Tuesday, June 17, 2008

manage carotid body tumor

fromClinical Neurology News:

Resection Remains Best Treatment for Carotid Body Tumors
Article Outline
Skip Angiography, and Other Surgical Pearls
CHICAGO — Surgical resection remains the treatment of choice for carotid body tumors, as presented in a review of 88 patients at one center.
Radiation therapy and chemotherapy are unsuitable alternatives because these rare tumors are too slow growing, and radiation exposes the carotid arteries to radiation arteritis, accelerated atherosclerosis, and even necrosis, Dr. Thomas A. Whitehill said at a vascular surgery symposium sponsored by Northwestern University.
Preoperative percutaneous tumor embolization has been tried with mixed results, but can be an important adjunct when treating select patients with large tumors (greater than 6 cm). There has been one report of a successful use of covered stents to facilitate resection (J. Vasc. Surg. 2003;38:389–91).
The malignancy rate for carotid body tumors is hard to define because there are no reliable histologic markers, but is thought to range from 2% to 5%, he said. Even if benign on histologic exam, all tumors, once discovered, should be surgically removed because they will ultimately wrap around the internal and external carotid arteries, erode into the base of the skull, and entrap neighboring cranial nerves. Increasing size also can interfere with speech, swallowing, and respiration, said Dr. Whitehill of the vascular surgery division of University of Colorado Health Science Center, Denver.
From 1993 to 2007, Dr. Whitehill and colleagues surgically resected 88 Shamblin classification II or III carotid body tumors, with an average diameter of 10.4 cm (range 5–16 cm). The patients ranged in age from 30 to 40 years.
Surgery time ranged from 4 to 14 hours, with an average blood loss of 375 mL (range 50–1800 mL). An internal carotid artery (ICA) resection bypass was performed in three patients, and ICA ligation in none.
Complications were relatively low, Dr. Whitehill said, and included cranial nerve IX neuropraxia (4%) or injury (1%), cranial nerve XII neuropraxia (30%), and superior laryngeal nerve injury (10%). There were no strokes or deaths.
Surgical advances and the widespread use of CT and MRI have decreased the overall risk of postoperative stroke over the past 25 years from about 30% to less than 2%, although the incidence of cranial nerve injury remains high at 15%–35%, he said.
Skip Angiography, and Other Surgical Pearls
Dr. Thomas A. Whitehill offered tips for carotid body tumors.
▸ Skip the angiography suite when making the diagnosis, and focus on CT imaging, preferably axial cuts rather than reconstructions. MRI may be slightly better at evaluating distant, metastatic deposits at the skull base.
▸ A nerve stimulator may be useful for preoperative identification of the cranial nerve.
▸ Do preoperative vocal cord and speech evaluations.
▸ Consider serial embolization in patients who are too old or have too many comorbidities to tolerate surgery.
▸ On a side CT view, draw a line between the mastoid tip and the angle of the mandible to get an idea of how high an exposure is needed and to help with preoperative planning.
▸ Utilize nasotracheal intubation in most patients, as it provides greater mobility with the mandible when resecting large tumors.
▸ In high access cases, mobilize the parotid gland anteriorly, up to the level of the facial nerve.
▸ Gain vascular control, if possible, and mobilize the tumor circumferentially to assess the extent of disease.
▸ Resect the tumor from proximal to distal.
▸ Fine mosquito clamp dissection and 3–0 or 4–0 silk ligation can give the best hemostasis.
▸ Send all suspicious lymph nodes for frozen permanent sections.
▸ Rather than using maxillomandibular arch bar fixation to obtain mandibular subluxation, consider interdental cross-wiring between the maxilla and mandible using bicuspids in dentate patients and Steinmann pins in patients with no teeth.
▸ For very distal tumors, cutting the digastric muscle will get you within 2 cm of the skull base.
▸ For large tumors, ligating the external carotid artery near its takeoff provides greater mobility.
▸ Avoid ligation of the internal carotid artery.
▸ If a tumor is 6 cm or more in diameter, consider preoperative embolization.
▸ Pushing the tumor completely through the bifurcation or pulling it anteriorly through the bifurcation may improve exposure angles and ease dissection.
▸ Take your time after the tumor is cleared of the two carotid arteries. The posterior surface and medial side of the tumor still must be separated from the deeper parapharyngeal tissues. Haste at this stage can result in the superior or inferior laryngeal nerves being transected or medial pharyngeal injuries, causing substantial swelling and neck pain in patients.

Tuesday, June 03, 2008

Typing PSP

"The postmortem room has become the temple of truth" (Donald Calne, re PSP) (Neurology 2008)Current nomenclature"Richardson disease" corresponds with initial descriptions. There is a gradual onset of postural instability and falls within the first two years, with vertical supranuclear gaze palsy, a frontal dysexecutive syndrome, rigidity and bradykinesia that is not responsive to leveodopa, and a life expectancy of six years.A second milder group at pm (post-mortem) have PSP tau pathology that is more restricted and less severe are called PSP-P (PSP-parkinsonism). They have assymmetric bradykinesia of the limbs, an initial response to levodopa, tremor and limb dystonia without early falls, eye movement problems, or cognitive dysfunction. Most patients with "atypical PSP" are in this category. The third rarer category is pure akinesia with gait freezing (PAGF). There is gradual onset of unsteady or slow gait and hypophonia progressing to gair freezing and start hesitation, without limb rigidity or tremor. There is no response to levodopa and there is no dementia or opthalmoplegia in the first five years. In types 2 and 3 the median duration of the disease is around ten years. Other patients with similar tau-PSP pathology present with corticobasal ganglionic degeneration, progressive nonfluent aphasia, or apraxia of speech. References up to date:Williams DR, de Silva R, Pavour DC et al. Characteristics of two distinct clinical phenotypes in pathologically proven progressive supranuclear palsy: Richardson' syndrome and PSP - parkinsonism. Brain 2005; 128:1247-1258.Williams DR, Holton JL, Strand C. et al. Pathological tau burden and distribution distinguishes progressive supranuclear palsy-parkinsonism from Richardson's syndrome. Brain 2007; 130: 1566-1576.Mizusawa H, Mochizuki A , Ohkoshi N, et al. Progressive supranuclear palsy presenting with pure akinesia. Adv Neurol 1993; 60: 618-621.Josephs KA, Duffy JR, Strand EA et al. Clinicopathological and imaging correlates of progressive aphasia and apraxia of speech. Brain 2006; 129: April 13.Tsuboi Y, Josephs KA, Boeve BF et al. Increased tau burden in the cortices of progressive supranuclear palsy presenting with corticobasal syndrome. Mov Disord 2005; 20: 982-988.

Sunday, June 01, 2008

Limbic encephalitis : An expanding concept: teratomas and "things"

Graus F, Saiz A. Neurology 2008; 70: 500-501 (editorial) . Also see http://dementianotes.blogspot.com/2008/06/vgkc-autoantibodies-mimicking-cjd.html re VGKC antibodies in particular.

A syndrome of encephalitis in 12 women with teratomas of the ovary follows a predictable clinical pattern. A prodromal fever, is followed in a few days by a prominent psychiatric syndrome or short term memory loss, then, seizures, then progressive unresponsiveness (catatonia like stage) , dyskinesias, autonomic instability, and central hypoventilation. ICU support for weeks or longer may be necessary, and patients recover generally after tumor removal or immunotherapy (pheresis or IVIG). MRI is usually negative (9/12). All patients had CSF and serum antibodies against components of NMDA receptor (NMDAR) especially 2 subunits NR1/NR2). These particular patients express NR1, which is ubiquitously expressed in brain, but in these patients distributes with NR2 (basal forebrain) and disappears with treatment. This contrasts with NR2B which is seen in Rasmussen's excephalitis, refractory epilepsy, and stroke. In neuropsych lupus, this epitype leads to apoptosis.

Iizuka et al. now describe this epitype in Japanese juvenile non-herpetic encephalitis (with NMDAR). They emphasize the abnormal movements, especially orolingual after initial psychiatric syndrome and catatonic like state. These patients can reverse even after long periods of ventilator dependence.

Update  pearls for NMDAR  from Neurology 2014; 82: 550-551 (editorial)

1.  Tests for:  CSF with HEK cells expressing GluN1/2 subunuts of the NMDAR cell based assay. or serum.  with serum there is a 15 % false negative/positive result

2.  Adult men more often presented with seizures (18 %) whereas women more oftenpresent with behavior/psych symptoms  

3.  Among women, 41 % had tumors, all ovarian teratomas.  Among men only one had a tumor likely unrelated schwannoma.