EUH Dressler Conference: Review of polymyositis

The Bottom Line: Inflammatory idiopathic myopathies (IIM) are a group of rare autoimmune diseases characterized by proximal skeletal muscle weakness, raised muscle enzymes and extramuscular organ involvement, most frequently the lungs, resulting in interstitial lung disease (ILD). Numerous autoantibodies are associated with the disease, many linked to different clinical phenotypes.  Polymyositis predominantly presents with proximal symmetrical muscle weakness, while dermatomyositis is characterized by skin and muscle involvement; both are associated with extramuscular features.

Clark, K., & Isenberg, D. (n.d.). A review of inflammatory idiopathic myopathy focusing on polymyositis. European Journal of Neurology., 25(1), 13-23.

The main aims of treatment are to suppress inflammation, improve muscle power and prevent chronic damage to muscles and extramuscular organs. However, there is a lack of robust data to guide treatment.  Glucocorticoids remain the mainstay of treatment in IIM. Initial dosing is approximately 0.5 mg/kg of prednisolone, but the many side effects of steroids encourage a reducing regime over the first 2 months.  Methotrexate and azathioprine are often used as first line disease modifying anti-rheumatic drugs. A Cochrane review found insufficient evidence of improved efficacy using one DMARD (methotrexate, azathioprine or cyclosporine) in combination with corticosteroids in preference to another.

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EUHM Resident Report: What is the correlation of HSV encephalitis and intracerebral hemorrhage?

The mechanism of hemorrhagic complication in HSV encephalitis is unclear. The possible mechanisms  include small vessel rupture due to vasculitis and transient hypertension caused by increased intracranial pressure. Gyral pattern of the hemorrhage may suggest that the hemorrhagic complication in HSV encephalitis may be due to associated vasculitis

Takeuchi, S., & Takasato, Y. (n.d.). Herpes simplex virus encephalitis complicated by intracerebral hematoma. Neurology India., 59(4), 594-596.

Herpes simplex virus (HSV) encephalitis is the most common cause of sporadic encephalitis, with a mortality of 70% if untreated. Treatment with acyclovir is associated with reduced mortality. Petechial cortical hemorrhages are common in HSV encephalitis, whereas frank hematoma is extremely rare; only 10 cases have been reported in the literature.

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Intracerebral hematoma can complicate HSE even when the evolution is favorable. It should be suspected whenever neurologic deterioration appears and should be distinguished from acyclovir resistance and toxicity, since the management of these entities differs substantially.

Rodríguez-Sainz, A., Escalza-Cortina, I., Guio-Carrión, L., Matute-Nieves, A., Gómez-Beldarrain, M., Carbayo-Lozano, G., & Garcia-Monco, J. (2013). Intracerebral hematoma complicating herpes simplex encephalitis. Clinical Neurology and Neurosurgery, 115(10), 2041-2045.

Intracranial bleeding, although infrequent, can complicate the evolution of herpes simplex encephalitis and should be borne in mind since its presence may require neurosurgery. Although its presentation may overlap the encephalitic features, the lack of improvement or the worsening of initial symptoms, particularly during the second week of admission, should lead to this suspicion and to perform a neuroimaging study.

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HSV enters the brain through the direct neuronal transmission from the peripheral site to the brain through the trigeminal or olfactory nerve. The usual manifestation of HSE is fever, headache, seizures, and change in mental status evolving over several days. Atypical manifestation includes intracerebral hemorrhage which has been reported mainly in infants and young children. Intracerebral hematoma in HSE in adults is rare. There are some reports of the occurrence of hematoma in HSE in the adults. The exact mechanism of hemorrhage in HSE is unclear. Vasculitis causing small vessel rupture and transient hypertension due to raised intracranial pressure has been proposed for hemorrhage in HSE.

Mahale, R., Mehta, A., Shankar, A., Miryala, A., Acharya, P., & Srinivasa, R. (2016). Bilateral Cerebral Hemorrhage in Herpes Simplex Encephalitis: Rare Occurrence. Journal of Neurosciences in Rural Practice., 7(Suppl 1), S128-S130.

The most frequent cause of sporadic encephalitis is herpes simplex encephalitis (HSE). It carries a mortality of 70% if left untreated. With the usage of acyclovir in the management of HSE and early diagnosis, the mortality rate has been reduced to 19%. Herpes simplex virus (HSV) causes hemorrhagic necrotizing encephalitis involving the frontal and medial temporal lobes. Petechial cortical hemorrhages have been reported in HSE; however, frank hematoma is rare.

Neurologic testing in diagnosis of syncope

Bottom line: Unless there are additional neurologic signs or symptoms, neurologic testing for syncope is rarely helpful.

Source

Linzer, M, et al. “Diagnosing syncope. Part 1: Value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians.” Annals of Internal Medicine 126.12 (1997):989-96.
A review of the literature on diagnostic testing for syncope resulted in this guideline and its conclusion that “neurologic testing is rarely helpful unless additional neurologic signs or symptoms are present (diagnostic yield of electroencephalography, computed tomography, and Doppler ultrasonography, 2% to 6%).”

 

When should a head CT be performed prior to a lumbar puncture?

Lumbar puncture/Procedure considerations/Neuroimaging in Dynamed

The section on Testing to Consider Prior to Performing an LP in DynaMed’s entry for lumbar puncture summarizes two prospective cohort studies and lists clinical findings such as age and aspects of clinical history and specific neurologic findings that were predictive of cranial lesions that contraindicated LP: age > 60 years, immunocompromised status, history of central nervous system disease, history of seizure within 1 week, abnormal level of consciousness, and focal findings on neurological exam.

Hasbun R, Abrahams J, Jekel J, Quagliarello VJ. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. N Engl J Med. 2001 Dec 13;345(24):1727-33. 235 patients with suspected meningitis received CT before lumbar puncture. RESULTS: Abnormal CT in 24% of patients in the study; 5% had evidence of a mass effect. Factors associated with an abnormal head CT were age ≥ 60 years, immunocompromised, history of CNS disease, history of seizure within one week before presentation.

Gopal AK Cranial computed tomography before lumbar puncture: a prospective clinical evaluation. Arch Intern Med. 1999 Dec 13-27;159(22):2681-5. Of 113 patients with urgent circumstances necessitating CT, 15% of CTs showed new lesions but only 2.7% had lesions that contraindicated LP

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What are the neurologic sequelae of NSAID toxicity, and do these include aseptic meningitis?

The Bottom Line: One of the important neurologic side-effects attributed to the over-use of NSAIDs is aseptic meningitis.

Reference: Auriel et al.  Nonsteroidal anti-inflammatory drugs exposure and the central nervous system.  Handb Clin Neurol 2014;119:577-84.

Summary: CNS effects of NSAID toxicity range from drowsiness to coma. Case reports have identified numerous neurologic sequelae including ataxia, vertigo, dizziness, recurrent falls, nystagmus, headache, encephalopathy, and disorientation. Seizures have also been reported, mostly after overdose ingestions, but even therapeutic doses have occasionally been associated with seizures.  The clinical signs of drug-induced meningitis are similar to those of infectious meningitis and include fever, headache, photophobia, and stiff neck. The laboratory findings are also similar, including cerebrospinal fluid (CSF) pleocytosis of several hundred or thousand cells, mainly neutrophils, elevated levels of protein, normal or low glucose levels and negative cultures.

McDonald criteria for diagnosis of multiple sclerosis

Bottom line: Table 3 from study by the Magnims European research network provides estimated data (95% confidence interval) for sensivity, specificity, accuracy, positive predictive value, positive likelihood ratio, and negative likelihood ratio for old and new McDonald criteria (divided up by overall criteria (dissemination in space (DIS) and dissemination in time (DIT)), DIS criteria, DIT criteria, and DIT on follow-up scan. Table 3 is available here.

McDonald criteria:
The revised criteria includes key changes related to use and interpretation of DIS and DIT imaging criteria as stated in published study by the Magnims European research network. The authors of the revised McDonald criteria (2011) claim that the criteria have been simplified while preserving diagnostic sensitivity and specificity, addressing their applicability across various populations, and possibly allowing them to be used widespread and more uniformly.

Sources:

Revised McDonald criteria:
Polman, Chris H, et al. “Diagnostic criteria for multiple sclerosis: 2010 revisions to the McDonald criteria.” Annals of neurology 69.2 (2011):292-302.

Study by Magnims European research network:
Swanton, Josephine K, et al. “MRI criteria for multiple sclerosis in patients presenting with clinically isolated syndromes: a multicentre retrospective study.” Lancet neurology 6.8 (2007):677-86.

 

Responsive Nerve Simulator (RNS) for Epilepsy

How it works

“The RNS® System (NeuroPace, Mountain View, CA) provides responsive cortical stimulation via a cranially implanted programmable neurostimulator connected to 1 or 2 recording and stimulating depth or subdural cortical strip leads that are surgically placed in the brain according to the seizure focus. The neurostimulator continually senses electrocorticographic activity and is programmed by the physician to detect abnormal electrocorticographic activity and then provide stimulation. The physician adjusts detection and stimulation parameters for each patient to optimize control of seizures.” The source article by Morrell includes information on its effectiveness.

Brief notes on the neurostimulator, cortical strip leads, depth leads, remote monitor, want, magnet, programmer, want, and patient data management system (PDMS) for the NeuroPace RNS can be found here.

Additional information

NeuroPace RNS user manuals for patients and physicians are available here.

The NeuroPace RNS is intended for patients who have been diagnosed as having no more than 2 seizure foci, have not responded to two or more anti-epileptic medications, and are currently having frequent, disabling seizures. Here is the source.

Citation for source article by Morrell

Morrell, Martha J. “Responsive cortical stimulation for the treatment of medically intractable partial epilepsy.” Neurology 77.13 (2011):1295-304.

Efficacy and timing of steroids for meningitis

Bottom line: Cochrane systematic review found support for use of corticosteroids in meningitis patients in high-income countries. Administering corticosteroids with the first dose of antibiotics as opposed to after the first dose led to similar results with regard to mortality and slightly more favorable results for severe hearing loss and short-term neurological signs.

Source and complete quotes:

Brouwer, Matthijs C, et al. “Corticosteroids for acute bacterial meningitis.” Cochrane Database of Systematic Reviews 6(2013):CD004405.

“Corticosteroids significantly reduced hearing loss and neurological sequelae, but did not reduce overall mortality. Data support the use of corticosteroids in patients with bacterial meningitis in high-income countries. We found no beneficial effect in low-income countries.”

“Subgroup analysis on timing of corticosteroids (before or with the first dose of antibiotics versus after the first dose of antibiotics) showed similar results for mortality (RR 0.87 95% CI 0.69 to
1.09 (I2 statistic 52%, random-effects model); RR 0.83, 95% CI 0.55 to 1.26) (Analysis 6.1; Analysis 6.2; Analysis 6.3; Analysis 6.4). For subgroup analyses of severe hearing loss and short-term neurological sequelae, administration after the first dose of antibiotics had slightly more favourable point estimates than studies with early administration of corticosteroids, but there was no significant heterogeneity between subgroups.”