LEUKEMIA in Objective-C

Making ECC200 in Objective-C LEUKEMIA

Peripheral neuropathy occurs in up to 55% of patients with leukemia46,50 53 Mononeuropathy or mononeuropathy multiplex can occur due to hemorrhage or leukemic in ltration into cranial or peripheral nerves, including the spinal roots As one might expect, symmetric polyneuropathy due to leukemic in ltration of the nerves is unusual but has been described Electrophysiological studies typically demonstrate features of a multifocal axonal sensorimotor neuropathy Nerve biopsies can demonstrate leukemic in ltration of the nerve, axonal degeneration, and segmental demyelination Vasculitis has also been suggested as a cause of peripheral neuropathy in hairy cell leukemia35,36

This rare malignancy is characterized by intravascular proliferation of large, atypical, lymphoid B cells44,45,54 56 The CNS and skin are the most common sites of involve-

The brachial plexus can be involved due to regional spread of a local tumor (ie, Pancoast tumor metastasi, or radiation-induced injury) Metastatic disease is responsible for most causes of brachial plexopathy in cancer patients, 78% in one large series62 Lung and breast cancers are the most common culprits The tumors most often spread via the lymphatics to the lateral group of axillary lymph nodes, where divisions of the lower trunk of the brachial plexus are located Lung cancers in the apices of the lungs may also invade the paravertebral space, the extraspinal C8 T3 mixed spinal nerves, the sympathetic chain, and the stellate ganglia Most patients complain of pain in the shoulder area radiating down the arm into the ngers, in particular the fourth and fth digits Sensory loss and weakness usually conform to the distribution of the lower trunk and a Horner s syndrome due to involvement of the sympathetic chain or stellate ganglia is often seen The arm may appear swollen because of associated lymphedema Signs and symptoms attributable to involvement of the upper and middle trunk of the brachial plexus are much less common and, when present, suggest epidural extension of the tumor Radiation plexitis is usually associated with doses greater than 6000 rads and can present 3 months to 26 years (mean 6 years) following radiation treatment to the region62 Paresthesias and lymphedema of the affected arm are common Pain occurs in only 15% of patients and is usually not as severe, which may help distinguish radiation-induced plexitis from tumor invasion Further, the upper plexus is involved in 77% and diffuse plexus involvement occurs in 23% of patients with radiation plexitis Some studies note that the entire plexus is more commonly involved than just the upper trunk MRI or CT scan may demonstrate malignant invasion of the plexus and perhaps extension to the epidural space Motor and sensory NCS reveal reduced amplitudes of involved nerves Myokymic discharges may be appreciated on EMG and when seen are highly suggestive of radiation-induced damage However, the absence of myokymia does not exclude radiation plexopathy When noninvasive testing cannot differentiate between metastatic and radiation diseases, surgical exploration and biopsy may be required for de nitive diagnosis Neoplastic invasion of the brachial plexus can be treated with radiation therapy Pain may be improved but the prognosis for return of motor function is poor Treatment of the pain with transcutaneous stimulation, sympathetic blockage, and dorsal rhizotomies has been disappointing

distant neoplasms (27%)63 Colorectal, cervical, lymphoma, sarcoma, and breast cancers are the most common associated cancers The lumbar plexus is involved in 31%, lumbosacral trunk in 51%, and entire lumbosacral plexus in 18% of patients with malignant invasion of the plexus63,64 Patients usually complain of an insidious onset of pain, numbness, weakness, and edema of the lower limb Approximately 25% of patients have involvement of both legs Fewer than 10% of patients develop bowel or bladder incontinence or impotence Radiation-induced lumbosacral plexopathy can develop 1 31 years (mean 5 years) after completion of treatment It usually manifests as slowly progressive weakness, and, unlike plexopathy secondary to tumor invasion, pain is present in only half the patients and typically is not as severe Typically, there is symmetrical involvement of both legs, with the distal muscles being more affected than proximal muscles Bowel and bladder incontinence may occur secondary to nerve injury or due to radiation-induced proctitis or cystitis MRI or CT of the lumbosacral spine and pelvis can demonstrate the tumor invading the lumbosacral plexus and perhaps extension into the epidural space On EMG, brillation potentials and positive sharp waves are found in the paraspinal muscles in approximately 50% of patients with radiation-induced damage, suggesting that the disorder is more appropriately termed a radiationinduced radiculoplexopathy Myokymic discharges are seen on EMG in over 50% of patients with radiationinduced lumbosacral radiculoplexopathy

NONINFILTRATIVE PERIPHERAL NEUROPATHIES ASSOCIATED WITH LYMPHOPROLIFERATIVE DISORDERS AND PLASMACYTOMAS

There is increased incidence of monoclonal gammopathies in patients with peripheral neuropathy, and neuropathies may be more frequent in patients with monoclonal gammopathies than in the general population65 Approximately 10% of patients with otherwise idiopathic peripheral neuropathies have monoclonal proteins compared to 25% of patients with peripheral neuropathies secondary to other diseases66,67 A causal relationship of demyelinating sensorimotor polyneuropathy and monoclonal IgM has been established (see 12, and discussion on DADS neuropathy)67,68 Antibodies directed against myelinassociated glycoprotein (MAG) are present in at least 50% of patients of these patients However, what relationship, if any, IgA and IgG monoclonal gammopathies have to the pathogenesis of the peripheral neuropathies is not clear Unlike IgM-associated demyelinating neuropathies, IgA and IgG immunoglobulin deposition is generally not seen on nerve sheaths in patients with