color Number/size Palpable? Tender? Distribution
Physical exam (cont)
Joints Warm/tender/tense Boggy Range of motion:○ Chronic arthropathy?○ Hyperextensible?
2
2
2
2
1
May suggest an underlying
collagen disorder
Initial lab evaluation of suspected coagulopathy
CBC/smear PT/INR aPTT Platelet function analysis?
Thrombocytopenia If isolated and mild (>100k), often not
significant (MPV?) If isolated and severe, think ITP
Thrombocytopenia If isolated and mild (>100k), often not
significant (MPV?) If isolated and severe, think ITP Associated anemia?
Blood loss; hypersplenism, Evans syndrome, TTP
Thrombocytopenia If isolated and mild (>100k), often not
significant (MPV?) If isolated and severe, think ITP Associated anemia?
Blood loss, hypersplenism, Evans syndrome, TTP Neutropenia?
Viral illness, autoimmune, acute leukemia
Thrombocytopenia If isolated and mild (>100k), often not
significant (MPV?) If isolated and severe, think ITP Associated anemia?
Blood loss, hypersplenism, Evans syndrome, TTP Neutropenia?
Viral illness, autoimmune, acute leukemia Pancytopenia?
Acute leukemias, aplastic anemia, neuroblastoma
Platelet morphology
Larger platelets often suggest a destructive process, e.g., ITP
Platelet morphology
Large platelets often suggest a destructive process
Dysfunctional platelets may look abnormal Gray platelet syndrome Bernard-Soulier syndrome Bloodjournal.com
Platelet morphology
Large platelets often suggest a destructive process
Dysfunctional platelets may look abnormal Gray platelet syndrome Bernard-Soulier syndrome
But most dysfunctional platelets looknormal
Platelet function PFA-100
in vitro “substitute” for template bleeding time Theoretical screen for platelet function defects
and vWD Issues with sensitivity/specificity, reproducibility
Platelet function Platelet function analysis Platelet aggregometry
Not available in Reno Patient must be sent (fresh specimen required)
Electron microscopy, gene profiles
F X F Xa
Prothrombin (F II)
Thrombin (F IIa)
Fibrinogen Fibrin monomer
Cellular injury:
Tissue Factor
F VIIa F VII
F V F Va
Fibrin multimerCrosslinked fibrin
TFPI
F XIIIF XIIIa
Contact system:
HMWK, PK, F XII Kallikrein, F XIIa
F XI F XIa
F IX F IXa
F VIII F VIIIa
Protein C + thrombomodulin
Protein S
Activated Protein Ca
Antithrombin
Heparin cofactor II
PT/INR
Contact system:
HMWK, PK, F XII Kallikrein, F XIIa
F XI F XIa
F IX F IXa
F X F Xa
Prothrombin (F II)
Thrombin (F IIa)
Fibrinogen Fibrin monomer
F VIII F VIIIa
F V F Va
Fibrin multimerCrosslinked fibrin
F XIIIF XIIIa
Cellular injury:
Tissue Factor
F VIIa F VII
Protein C + thrombomodulin
Protein S
Activated Protein Ca
Antithrombin
TFPI
Heparin cofactor II
aPTT
Prolonged aPTT with normal PT/INR Deficiency versus inhibitor
Mixing studies help distinguish○ Correction implies something is “missing”○ Lack of correction implies “active” inhibition
Prolonged aPTT with normal PT/INR Deficiency versus inhibitor
Mixing studies help distinguish Inhibitor: possible “Lupus anticoagulant”
In young children, usually benign/transient If persistent, risk of clotting, not bleeding!
Prolonged aPTT with normal PT/INR Deficiency versus inhibitor
Mixing studies help distinguish Inhibitor: possible Lupus anticoagulant
In young children, usually benign/transient Risk of clotting, not bleeding!
Deficiency: fVIII, fIX: hemophilia vWF: “carrier” for fVIII fXI: Ashkenazi? (“hemophilia C”) fXII: relatively common; does not cause bleeding!
2nd-tier coag testing
Mixing studies Specific factor levels von Willebrand panel Fibrinogen Thrombin time factor XIII
775-982-5427775-982-KIDS912-658-5223
High Uintas Wilderness Area, Utah
Questions?
“Common” pediatric bleeding disorders
ITP von Willebrand disease Hemophilia
ITP (idiopathic thrombocytopenic purpura)
ITP (immune thrombocytopenic purpura)
ITP (immune thrombocytopenia)
ITP (immune thrombocytopenia)
• Antibody-mediated platelet destruction• “Acute” (resolves within 6-12 months) most common in toddlers• Abrupt onset of bruising/petechiae; otherwise “well”• Isolated, profound thrombocytopenia• Debate re best management: observation is often appropriate• More likely to persist (“chronic” ITP) in older/female patients
• Immune suppression• Splenectomy• Thrombopoietin analogues
von Willebrand disease
Hereditary Pseudohaemophilia (1926)
von Willebrand disease
Dominantly inherited (types 1 and 2) Relatively common Rarely life-threatening
von Willebrand disease
Dominantly inherited (types 1 and 2) Relatively common Rarely life-threatening Mucocutaneous bleeds
Menorrhagia Dental/oral bleeds Post-tonsillectomy/adenoidectomy
von Willebrand disease
Deficiency or dysfunction of von Willebrand factor (vWF)
(Type 1) (Type 2)
von Willebrand disease
Deficiency or dysfunction of von Willebrand factor (vWF), which: Mediates initial platelet adhesion at sites of
vascular injury
(Type 1) (Type 2)
von Willebrand disease
Deficiency or dysfunction of von Willebrand factor (vWF) Mediates initial platelet adhesion at sites of
vascular injury
Self-polymerizes to form multimers Binds and stabilizes factor VIII
“von Willebrand panel” assays all of these
von Willebrand disease
Work-up: aPTT may be normal or mildly prolonged PFA-100 “should” be abnormal
von Willebrand disease
Work-up: aPTT may be normal or mildly prolonged PFA-100 “should” be abnormal von Willebrand panel○ Notoriously variable○ Lower limits of normal are debated
von Willebrand disease
Work-up: aPTT may be normal or mildly prolonged PFA-100 “should” be abnormal von Willebrand panel○ Notoriously variable○ Lower limits of normal are debated <50% suggestive <40% suspicious <30% definitive
von Willebrand disease
Work-up: aPTT may be normal or mildly prolonged PFA-100 “should” be abnormal von Willebrand panel○ Notoriously variable○ Lower limits of normal are debated <50% suggestive <40% suspicious <30% definitive (maybe)
von Willebrand panel/profile vWF antigen
How much protein? vWF (a.k.a. ristocetin cofactor) activity
How well does it function? fVIII activity
Because vWF “carries” factor VIII
von Willebrand panel/profile (multimeric) vWF antigen
How much protein? vWF (a.k.a. ristocetin cofactor) activity
How well does it function? fVIII activity
Because vWF “carries” factor VIII Multimer pattern
Gel electrophoresis to assess “stacking” of vWF
von Willebrand panel/profile (multimeric)
Type 1 vWD (most common) Quantitative deficiency: ↓ antigen/activity +/- VIII
von Willebrand panel/profile (multimeric)
Type 1 vWD Quantitative deficiency: ↓ antigen/activity +/- VIII
Type 3 vWD (very rare) Homozygous Type 1: absent antigen/activity/VIII
von Willebrand panel/profile (multimeric)
Type 1 vWD Quantitative deficiency: ↓ antigen/activity +/- VIII
Type 3 vWD Homozygous Type 1: absent antigen/activity/VIII
Type 2 vWD Qualitative defect:○ 2A: ↓ ↓ ↓ activity with ↓ antigen○ 2B: ↓ activity/antigen + ↓ platelets○ 2N: ↓ activity/antigen + ↓ ↓ fVIII
+/- abnormalmultimers
von Willebrand panel/profile (multimeric)
Type 1 vWD Quantitative deficiency: ↓ antigen/activity +/- VIII
Type 3 vWD Homozygous Type 1: absent antigen/activity/VIII
Type 2 vWD Qualitative defect:○ 2A: ↓ ↓ ↓ activity with ↓ antigen○ 2B: ↓ activity/antigen + ↓ platelets○ 2N: ↓ activity/antigen + ↓ ↓ fVIII○ 2M: ↓ ↓ ↓ activity with ↓ antigen w normal multimers
von Willebrand panel/profile (multimeric)
Type 1 vWD Quantitative deficiency: ↓ antigen/activity +/- VIII
Type 3 vWD Homozygous Type 1: absent antigen/activity/VIII
Type 2 vWD Qualitative defect:○ 2A: ↓ ↓ ↓ activity with ↓ antigen OR○ 2B: ↓ activity/antigen + ↓ platelets OR○ 2N: ↓ activity/antigen + ↓ ↓ fVIII
Hemophilia A?
vWD treatment
DDAVP (desmopressin, Stimate® spray) Effective for type 1 “Releases” vWF from platelets and endothelium 2- to 3-fold “boost” with T1/2 ~12 hours
vWD treatment
DDAVP (desmopressin, Stimate® spray) Effective for type 1 “Releases” vWF from platelets and endothelium 2- to 3-fold “boost” with T1/2 ~12 hours
vWF concentrates (I.V.) Effective for all types Plasma-derived (Humate-P ®, Wilate ®, etc.) New recombinant (VONVENDI)
“Non-specific” tx for bleeding (e.g., vWD)
Avoid “blood thinners” (ASA, NSAIDs) For menorrhagia, hormonal therapies
are often most effective even in the setting of a coag disorder
Anti-fibrinolytics: Oral or topical Tranexamic acid (Lysteda™) Aminocaproic acid (Amicar™)
Hemophilia:
Congenital deficiency of clotting factor
VIII or IX.
Factors VIII and IX
Factor IX is vitamin K-dependent serine protease Factor VIII is cofactor for IXa; circulates bound
(noncovalently) to vWF IXa + VIIIa = “factor Xase” Both involved in “intrinsic” pathway; deficiencies
cause prolonged aPTT Both genes on X chromosome; affected males,
carrier females (+/- symptomatic)
Fully manifest in males onlyAll daughters of affected males are carriersOffspring of carrier females at 50% risk:
Hemophilia if maleCarrier if female
BUT: 25-30% of cases result from newmutation
AND: Many female carriers are symptomatic:
menorrhagiabruising arthritis
BUT: Factor levels are not always predictive; consider genetic testing
*
Hemophilia A
Congenital factor VIII deficiency ~1 in 6000 live male births ~400 new US cases per year ~30% are de novo mutations
Hemophilia B
Congenital factor IX deficiency ~1 in 20,000 live male births ~100 new US cases per year 25-30% are de novo mutations
Bleeding in hemophiliacs
Post-circumcision; ↑ aPTT Mucous membranes Soft tissue Hemarthroses (“target” joints) Intracranial Menorrhagia (in carrier females)
Hemophilia work-up Prompted by family history (maternal carrier
or affected male sibling) or by bleeding symptoms
aPTT prolonged with factor < ~40%
Hemophilia work-up aPTT prolonged with factor < ~40% Is it fVIII or fIX? (or fXI or fXII….)
Specific activity
Hemophilia work-up aPTT prolonged with factor < ~40% Is it fVIII or fIX? (or fXI or fXII….)
Specific activity Genetic testing can I.D. F8 or F9
mutation/deletion in >95% of cases Knowing mutation can help predict, e.g., risk of
developing an inhibitor Once mutation is known, screening female family
members is easier/cheaper
Hemophilia severity
Normal range for VIII or IX is ~50 to ~150% Levels below 40% = hemophilia
5-39% = “mild” 1-5% = “moderate” <1% = “severe”
Correlates with bleeding tendency, especially spontaneous bleeds (but significant variability within groups)
Some female carriers have <40% fVIII activity;
often symptomatic
Managing bleeds Remember the basics:
RICE for joint / soft tissue bleeds
Managing bleeds Remember the basics:
RICE for joint / soft tissue bleeds For nosebleeds, pressure, ice
Managing bleeds Remember the basics:
RICE for joint / soft tissue bleeds For nosebleeds, pressure, ice, Afrin
Managing bleeds Remember the basics:
RICE for joint / soft tissue bleeds For nosebleeds, pressure, ice, Afrin Bacon fat (source of thrombin) For mouth bleeds: tea bags Various OTC proprietary clotting agents
Managing bleeds Remember the basics:
RICE for joint / soft tissue bleeds For nosebleeds, pressure, ice, Afrin Bacon fat (source of thrombin) For mouth bleeds: tea bags Various OTC proprietary clotting agents
Antifibrinolytics (Rx)
Aminocaproic acid (Amicar™) Tranexamic acid (Lysteda™)
Managing bleeds (cont.)
DDAVP (for mild-moderate hemophilia A or symptomatic carriers) “Stimate” nasal spray (Desmopressin1.5 mg/mL) Causes release of stored vWF/fVIII Typically, 2- to 3-fold increase in VIII activity○ So not useful in severe hemophilia
Tachyphylaxis Fluid retention (may cause hyponatremia)
Dosing factor 8 or 9 (I.V.)
For management of bleeding, goal is to attain level commensurate with risk: 20-40% for soft tissue bleeds 50-70% for joint bleeds >100% for life-threatening bleed/injury
Dosing factor 8 or 9 (I.V.)
For management of bleeding, goal is to attain level commensurate with risk: 20-40% for soft tissue bleeds 50-70% for joint bleeds >100% for life-threatening bleed/injury
For factor 8, activity increases ~2% for each unit/kg; T1/2 ~12 hours
For factor 9, activity increases ~1% for each unit/kg; T1/2 ~20 hours
Factors for managing hemophilia Factor VIII
Recombinant○ 1st generation
Recombinate – Baxter ○ 2nd generation
Helixate FS – CSL-Behring Kogenate FS – Bayer
○ 3rd generation Advate – Baxter Kovaltry – Bayer NovoEight – Novo-Nordisk Xyntha (B-domain-deleted) – Wyeth Eloctate (Fc fusion) – Biogen Adynovate (PEGylated) – Baxter Jivi (PEGylated) – Bayer Afstyla (single chain) – CSL Behring Nuwiq (human cell line) – OctaPharma
Plasma-derived Hemofil-M – Baxter Koate-DVI – Kedrion Monoclate – CSL Behring
No albumin in final product
No albumin in cell culture or final product
“Engineered” products
Factors for managing hemophilia Factor IX
Recombinant○ 3rd generation
Benefix – Pfizer Rixubis – Baxter Alprolix (Fc fusion) – Biogen Idelvion (PEGylated) – CSL Behring
Plasma-derived Bebulin – Baxter Mononine – CSL-Behring
Different approaches to hemophilia prophylaxis
(…in hemophilia)
• Emicizumab (“ACE 910,” Hemlibra®)– Bi-specific antibody– Binds factors IX and X– Similar to what fVIII does:
Novel approaches
• Emicizumab (“ACE 910,” Hemlibra®)– Bi-specific antibody– Binds factors IX and X– Similar to what fVIII does:– Initial trials in inhibitor patients– Significant benefit given SQ
q 2-4 wks– Recently FDA approved for non-inhibitor pts
Novel approaches
Novel approaches
• Fitusiran (Alnylam pharmaceuticals)
– siRNA against antithrombin III– Phase 3 trials coming soon– Phase 1-2 trials suggest safety and efficacy
given SQ q 4 weeks– Effective in hemophilia A or B and potentially
in other rare bleeding disorders
Gene therapy Hemophilia as a model disease for GT
Protein circulates in blood Small amounts have clinical benefit No need for complex regulation
Hemophilia B first (smaller gene) Two types of vector under development
AAV – primarily extrachromosomal Lentivirus - integrates
Trials underway
Objectives Review history and physical exam as
they relate to a potential bleeding disorder Discuss step-wise laboratory evaluation:
screening labs and follow-ups Review some common congenital and
acquired bleeding disorders, and their management
775-982-5427775-982-KIDS912-658-5223
QUESTIONS?