ADEM A Long term followup study of 84 pediatric patients.
Argentinian series of patients admitted to the National Hospital. Preceding illnesses occurred in 74 %: 35 % nonspecific RTI 12 % immunization , 11 % GI illness, rest nonspecific febrile,varicella, HSVE, mumps, rubells or undefined.
Age at onset was 5.3 years +/- 3.8 years with a male predominance. The presentation was usually hemiparesis (76 %) with unilateral or bilateral long tract signs (85 %0 and mental status changes (69%). None had oligoclonal banding. High dose coricosteroids use was associated with a good recovery and minimal/no disability. 90 % were monophasic, 10 % were biphasic. Disability was often based on optic nerve involvement at presentation.
Saturday, July 29, 2006
Sunday, July 23, 2006
Xyrem facts
Gamma hydroxybutyrate (GHB) was approved for oral treatment of cataplexy in patients with narcolepsy, and also in excessive daytime somnolence in the same patients. Xyrem is a rapid acting hypnotic with a short half life, increasing the duration of stage 3 and 4 sleep. It does not cause tolerance or dependence upon abrupt cessation, but abuse has been reported with craving and severe dependence. It can cause respiratory depression and death if taken with other sedatives. It can worsen sleep apnea, cause HA/N/V/dizziness, depression, nocturnal urinary incontinence, sleepwalking, and has sodium which could be a problem in patients with CHF, CRF or HTN.
Dosing: begin at 4.5 g per night: 2.25 g at bedtime when in bed 2-4 hours after a meal and repeat 2.5-4 hours later. Titrate by 1.5 grams per night eavery 2 weeks to a total of 9 grams. Xyrem is a available as an oral solution in 180 ml bottles with 500 mg/ml.
Central pharmacy prescriptions are available at the Xyrem success program, 1866 997 3688
Dosing: begin at 4.5 g per night: 2.25 g at bedtime when in bed 2-4 hours after a meal and repeat 2.5-4 hours later. Titrate by 1.5 grams per night eavery 2 weeks to a total of 9 grams. Xyrem is a available as an oral solution in 180 ml bottles with 500 mg/ml.
Central pharmacy prescriptions are available at the Xyrem success program, 1866 997 3688
Nelarabine (Arranon) for ALL causes neurotoxicity
Nelarabine is a nucleoside analog approved by the FDA for treatment of patients with refractory T-cell ALL and T-cell lymphoblastic lymphoma (T-LBL). These diseases are usually treated aggressively with combination chemotherapy (vincristine, prednisone, anthracycline, asparaginase, cyclophosphamide and cytarabine). It is demythylated to ara-G (ara-GTP) which is incorporated into dna, causing apoptosis and fragmentation. 18 % of refractory patients (5/28) has a complete response. Median survival was 20 weeks. Among children, 9/39 (23%) had a CR with median survival of 13 weeks. The most common AE's are anemia, leukopenia, thrombocytopenia, HA, somnolence and GI effects, dyspnea and peripheral neuropathy. Neurotoxicity, which can be fatal, is dose limiting; paresthesia, ataxia, ocnfusion, convulsions, and coma.
Tuesday, July 18, 2006
Obturator and combined obturator/femoral neuropathy
Obturator neuropathy-- sensory symptoms, including paresthesias and pain, possibly radiating in medial thigh. Motor involvement leads to trouble walking, due to inability to adduct the thigh, so thigh will be abducted and the gait is wide based. Examination-- weakness of thigh adductors is seen. There are no deep tendon reflex changes but the adductor tendon reflex may be absent.Etiology-- extension or lateral movements of leg that stretch it through the pelvis. Most cases are due to severe trauma: gunshot wounds, pelvic fracture or major trauma, and very rarely, childbirth.
Combined obturator/femoral neuropathy-- much more common, occurs in upper plexus lesions near psoas muscle. Causes include retroperitoneal hematoma, metastatic cancer and lymphoma. Clinically the quadriceps and the adductors are both paralyzed leading to a functional deficit of the leg.
Within pelvis the obturator nerve is medial to femoral or sciatic lesions and rare cases occur due to cement extrusion after hip surgery and after pelvic fracture.
Combined obturator/femoral neuropathy-- much more common, occurs in upper plexus lesions near psoas muscle. Causes include retroperitoneal hematoma, metastatic cancer and lymphoma. Clinically the quadriceps and the adductors are both paralyzed leading to a functional deficit of the leg.
Within pelvis the obturator nerve is medial to femoral or sciatic lesions and rare cases occur due to cement extrusion after hip surgery and after pelvic fracture.
Monday, July 17, 2006
Arsenic poisoning affects upgaze
Nakamagoe et al. Upward gaze-evoked nystagmus withorganoarsenic poisoning.
The authors report 3 patients who drank well water contaminated with very high levels of an organoarsenic compound, diphenyarsenic acid, believed to originate in emetic agents used in WWII.
Clinical presentation included articulation disorder, twitching and tremors of the hands and feet, gait disturbance and oscillopsia. The patient had upbeat nystagmus and abnormal vertical smooth pursuit movements, and impaired vertical gaze-holding. The patients also had myoclonus with long tract signs, truncal and limb ataxia. MRI showed subtle midbrain changes. Symptoms improved with removal of exposure.The authors speculate that the toxin hits the rostral interstitial nucleus of Cajal.
The authors report 3 patients who drank well water contaminated with very high levels of an organoarsenic compound, diphenyarsenic acid, believed to originate in emetic agents used in WWII.
Clinical presentation included articulation disorder, twitching and tremors of the hands and feet, gait disturbance and oscillopsia. The patient had upbeat nystagmus and abnormal vertical smooth pursuit movements, and impaired vertical gaze-holding. The patients also had myoclonus with long tract signs, truncal and limb ataxia. MRI showed subtle midbrain changes. Symptoms improved with removal of exposure.The authors speculate that the toxin hits the rostral interstitial nucleus of Cajal.
Sunday, July 16, 2006
Neurologic causes of unilateral hearing loss
Sjogren's syndrome
Susac's syndrome- subacute encephalopathy, branch retinal a occlusion and SN hearing loss.
Giant cell arteritis
Vertebral artery dissection with PICA stroke
AICA stroke
CIDP
viral/postviral infection
syphilis
lyme disease
autoimmune inner ear disease
acoustic neurinoma
Meniere's disease
perilymph fistula
HIV
ototoxic drugs
MS
trauma
siderosis
deferoxamine
other drugs
Susac's syndrome- subacute encephalopathy, branch retinal a occlusion and SN hearing loss.
Giant cell arteritis
Vertebral artery dissection with PICA stroke
AICA stroke
CIDP
viral/postviral infection
syphilis
lyme disease
autoimmune inner ear disease
acoustic neurinoma
Meniere's disease
perilymph fistula
HIV
ototoxic drugs
MS
trauma
siderosis
deferoxamine
other drugs
Facial pain and trigeminal neuralgia
Hentschel K et al. Facial Pain. The Neurologist 2005; 11:244-249
Pearls with trigeminal neuralgia
Up to ten percent of patients harbor an intracranial lesion.
More than half of patients achieve remission periods of 6 months or more.
Early treatment with anti HSV medicine and corticosteroids accelerates healing and reduces the duration of postherpetic pain.
The surgical procedures of choice for trigeminal neuralgia for the 30 % of patients who are refractory is a percutaneous radiofrequency or glycerol trigeminal rhizotomy. Complications include corneal anesthesia, anesthesia dolorosa, dysethesias, and masseter muscle weakness and are uncommon. Microvascular decompression is definitive, but is reserved because of the need for a craniotomy. Gamma knife radiosurgery is gaining popularity.
Rare causes of facial pain that need consideration include:
* NASOPAHRYNGEAL CARCINOMA
* PULMONARY CARCINOMA WITH INVASION OF THE VAGUS NERVE presenting as ache in ear
* MANDIBULAR/MAXILLARY CAVITIES ,ABSCESSES, CRACKED TOOTH SYNDROME
* CAROTIDYNIA OR CAROTID DISSECTION
* VASCULAR SUGGESTIVE OF MIGRAINE OR CLUSTER HEADACHE
* POST-TRAUMATIC OR POSTSURGICAL PAIN
* POSTERIOR FOSSA TUMORS
Pearls with trigeminal neuralgia
Up to ten percent of patients harbor an intracranial lesion.
More than half of patients achieve remission periods of 6 months or more.
Early treatment with anti HSV medicine and corticosteroids accelerates healing and reduces the duration of postherpetic pain.
The surgical procedures of choice for trigeminal neuralgia for the 30 % of patients who are refractory is a percutaneous radiofrequency or glycerol trigeminal rhizotomy. Complications include corneal anesthesia, anesthesia dolorosa, dysethesias, and masseter muscle weakness and are uncommon. Microvascular decompression is definitive, but is reserved because of the need for a craniotomy. Gamma knife radiosurgery is gaining popularity.
Rare causes of facial pain that need consideration include:
* NASOPAHRYNGEAL CARCINOMA
* PULMONARY CARCINOMA WITH INVASION OF THE VAGUS NERVE presenting as ache in ear
* MANDIBULAR/MAXILLARY CAVITIES ,ABSCESSES, CRACKED TOOTH SYNDROME
* CAROTIDYNIA OR CAROTID DISSECTION
* VASCULAR SUGGESTIVE OF MIGRAINE OR CLUSTER HEADACHE
* POST-TRAUMATIC OR POSTSURGICAL PAIN
* POSTERIOR FOSSA TUMORS
Assessing anisocoria and Horner's syndrome
The first step is to determine which pupil is abnormal. Ptosis and opthalmoparesis on the side of the larger pupil suggests a third nerve paresis on that side. Ptosis on the side with the smaller pupil suggests a Horner's syndrome. If the pupils appear equal in normal lighting, try to darken the room. Anisocoria that is more pronounced in a darker room suggests a Horner's syndrome on the side with the smaller pupil. If its more pronounced in light, it suggests a parasympathetic defect on the side with the larger pupil.
Horner's syndrome may have upper lid ptosis and sometimes reverse lower lid ptosis, giving the (false) impression of enopthalmos. Acutely there is also hyperemia or the conjunctiva. Horner's in isolation usually is a postganglionic Horner's and it usually is due to one of two conditions, cluster headache and carotid dissection, which are not confused clinically.
Horner's syndrome may have upper lid ptosis and sometimes reverse lower lid ptosis, giving the (false) impression of enopthalmos. Acutely there is also hyperemia or the conjunctiva. Horner's in isolation usually is a postganglionic Horner's and it usually is due to one of two conditions, cluster headache and carotid dissection, which are not confused clinically.
Botulism
Botulism causes descending symmetric paralysis due to impaired neurotransmission at theneuromuscular junction and cholinergic autonomic synapses. It is due to Clostridium Botulinum, a spore forming anaerobic Gram-positive bacillus in the soil, that produces A, B, and C type neurotoxins. There are four clinical types: food borne botulism, wound botulism, and intestinal colonization in infants and in adults.
Routes of infection are ingestion of contaminated canned meats or goods, spore contaminated wound infections, especially in heroin addicts who engage in subcutaenous injections called "skin popping," and GI colonization in infants. In infants, onset is 8-36 hours after eating, in wounds 4-17 days after injury, when toxin binds and irreversibly blocks all postganglionic parasympathetic synapses, and all ganglionic synapses.
The presentation is often external opthalmoplegia and ptosis, coinciding with dilated poorly reactive pupils, paralysis of accomodation, then dysphagia, dysarthria, dysphonia, and symmetric descending paralysis. Patients should be monitored for impending cardiovascular collapse.
BOTULISM IS DIFFERENTIATED FROM MG BY THE PRESENCE OF GASTROINTESTINAL SYMPTOMS, AND IMPAIRMENT OF PUPILLARY RESPONSES AND ACCOMODATION.
Diagnosis is by history and physical examination. Demonstrating toxin in GI contents, food, confirms. Equine trivalent antitoxin is suggested for adults within 24 hours, and infants may receive human immunoglobulin. Patients should be treated in the intensive care unit. Public health officials should be alerted.
Neurology review article linked describes clinical feature of type F in adults. Cases were sporadic, had incubation period of 24 hours about, and required intubation and ventilatory support for several weeks. Type F (compared to type B) were more likley to have respiratory and extremity weakness, limb weakness and absent deep tendon reflexes and require earlier intubation. Usually antitoxin was given within four days. Diagnosis was made by serum (69 %) and stool culture (80%). Misdiagnosis of cardiopulmonary and respiratory disease was common.
Routes of infection are ingestion of contaminated canned meats or goods, spore contaminated wound infections, especially in heroin addicts who engage in subcutaenous injections called "skin popping," and GI colonization in infants. In infants, onset is 8-36 hours after eating, in wounds 4-17 days after injury, when toxin binds and irreversibly blocks all postganglionic parasympathetic synapses, and all ganglionic synapses.
The presentation is often external opthalmoplegia and ptosis, coinciding with dilated poorly reactive pupils, paralysis of accomodation, then dysphagia, dysarthria, dysphonia, and symmetric descending paralysis. Patients should be monitored for impending cardiovascular collapse.
BOTULISM IS DIFFERENTIATED FROM MG BY THE PRESENCE OF GASTROINTESTINAL SYMPTOMS, AND IMPAIRMENT OF PUPILLARY RESPONSES AND ACCOMODATION.
Diagnosis is by history and physical examination. Demonstrating toxin in GI contents, food, confirms. Equine trivalent antitoxin is suggested for adults within 24 hours, and infants may receive human immunoglobulin. Patients should be treated in the intensive care unit. Public health officials should be alerted.
Neurology review article linked describes clinical feature of type F in adults. Cases were sporadic, had incubation period of 24 hours about, and required intubation and ventilatory support for several weeks. Type F (compared to type B) were more likley to have respiratory and extremity weakness, limb weakness and absent deep tendon reflexes and require earlier intubation. Usually antitoxin was given within four days. Diagnosis was made by serum (69 %) and stool culture (80%). Misdiagnosis of cardiopulmonary and respiratory disease was common.
Myasthenia gravis and LEMS
Myasthenia gravis (MG) can mimic many of the aforesaid conditions. 75 % of patients present with ptosis or diplopia.
Diagnostic pearls-- a painless pupil sparing third nerve palsy suggests the possibility of a "pseudo-third nerve palsy" which may be due to MG. Variability, alternating quality between eyes, and presence of orbicularis oculi face weakness helps to make the diagnosis. Face weakness rules out CN palsy as a cause. Saccade velocities are preserved in the setting of limited eye movements especially with smaller eye movements (larger ones may induce fatigue). Diagnostic tests include Tensilon test, sleep test, or the ice test, or serum antibody tests or neurodriagnostic tests.
EMG/NCS pearls in MG-- typically with rep stim four to five stimuli is best; with more repair occurs and effect is harder to see. You should see a smooth tapering response with a best effect on fourth or fifth stimulus, and it should be confirmed in a second nerve. Mestinon and timespan should be held for about twelve hours prior to testing. After exercise, rest elicits repair followed by post exercise exhaustion. You may need to repeat post exercise test every 30 seconds for up to four or five minutes. Picture on NCS can be indistinguishable from LEMS. Recall though that anti VGCC is found in up to 90 % of LEMS patients. Clinical PEARL-- can check for facilitation of a DTR after exercise--if DTR returns, favoos LEMS. LEMS oftenhas a flat CMAP that returns to normal after exercise. Instability is seen on needle examination of affected muscles on EMG. At the Mayo, Tensilon is rarely done except with the LR green eye exam. Usually 3-4 nerves are tested including facial, spinal accessory. Look for finger extensor weakness in MG and if found, check radial nerve at EIP and spiral groove.
Diagnostic pearls-- a painless pupil sparing third nerve palsy suggests the possibility of a "pseudo-third nerve palsy" which may be due to MG. Variability, alternating quality between eyes, and presence of orbicularis oculi face weakness helps to make the diagnosis. Face weakness rules out CN palsy as a cause. Saccade velocities are preserved in the setting of limited eye movements especially with smaller eye movements (larger ones may induce fatigue). Diagnostic tests include Tensilon test, sleep test, or the ice test, or serum antibody tests or neurodriagnostic tests.
EMG/NCS pearls in MG-- typically with rep stim four to five stimuli is best; with more repair occurs and effect is harder to see. You should see a smooth tapering response with a best effect on fourth or fifth stimulus, and it should be confirmed in a second nerve. Mestinon and timespan should be held for about twelve hours prior to testing. After exercise, rest elicits repair followed by post exercise exhaustion. You may need to repeat post exercise test every 30 seconds for up to four or five minutes. Picture on NCS can be indistinguishable from LEMS. Recall though that anti VGCC is found in up to 90 % of LEMS patients. Clinical PEARL-- can check for facilitation of a DTR after exercise--if DTR returns, favoos LEMS. LEMS oftenhas a flat CMAP that returns to normal after exercise. Instability is seen on needle examination of affected muscles on EMG. At the Mayo, Tensilon is rarely done except with the LR green eye exam. Usually 3-4 nerves are tested including facial, spinal accessory. Look for finger extensor weakness in MG and if found, check radial nerve at EIP and spiral groove.
Dorsal midbrain syndrone & shunt dysfunction
Synonyms-- pretectal syndrome, Parinaud syndrome, syndrome of the superior colliculus.
Signs and symptoms classically include vertical gaze palsy, pupillary light-near dissociation, convergence-retraction nystagmus, lid retraction, and abnormalities of convergence and accomodation. Early on, however, one may see only conjugate upgaze paresis, involving only saccades and not smooth pursuit movements. Gaze evoked upbeat nystagmus, with intact reflex upgaze. Children who complain of trouble seeing near objects should be tested for upwards saccades, as these patients may be likely ot have pineal cysts or hydrocephalus, or if they have a ventriculoperitoneal shunt, shunt dysfunction.
In evaluation for shunt dysfunction, patients may have not only abnormal velocity and accuracy of upwards saccades, but also a sixth nerve palsy, nystagmus, esotropia, convergence spasm, and amblyopia consequent to visual loss from papilledema. According to Purvin et al, IT MAY TAKE CONSIDERABLE FORTITUDE TO INSIST ON THE DIAGNOSIS IN THE FACE OF ASSURANCES FROM THE RADIOLOGIST AND THE NEUROSURGEON THAT THE SHUNT IS WORKING PROPERLY.
Signs and symptoms classically include vertical gaze palsy, pupillary light-near dissociation, convergence-retraction nystagmus, lid retraction, and abnormalities of convergence and accomodation. Early on, however, one may see only conjugate upgaze paresis, involving only saccades and not smooth pursuit movements. Gaze evoked upbeat nystagmus, with intact reflex upgaze. Children who complain of trouble seeing near objects should be tested for upwards saccades, as these patients may be likely ot have pineal cysts or hydrocephalus, or if they have a ventriculoperitoneal shunt, shunt dysfunction.
In evaluation for shunt dysfunction, patients may have not only abnormal velocity and accuracy of upwards saccades, but also a sixth nerve palsy, nystagmus, esotropia, convergence spasm, and amblyopia consequent to visual loss from papilledema. According to Purvin et al, IT MAY TAKE CONSIDERABLE FORTITUDE TO INSIST ON THE DIAGNOSIS IN THE FACE OF ASSURANCES FROM THE RADIOLOGIST AND THE NEUROSURGEON THAT THE SHUNT IS WORKING PROPERLY.
Combined cranial neuropathies
A combination of 3rd, fourth, fifth and sixth dysfunction, on one side, especially if ocmbined with oculosympatheic dysfunction, suggests a parasellar lesion., infectious, neoplastic, inflammatory or vascular.
Tolosa Hunt syndrome-- THS is a syndrome of acute, painful opthalmoplegia due to idiopathic granulomatous disease in the cavernous sinus. Signs and symptoms include periorbital or hemicranial pain with ipsilateral effects of CN III, IV, V1, VI and Horners' syndrome. THS is a diagnosis of exclusion after other causes of cavernous sinus abnormality have been excluded. (see separate citation of evaluation for painful opthalmoplegia). MRI may be normal or abnormal and show enlargement of the cavernous sinus, enhancement of the adjacent dural wall, and abnormal soft tissue surrounding and narrowing the cavernous ICA. There may be extension of the soft tissue abnormality into the orbital apex, sphenoid sinus or floor of the middle cranial fossa. The etiology is unknown. Like orbital pseudotumor syndrome, oral corticosteroids are dramatically effective, often within 48 hours. Beware, as other conditions that mimic THS are also steroid responsive.
Tolosa Hunt syndrome-- THS is a syndrome of acute, painful opthalmoplegia due to idiopathic granulomatous disease in the cavernous sinus. Signs and symptoms include periorbital or hemicranial pain with ipsilateral effects of CN III, IV, V1, VI and Horners' syndrome. THS is a diagnosis of exclusion after other causes of cavernous sinus abnormality have been excluded. (see separate citation of evaluation for painful opthalmoplegia). MRI may be normal or abnormal and show enlargement of the cavernous sinus, enhancement of the adjacent dural wall, and abnormal soft tissue surrounding and narrowing the cavernous ICA. There may be extension of the soft tissue abnormality into the orbital apex, sphenoid sinus or floor of the middle cranial fossa. The etiology is unknown. Like orbital pseudotumor syndrome, oral corticosteroids are dramatically effective, often within 48 hours. Beware, as other conditions that mimic THS are also steroid responsive.
Causes of painful opthalmoplegia
* Aneurysmal third nerve palsy
* vasculopathic cranial palsy
* cavernous sinus disease (thrombosis, aneurysm, inflammatory(Tolosa Hunt, sarcoid, Wegener's))
* Carotid dissection
* pituitary apoloplexy
* Giant cell arteritis
* Nasopharygeal carcinoma
*Basilar meningits (infectious or neoplastic)
Suggested evaluation:
*Blood tests: CBC, ESR, metabolic profile, angiotensin converting enzyme, lysozyme, VDRL, FTA-ABS, antineurtrophilic cytoplasmic antibodies (ANCA)
*Chest X ray
*MRI with contrast and thin coronal cuts
* lumbar puncture
*Nasopahryngeal examination with "blind" biopsy
* vasculopathic cranial palsy
* cavernous sinus disease (thrombosis, aneurysm, inflammatory(Tolosa Hunt, sarcoid, Wegener's))
* Carotid dissection
* pituitary apoloplexy
* Giant cell arteritis
* Nasopharygeal carcinoma
*Basilar meningits (infectious or neoplastic)
Suggested evaluation:
*Blood tests: CBC, ESR, metabolic profile, angiotensin converting enzyme, lysozyme, VDRL, FTA-ABS, antineurtrophilic cytoplasmic antibodies (ANCA)
*Chest X ray
*MRI with contrast and thin coronal cuts
* lumbar puncture
*Nasopahryngeal examination with "blind" biopsy
Sixth nerve palsy
Sixth nerve palsies may be complete, with a complete esotropia and abduction defect or partial. The differential includes restrictive opthalmopathy or orbitopathy affecting the medial rectus muscle. In sixth nerve palsy but not restrictive eye disease there are characteristic slowing of abducting saccades.
Although the differential is extremely broad due to the length of the nerve, there are some helpful findings. Bilateral sixth nerve palsies are common at the clivus. Other cranial neuropathies (third, fourth, first division of fifth, or an ipsilateral Horner's) suggest a cavernous sinus lesion. Headache and pappilledema suggest a "false localizing" sign if increased intracranial pressure.
Among children, the commonest etiologies are trauma and tumor, usually a pontine glioma. Among 45 young adults without trauma,aged (20-50), one third have tumor, one fourth have multiple sclerosis, 9 % have a postviral infection, 7 % have IIH, and 7 % have meningitis (Peters et al.) Among the 15 tumor patients, only 3 had an isolated sixth nerve palsy, and among 11 patients with multiple sclerosis, an isolated sixth was the presenting sign in 8 of them. Thus MRI/LP are frequently appropriate in this group.
Among older adults, especially those with vascular risk factors, a vasculopathic or ischemic cause is the commonest. Beware of a patient with a history of malignancy. Beware of GCA; consider checking a sed rate and C reactive protein. Some opthalmalogists do not recommend neuroimaging for all patients in this group, but they do suggest careful followup, and imaging if the problem progresses after 2 weeks, fails to regress by two months, or other neurologic signs and symptoms occur. BILATERAL SIXTH NERVE PALSY IS NEVER VASCULOPATHIC. Clival bony lesions may be missed on quality neuroimaging, and sometimes lumbar puncture is required to identify increased intracranial pressure or meningitis. Consider metastases!
Although the differential is extremely broad due to the length of the nerve, there are some helpful findings. Bilateral sixth nerve palsies are common at the clivus. Other cranial neuropathies (third, fourth, first division of fifth, or an ipsilateral Horner's) suggest a cavernous sinus lesion. Headache and pappilledema suggest a "false localizing" sign if increased intracranial pressure.
Among children, the commonest etiologies are trauma and tumor, usually a pontine glioma. Among 45 young adults without trauma,aged (20-50), one third have tumor, one fourth have multiple sclerosis, 9 % have a postviral infection, 7 % have IIH, and 7 % have meningitis (Peters et al.) Among the 15 tumor patients, only 3 had an isolated sixth nerve palsy, and among 11 patients with multiple sclerosis, an isolated sixth was the presenting sign in 8 of them. Thus MRI/LP are frequently appropriate in this group.
Among older adults, especially those with vascular risk factors, a vasculopathic or ischemic cause is the commonest. Beware of a patient with a history of malignancy. Beware of GCA; consider checking a sed rate and C reactive protein. Some opthalmalogists do not recommend neuroimaging for all patients in this group, but they do suggest careful followup, and imaging if the problem progresses after 2 weeks, fails to regress by two months, or other neurologic signs and symptoms occur. BILATERAL SIXTH NERVE PALSY IS NEVER VASCULOPATHIC. Clival bony lesions may be missed on quality neuroimaging, and sometimes lumbar puncture is required to identify increased intracranial pressure or meningitis. Consider metastases!
Third nerve palsies
Associated symptoms (hemiplegia, tremor, ataxia) suggest a brainstem lesion. See separate sections on localization; this post covers emergencies primarily.
If meningismus or photophobia occur, do lumbar puncture to exclude an infiltrative lesion.
Cavernous sinus. superior orbital fissure lesions-- look for associated fourth nerve palsy, sixth nerve palsy, V1 dysfunction, or Horner's syndrome.
Isolated Third nerve palsy is vasculopathic, ie due to small vessel disease, or due to aneurysm, commonly posterior communicating artery aneurysm. Age greater than 50 and presence of major risk factors such as diabetes, hypertension, and hyperlipidemia favor vasculopathic origin. Third nerve palsy usually presents abruptly but may progress over one or two weeks. Ipsilateral retroorbital or head pain is usually present. Recovery over a period of months is typical. A small degre of anisocoria may be present (10/26 patients per Jacobson) but is almost always less than 2.5 mm.
Aneurysmal third nerve palsy includes younger patients aged 20-50 without risk factors. Pain occurs, but does not differentiate from vasculopathic third nerve palsy. However, pupillary dilatation occurs early, and occurs in 86-95 % of cases, whereas most vasculopathic cases spare the pupil. Trobe's "The Rule of the Pupil" states that in patients with an otherwise complete but pupil-sparing third nerve palsy do not have an aneurysm. IN cases of pupillary sparing aneurysms, other third nerve muscles are spared as well. If the third nerve palsy is partial, the state of the pupil does not help. 30-40 % of patients with partial third nerve palsies harbor an aneurysm. The pattern is different than in vasculopathic third nerve palsies: In vasculopathic cases there is incomplete paresis of all third nerve innervated muscles, but in partial third nerve palsies with aneurysm, patients are more likely to show weakness of just one or more but not all muscles.
MRA and CTA are extremely sensitive for the detection of aneurysms but are not yet 100 %, as they miss aneurysms smaller than 5 mm. Suggestions for on whom to perform angiography include all younger patients without risk factors, even those with low risk (pupil sparing but otherwise complete third nerve palsy). But for patients older than 50 with vascular risk factors and a pupillary sparing lesion can be managed expectantly, as the risk of an angiogram outweighs the benefit.
If meningismus or photophobia occur, do lumbar puncture to exclude an infiltrative lesion.
Cavernous sinus. superior orbital fissure lesions-- look for associated fourth nerve palsy, sixth nerve palsy, V1 dysfunction, or Horner's syndrome.
Isolated Third nerve palsy is vasculopathic, ie due to small vessel disease, or due to aneurysm, commonly posterior communicating artery aneurysm. Age greater than 50 and presence of major risk factors such as diabetes, hypertension, and hyperlipidemia favor vasculopathic origin. Third nerve palsy usually presents abruptly but may progress over one or two weeks. Ipsilateral retroorbital or head pain is usually present. Recovery over a period of months is typical. A small degre of anisocoria may be present (10/26 patients per Jacobson) but is almost always less than 2.5 mm.
Aneurysmal third nerve palsy includes younger patients aged 20-50 without risk factors. Pain occurs, but does not differentiate from vasculopathic third nerve palsy. However, pupillary dilatation occurs early, and occurs in 86-95 % of cases, whereas most vasculopathic cases spare the pupil. Trobe's "The Rule of the Pupil" states that in patients with an otherwise complete but pupil-sparing third nerve palsy do not have an aneurysm. IN cases of pupillary sparing aneurysms, other third nerve muscles are spared as well. If the third nerve palsy is partial, the state of the pupil does not help. 30-40 % of patients with partial third nerve palsies harbor an aneurysm. The pattern is different than in vasculopathic third nerve palsies: In vasculopathic cases there is incomplete paresis of all third nerve innervated muscles, but in partial third nerve palsies with aneurysm, patients are more likely to show weakness of just one or more but not all muscles.
MRA and CTA are extremely sensitive for the detection of aneurysms but are not yet 100 %, as they miss aneurysms smaller than 5 mm. Suggestions for on whom to perform angiography include all younger patients without risk factors, even those with low risk (pupil sparing but otherwise complete third nerve palsy). But for patients older than 50 with vascular risk factors and a pupillary sparing lesion can be managed expectantly, as the risk of an angiogram outweighs the benefit.
Third nerve palsies
Associated symptoms (hemiplegia, tremor, ataxia) suggest a brainstem lesion. See separate sections on localization; this post covers emergencies primarily.
If meningismus or photophobia occur, do lumbar puncture to exclude an infiltrative lesion.
Cavernous sinus. superior orbital fissure lesions-- look for associated fourth nerve palsy, sixth nerve palsy, V1 dysfunction, or Horner's syndrome.
Isolated Third nerve palsy is vasculopathic, ie due to small vessel disease, or due to aneurysm, commonly posterior communicating artery aneurysm. Age greater than 50 and presence of major risk factors such as diabetes, hypertension, and hyperlipidemia favor vasculopathic origin. Third nerve palsy usually presents abruptly but may progress over one or two weeks. Ipsilateral retroorbital or head pain is usually present. Recovery over a period of months is typical. A small degre of anisocoria may be present (10/26 patients per Jacobson) but is almost always less than 2.5 mm.
Aneurysmal third nerve palsy includes younger patients aged 20-50 without risk factors. Pain occurs, but does not differentiate from vasculopathic third nerve palsy. However, pupillary dilatation occurs early, and occurs in 86-95 % of cases, whereas most vasculopathic cases spare the pupil. Trobe's "The Rule of the Pupil" states that in patients with an otherwise complete but pupil-sparing third nerve palsy do not have an aneurysm. IN cases of pupillary sparing aneurysms, other third nerve muscles are spared as well. If the third nerve palsy is partial, the state of the pupil does not help. 30-40 % of patients with partial third nerve palsies harbor an aneurysm. The pattern is different than in vasculopathic third nerve palsies: In vasculopathic cases there is incomplete paresis of all third nerve innervated muscles, but in partial third nerve palsies with aneurysm, patients are more likely to show weakness of just one or more but not all muscles.
MRA and CTA are extremely sensitive for the detection of aneurysms but are not yet 100 %, as they miss aneurysms smaller than 5 mm. Suggestions for on whom to perform angiography include all younger patients without risk factors, even those with low risk (pupil sparing but otherwise complete third nerve palsy). But for patients older than 50 with vascular risk factors and a pupillary sparing lesion can be managed expectantly, as the risk of an angiogram outweighs the benefit.
If meningismus or photophobia occur, do lumbar puncture to exclude an infiltrative lesion.
Cavernous sinus. superior orbital fissure lesions-- look for associated fourth nerve palsy, sixth nerve palsy, V1 dysfunction, or Horner's syndrome.
Isolated Third nerve palsy is vasculopathic, ie due to small vessel disease, or due to aneurysm, commonly posterior communicating artery aneurysm. Age greater than 50 and presence of major risk factors such as diabetes, hypertension, and hyperlipidemia favor vasculopathic origin. Third nerve palsy usually presents abruptly but may progress over one or two weeks. Ipsilateral retroorbital or head pain is usually present. Recovery over a period of months is typical. A small degre of anisocoria may be present (10/26 patients per Jacobson) but is almost always less than 2.5 mm.
Aneurysmal third nerve palsy includes younger patients aged 20-50 without risk factors. Pain occurs, but does not differentiate from vasculopathic third nerve palsy. However, pupillary dilatation occurs early, and occurs in 86-95 % of cases, whereas most vasculopathic cases spare the pupil. Trobe's "The Rule of the Pupil" states that in patients with an otherwise complete but pupil-sparing third nerve palsy do not have an aneurysm. IN cases of pupillary sparing aneurysms, other third nerve muscles are spared as well. If the third nerve palsy is partial, the state of the pupil does not help. 30-40 % of patients with partial third nerve palsies harbor an aneurysm. The pattern is different than in vasculopathic third nerve palsies: In vasculopathic cases there is incomplete paresis of all third nerve innervated muscles, but in partial third nerve palsies with aneurysm, patients are more likely to show weakness of just one or more but not all muscles.
MRA and CTA are extremely sensitive for the detection of aneurysms but are not yet 100 %, as they miss aneurysms smaller than 5 mm. Suggestions for on whom to perform angiography include all younger patients without risk factors, even those with low risk (pupil sparing but otherwise complete third nerve palsy). But for patients older than 50 with vascular risk factors and a pupillary sparing lesion can be managed expectantly, as the risk of an angiogram outweighs the benefit.
Saturday, July 15, 2006
Fourth nerve (IVn.) Trochlear palsies emergency
Most trochlear palsies are not emergent. Most trochlear palsies are due to stroke, trauma, and rarely neoplasm or aneurysm. Rarer causes are GCA and increased ICP that occassionally need to be addressed. 0.02 % of low pressure headaches after lumbar puncture have an associated IV nerve palsy (Continuum August 2009).
Low flow dural based AVMS of the orbit
These non-traumatic fistulas are indirect and involve communication between small meningeal branches of the ICA or ECA and the cavernous sinus or tributaries. Symptoms are mild and subacute, compared to CCF. They include conjunctival injection, mild motility disturbance, and elevated intraocular pressure. MRI may be normal or show mild abnormality of the cavernous sinus, but often enlarged extaocular muscles or superior opthalmic veins are seen.
Carotid Cavernous Fistula CCF
This is a high flow shunting of blood from the carotid artery into the cavernous sinus. It is usually due to carotid trauma. Other causes are intracavernous aneurysm, Ehlers-Danlos syndrome, fibromuscular dysplasia, and pseudoxanthoma elasticum. Ocular signs and symptoms are pulsatile exopthalmos, periorbital congestion, opthalmoplegia (even a "frozen" globe), and increased intraocular pressure.
Two features distinguish CCF from cavernous sinus thrombosis: an audible supraorbital bruit (may or may not be present) and the presence of arterialized corkscrew episcleral veins. Marked enlargement of the superior opthalmic vein is easily visible on a CT or MRI. CCF is life threatening due to the possibility of intracranial hemorrhage or massive epistaxis. Vision loss, seizures and neurologic deficits are bad prognostic signs. Rapid diagnosis is critical. Transarterial balloon embolization is the preferred initial treatment, with a success rate over 90 %.
Two features distinguish CCF from cavernous sinus thrombosis: an audible supraorbital bruit (may or may not be present) and the presence of arterialized corkscrew episcleral veins. Marked enlargement of the superior opthalmic vein is easily visible on a CT or MRI. CCF is life threatening due to the possibility of intracranial hemorrhage or massive epistaxis. Vision loss, seizures and neurologic deficits are bad prognostic signs. Rapid diagnosis is critical. Transarterial balloon embolization is the preferred initial treatment, with a success rate over 90 %.
cavernous sinus thrombosis
This condition may also present with acute diplopia and orbital signs. Predisposing conditions for the septic variety include facial infections, especially those of the medial third of the face, especially gram positive Staphylococcus aureus. Chronic sinusitis can cause, but in this case consider gram negative staphylococci, Aspergillosis, and Mucoracea infections. Dental infections, especially the maxillary teeth , cause ten percent of infections and may be streptococci, fusobacteria, or Bacteroides species. Rarely it is caused via orbital cellulitis or hematogenous seeding, especially in immunocompromised patients. A few are due to prothrombotic conditions.
Presenting signs and symptoms are eye pain associated with proptosis, chemosis, ptosis, and opthalmoparesis. Altered sensorium, headache, nausea and vomiting are common and help to differentiate from orbital cellulitis. Fever and leukocytosis point to an infectious etiology. Eyelid edema suggests the original infection is in the ethmoid sinus, face, or dental areas. Opthalmoparesis usually starts as an isolated paresis of one muscle, often the abducens, in the setting of orbital congestion and proptosis. Fundus may show dilatation of ocular veins andlow grade disc swelling. Vision loss can be due to ischemia, low grade optic neuropathy, or neurotrophic keratopathy. CT and MRI show enlargement of superior opthalmic veins and possibly involved cavernous sinus. CSF shows evidence of infection. Mortality is 30 % in spite of therapy.
Presenting signs and symptoms are eye pain associated with proptosis, chemosis, ptosis, and opthalmoparesis. Altered sensorium, headache, nausea and vomiting are common and help to differentiate from orbital cellulitis. Fever and leukocytosis point to an infectious etiology. Eyelid edema suggests the original infection is in the ethmoid sinus, face, or dental areas. Opthalmoparesis usually starts as an isolated paresis of one muscle, often the abducens, in the setting of orbital congestion and proptosis. Fundus may show dilatation of ocular veins andlow grade disc swelling. Vision loss can be due to ischemia, low grade optic neuropathy, or neurotrophic keratopathy. CT and MRI show enlargement of superior opthalmic veins and possibly involved cavernous sinus. CSF shows evidence of infection. Mortality is 30 % in spite of therapy.
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