Classification Factor Activity, % Cause of Hemorrhage
Mild
>5-40
Major trauma or surgery
Moderate
1-5
Mild-to-moderate trauma
Severe
< 1
Spontaneous, hemarthrosis
Direct the examination to identify signs related to spontaneous or, with minimal
challenge, bleeding in the joints, muscles, and other soft tissues. Observe the
patient's stature. Examine the weight-bearing joints, especially the knees and
ankles, and, in general, the large joints for deformities or ankylosis. Look for
jaundice, other signs of liver failure (eg, cirrhosis from viral infection), and signs
of opportunistic infections in patients who are HIV seroconverted.
Diagnostic Considerations
Problems to be considered include vitamin K and other factor deficiencies. Other
congenital bleeding disorders must be excluded. These may include the following:
von Willebrand disease (autosomal dominant transmission)
Platelet disorders (eg, Glanzmann thrombasthenia)
Deficiency of other coagulation factors (ie, FV, FVII, FX, FXI, or fibrinogen)
Differentiating between severe hemophilia A and hemophilia B is almost clinically
impossible, but specific laboratory factor assays can help with the distinction.
Conditions that can increase FVIII levels (eg, age, ABO blood type, stress,
exercise) can obscure the diagnosis of hemophilia A.
Please see the following for more information:
Acquired Hemophilia
Hemophilia B
Hemophilia C
Differential Diagnoses
Acquired Hemophilia
Ehlers-Danlos Syndrome
Factor XI Deficiency
Glanzmann Thrombasthenia
Hemophilia C
Hemophilia, Type B
Physical Child Abuse
Platelet Disorders
von Willebrand Disease
Approach Considerations
Laboratory studies for suspected hemophilia include a complete blood cell count,
coagulation studies, and a factor VIII (FVIII) assay. Never delay indicated
coagulation correction pending diagnostic testing.
On the hemoglobin/hematocrit, expect normal or low values. Expect a normal
platelet count. On coagulation studies, the bleeding time and prothrombin time
(which assesses the extrinsic coagulation pathway) are normal.
Usually, the activated partial thromboplastin time (aPTT) is prolonged; however, a
normal aPTT does not exclude mild or even moderate hemophilia because of the
relative insensitivity of the test. The aPTT is significantly prolonged in severe
hemophilia.
For FVIII assays, levels are compared with a normal pooled-plasma standard,
which is designated as having 100% activity or the equivalent of FVIII U/mL.
Normal values are 50-150%. Values in hemophilia are as follows:
Mild: >5%
Moderate: 1-5%
Severe: < 1%
Spontaneous bleeding complications are severe in individuals with undetectable
activity (< 0.01 U/mL), moderate in individuals with activity (2-5% normal), and
mild in individuals with factor levels greater than 5%.
Aging, pregnancy, oral contraceptive use, and estrogen replacement therapy are
associated with increased levels. Because FVIII is a large molecule that does not
cross the placenta, the diagnosis can be made at birth with quantitative assay of
cord blood.
Differentiation of hemophilia A from von Willebrand disease is possible by
observing normal or elevated levels of von Willebrand factor antigen and ristocetin
cofactor activity. Bleeding time is prolonged in patients with von Willebrand
disease but normal in patients with hemophilia.
In patients with an established diagnosis of hemophilia, periodic laboratory
evaluations include screening for the presence of FVIII inhibitor and screening for
transfusion-related or transmissible diseases such as hepatitis and HIV infection.
Screening for infection may be less important in patients who receive only
recombinant FVIII concentrate.
Imaging studies for acute bleeds
Early and aggressive imaging is indicated, even with low suspicion for
hemorrhage, after coagulation therapy is initiated. Imaging choices are guided by
clinical suspicion and anatomic location of involvement.
Head CT scans without contrast are used to assess for spontaneous or traumatic
intracranial hemorrhage. Perform magnetic resonance imaging on the head and
spinal column for further assessment of spontaneous or traumatic hemorrhage.
MRI is also useful in the evaluation of the cartilage, synovium, and joint space.
Ultrasonography is useful in the evaluation of joints affected by acute or chronic
effusions. This technique is not helpful for evaluating the bone or cartilage. Special
studies such as angiography and nucleotide bleeding scan may be clinically
indicated.
Testing for Inhibitors
Laboratory confirmation of a FVIII inhibitor is clinically important when bleeding
is not controlled after adequate amounts of factor concentrate are infused during a
bleeding episode. For the assay, the aPTT measurement is repeated after incubating
the patient's plasma with normal plasma at 37°C for 1-2 hours. If the prolonged
aPTT is not corrected, the inhibitor concentration is titrated using the Bethesda
method.
By convention, more than 0.6 Bethesda units (BU) is considered a positive result
for an inhibitor. Less than 5 BU is considered a low titer of inhibitor, and more
than 10 BU is a high titer. The distinction is clinically significant, as patients with
low-titer inhibitors may respond to higher doses of FVIII concentrate.
Radiography
Radiography for joint assessment is of limited value in acute hemarthrosis.
Evidence of chronic degenerative joint disease may be visible on radiographs in
patients who are untreated or inadequately treated or in those with recurrent joint
hemorrhages. In these patients, radiographs may show synovial hypertrophy,
hemosiderin deposition, fibrosis, and damage to cartilage that progresses with
subchondral bone cyst formation.
Hemophilic arthropathy evolves through 5 stages, starting as an intra-articular and
periarticular edema due to acute hemorrhage and progressing to advanced erosion
of the cartilage with loss of the joint space, joint fusion, and fibrosis of the joint
capsules.
For discussion of the 5-stage Arnold-Hilgartner classification of
hemophilic arthropathy.
Approach Considerations
The treatment of hemophilia may involve management of hemostasis, management
of bleeding episodes, use of factor replacement products and medications,
treatment of patients with factor inhibitors, and treatment and rehabilitation of
patients with hemophilia synovitis.
Treatment of patients with hemophilia ideally should be provided through a
comprehensive hemophilia care center. These centers follow a multidisciplinary
approach, with specialists in hematology, orthopedics, dentistry, and surgery;
nurses; physiotherapists; social workers; and related allied health professionals.
Patients treated at comprehensive care clinics have been shown to have better
access to care, less morbidity, and better overall outcome.
Ambulatory replacement therapy for bleeding episodes is essential for preventing
chronic arthropathy and deformities. Home treatment and infusion by the family or
patient is possible in most cases. Prompt and appropriate treatment of hemorrhage
is important to prevent long-term complications and disability.
Dose calculations are directed toward achieving a factor VIII (FVIII) activity level
of 30-40% for most mild hemorrhages, of at least 50% for severe bleeds (eg, from
trauma) or prophylaxis of major dental surgery or major surgery, and 80-100% in
life-threatening hemorrhage. Hospitalization is reserved for severe or life-
threatening bleeds, such as large-soft tissue bleeds; retroperitoneal hemorrhage;
and hemorrhage related to head injury, surgery, or dental work.
Patients are treated with prophylaxis or intermittent, on-demand therapy for
bleeding events. Prophylaxis has been shown in many studies to prevent or at least
reduce the progression of damage to target sites, such as joints.
According to a
review of 6 randomized controlled trials, preventative therapy started early in
childhood, as compared to on-demand treatment, is able to reduce total bleeds and
bleeding into joints resulting in a decrease in overall joint deterioration and an
improvement in patient quality of life.
In most developed countries with access to recombinant product, prophylaxis is
primary (ie, therapy is started in patients as young as 1 y and continues into
adolescence). A cost-benefit analysis indicates that this approach reduces overall
factor use and significantly reduces morbidity.
In situations in which this is not
feasible, secondary prophylaxis (ie, therapy after a target joint has developed, to
prevent worsening of the joint) is instituted for a defined period.
Dosing is designed to maintain trough levels greater than 2%. This usually requires
the administration of FVIII 3 times per week. Individualized therapy (ie, tailored
prophylaxis) has been also used with success; the best approach has yet to be
determined.
Hospitalizing patients with internal bleeding, with uncontrollable bleeding, and
before elective surgery or other invasive procedures is advised.
Prehospital Care
Rapid transport to definitive care is the mainstay of prehospital care. Prehospital
care providers should do the following:
Apply aggressive hemostatic techniques
Assist patients capable of self-administered factor therapy
Gather focused historical data if the patient is unable to communicate
Emergency Department Care
Before a patient with hemophilia is treated, the following information should be
obtained:
The type and severity of factor deficiency
The nature of the hemorrhage or the planned procedure
The patient's previous treatments with blood products
Whether inhibitors are present and if so, their probable titer
Any previous history of desmopressin acetate (DDAVP) use (mild hemophilia A
only), with the degree of response and clinical outcome.
Use aggressive hemostatic techniques. Correct coagulopathy immediately. Include
a diagnostic workup for hemorrhage, but never delay indicated coagulation
correction pending diagnostic testing. If possible, draw blood for the coagulation
studies (see Workup), including 2 blue-top tubes to be spun and frozen for factor
and inhibitor assays.
If admission is indicated, disposition (ICU vs floor) should be based on severity of
hemorrhage and potential for morbidity and death. Choose attending service based
on etiology of hemorrhage. Hematology/ blood bank/pathology consultation is
mandatory.
Patients whose condition and bleeding are stabilized should be transferred to a
specialized center for further treatment and monitoring because a multidisciplinary
approach by specialists experienced in hemophilia may be required.
Further outpatient care for patients with minor hemorrhage (not life threatening)
consists of continued hemostatic measures (eg, brief joint immobilization,
bandage). Hematologist or primary care physician follow-up care is indicated. The
patient should continue factor replacement and monitoring.
If a patient has HIV seroconversion, arrange appropriate outpatient care at a
specialty infectious disease clinic, monitor the patient's CD4 count, observe the
patient for adverse effects of anti-HIV treatment, and monitor for and treat possible
opportunistic infections.
Factor VIII Concentrates
Various FVIII concentrates are now available to treat hemophilia A. Fresh frozen
plasma and cryoprecipitate are no longer used in hemophilia because of the lack of
safe viral elimination and concerns regarding volume overload.
Various purification techniques are used in plasma-based FVIII concentrates to
reduce or eliminate the risk of viral transmission, including heat treatment,
cryoprecipitation, and chemical precipitation. These techniques inactivate viruses
such as hepatitis B virus, hepatitis C virus, and HIV. However, the transmission of
nonenveloped viruses (eg, parvovirus and hepatitis A virus) and poorly
characterized agents (eg, prions) is still a potential problem.
Many recombinant FVIII concentrates are now available. The advantage of such
products is the elimination of viral contamination. Third-generation products
without any exposure to animal proteins are now available to further decrease this
risk. The effectiveness of these products appears comparable to that of plasma-
derived concentrates. Concerns regarding higher incidences of the presence of
inhibitor appear to be unwarranted.
With wider availability of improved products (ie, better stability, purity), use of
continuous infusion of factors has incrementally increased. Continuous
administration of antihemophilic factors prevents the peaks and valleys in factor
concentrations that occur with intermittent infusion; this benefit is particularly
important when treatment is required for prolonged periods.
Besides improved hemostasis, continuous infusions decreases the amount of factor
used, which can result in significant savings. The indications for this approach
include intracranial hemorrhage, vascular compromise, iliopsoas bleeding, and
preparation for surgery.
In most minor-to-moderate bleeding episodes, intermittent boluses are adequate.
Intermittent boluses can also be used prophylactically, especially in the treatment
of recurrent bleeding in target joints.
Doses of FVIII concentrate are calculated according to the severity and location of
bleeding. Guidelines for dosing are provided in Table 2 below. As a rule, FVIII 1
U/kg increases FVIII plasma levels by 2%. The reaction half-time is 8-12 hours.
Target levels by hemorrhage severity are as follows:
Mild hemorrhages (ie, early hemarthrosis, epistaxis, gingival bleeding): Maintain
an FVIII level of 30%
Major hemorrhages (ie, hemarthrosis or muscle bleeds with pain and swelling,
prophylaxis after head trauma with negative findings on examination): Maintain an
FVIII level of 50%
Life-threatening bleeding episodes (ie, major trauma or surgery, advanced or
recurrent hemarthrosis): Maintain an FVIII level of 80-90%. Plasma levels are
maintained above 40-50% for a minimum of 7-10 days.
Table 2. General Guidelines for Factor Replacement for the Treatment of Bleeding in
Hemophilia
Indication or Site of Bleeding
Factor level
Desired, %
FVIII
Dose,
IU/kg
*
Comment
Severe epistaxis; mouth, lip,
tongue, or dental work
20-50
10-25
Consider aminocaproic acid
(Amicar), 1-2 d
Joint (hip or groin)
40
20
Repeat transfusion in 24-48 h
Soft tissue or muscle
20-40
10-20
No therapy if site small and not
enlarging (transfuse if enlarging)
Muscle (calf and forearm)
30-40
15-20
None
Muscle deep (thigh, hip, iliopsoas) 40-60
20-30
Transfuse, repeat at 24 h, then as
needed
Neck or throat
50-80
25-40
None
Hematuria
40
20
Transfuse to 40% then rest and
hydration
Laceration
40
20
Transfuse until wound healed
GI or retroperitoneal bleeding
60-80
30-40
None
Head trauma (no evidence of CNS
bleeding)
50
25
None
Head trauma (probable or definite
CNS bleeding, eg, headache,
vomiting, neurologic signs)
100
50
Maintain peak and trough factor
levels at 100% and 50% for 14 d if
CNS bleeding documented
†
Trauma with bleeding, surgery
†
80-100
50
10-14 d
Variations in responses related to patient or product parameters make
determinations of factor levels important. These determinations are performed
immediately after infusions and thereafter to ensure an adequate response and
maintenance levels. Obtain factor assay levels daily before each infusion to
establish a stable pattern of replacement regarding the dose and frequency of
administration.
Desmopressin
Desmopressin vasopressin analog, or 1-deamino-8-D-arginine vasopressin
(DDAVP), is considered the treatment of choice for mild and moderate hemophilia
A. It is not effective in the treatment of severe hemophilia.
DDAVP stimulates a transient increase in plasma FVIII levels and results in
sufficient hemostasis to stop a bleeding episode or to prepare patients for dental
and minor surgical procedures. Other possible mechanisms of action are noted.
A test dose should be performed. It can be intravenously administered at a dose of
0.3 mcg/kg of body weight in the inpatient setting. Its peak effect is observed in
30-60 minutes.
A concentrated DDAVP intranasal spray is available for outpatient use. Its
effectiveness is similar to that of the intravenous preparation, although its peak
effect is observed later, at 60-90 minutes after administration.
Patients should be advised to limit water intake during treatment and to avoid 3
consecutive daily doses to a prevent hyponatremia. Several doses of DDAVP may
need to be infused every 12-24 hours before tachyphylaxis is observed.
The major adverse effects of DDAVP include asymptomatic facial flushing and
hyponatremia.
Management of Bleeding Episodes by Site
Musculoskeletal bleeding
The most common sites of clinically significant bleeding are joint spaces. Weight-
bearing joints in the lower extremities are often target areas for recurrent bleeding.
Joint hemorrhage is associated with pain and limitation in the range of motion,
which is followed by progressive swelling in the involved joint.
Immobilization of the affected limb and the application of ice packs are helpful in
diminishing swelling and pain. Early infusion upon the recognition of pain may
often eliminate the need for a second infusion by preventing the inflammatory
reaction in the joint. Prompt and adequate replacement therapy is the key to
preventing long-term complications. Cases in which treatment begins late or causes
no response may require repeated infusions for 2-3 days.
Do not aspirate hemarthroses unless they are severe and involve significant pain
and synovial tension. Some hemarthroses may pose particular problems because
they interfere with the blood supply.
Hip joint hemorrhages can be complicated by aseptic necrosis of the femoral head.
Administer adequate replacement therapy for at least 3 days.
Deep intramuscular hematomas are difficult to detect and may result in serious
muscular contractions. Appropriate and timely replacement therapy is important to
prevent such disabilities.
Iliopsoas muscle bleeding may be difficult to differentiate from hemarthrosis of the
hip joint. Physical examination usually reveals normal hip rotation but significant
limitation of extension.
Ultrasonography in the involved region may reveal a hematoma in the iliopsoas
muscle. This condition requires adequate replacement therapy for 10-14 days and a
physical therapy regimen that strengthens the supporting musculature.
Closed-compartment hemorrhages pose a significant risk of damaging the
neurovascular bundle. These occur in the upper arm, forearm, wrist, and palm of
the hand. They cause swelling, pain, tingling, numbness, and loss of distal arterial
pulses. Infusion must be aimed at maintaining a normal level of FVIII.
Other interventions include elevation of the affected part to enhance venous return
and, rarely, surgical decompression.
Oral bleeding
Oral bleeding from the frenulum and bleeding after tooth extractions are not
uncommon. Bleeding is aggravated by the increased fibrinolytic activity of the
saliva.
Combine adequate replacement therapy with an antifibrinolytic agent (epsilon-
aminocaproic acid [EACA]) to neutralize the fibrinolytic activity in the oral cavity.
Topical agents such as fibrin sealant, bovine thrombin, and human recombinant
thrombin can also be used.
Hematoma in the pharynx or epiglottic regions frequently results in partial or
complete airway obstruction; therefore, it should be treated with aggressive
infusion therapy. Such bleeding may be precipitated by local infection or surgery.
Administer prophylactic factor infusion therapy before an oral surgical procedure
to prevent the need for further treatment.
Dostları ilə paylaş: |