SLU NEURO-BOWL 2001 edited by Kitti Kaiboriboon, M.D., Laurence J. Kinsella , M.D. and John B. Selhorst, M.D. Department of Neurology Saint Louis University St. Louis, MO
SLU NEURO-BOWL 2001 The Neuro-Bowl is an educational exercise of the Department of Neurology at Saint Louis University. The program is modeled after the Neuro-Bowl of the American Academy of Neurology. One team of faculty members challenges another team of faculty. One resident and a neurologist from the clinical faculty also are members on each team. Questions are prepared by the remaining resident staff. Items are taken from contemporary literature and often favor physical signs, neuroimaging, diagnostic syndromes or studies, definitive treatments and complications of therapeutic efforts. Hopefully, the topics chosen will prepare us better to care for the patients we all serve.
SLU NEURO-BOWL 2001 Kinsella’s Synaptic Clefts Laurence J. Kinsella Thomas J. Geller L. James Willmore Enrique C. Leira Tonya M. DiTrapani vs. Mithen’s Association Neurons Francis A. Mithen Ghazala R. Hayat Salvador Cruz-Flores R. Edward Hogan Gisele R. Oliveira December 20, 2001
Question #1 What is the inheritance pattern of this 16-year-old boy’s muscular disease?
Answer #1 Facioscapulohumeral dystrophy derives its name from the muscle groups that are primarily afflicted. Initially facial muscles and the shoulder girdle are involved, and later foot extensors and pelvic-girdle muscles become affected. The heart is not implicated in most cases, though arrhythmias and conduction defects have been described. Mental impairment is not a feature, but retinal vascular disease and hearing loss occur. This autosomal dominant disorder is associated with subtelomeric deletion of chromosome 4q, with loss of 3.3 kb tandem-repeat units. Loss of ten or fewer repeats results in the disorder, and in general, the lower the number of repeats the more clinically severe the condition. However the function of the particular gene that causes this disorder is not clear. (Emery AE. The muscular dystrophies. Lancet 2002;359:687-695) Autosomal Dominant
Question #2 A 75-year-old man was admitted with the sudden onset of a right homonymous hemianopia. He also had anosmia for 11 years. Identify the cause of his presentation on the CT scan.
Answer #2 CT scanning shows an ill-formed hypodensity in the distribution of the left posterior cerebral artery which corresponds to his hemianopia and is likely the result of a left occipital infarct . There is an incidental giant aneurysm with curvilinear calcifications of the anterior cerebral artery. Unruptured aneurysms of the anterior cerebral artery most frequently cause visual symptoms, endocrine disorders, headache, dementia and emotional lability. This case is unusual in that the only apparent symptom was worsening hyposmia. (Manconi M et al. Anosmia in a giant ACA aneurysm. Arch Neuro 2001;58:1474-1475) Left occipital infarction
Question #3 A 21-month-old boy had normal growth and development until six months of age when he began to fail to thrive. Weight was less than three percentile, but length, head circumference and cognitive ability were appropriate for his age. His condition represents what syndrome?
Answer #3 Russell’s diencephalic syndrome is manifested by progressive emaciation and failure to thrive in an apparently alert infant. It is usually associated with a low-grade hypothalamic astrocytoma. Figure A shows the severe emaciation of the whole body and the characteristic thin facies, sometimes called "pseudohydrocephalic" appearance. Figure B, T1-weighted sagittal images after gadolinium enhancement, demonstrates the presence of a large tumor involving the hypothalamic region, distorting the chiasm and brain stem, and extending into the third ventricle. (Zafeiriou D et al. Russell's diencephalic syndrome. Neurology 2001;57:932) Russell’s diencephalic syndrome
Question #4 A 70-year-old man with Parkinson's disease underwent bilateral quadripolar electrode placement in the subthalamic nucleus. Several years later he required extraction of all of his maxillary teeth because of periodontal disease with osteonecrosis. The following day diathermy treatments were given to hasten soft tissue healing. After one hour of treatment he was found completely unarousable. Vital signs were normal. Pupils were small. All limbs withdrew to pain. MRI of the brain was obtained three days later. What is the cause of his neurological condition?
Answer #4 An MRI scan 3three days after the diathermy treatments showed a bilateral, symmetrical T2 lesion in the tegmentum of the pons and midbrain, cerebral peduncles and posterior limbs of the internal capsule (Upper panel). An MRI was repeated 32 days after the diathermy treatment and demonstrated a reduction of the T2 signal to the immediate proximity of the electrodes (Lower panel). The time course of the acute deterioration and the sequence of MRI changes indicate that the neurological event was caused by tissue damage around the subthalamic nucleus electrodes induced by diathermy. The mechanism by which diathermy interacted with the implanted leads or electrodes is believed to be by induction of an radiofrequency current and heating of the electrodes. Whether this was induction in the electrode wires through passage in the soft tissues of the neck or directly upon the DBS electrodes in the brain stem is uncertain. Radiofrequency burn of the basal ganglia and upper brainstem due to diathermal stimulation of deep brain electrodes (Nutt JG et al. DBS and diathermy interaction induces severe CNS damage. Neurology 2001;56:1384-1386)
Question #5 A 53-year-old man presented with a very slow progression over ten years of a left T-10 Brown-Sequard syndrome. Spinal MRI showed that the chronic myelopathy was due to what process?
Answer #5 T1-weighted MRI (A) revealed forward protrusion of the spinal cord at the T4–5 level. A CT myelogram (B to D) revealed ventral displacement of the spinal cord without a subarachnoidal cyst. The spinal cord herniated through an anterior dural defect; often a pseudomeningocoele lies anterior to the dura. Spinal cord herniation through an anterior dural defect (Kawachi I et al. Spontaneous spinal cord herniation. Neurology 2001;56:977) (Marchman LA et al. Idiopathic spinal cord herniation. Neurosugery 1999; 44:1129-33)
Question # 6 A 19-year-old man was hit on the back by a large door. Two days later, he developed transient arm dysesthesias and then severe back pain and leg weakness progressing to quadriplegia. He died of pulmonary embolism two weeks later. Autopsy revealed what explanation for his acute myelopathy?
Answer # 6 " Disc embolism " or nuclear pulposus emboli Sections from the superior (A) and inferior margins of the lesion showed acute ischemic infarction. The embolic fibrocartilaginous material, present in numerous sections of spinal arteries and arterioles (B), is periodic acid–Schiff positive and diastase resistant, is mucicarmine positive, and contains chondrocytes in lacunae. Embolism of nucleus pulposus material may involve retrograde venous transport and arteriovenous shunts. Predisposing factors are mild trauma or exercise. Premortem diagnosis is facilitated by a sudden, painful onset and a "stroke-in-evolution" pattern of progression. (Freyaldenhoven T et al. Fibrocartilaginous embolization. Neurology 2001;56;1354)
Question #7 A 62-year-old woman complained of headaches, blurred vision and spontaneous phosphenes that developed over a two-month period. She presented because in the supine, but not upright position, her head became grotesquely hyperemic. What is the cause of this physical finding?
Answer #7 Positional caput medusae occurred after a venous sinus thrombosis . This phenomenon may be explained by obstructed venous outflow along the internal jugular vein, the predominant means of cerebrovenous drainage in the supine position. The venous angiogram (supine position) revealed drainage of the superior sagittal sinus mainly along the superficial middle cerebral vein (arrow) and along the emissary veins through the diploe. In the upright position the spinal epidural veins may open as an additional drainage pathway and improve cerebral venous drainage. (Meyer B et al. Caput medusae after sinus venous thrombosis. Neurology 2001;57:1376) Venous Sinus Thrombosis
Question #8 An 89-year-old man presented with neck pain and fever. Examination disclosed resistance to neck flexion. Erythrocyte sedimentation rate was 97 mm/hour, and C-reactive protein was 8.4 mg/dl. Spinal fluid analysis and brain CT were normal. CT of neck showed periodontoid calcification (black arrows). What treatment led to rapid resolution of this man's illness?
Answer #8 Indomethacin CT scan of the cervical-occipital hinge. Thin curvilinear, double-band, periodontoid calcifications are detected in coronal and sagittal views (black arrows). Degenerative changes can be found at the articular surfaces (gray arrows). Calcium pyrophosphate dihydrate (CPPD) arthropathy may involve any joint. Cervical localization is related to several clinical presentations: meningeal syndromes, compressive myelopathy, or an association of feverish acute cervical pain and calcifications in the periodontoid space, described as the “Crowned Dens Syndrome.” After 50 mg of indomethacin , there was a rapid resolution of this man's Crowned Dens Syndrome and its associated CCPD arthropathy. (Mula M et al. Crowned dens syndrome. Neurology 2001;56:275)
Question #9 A 26-year-old woman presented with weakness of the right hand and dysarthria. Spinal fluid analysis disclosed a normal cell count and protein, but oligoclonal bands. MRI showed extensive high intensities in the left cerebral hemisphere. What procedure established the correct diagnosis?
Answer #9 Brain biopsy revealed primary cerebral amyloidoma Isolated cerebral amyloidomas are rare. Sometimes called primary CNS amyloidomas, they are a localized form of amyloid deposition. Clinically and radiographically, it is similar to a slow-growing neoplasm. The radiographic findings of CNS amyloidoma are typically patchy lesions with intense enhancement following contrast administration. The lesions have been predominantly described as heterogeneous on T2-weighted images and isointense to slightly hyperintense on T1-weighted images. The heterogeneous signal is felt to represent nonuniform deposits of amyloid protein. The correct diagnosis is unlikely to be made without a brain biopsy. Brain biopsy (B) reveals amyloid deposition in the white matter surrounded by lymphocytes, plasma cells, epithelioid cells and multinucleated giant cells. Apple- green birefringence of amyloid upon polarization, Congo red stain. Immunohistochemical stain for lambda light chains (C) shows high content of lambda light chain expressing plasma cells (brown reaction product), but no immunoreactivity of the amyloid. (Blattler T et al. Primary cerebral amyloidoma. Neurology 2001;56:777) (Symko SC et al. Imaging of cerebral and brain stem amyloidomas. AJNR 2001;22:1353-1356)
Question #10 These two middle-aged women presented with mild dementia, dysarthria, rigidity and postural instability. A predominant "Procerus sign" gives a gloomy appearance to the facies of both patients. In what neurological disease does this sign occur?
Answer #10 Progressive supranuclear palsy (PSP) PSP is characterized by vertical supranuclear gaze palsy, axial rigidity, akinesia, dysarthria, fronto-limbic dementia and postural instability. A typical facial expression, described as "astonished," "worried," or "reptile-like," has been described. The expression may be due to a focal dystonia of the procerus muscle as well as to a combination of very reduced blinking, lid retraction and gaze palsy. Procerus is a facial muscle that originates in the nasal bone and inserts in the skin in the center of the forehead between the eyebrows; it acts forming vertical wrinkles in the glabella region and bridge of the nose. Both patients show this typical sign, occurring without concomitant blepharospasm. The wrinkling is present with open and closed eyes. This sign could be called "the procerus sign." (Romano S et al. Procerus sign in PSP. Neurology 2001;57:1928)
Question #11 A 36-year-old man presented with diplopia and paresthesias. The high intensities in the MR scan indicated by the open arrows are caused by what underlying histopathological changes?
Answer #11 These are areas of perivenular inflammation that occur in multiple sclerosis. More than 85% of MS patients have ovoid periventricular lesions that are oriented perpendicularly to the long axis of the brain and lateral ventricles. This correlates well (Osborn A, ed. Diagnositic Neuroradiology 1994:757) with the histological localization of demyelination around subependymal and deep white matter medullary veins. The callososeptal interface is a typical location. The periventricular extension into the centrum semiovale, sometimes called “ Dawson's fingers .” Perivenular inflammation
Question #12 What is the name of this structure indicated by the arrows on the brain MRI scan of this 45-year-old man?
Answer #12 These are prominent vascular spaces or Virchow-Robin's spaces (VRS) which are shown in this autopsy specimen. Small VRSs are found in patients of all ages and are a normal anatomical variant. VRSs increase in size and frequency with advancing age. Other factors such as hypertension, dementia and incidental white-matter lesions are also associated with large VRSs, but are considered part of the aging process and are not independent variables. (Osborn A, ed. Diagnositic Neuroradiology 1994:750-752) Virchow-Robin's spaces
Question #13 A 57-year-old man presented with diplopia. This progressed to complete ophthalmoplegia, facial weakness and ataxia. Examination disclosed hyporeflexia, too. A brain MRI with gadolinium was obtained. What do the two arrows indicate?
Answer #13 MFS is thought to be a clinical subtype of the Guillian–Barré syndrome and is characterized by the neurological signs of ophthalmoplegia, gait ataxia and areflexia. Facial paresis also frequently occurs in MFS. Axial sections of brain MRI after double-dose gadolinium administration: T1-weighted and fat-suppressed technique demonstrates enhancement of 3rd (A), 6th (B), and 7th (not shown) cranial nerves bilaterally. MRI of the brain with a double dose of gadolinium may be a good confirmatory test for a diagnosis of MFS in the correct clinical setting. Contrast enhancement of the oculomotor and abducens nerves in a patient with Miller Fisher Syndrome (MFS). (Garcia-Rivera CA et al. Miller Fisher Syndrome. Neurology 2001;57:1755)
Question #14 A 35-year-old man who sprayed pesticides in a poorly ventilated basement developed a metallic taste and a garlic-like odor to his breath. Later that day, he developed drowsiness and headache. His condition deteriorated to stupor and profound hypotension. With supportive care, he recovered, but has a residual distal sensorimotor neuropathy. What is the cause of his condition?
Answer #14 <ul><li>Arsenic poisoning </li></ul><ul><ul><li>Signs and symptoms of arsenic intoxication include nausea, vomiting, colicky abdominal pain and profuse, watery diarrhea. Hypotension, fluid and electrolyte disturbances, mental status changes, electrocardiographic abnormalities, respiratory failure and death can result. Quantitative measurement of 24-hour urinary arsenic excretion is the only reliable laboratory test to confirm arsenic poisoning. Treatment includes gastric emesis or lavage, chelation therapy, electrolyte and fluid replacement, and cardiorespiratory support. </li></ul></ul><ul><ul><li>Arsenic-induced polyneuropathy is traditionally classified as an axonal-loss type, electrodiagnostically resulting in low amplitude or absent sensory and motor responses, relatively preserved proximal and distal motor conduction rates, and distal denervation. Acute arsenic toxicity must be suspected in patients with clinical and electrodiagnostic features supporting the Guillain-Barre syndrome. </li></ul></ul>(Donofrio PD et al. Acute arsenic intoxication as GBS-like. Muscle Nerve 1987;10:114-120)
Question #15 Some families have children with seizures occurring only at birth. The genetic mutation responsible for benign familial neonatal convulsion results in a defect in what component of the neuron?
Answer #15 <ul><li>Potassium channels </li></ul><ul><ul><li>Epilepsy affects >0.5% of the world's population and has a large genetic component. The most common human genetic epilepsies display a complex pattern of inheritance, and the identity of the susceptibility genes is largely unknown. Mutations in KCNQ2 or KCNQ3 cause benign familial neonatal convulsions (BFNC), a rare autosomal-dominant generalized epilepsy of newborns, by reducing the maximal current carried by the M-channels without affecting ion selectivity or gating properties. </li></ul></ul>(Berkovic SF et al. Genetics of the epilepsies. Curr Opin Neurol 1999;177-182)
Question #16 Name one of the two types of autosomal dominant ataxias that feature downbeat nystagmus.
Answer #16 <ul><li>Spinocerebellar Atrophy type 6 or </li></ul><ul><li>Episodic Ataxia type 2 </li></ul><ul><ul><li>Spinocerebellar ataxia type 6 (SCA6) was identified as a form of autosomal dominant cerebellar ataxia associated with small expansions of the trinucleotide repeat (CAG)n in the gene CACNL1A4 on chromosome 19p13. This gene encodes the alpha1 subunit of a P/Q-type voltage-gated calcium channel. Clinical and quantitative measurement of extraocular movements demonstrated a characteristic pattern of ocular motor and vestibular abnormalities, including horizontal and vertical nystagmus and an abnormal vestibulo-ocular reflex. </li></ul></ul><ul><ul><li>The SCA6 mutation is allelic with episodic ataxia type 2 (EA-2), but the two differ clinically because of the presence of progressive, rather than episodic, ataxia in SCA6. </li></ul></ul>(Gomez CM et al. Spinocerebellar ataxia type 6: gaze-evoked and vertical nystagmus, Purkinje cell degeneration, and variable age of onset. Ann Neurol 1997;42:933-950)
Question #17 Name an ancillary diagnostic study that would indicate the cause of the six-month dementia occurring in the patient with this MR scan?
Answer #17 CSF analysis for 14-3-3 protein occurs in 96% patients with Creuzfeldt-Jacob disease (CJD). The protein is not specific for CJD because it occurs in patients with herpes simplex encephalitis and acute cerebral infarction. However, in the appropriate setting the finding of the 14-3-3 protein in the spinal fluid is highly supportive of CJD. Findings in MRI have been reported in several cases of pathologically established CJD. Brain MRI might be normal or show either brain atrophy or symmetric, hyperintense signals of the basal ganglia in T2 weighted images as shown above. (Hsich G et al. The 14-3-3 as a marker for CJD. N Eng Med 1996;335:924-930) CSF analysis for 14-3-3 protein
Question #18 What is the recommended treatment for this 24-year-old man who has seizures and this MR scan?
Answer #18 Taenia solium neurocysticercosis is a common cause of epileptic seizures and other neurological morbidity in most developing countries. It is also an increasingly common diagnosis in industrialized countries because of immigration from areas where it is endemic. Its clinical manifestations are highly variable and depend upon the number, stage and size of the lesions as well as the host's immune response. Multiple cystic lesions, some with calcium, edema and contrast-enhancement are characteristic of cysticercosis. Treatment of choice is albendazole or, if allergic, praziquantel . (Del Brutto OH et al. Therapy for neurocysticercosis. Clin Infect Dis 1993;17:730-735) Albendazole or Praziquantel
Question #19 What is the case of this pathological finding?
Answer #19 These are intracytoplasmic inclusions or Negri bodies that are pathognomonic of rabies . Negri bodies are well-defined, often oval or elongated, eosinophilic cytoplasmic inclusions in neurons, which represent accumulations of viral particles. Negri bodies are most common in cerebellar Purkinje cells, hippocampal pyramidal cells and neocortical neurons. Smaller, less well-defined inclusion bodies, previously termed "lyssa bodies," are often more numerous than Negri bodies and also represent accumulations of virus. These findings are therefore as pathognomonic as Negri bodies. (Basgoz N et al. Case 21-1998. N Eng Med 1998;339:105-112) Rabies
Question #20 This is the MR scan of a 24-year-old woman who had measles encephalitis at five years of age and a subsequent poorly controlled seizure disorder. Examination was normal except for hyperactive tendon reflexes on the right. The MR scan is illustrative of what unique process?
Answer #20 The MR scan shows crossed cerebellar atrophy. In a 1985 article in Brain, Dr. HD Chung described four patients in which unilateral cerebral atrophy was associated with contralateral cerebellar atrophy. He proposed that this occurred due to transynaptic retrograde degeneration of frontal and thalamic pathways. (Chung HD. Retrograde crossed cerebellar atrophy. Brain 1985;108:881-895) Transynaptic retrograde degeneration
Question #21 A 35-year-old man developed a right lateral medullary syndrome while aiming his arrow on his inaugural bow hunt. What dynamic activity during angiography was required to demonstrate the cause of his "Bow Hunter's stroke?"
Answer #21 Anatomically, the vertebral artery courses through six foramina transversaria of the cervical vertebrae, passing through the groove on the surface of the arch of the atlas and then penetrating the dura mater. Bow hunter's stroke is a consequence of vertebrobasilar insufficiency as a result of mechanical occlusion or stenosis of the vertebral artery at the C1-C2 level by head rotation. In most cases, a dominant vertebral artery is involved. Twenty-degree head turning during vertebral angiography is the dynamic maneuver required to clearly show the vertebral artery occlusion occurring with alantoaxial rotation. (Matsuyama T et al. Bow Hunter’s stroke. Neurosurgery 1997;41:1393-1395) Twenty-degree head turn
Question #22 These skin lesions appeared over the buttocks in a young man who complained of intermittent burning and numbness of the fingers and toes. What is the diagnosis of his complaints and the findings that led to a favorable treatment?
Answer #22 Fabry’s disease is an X-linked recessive disorder caused by a deficiency of alpha-galactosidease A and storage of globotriaoxylceramide in lysosomes of blood vessels and nerves. This pathological deposition results in characteristic skin lesions, neuropathy, renal failure and stroke. Men are predominantly affected, but many female carriers have similar clinical involvement, including increased risk of stroke. Physical stigmata, such as angiokeratomas in skin and mucous membranes and characteristic benign corneal abnormalities, facilitate identification of Fabry’s disease. The finding of a marked decreased activity of alpha-galactosidase A in white blood cells or cultured skin fibroblasts confirms the diagnosis. Treatment thus far has been symptomatic only. Recently intravenous infusions of alpha-galactosidase A in patients with Fabry’s disease demonstrates the safety and efficacy of this treatment. (Brady RO et al. Clinical features of and recent advances in Fabry disease. JAMA 2002;284:2772-2775) Fabry’s disease
Question #23 Number 1 in the diagram depicts Wernicke's area in the left temporal lobe. A lesion in number 5 results in what specific neurological deficit?
Answer #23 A callosal apraxia occurs with lesions of the anterior corpus callosum. This is demonstrated by the ability to perform purposeful movements of the right hand and the inability to perform them in a dexterous and strong left hand. (Brazis PW, Masdeu JC, Biller J, eds. Localization in Clinical Neurology 2001;504 ) Callosal apraxia
Question #24 <ul><li>In the care of debilitated patients, it is important to realize that muscle protein turnover occurs at the following rate: </li></ul><ul><li> </li></ul><ul><ul><ul><li>50% in 14 days </li></ul></ul></ul><ul><ul><ul><li>100% in 14 days </li></ul></ul></ul><ul><ul><ul><li>50% in one month </li></ul></ul></ul><ul><ul><ul><li>100% in one month </li></ul></ul></ul><ul><ul><ul><li>50% in 90 days </li></ul></ul></ul>
Answer #24 Although skeletal muscle has a primary function of providing locomotion, it is a major depository of protein and free amino acids that are used for gluconeogenesis, wound healing and synthesis of antibodies and acute phase proteins during catabolic diseases. Loss of lean body mass is associated with loss of strength and immune function with an increased disability and mortality. Muscle protein turnover, the balance between protein synthesis and protein breakdown, is affected by various physiological states such as fasting, feeding, disease and aging resulting in a net increase or decrease in protein deposition. In the care of debilitated patients, it is important to realize that muscle protein turnover occurs at 100% in 14 days (B) (B) 100% in 14 days
Question #25 CANOMAD is a recently described disorder the includes C hronic A taxic N europathy, O phthalmoplegia, M -protein, A gglutination and D isialsoyl antibodies. The condition resembles a "chronic Miller Fisher syndrome." The IgM protein is an antibody directed to disialyated gangliosides. Interestingly, what other antibody is frequently elevated in CANOMAD?
Answer #25 GQ1b Antibody The clinical picture of CANOMAD consists of a chronic neuropathy with marked sensory ataxia and areflexia with relatively preserved motor function in the limbs. In addition, motor weakness affecting oculomotor and bulbar muscles as fixed or as relapsing-remitting features are observed. This distribution of clinical features is reminiscent of Miller Fisher syndrome, in which acute-phase anti-disialylated ganglioside IgG antibodies are found. Clinical electrophysiology and nerve biopsy show both demyelinating and axonal features. A partial response to intravenous immunoglobulin and other treatments is reported in some cases. (Willison HG et al. The clinical and laboratory features of chronic sensory ataxic neuropathy with anti-disialosyl IgM antibodies. Brain 2001;124:1968-1977)
Question #26 In women with menstrual migraine, the time of highest risk of headache is: A. First two days of menses B. Last two days of menses C. During the entire menstrual period D. Time of ovulation
Answer #26 (A) The first two days of menses The term "menstrual migraine" (MM) refers to migraine attacks that occur perimenstrually, although precise definitions vary. The International Headache Society suggests that migraine without aura is the predominant variant associated with the menstrual cycle and “requires that 90% of attacks should occur between two days before menses and the last day of menses.” The population base study demonstrated that attacks of migraine without aura, but not migraine with aura, were more likely to occur two days before onset of menses and on the first two days of menses. (Stewart WF et al. Menstrual cycle and headache in a population sample of migraineurs. Neurology 2000;55:1517-1523)
Question #27 A 32-year-old, former equipment operator avulsed a cervical root when his crane tipped over. He presented 10 years later because of an insidiously progressive gait ataxia. Examination was remarkable for bilateral deafness, generalized hyper-reflexia, extensor plantar signs and a wide-based gait. MR scanning was additionally remarkable. What is his diagnosis?
Answer #27 Superficial siderosis (SS) of the CNS The triad of progressive bilateral deafness, cerebellar ataxia and myelopathy allow a bedside diagnosis of SS . MR scanning shows a distinctive black rim of characteristic hypointensities overlying the vermis and adjacent cerebellum, brain stem, basal cisterns, spinal cord and eighth nerve on T-2 images. The usual sources of subarachnoid bleeding in SS are dural abnormalities, vascular lesions and tumors. Dural abnormalities including CSF-containing cavities (meningoceles and arachnoid cysts and posthemispherectomy), cervical nerve root lesions (avulsions and epidural cysts), and chronic subdural hematomas account for almost half of the patients with an identifiable source of bleeding. Vascular lesions associated with SS include arteriovenous malformations, unruptured aneurysms and cavernous angiomas. SS also can be caused by chronic bleeding from a brain or spinal cord tumor—most commonly an ependymoma. In some patients a source of subarachnoid bleeding is not found. (Fishman RA. Superficial siderosis. Ann Neurol 1993;34:635-636)
Question #28 With the advent of HAART (highly active antiretroviral treatment) being prescribed for AIDS patients, what common focal brain lesion has declined?
Answer #28 During the HAART era, AIDS-related primary CNS lymphoma (PCNSL) showed a strong decline, toxoplasmic encephalitis remained stable, and progressive multifocal leukoencephalopathy showed a slight increase. Focal white matter lesions without mass effect or contrast enhancement became the most frequently seen focal brain lesion. These observations were consistent with the fact that PCNSL is a manifestation of the advanced immunosuppression phase of AIDS, and its onset may be influenced by the immune reconstitution observed with HAART. In contrast, systemic non-Hodgkin’s lymphoma, which relates differently to immunosuppression, did not seem to decline during the HAART era. The hypothesis that the reduced occurrence of PCNSL is directly related to the effect of HAART on immune recovery was further supported by the beneficial effect of antiretroviral and immune therapy on prognosis in AIDS-related PCNSL. (Ammassari A et al. AIDS-related focal brain lesions in the era of highly active antiretroviral therapy. Neurology 2000;55:1194-1200) Primary CNS lymphoma
Question #29 A 48-year-old man ingested an unknown chemical compound. Several hours later he was found comatose. CT and a latter MR scan implicated what intoxicant?
Answer #29 Non-enhanced CT brain showed low attenuation, primarily in the subcortical white matter of both cerebral hemispheres, as well as abnormal hypodensity of the putamen. Additional focus of hemorrhage involved the right putamen (A). MRI flair sequence demonstrated an increased signal, especially in the subcortical white matter of both cerebral hemispheres. The brighter signal involving the putamen represents edema, as well as coexistent blood products on the right (B). This was consistent with primarily subcortical white matter infarction and bilateral putamenal necrosis with right-sided hemorrhage, documented on postmortem examination (C). The presence of subcortical white matter (with relative sparing of centrum semiovale) and putamenal injury are typical of severe methanol toxicity. This is likely related to methanol metabolism to formates, hypoxemia, severe acidosis and coexistent circulatory depression. (Feris CS et al. Severe brain injury in methanol ingestion. Neurology 2000;54:1239) Methanol
Question #30 What is the most common pathogen responsible for brain abscess?
Answer #30 A brain abscess consists of localized free or encapsulated pus within the brain substance. Predisposing conditions are always present. Pyogenic organisms gain access to the brain substance by one of three routes. The first is through the blood stream either from a remote infection or in association with a cardiopulmonary malfunction, most commonly cyanotic congenital heart disease with a right-to-left shunt. The second is by extension of contiguous infections such as leptomeningitis, infections of the middle ear or infections of the paranasal sinuses, either directly or a result of septic thrombophelebitis of bridging veins. The third is a complication of a penetrating wound. The most common causative organisms in order of frequency are anaerobic and microaerophilic streptococi (60-70%), Fusobacterium species, Beta-hemolytic streptococci, S. aureus and pneumococci. Anaerobic organisms alone cause approximately 56% of brain abscesses, aerobic bacteria 18%, and mixed aerobic and anaerobic bacteria 26%. Treatment should include a diligent search for the source of infection. Initial therapy should include coverage for anaerobic as well as aerobic organisms. The antibiotics of choice are generally IV penicillin G, chloramphenicol or metronidazole. Oxacillin or methicillin also should be started until it is established that a Beta-lactamase-producing organism is not involved. It is continued for a minimum of three weeks, and often for 4-6 weeks. Sugical therapy is indicated when the patient does not improve after 24 hours of antibiotic therapy, when clinical status deteriorates, or when there is life-threatening displacement of cerebral structures. Sinusitis or mastoiditis contiguous to a brain abscess should be treated vigorously, usually with prompt surgery. A short couse of corticosteroids to reduce life-threatening edema can be used safely. (Weil ML et al. Infections of the nervous system. Menkes JH, Sarnat HB, eds. Child Neurology , 6 th ed: 467-626) Anaerobic and microaerophilic streptococi
Question #31 A healthy 52-year-old woman began to decline intellectually. She made mistakes in her job as a bookkeeper and had difficulty taking phone messages. She also began to stumble with occasional falls and became depressed. MR scan of the brain revealed a convexity meningioma that was successfully removed. She did not, however, improve. Why?
Answer #31 Genetic analysis of this patient showed 44 CAG repeats that established a diagnosis of HD. Chorea can be absent in the early stages of the dementia. Abnormalities are limited to the brain. The caudate nucleus, particularly its paraventricular portion, is the most affected. Cell death within the striatum does not affect all neurons equally. The medium-sized GABA-ergic spiny projection neurons are the first to be affected. The mechanism for this selective vulnerability is still unclear. The gene for HD is mapped to the telomere (tip) of the short arm of chromosome 4. (Reich SG. Neurovignette. The Neurologist 2001;7:308) MRI shows markedly shrunken caudate nucleus, the pathognomonic sign for Huntington’s disease .