OVERVIEW
Radiation neuropathy is characterized by late onset, slow progression and poor outcome. Its clinical manifestations are slow, progressive aggravation of sensory-motor dysfunction, severe pain, and loss of function in the innervated area, which seriously affects the quality of survival of patients.
Causes
Direct and indirect damage to brachial plexus, lumbosacral plexus and glossopharyngeal nerve caused by radiation therapy, and other improper protection or accidental contact with discarded radioactive sources can also lead to this disease, which is mainly seen in three cases: supraclavicular and axillary radiation therapy for breast cancer, radiation therapy for all kinds of pelvic diseases, and limb radiation therapy for soft tissue sarcoma. The most common form is post-radiation brachial plexopathy, which is usually seen after radiotherapy for breast cancer.
Symptoms.
Radiation therapy is the best treatment option for breast cancer, neck tumors, testicular tumors and lymphomas, and is also the most likely to cause post-radiation brachial plexus and lumbosacral plexus injuries. Radiation therapy for nasopharyngeal tumors can cause injury to the glossopharyngeal nerve. Optic nerve and optic cross injuries can occur after radiation therapy for pituitary tumors and craniopharyngiomas.
Its main clinical manifestations are slow, progressively worsening sensory deficits, muscle atrophy, limb weakness, decreased tendon reflexes, pain, and limb edema. Most patients with radiculopathy of the brachial plexus firstly manifest hypesthesia or abnormal sensation in the fingers, and some of them may have hand and finger weakness at the same time. As the disease progresses, pain in the affected limbs may appear gradually. A few patients start with sudden onset of dyskinesia. Motor sensory abnormalities and decreased tendon reflexes can be seen on physical examination. The upper and lower brachial plexus are often involved at the same time, and early damage to the upper brachial plexus is often predominant. Very few patients involve the phrenic nerve, causing diaphragmatic paralysis.
Examination
1. Blood tests include routine blood tests, liver function, kidney function, and routine blood sedimentation tests.
2. Immunoglobulin electrophoresis and other autoimmune-related serologic tests.
3. Neuroelectrophysiologic, CT, MRI examination and other peripheral neuropathies for differentiation. Neurophysiological examination shows loss of nerve potentials, fibrillatory potentials and muscle fiber convulsive discharges, slowing of motor and sensory nerve conduction, and motor conduction block can be detected between the cervical medulla and the supraclavicular region. Somatosensory evoked potentials are seen to be absent in N9.
Diagnosis
It mainly relies on history, clinical manifestations and neurological physical examination, auxiliary examination.
Differential diagnosis
Brachial plexus MRI can identify whether it is recurrent breast or neck tumor invading the nerves or combined post-radiation neuropathy. MRI of the skull base can identify the recurrence of nasopharyngeal tumor and radioglossopharyngeal nerve injury.
Complications
Systemic damage, especially digestive dysfunction and hematologic lesions are common.
Treatment
Radiation neuropathy becomes irreversible damage with poor therapeutic effect, and is mainly treated symptomatically. The main therapeutic methods to reduce radiation peripheral nerve injury and post-treatment include: controlling diabetes and hypertension; avoiding the use of pro-fibrotic drugs and statins; avoiding local trauma within the radiation area; actively applying glucocorticoids to control the acute inflammatory response in order to reduce the scope and density of inflammation-related fibrosis; avoiding unnecessary irradiation as much as possible; optimizing the radiation treatment modality.
Since the purpose of the release surgery is to stop the progression of the disease, most scholars advocate that the earlier the surgery, the better, and that the best time for surgery is when the sensory abnormality has just appeared but there is no pain yet. Some mild cases may resolve spontaneously within 6 to 9 months.
Prevention
1. Prevention and treatment of primary diseases and strict control of radiotherapy indications.
2. Strengthen radiation protection and management of discarded radioactive sources.