Haemophilia
Description
- A - factor VIII deficiency (~80-85%)
- B - factor IX deficiency, "Christmas disease" (~15-20%)
- Both X-linked recessive - the two commonest congenital coagulation factor deficiencies
- Clinically indistinguishable - only the factor assay separates them
- C - factor XI deficiency: autosomal, Ashkenazi Jewish, mild
- Bleeding poorly correlates with factor level; usually stops with pressure; mucosal/post-surgical rather than joint bleeding
Severity by factor activity
| Level | Bleeding | |
|---|---|---|
| Severe | <1% | Spontaneous joint and muscle bleeds |
| Moderate | 1-5% | Bleeding after minor trauma; occasional spontaneous |
| Mild | 5-40% | Only after surgery or major trauma; delayed post-operative bleeding |
- The pattern is delayed re-bleeding, not immediate - the platelet plug forms normally
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