Hemophilia is an inherited X –linked recessive bleeding disorder, due to deficiencies of clotting factors VIII or IX. Musculoskeletal dysfunction occurs commonly in patients with hemophilia. Hemarthroses and hematomas are the usual occurrences in these patients, especially in severely affected patients, in whom bleeding can occur spontaneously or following minimal stresses such as an intramuscular injection. Bleeding into muscle is said to account for between 10-30% of all musculoskeletal episodes.
These patients usually present with pain, bruising, swelling and reduced range of movements with stretching of the affected muscle producing severe pain. The muscles commonly involved are iliopsoas, gastrocnemius, forearm flexor muscles and less commonly gluteal. Muscle bleeds in hematomas can result in compressive neuropathy [like iliopsoas bleeds can cause femoral nerve palsy, gluteal bleeds could cause sciatic nerve palsy] and permanent disability, if not treated promptly.
Ultrasound serves as an effective and inexpensive modality to diagnose these bleeds and hematomas, especially in regions not easily accessible clinically. Ultrasound demonstrates whether the hematoma is solid or liquid and can also aid in detecting secondary complications such as an infected hematoma. It can provide guidance for aspiration and drainage. CT and MRI scanning are more definitive, particularly MRI, in determing if a collection is comprised of hemorrhage. These modalities are used when ultrasound results are inconclusive or to delineate the complete extent of a bleed and exclude any neurologic compression or secondary obstruction (for example, genitourinary obstruction in the case of a retroperitoneal bleed).
If the muscle bleed occurs close to a joint, ultrasound can detect changes of hemophilic arthropathy that may include joint effusions, soft tissue swelling, and maybe even osseous erosion. Ultrasound can also detect hemophilic pseudotumors, which are large chronic encapsulated fluid collections that can destroy bone and may be associated with great morbidity.
Thus, ultrasound plays an important role in the early detection of these bleeds and hematomas and it is advisable to follow them up, until their complete resolution. This can save the patient significant morbidity.