Headaches Attributed to Disorders of Homeostasis

Headaches attributed to disorders of homeostasis include those different headache types associated with metabolic and systemic diseases. These are headache disorders occurring in temporal relation to a disorder of homeostasis including hypoxia, high altitude, airplane travel, diving, sleep apnea, dialysis, autonomic dysreflexia, hypothyroidism, fasting, cardiac cephalalgia, hypertension and other hypertensive disorders like pheochromocytoma, hypertensive crisis, and encephalopathy, as well as preeclampsia or eclampsia. The proposed mechanism behind the causation of these headache subtypes including diagnostic criteria, evaluation, treatment, and overall management will be discussed.

The Toronto Concussion Study: a prospective investigation of characteristics in a cohort of adults from the general population seeking care following acute concussion, 2016-2020

Purpose

There is limited research regarding the characteristics of those from the general population who seek care following acute concussion.

Methods

To address this gap, a large cohort of 473 adults diagnosed with an acute concussion (female participants = 287; male participants = 186) was followed using objective measures prospectively over 16 weeks beginning at a mean of 5.1 days post-injury.

Results

Falls were the most common mechanism of injury (MOI) (n = 137, 29.0%), followed by sports-related recreation (n = 119, 25.2%). Male participants were more likely to be injured playing recreational sports or in a violence-related incident; female participants were more likely to be injured by falling. Post-traumatic amnesia (PTA) was reported by 80 participants (16.9 %), and loss of consciousness (LOC) was reported by 110 (23.3%). In total, 54 participants (11.4%) reported both PTA and LOC. Male participants had significantly higher rates of PTA and LOC after their injury compared to their female counterparts. Higher initial symptom burden was associated with a longer duration of recovery for both male and female participants. Female participants had more symptoms and higher severity of symptoms at presentation compared to male participants. Female participants were identified to have a longer recovery duration, with a mean survival time of 6.50 weeks compared to 5.45 weeks in male participants (p < 0.0001). A relatively high proportion of female and male participants in this study reported premorbid diagnoses of depression and anxiety compared to general population characteristics.

Conclusion

Although premorbid diagnoses of depression and/or anxiety were associated with higher symptom burden at the initial visit, the duration of symptoms was not directly associated with a pre-injury history of psychological/psychiatric disturbance. This cohort of adults, from the general population, seeking care for their acute concussion attained clinical and functional recovery over a period of 4-12 weeks.

Revisiting the ICHD-3 criteria for headache attributed to mild traumatic injury to the head: Insights from the Toronto Concussion Study Analysis of Acute Headaches Following Concussion

BACKGROUND

There is limited prospective data on the prevalence, timing of onset, and characteristics of acute headache following concussion/mild traumatic brain injury.

METHODS

Adults diagnosed with concussion (arising from injuries not related to work or motor vehicle accidents) were recruited from emergency departments and seen within one week post injury wherein they completed questionnaires assessing demographic variables, pre-injury headache history, post-injury headache history, and the Sport Concussion Assessment Tool (SCAT-3) symptom checklist, the Sleep and Concussion Questionnaire (SCQ) and mood/anxiety on the Brief Symptom Inventory (BSI).

RESULTS

A total of 302 participants (59% female) were enrolled (mean age 33.6 years) and almost all (92%) endorsed post-traumatic headache (PTH) with 94% endorsing headache onset within 24 hours of injury. Headache location was not correlated with site of injury. Most participants (84%) experienced daily headache. Headache quality was pressure/squeezing in 69% and throbbing/pulsing type in 22%. Associated symptoms included: photophobia (74%), phonophobia (72%) and nausea (55%). SCAT-3 symptom scores, Brief Symptom Inventory and Sleep and Concussion Questionnaire scores were significantly higher in those endorsing acute PTH. No significant differences were found in week 1 acute PTH by sex, history of migraine, pre-injury headache frequency, anxiety, or depression, nor presence/absence of post-traumatic amnesia and self-reported loss of consciousness.

CONCLUSIONS

This study highlights the very high incidence of acute PTH following concussion, the timing of onset and characteristics of acute PTH, the associated psychological and sleep disturbances and notes that the current ICHD-3 criteria for headaches attributed to mild traumatic injury to the head are reasonable, the interval between injury and headache onset should not be extended beyond seven days and could, potentially, be shorted to allow for greater diagnostic precision.

A real-world, observational study of erenumab for migraine prevention in Canadian patients

Objectives

To assess real‐world effectiveness, safety, and usage of erenumab in Canadian patients with episodic and chronic migraine with prior ineffective prophylactic treatments.

Background

In randomized controlled trials, erenumab demonstrated efficacy for migraine prevention in patients with ≤4 prior ineffective prophylactic migraine therapies. The “Migraine prevention with AimoviG: Informative Canadian real‐world study” (MAGIC) assessed real‐world effectiveness of erenumab in Canadian patients with migraine.

Methods

MAGIC was a prospective open‐label, observational study conducted in Canadian patients with chronic migraine (CM) and episodic migraine (EM) with two to six categories of prior ineffective prophylactic therapies. Participants were administered 70 mg or 140 mg erenumab monthly based on physician’s assessment. Migraine attacks were self‐assessed using an electronic diary and patient‐reported outcome questionnaires. The primary outcome was the proportion of subjects achieving ≥50% reduction in monthly migraine days (MMD) after the 3‐month treatment period.

Results

Among the 95 participants who mostly experienced two (54.7%) or three (32.6%) prior categories of ineffective prophylactic therapies and who initiated erenumab, treatment was generally safe and well tolerated; 89/95 (93.7%) participants initiated treatment with 140 mg erenumab. At week 12, 32/95 (33.7%) participants including 17/64 (26.6%) CM and 15/32 (48.4%) EM achieved ≥50% reduction in MMD while 30/86 (34.9%) participants including 19/55 (34.5%) CM and 11/31 (35.5%) EM achieved ≥50% reduction in MMD at week 24. Through patient‐reported outcome questionnaires, 62/95 (65.3%) and 45/86 (52.3%) participants reported improvement of their condition at weeks 12 and 24, respectively. Physicians observed improvement in the condition of 78/95 (82.1%) and 67/86 (77.9%) participants at weeks 12 and 24, respectively.

Conclusion

One‐third of patients with EM and CM achieved ≥50% MMD reduction after 3 months of erenumab treatment. This study provides real‐world evidence of erenumab effectiveness, safety, and usage for migraine prevention in adult Canadian patients with multiple prior ineffective prophylactic treatments.

Real-world persistence of erenumab for preventive treatment of chronic and episodic migraine: Retrospective real-world study

OBJECTIVE

To describe the real-world treatment persistence (defined as the continuation of medication for the prescribed treatment duration), demographics and clinical characteristics, and treatment patterns for patients prescribed erenumab for migraine prevention in Canada.

BACKGROUND

The effectiveness of prophylactic migraine treatments is often undermined by poor treatment persistence. In clinical trials, erenumab has demonstrated efficacy and tolerability as a preventive treatment, but less is known about the longer term treatment persistence with erenumab.

METHODS

This is a real-world retrospective cohort study where a descriptive analysis of secondary patient data was conducted. Enrollment and prescription data were extracted from a patient support program for a cohort of patients prescribed erenumab in Canada between September 2018 and December 2019 and analyzed for persistence, baseline demographics, clinical characteristics, and treatment patterns. Descriptive analyses and unadjusted Kaplan-Meier (KM) curves were used to summarize the persistence and dose escalation/de-escalation at different timepoints.

RESULTS

Data were analyzed for 14,282 patients. Median patient age was 47 years, 11,852 (83.0%) of patients were female, and 9443 (66.1%) had chronic migraine at treatment initiation. Based on KM methods, 71.0% of patients overall were persistent to erenumab 360 days after treatment initiation. Within 360 days of treatment initiation, it is estimated that 59.3% (KM-derived) of patients who initiated erenumab at 70 mg escalated to 140 mg, and 4.4% (KM-derived) of patients who initiated at 140 mg de-escalated to 70 mg.

CONCLUSIONS

The majority of patients prescribed erenumab remained persistent for at least a year after treatment initiation, and most patients initiated or escalated to a 140 mg dose. These results suggest that erenumab is well tolerated, and its uptake as a new class of prophylactic treatment for migraine in real-world clinical practice is not likely to be undermined by poor persistence when coverage for erenumab is easily available.

Canadian Headache Society systematic review and recommendations on the treatment of migraine pain in emergency settings

BACKGROUND

There is a considerable amount of practice variation in managing migraines in emergency settings, and evidence-based therapies are often not used first line.

METHODS

A peer-reviewed search of databases (MEDLINE, Embase, CENTRAL) was carried out to identify randomized and quasi-randomized controlled trials of interventions for acute pain relief in adults presenting with migraine to emergency settings. Where possible, data were pooled into meta-analyses.

RESULTS

Two independent reviewers screened 831 titles and abstracts for eligibility. Three independent reviewers subsequently evaluated 120 full text articles for inclusion, of which 44 were included. Individual studies were then assigned a US Preventive Services Task Force quality rating. The GRADE scheme was used to assign a level of evidence and recommendation strength for each intervention.

INTERPRETATION

We strongly recommend the use of prochlorperazine based on a high level of evidence, lysine acetylsalicylic acid, metoclopramide and sumatriptan, based on a moderate level of evidence, and ketorolac, based on a low level of evidence. We weakly recommend the use of chlorpromazine based on a moderate level of evidence, and ergotamine, dihydroergotamine, lidocaine intranasal and meperidine, based on a low level of evidence. We found evidence to recommend strongly against the use of dexamethasone, based on a moderate level of evidence, and granisetron, haloperidol and trimethobenzamide based on a low level of evidence. Based on moderate-quality evidence, we recommend weakly against the use of acetaminophen and magnesium sulfate. Based on low-quality evidence, we recommend weakly against the use of diclofenac, droperidol, lidocaine intravenous, lysine clonixinate, morphine, propofol, sodium valproate and tramadol.

Metabolic headaches

This article discusses headaches secondary to disorders of homeostasis, which include headaches attributed to (1) hypoxia and/or hypercapnia (high-altitude, diving, or sleep apnea), (2) dialysis, (3) arterial hypertension (pheochromocytoma, hypertensive crisis without hypertensive encephalopathy, hypertensive encephalopathy, preeclampsia or eclampsia, or autonomic dysreflexia), (4) hypothyroidism, (5) fasting, (6) cardiac cephalalgia, and (7) other disorder of homeostasis. Clinical features and diagnosis as well as therapeutic strategies are discussed for each headache type.

Canadian Headache Society Guideline: acute drug therapy for migraine headache

OBJECTIVES

The primary objective of this guideline is to assist the practitioner in choosing an appropriate acute medication for an individual with migraine, based on current evidence in the medical literature and expert consensus. It is focused on patients with episodic migraine ( headache on ≤ 14 days a month).

METHODS

A detailed search strategy was used to find a relevant meta-analyses, systematic reviews and randomized double-blind controlled trials. Recommendations were graded with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group, using a consensus group. In addition, a general literature review and expert consensus were used for aspects of acute therapy for which randomized controlled trials were not available.

RESULTS

Twelve acute medications received a strong recommendation for use in acute migraine therapy (almotriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, sumatriptan, zomitriptan, ASA, ibuprofen, naproxen sodium, diclofenac potassium, and acetaminophen). Four received a weak recommendation for use (dihydroergotamine, ergotamine, codeine-containing combination analgesics, and tramadol- containing medications). Three of these were NOT recommended for routine use (ergotamine and codeine- and tramadol- containing medications). Strong recommendations were made to avoid use of butorphanol and butalbital- containing medications. Metoclopramide and domperidone were strongly recommended for use when necessary. Our analysis also resulted in the formulation of eight general acute migraine management strategies. These were grouped into: 1) two mild-moderate attack strategies, 2) two moderate-severe attack or NSAID failure strategies, 3) three refractory migraine strategies, and 4) a vasoconstrictor unresponsive-contraindicated strategy. Additional were developed for menstrual migraine during pregnancy, and migraine during lactation.

CONCLUSION

This guideline provides evidence-based advice on acute pharmacological migraine therapy, and should be helpful to both health professionals and patients, The available medications have been organized into a series of strategies based on patient clinical features. These strategies may help practitioners make appropriate acute medication choices for patients with migraine.

Canadian Headache Society guideline for migraine prophylaxis

OBJECTIVES

The primary objective of this guideline is to assist the practitioner in choosing an appropriate prophylactic medication for an individual with migraine, based on current evidence in the medical literature and expert consensus. This guideline is focused on patients with episodic migraine (headache on ≤ 14 days a month).

METHODS

Through a comprehensive search strategy, randomized, double blind, controlled trials of drug treatments for migraine prophylaxis and relevant Cochrane reviews were identified. Studies were graded according to criteria developed by the US Preventive Services Task Force. Recommendations were graded according to the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group. In addition, a general literature review and expert consensus were used for aspects of prophylactic therapy for which randomized controlled trials are not available.

RESULTS

Prophylactic drug choice should be based on evidence for efficacy, side-effect profile, migraine clinical features, and co-existing disorders. Based on our review, 11 prophylactic drugs received a strong recommendation for use (topiramate, propranolol, nadolol, metoprolol, amitriptyline, gabapentin, candesartan, butterbur, riboflavin, coenzyme Q10, and magnesium citrate) and 6 received a weak recommendation (divalproex sodium, flunarizine, pizotifen, venlafaxine, verapamil, and lisinopril). Quality of evidence for different medications varied from high to low. Prophylactic treatment strategies were developed to assist the practitioner in selecting a prophylactic drug for specific clinical situations. These strategies included: first time strategies for patients who have not had prophylaxis before (a beta-blocker and a tricyclic strategy), low side effect strategies (including both drug and herbal/vitamin/mineral strategies), a strategy for patients with high body mass index, strategies for patients with co-existent hypertension or with co-existent depression and /or anxiety, and additional monotherapy drug strategies for patients who have failed previous prophylactic trials. Further strategies included a refractory migraine strategy and strategies for prophylaxis during pregnancy and lactation.

CONCLUSIONS

There is good evidence from randomized controlled trials for use of a number of different prophylactic medications in patients with migraine. Medication choice for an individual patient requires careful consideration of patient clinical features.

Cost of health care among patients with chronic and episodic migraine in Canada and the USA: results from the International Burden of Migraine Study (IBMS)

OBJECTIVE

To evaluate and compare healthcare resource use and related costs in chronic migraine and episodic migraine in the USA and Canada.

BACKGROUND

Migraine is a common neurological disorder that produces substantial disability for sufferers around the world. Several studies have quantified overall costs associated with migraine in general, with recent estimates ranging from $581 to $7089 per year. Although prior studies have characterized the clinical and humanistic burden of chronic migraine relative to episodic migraine, to the best of our knowledge only 1 previous study has compared chronic migraine and episodic migraine healthcare costs. The purpose of this study was to quantify and compare the direct medical costs of chronic migraine and episodic migraine using medical resource use data collected as part of the International Burden of Migraine Study.

METHODS

Cross-sectional data were collected from respondents in 10 countries via a Web-based survey. Respondents were classified as chronic migraine (≥15 headache days/month) or episodic migraine (<15 headache days/month). Data collection included socio-demographic and clinical characteristics and medical resource use for headache (clinician and emergency department visits and hospitalizations over the preceding 3 months and medications over the preceding 4 weeks). Unit cost data were collected outside of the Web-based survey using publicly available sources and then applied to resource use profiles. Cost estimates are presented in 2010 US and Canadian dollars.

RESULTS

In this manuscript, the analysis included data from respondents with migraine in the USA (N=1204) and Canada (N=681). The most common medical services utilized by all respondents included headache-specific medication, healthcare provider visits, emergency department visits, and diagnostic testing. In the USA, approximately one-quarter (26.2%) of chronic migraine participants vs 13.9% of episodic migraine participants reported visiting a primary care physician in the preceding 3 months (P<.001). In Canada, one-half (48.2%) of chronic migraine participants had a primary care physician visit, compared with 12.3% of episodic migraine subjects (P< .0001). Total mean headache-related costs for participants with chronic migraine in the USA were $1036 (±$1334) over 3 months compared to $383 (±807, P< .001) for persons with episodic migraine. In Canada, total mean headache-related costs among chronic migraine subjects were $471 (±1022) compared to $172 (±920, P< .001) for episodic migraine subjects.

CONCLUSIONS

Chronic migraine was associated with higher medical resource use and total costs compared to episodic migraine. Therapies that reduce headache frequency could become important approaches for containing or reducing headache-related medical costs.

Headaches attributable to infectious diseases

Headache is the most common symptom that humans experience. While the vast majority of headaches are due to benign primary headache disorders, a small but important minority of headaches are due to secondary causes. Whereas significant emphasis is placed on educating physicians regarding prompt recognition of subarachnoid hemorrhage and headaches secondary to brain tumors, attention toward headaches secondary to infectious causes is often neglected. Unfortunately, a missed or delayed diagnosis of a headache secondary to meningitis, encephalitis, brain abscess, subdural empyema, or other infectious etiologies can lead to dire consequences for both the patient and physician. Accordingly, this article provides an overview of headaches attributed to systemic and intracranial infectious causes.

Patterns of care and outcomes after computed tomography scans for headache

BACKGROUND

concerns exist about potential overuse of computed tomography (CT) scans for headache in ambulatory care.

METHODS

we sought to examine health services use, brain tumor diagnosis, and death during the year after CT scanning for headache by linking records of an audit of 3930 outpatient CT brain scans performed in 2005 in Ontario, Canada, to administrative databases.

RESULTS

of 623 patients receiving CT scans for a sole indication of headache, few (2.1%) scans contained findings potentially causing their headache. For most patients, the index CT scan was the only one received over an 11-year period. However, 28.4% of patients received 1 or more CT brain scans during the preceding decade and 6.7% received 1 or more CT brain scans during the subsequent year. Of the 473 patients (75.9%) whose index scan was ordered by a primary care physician, most (80.3%) did not see a specialist during follow-up. One patient with an indeterminate finding on the index scan was diagnosed with a malignant brain tumor (0.2%), and 6 patients (1.0%) died during follow-up. Among the 4 deaths in which the cause could be determined, none were due to central nervous system causes.

CONCLUSION

because of the potential risk of cancer from exposure to ionizing radiation, efforts should be made to avoid CT scanning for headache when the likelihood of serious illness is low. Evidence-based decision rules that identify which patients with headache do not require neuroimaging may decrease the use of CT scans in situations of little benefit.

From psychoneurosis to ICHD-2: an overview of the state of the art in post-traumatic headache

Post-traumatic headache (PTH) is an important public health issue - head injuries are common, headache is the most common sequelae of head injuries, and PTH can be particularly disabling. Fortunately, for most individuals with PTH, the headache gradually dissipates over a period of several days, weeks, or months either spontaneously or aided by non-pharmacologic and/or pharmacologic management. Regrettably, for a minority of head-injured individuals, the PTH is intractable and disabling despite aggressive and comprehensive treatment. Unfortunately, there are many prejudices against individuals with PTH. Frequently, the presence or absence of litigation and/or the mechanism of head injury (sports-related trauma, slip-and-fall injury, motor vehicle accident, or military service-related injury) biases physicians' views on the legitimacy of the patient's PTH. Accordingly, this review attempts to summarize the state of the art of our understanding of PTH. This clinical review highlights: (a) views on PTH throughout the last few centuries, (b) the ICHD-2 classification of PTH, (c) the epidemiology of head injuries and PTH, (d) the clinical characteristics of PTH, (e) PTH related postconcussive symptoms, (f) pathophysiology of PTH, (g) evaluation of PTH, and (h) management of PTH.

Binge alcohol consumption by non-alcohol-dependent women during pregnancy affects child behaviour, but not general intellectual functioning; a prospective controlled study

Effects of binge ethanol consumption during early gestation on child neurodevelopment have not been elucidated. To study whether binge drinking affects cognitive abilities and behavior of exposed children, a prospective observational study comparing 51 children exposed to binge drinking during the first trimester of pregnancy to 51 children not exposed to any teratogens was conducted. The children's physical development, intelligence, language abilities and behavior were assessed. Temperament test results showed that children exposed in utero to maternal binge drinking displayed a greater degree of disinhibited behavior and that this behavior was associated with early drinking variables. Although binge alcohol drinking by non-alcohol-dependent women during the first trimester of pregnancy does not appear to affect intelligence or cognitive and language development of young children, binge drinking in pregnancy does increase the likelihood of certain behavioral characteristics that might predispose these children to later behavioral dysfunction.

Chronic daily headache: a rational approach to a challenging problem

Chronic daily headache (CDH) is a significant public health problem with 3 to 5% of the population worldwide experiencing daily or near-daily headaches. Patients with CDH can be particularly challenging, and clinicians require a systematic approach to help guide investigations and management. The revised 2004 International Headache Society Classification Criteria introduces formalized criteria for several CDH disorders including chronic migraine and medication overuse headache as well as new daily persistent headache, hemicrania continua, hypnic headache, and SUNCT syndrome. Medication overuse is common in patients with CDH who present to physicians. Familiarity and comfort with drug-withdrawal and detoxification strategies is therefore essential. Patients with chronic migraine and chronic cluster experience significant disability and diminished quality of life. The ability to manage these patients effectively is a rewarding clinical experience.

A family perspective of family/staff interaction in long-term care facilities

This article explores the ways that families perceive their relationships with the staff in long-term care facilities. Qualitative interviews were conducted with 27 families who had elder members in two facilities in Ontario, Canada. The families identified the staff characteristics that they valued and the ways they developed relationships with staff members.

Avulsion fracture of the sublime tubercle of the ulna: a newly recognized injury in the throwing athlete

OBJECTIVE

The purpose of this report is to describe the imaging features in three cases of avulsion injury of the sublime tubercle of the ulna that occurred in throwing athletes.

CONCLUSION

Avulsion fracture of the sublime tubercle of the ulna is a potential cause of chronic medial elbow pain in the throwing athlete. This entity is best evaluated with a combination of plain radiographs and coronal MR images, particularly gradient-echo images that show the continuity of the avulsed fragment with the ulnar collateral ligament.

Characteristics of pregnant women who engage in binge alcohol consumption

OBJECTIVE

To characterize pregnant women who engage in binge drinking and to identify other risk behaviour that these women engage in.

DESIGN

Observational study based on retrospective review of records.

SETTING

A telephone and outpatient counselling service in Toronto that advises pregnant women about exposure to drugs, chemicals, radiation and infections during pregnancy and lactation.

PARTICIPANTS

All pregnant women who sought counselling concerning fetal risk of exposure to binge drinking from 1985 to 1994 as well as those counselled by telephone from 1993 to 1994, and an equal number of control women who sought counselling.

OUTCOME MEASURES

Information about binges, demographic factors, history of elective and spontaneous abortion, and use of psychotropic drugs and cigarettes as well as marijuana, cocaine and other illicit drugs.

RESULTS

Of the 3800 women seen in the clinic, 119 (3.1%) reported binge drinking during pregnancy; of the 19,991 women counselled by telephone, 153 (0.8%) reported binge drinking during pregnancy. The mean number of drinks per binge was 7.2 (standard deviation 2.5). None of the women was an alcoholic; 83.1% had binged fewer than 10 times during their pregnancy. A large majority (84.0%) of the women had a binge early in the first trimester (before 6 weeks' gestation). In comparison with control women, the women who had engaged in binge drinking were significantly younger (mean 30.0 v. 27.9 years, p < 0.0001) and more likely to be single (12.2% v. 54.6%, p < 0.0001), to be white (69.2% v. 92.9%, p < 0.004), to smoke (19.3% v. 57.1%, p < 0.0001) and to use cocaine (1.1% v. 11.0%, p < 0.0001), marijuana (3.0% v. 19.3%, p < 0.0001) and other illicit drugs (0.7% v. 9.2%, p < 0.0001).

CONCLUSIONS

Pregnant women who report binge alcohol consumption often report use of cigarettes, cocaine, marijuana and other illicit drugs as well, all of which represent a significant risk to the fetus. Rigorous efforts should be made to prevent the socially accepted binge consumption of alcohol among young, sexually active women.

Mild maternal drinking and pregnancy outcome: perceived versus true risks

Millions of fetuses worldwide every year are exposed to mild maternal alcohol consumption during the first trimester of pregnancy. Health professionals and agencies often suggest that even mild drinking can affect the fetus, despite many studies refuting this fact. To characterize women's perception of the teratogenic risk of alcohol we studied 30 nonpregnant adult women aged 19-52 years. They first watched a videotape which includes alarming information of fetal risk after mild drinking. Following the movie, women's views changed significantly towards believing that even one drink during pregnancy can harm the fetus. Scientists and physicians should refrain from unfounded statement of fetal risks from mild alcohol consumption. These may lead to unnecessary termination of otherwise wanted pregnancies.

Drug administration errors: a study into the factors underlying the occurrence and reporting of drug errors in a district general hospital

Drug administration is one of the highest risk areas of nursing practice and a matter of considerable concern for both managers and practitioners. The aim of this study, carried out in a district general hospital, was to identify any common themes that underlie the occurrence and reporting of drug administration errors. Data were collected from a variety of sources: drug error reports, questionnaires to nurses and nurse managers, and interviews with nurses who had been involved in drug errors. Several areas of particular concern emerged, including: the nurses' confusion regarding the definition of drug errors and the appropriate actions to take when they occurred; their fear of disciplinary action; their loss of clinical confidence; the variation in managerial response; and a possible lack of nurses' mathematical skills. The results from the study demonstrated that it was likely that many drug errors were not reported, for a variety of reasons. It is recommended that all of these issues are addressed as a matter of urgency, for the sake of both patients and nurse practitioners.

Quantitative genetics of sex ratio traits in the parasitic wasp, Nasonia vitripennis

We detected significant parent-offspring regressions for the first sex ratio (the sex ratio produced by a female in a fresh host) and the second sex ratio (the sex ratio produced by a female in a previously parasitized host) in the parasitic wasp, Nasonia vitripennis. For both traits, estimates of the narrow-sense heritability range from approximately 0.05 to approximately 0.15 (depending on how the data are analyzed). The study population was derived from isofemale strains created from wasps captured in a single bird nest. The same population exhibited no significant parent-offspring regression for the brood sizes associated with the first and second sex ratios. There may be a significant negative parent-offspring regression for diapause proportion in the first sex ratio broods. The estimates of the genetic correlations between first and second sex ratios are positive although almost all are not significantly different from 0.0. To our knowledge, this study is the first "fine-scale" analysis of genetic variation for sex ratio traits in any species of insect. Such studies are an essential part of the assessment of the validity of claims that sex ratio traits are locally optimal.

Outcome after maternal varicella infection in the first 20 weeks of pregnancy

BACKGROUND

Infection with the varicella-zoster virus during pregnancy can produce an embryopathy characterized by limb hypoplasia, eye and brain damage, and skin lesions. The risk is greatest when infection occurs during the first 20 weeks of pregnancy, but the magnitude of the risk is uncertain.

METHODS

We studied 106 women with clinically diagnosed varicella infection in the first 20 weeks of pregnancy and compared the outcomes with those in 106 age-matched, nonexposed controls.

RESULTS

Among the women with varicella, there was a trend toward more elective terminations of pregnancy (14 percent, vs. 7.5 percent among the controls; P = 0.1), corresponding to a significantly higher perception of teratogenic risk (P = 0.03). The proportions of miscarriages and live births and the mean birth weights were similar in the two study groups; there were more premature births (< or = 37 weeks) among the women with varicella infection (14.3 percent vs. 5.6 percent, P = 0.05). Congenital defects occurred in four infants born to the women with varicella (varicella embryopathy, hydrocephalus, meningocele and clubfeet, and hammer toe) and two infants born to the controls (ventricular septal defect and hip dislocation). The risk of varicella embryopathy after infection in the first 20 weeks was 1.2 percent (95 percent confidence interval, 0 to 2.4 percent). When we pooled our results with those from other prospective studies, the mean risk of embryopathy after infection with varicella-zoster virus in the first trimester was 2.2 percent (95 percent confidence interval, 0 to 4.6 percent).

CONCLUSIONS

The absolute risk of embryopathy after maternal varicella infection in the first 20 weeks of pregnancy is about 2 percent.

Continuous passive motion after arthroscopically assisted anterior cruciate ligament reconstruction: comparison of short- versus long-term use

The use of continuous passive motion (CPM) following anterior cruciate ligament (ACL) reconstruction has become common. The duration of use of CPM for maximal therapeutic benefit is not known. This study compared 4-day CPM use with 14-day CPM use following arthroscopic ACL reconstruction using a bone-patellar tendon-bone autograft prospectively in 20 patients. The patients were randomly allocated to the CPM 4-day group [6 h daily CPM for 4 days in hospital followed by intermittent passive motion (IPM) at home] or to the CPM 14-day group (6 h daily CPM for 14 days). The objective parameters measured were girth measurements at four lower limb locations for joint swelling and muscle atrophy; range of motion of the knee, measured goniometrically; and KT-1000 arthrometry measurements for joint laxity. The measurements were made prior to surgery, and on days 2, 7, 14, and 42, postoperatively. There were no statistically significant differences (p greater than 0.05) at 42 days postoperatively between groups in all parameters measured with the exception of KT-1000 laxity at 42 days.

The comparative biology of genetic variation for conditional sex ratio behavior in a parasitic wasp, Nasonia vitripennis

Using genetic markers, we tracked the sex ratio behavior of individual females of the parasitic wasp, Nasonia vitripennis, in foundress groups of size 1, 2, 4, 8 and 16. Comparison of 12 isofemale strains extracted from a natural population reveals significant between-strain heterogeneity of sex ratios produced in all sizes of foundress group. Under simple assumptions about population structure, this heterogeneity results in heterogeneity of fitnesses. The strains differ in their conditional sex ratio behavior (the sex ratio response of a female to foundress groups of different sizes). Females of some strains produce more males as foundress group size increases (up to size eight). Females of another strain produce more males when not alone but do not respond differentially to group size otherwise. Females of two other strains show no conditional sex ratio behavior. Females of only two strains behave differently in foundress groups of size 8 and 16. Correlation and regression analyses indicate that the strains differ significantly in their fit to the predictions of an evolutionarily stable strategy (ESS) model of conditional sex ratio behavior. Such heterogeneity contradicts the notion that females of this species possess conditonal sex ratio behavior that is optimal in the ESS sense. The results imply that this ESS model is useful but not sufficient for understanding the causal basis of the evolution of this behavior in this species. This is the first report on the sex ratio behavior of individual females in multiple foundress groups in any species of parasitic wasp. Data of this type (and not foundress group or "patch" sex ratios) are essential for testing evolutionary models that predict the sex ratio behaviors of individuals. We suggest that a test for an ESS model include the answers to two important questions: 1) is the model quantitatively accurate? and 2) is there reasonable evidence to indicate that natural selection has caused individuals to manifest the ESS behavior?

A mass-spectrometric investigation of the mechanism of the semisynthetic transformation of pig insulin into an ester of insulin of human sequence

In the trypsin-mediated semisynthetic transformation of pig insulin into an ester of insulin of human sequence, the B30 alanine residue of the pig hormone is replaced by an ester of threonine. The mechanism of this reaction was investigated by carrying out the transformation in a medium containing water enriched with 18O. Subsequent analysis by combined g.l.c.-mass spectrometry demonstrated that the oxygen isotope, is incorporated into the B29 carbonyl group of the insulin ester product. This result, together with those of appropriate controls, supports the conclusion that the transformation occurs, in the system studied, by a mechanism involving hydrolysis followed by coupling, and not by direct transpeptidation as has been previously found the case for another such system [Markussen & Schaumberg (1983) in Peptides 1982 (Bláha & Malon, eds.), pp. 387-394, W. de Gruyter, Berlin and New York].