1. Patients on anticoagulation or with bleeding disorders develop hematomas that compress nerves.
2. Hemorrhage into nerves occurs particularly in patients with bleeding disorders, including leukemia, hemophilia and thrombocytopenia
3. Acute stretch injuries may rupture an intraneural blood vessel and cause bleeding into a nerve. For example, the common peroneal nerve in popliteal fossa may be affected after a severe inversion injury of the ankle.
Sunday, January 6, 2008
Injection Injuries into nerves
Mechanism
1. injection injury of nerve
2. Hematoma or hemorrhage around injection site (hours later)
3. Scarring around injection site (weeks later).
1. injection injury of nerve
2. Hematoma or hemorrhage around injection site (hours later)
3. Scarring around injection site (weeks later).
Metastases to the peripheral nerves
1. These are rare and occur with lymphoma and leukemia. It may be due to spread rather than metastasis per se.
2. Compression of peripheral nerves is much more common, eg. brachial plexopathy and lumbar plexopathy.
3. Hemorrhage into the nerve is another possible mechanism.
4. Presentation can include mononeuropathy multiplex, radiculopathy, mononeuropathy, and polyneuropathy.
5. Paraneoplastic syndromes of the peripheral nerves are described.
2. Compression of peripheral nerves is much more common, eg. brachial plexopathy and lumbar plexopathy.
3. Hemorrhage into the nerve is another possible mechanism.
4. Presentation can include mononeuropathy multiplex, radiculopathy, mononeuropathy, and polyneuropathy.
5. Paraneoplastic syndromes of the peripheral nerves are described.
Malignant peripheral nerve sheath tumors (MPNST) Pearls
1. Term includes malignant schwannoma and neurogenic sarcoma
2. In NF-1 MPNST's can occur (2-16 % of patients with NF-1 develop one over their lifetime), or they can occur sporadically, or post-radiation.
3. Occassionally a previously existing benign neurofibroma can transform and become malignant.
4. They are located in the same areas as solitary and plexiform neurofibromas.
5. Pain and nerve dysfunction are greater than in benign tumors.
6. The tumors can become large before being detected.
7. Therapy involves amputation, radiation, chemotherapy.
8. The prognosis is poor with local recurrences and metastases to the lungs.
2. In NF-1 MPNST's can occur (2-16 % of patients with NF-1 develop one over their lifetime), or they can occur sporadically, or post-radiation.
3. Occassionally a previously existing benign neurofibroma can transform and become malignant.
4. They are located in the same areas as solitary and plexiform neurofibromas.
5. Pain and nerve dysfunction are greater than in benign tumors.
6. The tumors can become large before being detected.
7. Therapy involves amputation, radiation, chemotherapy.
8. The prognosis is poor with local recurrences and metastases to the lungs.
Other benign peripheral nerve tumors
1. Besides schwannomas and neurofibromas, other types are rare.
2. The fibrolipoma is a rare fatty tumor that presents as a swelling often in the median nerve, causing motor and sensory symptoms.
3. The intraneural perineuroma (aka hypertrophic neuropathy) usually involves a single peripheral nerve and causes painless but slowly progressive wasting and weakness, with mild or no sensory loss.
4. Non-nerve sheath tumors include: ganglion cysts, hypertrophic neuropathy, lipomas, hemangiomas, and desmoid tumors. Metastases to nerves can also occur (would be classified as malignant though)
2. The fibrolipoma is a rare fatty tumor that presents as a swelling often in the median nerve, causing motor and sensory symptoms.
3. The intraneural perineuroma (aka hypertrophic neuropathy) usually involves a single peripheral nerve and causes painless but slowly progressive wasting and weakness, with mild or no sensory loss.
4. Non-nerve sheath tumors include: ganglion cysts, hypertrophic neuropathy, lipomas, hemangiomas, and desmoid tumors. Metastases to nerves can also occur (would be classified as malignant though)
Peripheral neurofibromas pearls
1. Solitary NF's in otherwise healthy patients (ie. , those without NF-1) may be painless or painful subcutaneous swelling without neurologic features, unless they arise from a major nerve trunk or plexus in which case they may have motor and sensory dysfunction.
2. Multiple neurfibromas such as seen in NF-1 do not transform and are a cardinal feature of NF-1.
3. Plexiform neurofibromas arise from deeply situated nerves and can be very damaging but are highly prevalent in NF-1; in one study 35 % of patients had them in the abdomen and pelvis and four percent in chest and supraclavicular areas. Surgical results for plexiform neurofibromas are not nearly as good as solitary type.
4. In patients without NF-1, spinal tumors are usually schwannomas.
2. Multiple neurfibromas such as seen in NF-1 do not transform and are a cardinal feature of NF-1.
3. Plexiform neurofibromas arise from deeply situated nerves and can be very damaging but are highly prevalent in NF-1; in one study 35 % of patients had them in the abdomen and pelvis and four percent in chest and supraclavicular areas. Surgical results for plexiform neurofibromas are not nearly as good as solitary type.
4. In patients without NF-1, spinal tumors are usually schwannomas.
Schwannoma of the peripheral nerve (benign)
Pearls
1. The most common peripheral nerve tumors occur in any peripheral nerve but especially the spinal nerves, peroneal nerve, ulnar nerve, sympathetic nerves and vagus nerves.
2. In a peripheral nerve the presentation is that of a mass that is often painless with paresthesias and positive Tinel's sign over the nerve. The exception of greater findings occurs if the nerve is in a restricted space such as carpal or fibular tunnel.
3. Schwannomas of deep nerves such as sciatic are difficult to detect.
4. Scwannomas that arise from spinal or sympathetic nerves may extend into and compress the spinal cord.
5. Multiple schwannomas occur primarily but not exclusively in NF-2.
6. 62% neurofibromas, 38% schwannomas
In schannomas function preserved in 89% after resection
1. The most common peripheral nerve tumors occur in any peripheral nerve but especially the spinal nerves, peroneal nerve, ulnar nerve, sympathetic nerves and vagus nerves.
2. In a peripheral nerve the presentation is that of a mass that is often painless with paresthesias and positive Tinel's sign over the nerve. The exception of greater findings occurs if the nerve is in a restricted space such as carpal or fibular tunnel.
3. Schwannomas of deep nerves such as sciatic are difficult to detect.
4. Scwannomas that arise from spinal or sympathetic nerves may extend into and compress the spinal cord.
5. Multiple schwannomas occur primarily but not exclusively in NF-2.
6. 62% neurofibromas, 38% schwannomas
In schannomas function preserved in 89% after resection
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