Workup for Frequent Bruising in an 18-Month-Old
An 18-month-old with frequent bruising requires immediate assessment for both child abuse and bleeding disorders, with the workup intensity determined by bruise location and pattern. 1
Critical Initial Assessment
History Elements That Matter
Obtain these specific details:
- Trauma history: Does the caregiver's explanation match the bruising pattern and severity?
- Bleeding symptoms: Any history of bleeding after circumcision, umbilical stump bleeding, excessive bleeding after dental procedures, or epistaxis? 1
- Family history: Specifically ask about named bleeding disorders (hemophilia, von Willebrand disease) or ethnicity with higher bleeding disorder prevalence (Ashkenazi Jewish for Factor XI deficiency) 1
- Medications: Document all medications and alternative therapies that may increase bleeding 1
- Developmental status: Is the child mobile? Non-mobile infants with bruising are highly concerning for abuse 1
Physical Examination: Location Is Everything
The location of bruising determines your next steps 2:
High-risk locations (warrant skeletal survey and abuse evaluation):
- Cheek, eye area, ear, neck
- Upper arm, upper leg
- Hand, foot
- Torso, buttocks, genital area
- Any bruising in a non-mobile infant (< 6 months)
Lower-risk locations:
- Nonpatterned bruising over bony prominences (shins, knees, elbows) in mobile children ≥ 12 months
Patterned bruising (slap marks, object imprints, loop marks) indicates abuse and does NOT require bleeding disorder workup 1
Laboratory Evaluation Algorithm
When to Test for Bleeding Disorders
DO NOT test if 1:
- Caregiver's trauma description sufficiently explains the bruising
- Child or independent witness provides history of trauma
- Abusive patterned bruising is present
- Other clear signs of abuse exist (fractures, burns, internal trauma)
DO test if 1:
- Bruising location is high-risk (see above) without adequate trauma explanation
- Any intracranial hemorrhage concerning for abuse
- History suggests bleeding disorder (bleeding after circumcision, umbilical bleeding, etc.)
- Family history of bleeding disorder
Initial Laboratory Panel
Order these tests simultaneously 1:
- Complete blood count with platelet count (screens for ITP, thrombocytopenia)
- Peripheral blood smear
- PT (prothrombin time) and INR
- aPTT (activated partial thromboplastin time)
- Fibrinogen level
- von Willebrand factor (vWF) antigen and activity (critical—not detected by PT/aPTT)
Rationale: This panel detects conditions with prevalence > 1 per 500,000, including ITP, all factor deficiencies except Factor XIII, and von Willebrand disease 1
Interpreting Results
Normal PT and aPTT: Suggests platelet disorder or von Willebrand disease 1
- Check vWF results
- Consider hematology consultation for platelet function testing if vWF normal
Normal PT, prolonged aPTT: Intrinsic pathway defect (Factors VIII, IX, XI, XII) 1
- Perform mixing study
- Note: Mild hemophilia may have normal aPTT but still cause significant bleeding 1
Prolonged PT, normal aPTT: Extrinsic pathway defect (Factor VII) or vitamin K deficiency 1
Both prolonged: Consider DIC, liver disease, or combined deficiencies 1
Critical Pitfalls to Avoid
Von Willebrand factor is an acute phase reactant: Levels can be falsely elevated during acute illness. If suspicion remains high, repeat testing 2-3 times 1, 3
Traumatic brain injury causes transient coagulopathy: Prolonged PT/aPTT after head trauma does NOT automatically indicate a primary bleeding disorder 1
False-positive aPTT: Can occur with lupus anticoagulant or Factor XII deficiency (which doesn't cause bleeding) 1
Specimen handling matters: Coagulation tests are extremely sensitive to handling. Use experienced laboratories 1
Positive bleeding disorder test ≠ excludes abuse: Von Willebrand disease is common (1 in 100-1000). Some children with VWD will be abused. VWD rarely causes intracranial hemorrhage, so abuse must still be considered 1
Skeletal Survey Considerations
Perform skeletal survey if 2:
- Child < 12 months with bruising in high-risk locations (listed above)
- Child < 6 months with ANY bruising (rare exceptions only)
- Child 12-24 months with bruising in high-risk locations
When to Consult Specialists
Pediatric hematology consultation if 1:
- Initial testing suggests bleeding disorder
- Need for platelet function testing (PFA-100, platelet aggregation)
- Testing for rare conditions needed
- Interpretation of equivocal results
Child abuse pediatrician consultation if 1:
- Complex or concerning cases
- Discrepancy between history and findings
- Need for coordinated abuse evaluation
Special Consideration: Change in Home Setting
If bruising is concerning for abuse but testing shows possible bleeding disorder, a short-term change in home setting can provide valuable diagnostic information 1. If bruising resolves or only occurs in typical accidental locations after removal, this supports abuse as the cause. However, balance this against the trauma of removing a child from home.