By H. Rhobar. Bryant College.
More research is needed on MR spectroscopy as a tool to lateralize the epilepsy Table 11 order amoxil 250mg with amex. Functional MRI can help to lateralize language in the workup of patients for epilepsy surgery (limited evidence) cheap amoxil 500 mg on-line. Functional MRI has a sen- sitivity greater than 91% for language lateralization cheap 250 mg amoxil with mastercard, when the intracarotid Amytal test (Wada test) is used as the reference standard (Table 11 cheap 250 mg amoxil otc. In the level II meta-analysis study (moderate evidence) reported by Spencer (38), ictal SPECT was performed in 108 patients. In temporal lobe epilepsy the diagnostic sensitivity for ictal or postictal SPECT is 90% and the speci- ﬁcity of 73%. In extratemporal lobe epilepsy ictal SPECT sensitivity decreases to 81% and speciﬁcity increases to 93% when using EEG criteria as the standard of reference. Interictal SPECT sensitivity and speciﬁcity were found to be signiﬁcantly lower, at 66% and 68%, respectively, for temporal lobe, and at 60% and 93%, respectively, for extratemporal regions when compared to EEG. The pooled data were gathered from 624 interictal, 101 postictal, and 136 ictal cases. The results from this study showed that the sensitivity of technetium-99m labeled hexamethyl-propylene amine oxime (HMPAO) SPECT in localizing a temporal lobe epileptic focus increases from 44% in interictal studies to 75% in postictal studies and reaches 97% in ictal studies. In 119 patients with known unilateral temporal lobe epilepsy, correct localization by ictal SPECT was demonstrated in 97% of cases. In extratemporal epilepsy, the yield of ictal SPECT studies was 92% and that of postictal SPECT studies was 46%. In 58% of the studies the sub- traction images "contributed additional information" but were confusing in 9%. In a level III study (limited evidence) of 312 patients pooled by Spencer (38), PET was compared to EEG for localization. A total of 205 patients had reduced temporal lobe metabolism of which 98% were concordant with EEG ﬁndings. Thirty-two patients had hypometabolism in an extratempo- ral location, which was concordant with EEG in 56% of cases. The abnor- malities in 75 patients were not localized by PET, 36 of whom had temporal lobe EEG abnormalities. The diagnostic sensitivity for ﬂuorodeoxyglucose (FDG)-PET was 84% (speciﬁcity of 86%) for temporal, and 33% (speciﬁcity of 95%) for extratemporal epilepsy, respectively. A level III study (limited evidence) of single-voxel proton MR spec- troscopy (MRS) was performed to lateralize seizures; MRS was compared with MRI and PET in a case series of 33 HS patients (48). The sensitivity of MRS and PET in lesion lat- eralization was 85% for both, using MRI as the reference standard. Functional MRI is a new technique based on the ability to detect small amounts of paramagnetic susceptibility produced by blood-oxygen level changes linked to brain cortical activity. Although fMRI is still under inves- tigation and is without Food and Drug Administration (FDA) approval, it has shown promise as an examination that might replace the more inva- sive and expensive Wada intracarotid amobarbital exam in the lateraliza- tion and location of language in patients who are candidates for epilepsy surgery. One level III case-series paper (limited evidence) (49) describes procedures and results of language dominance lateralization in 100 patients with partial epilepsy performing a covert word generation task. The reference standard was a bilateral Wada intracarotid amobarbital test (IAT) performed in all cases. Divergent results between the tasks included two cases in which the IAT showed absence of lateralization. One case showed Chapter 11 Neuroimaging of Seizures 209 bilateral fMRI activation and lateralized IAT. The Miami Children’s Hospital Group, in a prospective study (moder- ate evidence), enrolled prospectively 60 subjects to determine the role of fMRI in the diagnostic evaluation and surgical treatment of patients with seizure disorders. The authors concluded that fMRI inﬂuences the seizure team’s diagnostic and therapeutic decision making (51).
The OKR suggests that radi- ography should be performed on the acutely injured knee when the patient has one or more of the following criteria: (1) age 55 years or older purchase 500mg amoxil with amex, (2) iso- lated tenderness of the patella (no other knee bone tenderness) order 500 mg amoxil with mastercard, (3) ten- derness of the head of the ﬁbula amoxil 250 mg visa, (4) inability to ﬂex the knee to 90 degrees order amoxil 250mg on-line, or (5) inability to bear weight both immediately and in the emergency department for four steps. Initial assessment of the interobserver reliabil- ity of the OKR suggested excellent agreement between physicians (27); however, more recent work evaluating the agreement between nurses and physicians has been less impressive (20,28,29). These variable results emphasize the need for thorough training and support for clinicians before implementing the OKR. Clinical decision rules for radiography of acute knee injury % Sensitivity Speciﬁcity Validation Rule Criteria for radiography (Ref. Patient does not need radiograph if: 100 (26) 34 (26) 26 (26) • Able to walk without limping • Twist injury without effusion Chapter 15 Imaging for Knee and Shoulder Problems 277 A recent systematic review found 11 studies evaluating the diagnostic accuracy of the OKR (10). Six of these studies were suitable for inclusion in a meta-analysis, of which four were considered to be of high quality (i. While this provides strong evidence (level I) that the OKR is sensitive at predicting fracture, it does not prove that it is a cost-effective method of organizing care. Based on case series, several authors have speculated that adherence to the OKR would reduce the utilization of knee radiography in the emer- gency department by between 17% and 49% (25,27,30–35). However, these estimates rely on the assumption that clinicians would rigidly follow the OKR and would not be swayed by fears of missed diagnoses or patient expectations of imaging. Only one controlled trial has evaluated whether radiography utilization can be curtailed in practice following the intro- duction of the OKR (22). Stiell and colleagues (22) enrolled 3907 patients with isolated knee trauma at four hospitals in a prospective, controlled, before-and-after study. In the hospitals where the OKR was introduced, the absolute rate of radiography requests fell by 20. By comparison, there was a minimal (1%) reduction at the control hospitals; this disparity was statistically signiﬁcant. Furthermore, patients who were not imaged spent less time in the emergency department and had lower follow-up costs than their counterparts who were referred for radiography. Therefore, there is moderate evidence (level II) that the OKR has a beneﬁcial impact. Cost-Effectiveness Analysis The same research group has also developed a simple cost-beneﬁt decision model comparing the OKR to usual practice (36). The reduced costs of imaging, follow-up care, and days off from work observed after the imple- mentation of the OKR are balanced against the potential for increased malpractice costs. However, in the primary analysis, the model did not quantify any costs that might result from the delayed recovery of patients with fractures falsely diagnosed as normal. The authors conclude that the introduction of the OKR resulted in a modest ($34) saving per patient, but, due to the high volume of minor knee injuries, the total economic impact is large. If the sensitivity of OKR falls more than 1% below that of usual practice, the conclusions are reversed. Until a broader body of research is available comparing the sensitivity and speciﬁcity of OKR to usual practice, we con- sider that there is limited evidence (level III) to support the hypothesis that the OKR is cost-effective in emergency departments. In many cases plain radiography is all that is required to allow the clini- cian to proceed with conservative therapy. If a fracture is seen, there is increasing use of computed tomography (CT) or MRI to determine whether structures such as the tibial plateau are depressed to an extent that war- rants surgical elevation. Because there are anecdotal accounts of CT and MRI identifying fractures when plain radiographs are normal, some clini- cians seek reassurance from CT/MRI in equivocal cases. Different clini- cians have different thresholds for this need for reassurance, and there is 278 W. Even when plain radi- ographs show subtle tibial plateau depression and CT in the coronal or sagittal plane shows 2- to 5-mm depression, clinicians vary in their subse- quent management decisions; some may proceed with surgical elevation and some may not. The evidence that patients with a 4-mm depression do signiﬁcantly better with surgery than without is also scant. However, with increasingly noninvasive techniques now on offer there is a trend toward more imaging being used as a roadmap for intervention. Applicability to Children The diagnostic performance of the OKR may be altered in the skeletally immature knee due to open growth plates and secondary ossiﬁcation centers resulting in different injury patterns (37). Additionally, tests such as weight bearing, which rely on considerable patient interaction, may not be as valid in the youngest children. Due to the small numbers of children in the youngest age category, these authors endorsed the OKR in children 5 years of age or over.
Therefore order amoxil 500 mg with amex, a malfunction of this inhibitory system could also lead Nociceptors to widespread pain buy 500 mg amoxil otc. In skeletal muscles trusted 250mg amoxil, there are three types of nocicep- tors that encode the intensity of noxious stimuli: Pain localization (a) Speciﬁc mechanical nociceptors responding only In both clinical and experimental scenarios cheap 250mg amoxil visa, focal stim- to high-intensity stimuli. It has been suggested that mechanisms of temporal (c) The free nerve endings in muscle tissue concen- summation contribute to pain diffusion, while referred trated around small arterioles and capillaries pain is related to the intensity of the stimuli. The fact between the muscle ﬁbres and not activated by nor- that pain and hyperalgesia can spread to areas far mal muscle movement or increasing muscle tension. Sensitization of neurones in the is transduced and carried to the CNS by A - and DH and other areas of somatosensory pathways follows C-afferent ﬁbres. This is reﬂected by: ischaemic contractions and are sensitized following tissue lesion and inﬂammation. When muscles are healthy, most dorsal horn (DH) • Expansion of the peripheral receptive ﬁelds of neurones receive projections from A -afferent ﬁbres, central neurones. DH neur- ones receiving exclusive projections from C-afferent ﬁbres are quite rare. The effect of C-afferent ﬁbres on Pain measurement DH neurones increases greatly following inﬂamma- tion. Thus, it has been suggested that, in the absence Clinical inspection of peripheral muscle pathology, acute pain is mainly due to A -ﬁbres, while chronic muscle pain is related In examining the muscular system, one should not to C-ﬁbres. This can be performed by: 1997), myositis-induced hyperexcitability of DH neurones involves the activation of neurokinin 1 • Observing movements. They constitute a large group of muscle dis- can be expressed unidimensionally with categorical orders characterized by hypersensitive sites (called TP) rating scales, numerical rating scales and visual ana- within: one or more muscles, the underlying connect- logue scales. Symptoms include: using the McGill pain questionnaire (MPQ) and a diagram allowing patients to mark the areas of pain. Although local pain may also be present, the symp- • Referred pain – most frequently manifested as sec- toms are usually referred to a deep area in muscle dis- ondary hyperalgesia, in dermatomes and myotomes tant from the TP. Symptoms Trigger Points (TP) Clinical syndromes A TP (also known as a trigger area, trigger zone or myal- gic spot) is so named because its stimulation, by pres- Muscle pain is not synonymous with muscle disease. Muscle tissue During a physical examination, systematic palpation represents a large amount of body weight (up to 30% of muscles may cause the patient to jump, wince, or of overall body mass in young athletes) and is pro- cry out, because of pressure on the extremely tender vided with a rich innervation. TPs can develop in any muscle of the body, but plaints’ that cannot be attributed to diseases of the occur most frequently in: spine, joints or connective tissues have their source in Neck. They are usually located in the mid-portion of the 2 Fibromyalgia syndrome (FMS), with diffuse pain. Only active TPs are responsible for clin- • Fibromyalgia: Characterized by local tenderness at ical pain complaints. A latent TP may cause limi- tation of range of movement and weakness in the affected muscle. Myofascial pain syndromes Taut band These syndromes occur frequently, may cause severe disabling pain and once recognized, are relatively According to Travell and Simons (1983), a palpable simple to manage. They have been described using a taut band associated with a TP is a critically important MYOFASCIAL/MUSCULOSKELETAL PAIN 131 area. This is the spillover reference zone, in which pain is felt only in some patients (Figure 19. The clinician can use the predictability of pain patterns as a reference to locate the source of myofascial pain (i. Deep (often continuous) hyperalgesia or ten- derness are associated with pain in the reference zone. Local twitch response Snapping palpation across the TP elicits a local twitch (a) (b) response, due to transient contraction of the taut band ﬁbres. This is an objective physical sign that occurs only after this type of mechanical stimulation.
There is certainly a vocal pressure group within the m edical profession calling for the reinstatem ent of the hum ble case report as a useful and valid contribution to m edical science cheap 500mg amoxil amex. The doctor wishes to alert his colleagues worldwide to the possibility of drug related dam age as quickly as possible order amoxil 500 mg overnight delivery. The pinnacle of the hierarchy is buy amoxil 250mg visa, quite properly buy amoxil 500 mg online, reserved for secondary research papers, in which all the prim ary studies on a particular subject have been hunted out and critically appraised according to rigorous criteria (see Chapter 8). N ote, however, that not even the m ost hard line protagonist of evidence based m edicine would place a sloppy m etaanalysis or a random ised controlled trial that was seriously m ethodologically flawed above a large, well designed cohort study. And as Chapter 11 shows, m any im portant and valid studies in the field of qualitative research do not feature in this particular hierarchy of evidence at all. In other words, evaluating the potential contribution of a particular study to m edical science requires considerably m ore effort than is needed to check off its basic design against the six point scale above. I was soon invited out to lunch by two charm ing registrars, who (I later realised) were seeking m y help with their research. W hen they assured m e that the average 90 year old would hardly notice the procedure, I sm elt a rat and refused to cooperate with their project. I was naïvely unaware of the seriousness of the offence being planned by these doctors. D oing any research, particularly that which involves invasive procedures, on vulnerable and sick patients without full consideration of ethical issues is both a crim inal offence and potential grounds for a doctor to be "struck off" the m edical register. G etting ethical approval for one’s research study can be an enorm ous bureaucratic hurdle,58 but it is nevertheless a legal requirem ent (and one which was, until recently, frequently ignored in research into the elderly and those with learning difficulties59). M ost editors routinely refuse to publish research which has not been approved by the relevant research ethics com m ittee but if you are in doubt about a paper’s status, there is nothing to stop you writing to ask the authors for copies of relevant docum ents. The random ised trial which showed that neural tube defects could be prevented by giving folic acid supplem ents to the m other in early pregnancy60 is said to have been held back for years because of ethics com m ittee resistance. H ow to use an article evaluating the clinical im pact of a com puter-based clinical decision support system. Random ised trial of intravenous streptokinase, aspirin, both, or neither am ong 17187 cases of suspected acute m yocardial infarction: ISIS-2. Publication bias: evidence of delayed publication in a cohort study of clinical research projects. Seeing what you want to see in random ised controlled trials: versions and perversions of the U K PD S data. Com peting or com plem entary: ethical considerations and the quality of random ised trials. M ortality in relation to sm oking: 40 years’ observations on m ale British doctors. Itraconazole prevents terfenadine m etabolism and increases the risk of torsades de pointes ventricular tachycardia. This chapter considers five essential questions which should form the basis of your decision to "bin" it, suspend judgem ent or use it to influence your practice. There is, in theory, no point in testing a scientific question which som eone else has already proved one way or the other. Only a tiny proportion of m edical research breaks entirely new ground and an equally tiny proportion repeats exactly the steps of previous workers. The vast m ajority of research studies will tell us (if they are m ethodologically sound) that a particular hypothesis is slightly m ore or less likely to be correct than it was before we added our piece to the wider jigsaw. H ence, it m ay be perfectly valid to do a study which is, on the face of it, "unoriginal". Indeed, the whole science of m eta-analysis depends on there being several studies in the literature which have 59 H OW TO READ A PAPER addressed the sam e question in pretty m uch the sam e way. The practical question to ask, then, about a new piece of research is not "H as anyone ever done a sim ilar study before? One of the first papers that ever caught m y eye was entitled "But will it help my patients with m yocardial infarction? The m ain reasons why the participants (Sir Iain Chalm ers has argued forcefully against calling them "patients")2 in a clinical trial or survey m ight differ from patients in "real life" are as follows. H ence, before swallowing the results of any paper whole, ask yourself the following questions.
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