An objective way to predict remission and relapse in Cushing disease using Bayes' theorem of probability

OBJECTIVE

In this study on patients with Cushing disease, post-transsphenoidal surgery (TSS), we attempt to predict the probability of remaining in remission, at least for a year and relapse after that, using Bayes' theorem and the equation of conditional probability. The number of parameters, as well as the weightage of each, is incorporated in this equation.

DESIGN AND METHODS

The study design was a single-centre ambispective study. Ten clinical, biochemical, radiological and histopathological parameters capable of predicting Cushing disease remission were identified. The presence or absence of each parameter was entered as binary numbers. Bayes' theorem was applied, and each patient's probability of remission and relapse was calculated.

RESULTS

A total of 145 patients were included in the study. ROC plot showed a cut-off value of the probability of 0.68, with a sensitivity of 82% (range 73-89%) and a specificity of 94% (range 83-99%) to predict the probability of remission. Eighty-one patients who were in remission at 1 year were followed up for relapse and 23 patients developed relapse of the disease. The Bayes' equation was able to predict relapse in only 3 out of 23 patients.

CONCLUSIONS

Using various parameters, remission of Cushing disease can be predicted by applying Bayes' theorem of conditional probability with a sensitivity and a specificity of 82% and 94%, respectively. This study provided an objective way of predicting remission after TSS and relapse in patients with Cushing disease giving a weightage advantage to every parameter.

Real-world experience of using stereotactic radiotherapy combined with anti-vascular endothelial growth factor to treat neovascular AMD

INTRODUCTION

Adjunctive treatment or longer-acting drugs are required to treat nAMD to help ease burdens for patients and hospital clinics alike. Stereotactic therapy is one such option, providing a reduction in the number of injections over time.

OBJECTIVE

To determine the clinical outcomes in a cohort of patients with nAMD receiving a combination therapy of stereotactic radiotherapy (SRT) with intravitreal anti-VEGF injections (IVI).

METHOD

A retrospective analysis of 74 patients with nAMD, who had received IVI and SRT (16 Gray maximum dose to the macula) at a large tertiary university eye hospital, between March 2018 and September 2019 was performed. The number of IVIs, visual acuity (VA), and central retinal thickness (CRT) were evaluated at 12, 24, and 36 months after patients received SRT and compared to the same time interval prior to SRT.

RESULTS

Follow-up data at 12, 24, and 36 months following and prior to SRT was available for 74, 48, and 22 patients respectively. Overall there was a significant reduction in the number of injections post-SRT. Twelve months following SRT, the median number of IVI was reduced by 1 (p < 0.05). The reduction in the median number of IVI was significantly reduced by 3 and 6 injections at 24- and 36-month follow-up respectively (p < 0.05). The CRT was significantly reduced post-SRT compared to the baseline values at all time periods. There was no statistically significant difference in VA at 12-month follow-up compared to baseline. The VA, however, significantly decreased at 24- and 36-month follow-up (p < 0.05).

CONCLUSION

A therapy combining SRT with IVI has shown an overall reduction in the number of injections required in nAMD patients at 12, 24, and 36 months following SRT compared to IVI treatment alone. These real-world outcomes are comparable to other studies while also confirming the maintenance of the reduced frequency of required IVI for patients with nAMD.

Intravitreal Fluocinolone 0.19mg Implant in the Management of Chronic Non-Infectious Uveitis: 12-Month Outcomes from a Single Tertiary Centre

AIM

To present efficacy and safety of 0.19 mg fluocinolone acetonide insert (FAi) to treat chronic noninfectious uveitis (NIU) in a single referral center.

METHODS

A retrospective observational clinical study of 11 eyes with NIU complicated by chronic cystoid macular edema (CMO).

RESULTS

The main indication for treatment was chronic CMO in all 11 eyes. The mean central retinal thickness (CRT) at baseline was 435 μm ± 176, improving to 296 μm ± 67 at 12 months. Raised intraocular pressure (IOP) was the commonest adverse event. An IOP >21 mmHg was observed in three eyes, and >30 mmHg in one eye, managed with topical therapy. The mean best corrected visual acuity (BCVA) was stable at 12 months. There were no observed recurrences of uveitis. Two eyes received adjunctive treatment for worsening CRT.

CONCLUSIONS

Our results suggest FAi is an effective maintenance treatment for NIU with favorable functional and anatomical outcomes.

Comparison of 3-year outcomes of photodynamic therapy combined with intravitreal ranibizumab or aflibercept for polypoidal choroidal vasculopathy in a European cohort

PURPOSE

Combined use of photodynamic therapy (PDT) with intravitreal anti-vascular endothelial growth factors (anti-VEGF) agents, such as ranibizumab (IVR) or aflibercept (IVA), has been shown to be effective for treating polypoidal choroidal vasculopathy (PCV). However, it is currently not well established which anti-VEGF agent provides superior outcomes for performing combination therapy. The present study compares the visual outcomes and re-treatment burden of combination therapy of PDT with either IVR or IVA in a European cohort of patients with PCV.

METHODS

A retrospective analysis was done on PCV patients who had received combination therapy of PDT with either IVR or IVA. The demographic characteristics, visual outcome, and anti-VEGF re-treatment exposures were analysed and compared.

RESULTS

A total of forty-four eyes (n = 11 male, 25%) were included in the analysis: 7 patients received IVR, 19 started with IVR but switched to IVA (IVS), and 18 received IVA, in combination with PDT. The BCVA improved in all three groups at 6-, 12-, 18-, 24-, 30-, and 36-month follow-ups after PDT, although the improvement was not statistically significant in the IVR group. The number of intravitreal anti-VEGF injections required/year after PDT was significantly fewer than before PDT. Significantly less eyes in the IVS group attained a good visual acuity of more than 70 ETDRS letters at the final visit.

CONCLUSION

Both IVR and IVA combined with PDT were effective treatments for the European cohort of patients with PCV. In eyes refractory to IVR, performing PDT promptly may be more beneficial than switching to IVA.

Real-world outcomes of combined therapy of photodynamic therapy with anti-vascular endothelial growth factor for polypoidal choroidal vasculopathy

OBJECTIVES

To describe the real-world outcomes of photodynamic therapy (PDT) as a rescue therapy in eyes with polypoidal choroidal vasculopathy (PCV) refractory to anti-vascular endothelial growth factor (VEGF) monotherapy in a British cohort of patients.

METHODS

This is a retrospective chart review of 53 eyes with PCV. Based on the timing of PDT, the eyes were stratified into two groups (9 in the Initial-PDT group, 44 in the Deferred group). The number of anti-VEGF injections/year and the best corrected visual acuity (BCVA) before and after PDT were analysed. Multivariate regression model was created to identify factors predictive of visual outcome and treatment burden after PDT.

RESULTS

The Deferred group received a mean of 9.4 injections/year but significantly reduced to 7.2 after PDT (p < 0.001). The Initial-PDT group required significantly fewer injections after PDT compared to the Deferred group (p = 0.004). The Deferred group experienced improvement in BCVA from 58.7 letters at baseline to 63.8 at 18-months follow-up (p < 0.001), but no significant increase was observed in the Initial-PDT group (p = 0.310). Better baseline BCVA is associated with higher likelihood of achieving good BCVA ≥ 70 letters after PDT (Odd Ratio=1.12, 95% CI: 1.03-1.21, p = 0.006), while increased number of anti-VEGF injections/year before PDT reduces the likelihood of easing treatment burden to ≥12 weeks apart between each injection after PDT (Odd Ratio=0.724, 95% CI: 0.58-0.91, p = 0.006).

CONCLUSIONS

PDT as a rescue therapy is beneficial in the long-term management of PCV, particularly in eyes that had experienced a significant period of prior exposure to anti-VEGF monotherapy.

Impact of COVID-19-associated anxiety on the adherence to intravitreal injection in patients with macular diseases a year after the initial outbreak

Background:

As the primary burden of treating COVID-19 patients began to ease in the United Kingdom, ophthalmology clinic volume within the National Health Service has since recovered. Alarmingly, the rate of non-attendance remains higher than the pre-pandemic level.

Purpose:

The purpose was to assess how the perceived risk of contracting coronavirus disease 2019 (COVID-19) influences the willingness of individuals with sight-threatening macular conditions to attend intravitreal anti-vascular endothelial growth factor (anti-VEGF) injection appointments during the second wave of the pandemic.

Methods:

This prospective cross-sectional survey was conducted at the Macular Treatment Centre, Manchester Royal Eye Hospital. Patients who missed their appointment in January 2021 were invited to complete an anonymous survey over the telephone. The survey consisted of two parts: (1) a 23-item questionnaire aiming to assess fear of contracting COVID-19 in different hospital-related settings; and (2) the validated COVID-19 Anxiety Syndrome Scale (C-19ASS) to evaluate COVID-19-related anxiety.

Results:

A total of 104 patients agreed to participate in the survey. Only a small proportion of patients believed COVID-19 vaccination (23 out of 88, 26.1%) had influenced their willingness to attend injection appointments. Majority of patients felt concerned about contracting COVID-19 during hospital appointments (n = 63, 60.6%). Only a minority of patients (n = 36, 34.6%) agreed with the hospital guidance on minimising clinical examinations during clinic visit. The C-19ASS was significantly higher in female patients, those older than 70 years and those with mobility issues. Higher C-19ASS, older age and living alone were predictors of clinic nonattendance.

Conclusion:

COVID-19 anxiety and fear of viral exposure could adversely affect patient adherence to clinic appointments during the pandemic. Particular attention should be provided to older patients, those who live alone and patients with impaired mobility. This is particularly relevant as hospital eye services across the world are in the process of restarting.

IMAGE ANALYSIS OF OPTICAL COHERENCE TOMOGRAPHY SCANS TO EXPLORE ESTABLISHED AND NOVEL CHOROIDAL FEATURES IN PATIENTS WITH CENTRAL SEROUS CHORIORETINOPATHY

PURPOSE

To explore the characteristics of choroidal tissue in patients with and without central serous chorioretinopathy (CSC) using an automated system of image analysis to determine known and novel metrics.

METHODS

This was a retrospective case-control analysis of optical coherence tomography scans of patients seen at Manchester Royal Eye Hospital, UK, comparing patients with active CSC to an age-matched and gender-matched group with no CSC using a purpose-built automated system of image analysis. The expert system segments and measures established and novel features of choroid using a combination of thresholding, noise removal, and morphological techniques.

RESULTS

A total of 72 patients were included in this study, with 40 included in the group with CSC and 32 patient controls with no CSC. There were significant increases from normal to CSC of median choroidal vascularity index, 54.7(median absolute deviation = 9.8) to 61.2(4.3), and all choroidal thickness indices including maximum depth, from 249.0(90.1) µm to 372.3(80.3) µm. For novel measures, there was a significant increase in tissue entropy from 6.68(0.28) to 6.95(0.17) and area of the largest five vessels from 6.28(3.04) mm2 to 9.10(3.49) mm2. The ratio of vessel lumen to stromal tissue intensity was conversely significantly reduced from 0.674(0.11) in normal patients to 0.59(0.06) in CSC.

CONCLUSION

The automated system of choroidal analysis expands on the utility of known measures and introduces novel metrics. These findings contribute pathophysiological insights and metrics for further assessment and research on conditions affecting choroidal tissue.

Detection of Pre-clinical Involvement of the Second Eye in Viral Acute Retinal Necrosis Using Optical Coherence Tomography

PURPOSE

To report the detection of retinitis in the second eye of a patient with viral acute retinal necrosis (ARN), before the appearance of clinical change, using swept-source optical coherence tomography.

RESULTS

A 63 year-old male developed right-sided varicella-zoster virus (VZV) ARN, confirmed with aqueous sampling. High-dose intravenous aciclovir caused renal impairment and was suspended for two-days. One day later, left eye macular SS-OCT revealed focal retinal thickening and disruption of retinal architecture without clinically detectable retinitis. The patient was asymptomatic. Aqueous sampling was VZV PCR positive. He received bilateral foscarnet injections and renal adjusted dose of aciclovir. The left OCT signs improved with full restoration of retinal layers.

CONCLUSIONS

We report for the first time the use of OCT to detect pre-clinical second eye retinitis during ARN. Prompt diagnosis and combined systemic and intensive local antiviral therapy resulted in a favourable structural and functional outcome.

Effectiveness of Interventional Strategies in Modulating Knowledge and Attitude of Health Care Professionals for Promoting Organ Donation: A Study in Tertiary Care Public Hospital of North India

Objective:

To evaluate the impact of interventional “educational module” on knowledge and attitude regarding organ donation amongst resident doctors and nurses in the Institute of National Importance.

Study Design:

Interventional and prospective.

Methods:

We devised an interactive educational module covering various aspects of organ donation through a series of audiovisual lectures and information booklets. Resident doctors and nurses posted in those areas of the 1948-bedded Postgraduate Institute of Medical Education and Research (PGIMER), where head injury patients were treated and were subject to intervention using this module. The pre and postinterventional scores of their knowledge and attitude regarding organ donation were compared to find out impact of the intervention.

Results:

A total of 242 nurses and 87 resident doctors participated in this research. Higher knowledge score was observed preintervention amongst doctors as compared to nurses. Significant improvement was seen in total knowledge scores of both groups postintervention. Doctors had better scores for the “concept of organ donation,” while nurses were more familiar with “procedures and protocols.” Both had low knowledge about “clinical criteria for brain death” and “legal issues” preintervention which improved significantly postintervention. The positive impact of intervention was also observed on attitude in both categories. A significant impact of intervention was observed on overall propensity of doctors and nurses to promote organ donation, for pledging their own organs and for counseling of the patient/attendants on this cause.

Conclusion:

Scientifically designed educational modules have a promising role in improving awareness and attitude of health care professionals regarding organ donation and their propensity to be prospective donors, effective counselors, and advocates of organ donation.

Visual and anatomical outcomes of central serous chorioretinopathy patients presenting to a tertiary unit: a prospective analysis

Aim

The aim of this study was to prospectively define the characteristics and outcomes of a cohort of central serous chorioretinopathy patients using optical coherence tomography imaging to determine anatomical disease resolution. Much of the literature available on the characteristics of central serous chorioretinopathy patients pre date the advent of OCT imaging, with conclusive epidemiological evidence being scarce. We describe a cohort of patients presenting to a large centre over the course of a year.

Methods

Prospective data collection was undertaken for all patients diagnosed with central serous chorioretinopathy at our unit over the course of 1 year. All patients underwent thorough history taking and optical coherence tomography imaging.

Results

In total, 59 eyes from 51 patients were diagnosed with central serous chorioretinopathy between April 2017 and April 2018; 23 (45.1%) patients had optical coherence tomography evidence of complete anatomical resolution within a year, with three (5.88%) patients suffering a worse visual acuity compared with that at presentation at 1-year end point; and three patients developed secondary choroidal neovascular membranes.

Conclusion

Our study reports much-needed prospective outcomes of patients with central serous chorioretinopathy, which helps to guide clinicians when deciding treatment strategies, as well as better informing patients of their prognosis for visual improvement.

Intra and inter-rater agreement of inflammatory choroidal neovascular membrane measurements using optical coherence tomography angiography

PURPOSE

Automated measurement algorithm software is not routinely available in optical coherence tomography angiography (OCTA) devices and manual measurement of choroidal neovascular membrane (CNVM) size is necessary. Our aim was to determine intra- and inter-rater agreement of inflammatory CNVM manual measurements obtained with OCTA.

METHODS

OCTA (Triton® Topcon Corporation) images in patients with inflammatory CNVM were imported into ImageJ software v1.50 (NIH image). Two experienced observers performed manual area and perimeter measurements independently, and one of the observers performed the same measurements twice. Agreement was evaluated with intraclass correlation coefficients (ICC) and concordance correlation coefficients (CCC). Bland-Altman plots were plotted to graphically assess concordance. Statistical analysis was performed using STATA v13.0.

RESULTS

Sixteen eyes of 16 subjects, with a mean age of 39.0 ± 16.6 years (range 13-71), were included. Mean CNVM area and perimeter was 124.83 ± 117.80 and 4.20 ± 2.00 mm, respectively. Intra-rater ICC for both area and perimeter measured was 0.99 (95% confidence interval (CI) 0.99-0.99). Inter-rater ICC for area and perimeter measured was 0.95 (95%CI 0.87-0.98) and 0.81 (95%CI 0.17-0.94), respectively. Intra-rater CCC for both area and perimeter measured was 0.99 (95%CI 0.99-0.99). Inter-rater CCC for both area and perimeter measured was 0.91 (95%CI 0.81-0.99) and 0.66 (95%CI 0.44-0.88), respectively.

CONCLUSIONS

Inflammatory CNVM manual measurement showed high intra-rater agreement and moderate inter-rater agreement. Repeatability and reproducibility studies are essential in manual analysis to establish thresholds that can distinguish measurements variation from true clinical change. An automatic algorithm may be helpful to accurately grade lesions and monitor disease activity and response to treatment.

An unusual case report of primary vitreoretinal lymphoma

Background

Primary vitreoretinal lymphoma (PVRL) is a rare ocular condition and its diagnosis remains a challenge. The clinical presentation is variable and it can masquerade as chronic intermediate or posterior uveitis. We report an unusual case of primary central nervous system lymphoma (PCNSL) presenting as migrating retinal lesions with unique shapes. The diagnostic challenges are described and the clinical features of intraocular lymphoma are reviewed.

Case presentation

A 53 year-old gentleman presented with unilateral visual disturbance and a wide area of retinal whitening with sharp borders temporal to the macula, corresponding to hyper-reflective subretinal changes on optical coherence tomography (OCT). The lesion resolved spontaneously after 6 weeks but was replaced by multiple punctate sub-retinal and sub-retinal pigment epithelial lesions. The second eye was involved 4 months later and there were new areas of hyper-reflective changes in both eyes, which migrated nasally within a week, with no evidence of scarring in the previous sites. The diagnosis of diffuse B-cell lymphoma was made on brain biopsy when the patient subsequently presented with acute confusion and magnetic resonance imaging brain scan showed a frontal lesion. Following systemic chemotherapy, the sub-retinal changes resolved with complete restoration of retinal architecture and improvement in visual acuity.

Conclusion

We report an unusual case of PVRL presenting as migrating retinal lesions with unique shapes. PVRL is a great imitator and a high index of clinical suspicion is required in unexplained ocular lesions to prevent a delay in diagnosis.

Posterior midline approach for large anterior/anterolateral foramen magnum tumours

The standard surgical approaches described for excision of anterior or anterolaterally placed foramen magnum (FM) tumours are the far lateral approach, the extreme lateral approach and the transoral approach. In general the posterior midline approach is considered not suitable for these lesions. We have operated on 27 patients with benign anterior/anterolaterally placed FM tumours in the last 8 years. Thirteen of these were operated via the posterior midline approach. All these 13 patients had large or giant tumours displacing the cervicomedullary region posteriorly and laterally. This allowed adequate access through this approach with minimal handling of neural tissue. For small lesions, the far lateral approach was used. Most of the patients improved significantly neurologically. We recommend the standard midline posterior approach for large/giant FM tumours as the tumour size itself provides enough working space for the surgeon. For small lesions, the far lateral approach is preferred.

Orbital roof growing fractures: a report of four cases and literature review

Trivial injuries among paediatric patients are usually underestimated. Such injuries may account for delayed problems such as growing fractures of skull vault. Growing fracture of the orbital roof is rarely reported. Four cases of paediatric cranial trauma with growing orbital roof fractures are presented. Three cases required only dural repair, while the fourth patient underwent both duraplasty and cranioplasty, due to a large orbital roof defect. At follow-up, all had satisfactory outcome. Trivial injuries among children should be evaluated with caution. The development of orbital symptomatology should ask for a complete radiological survey. The orbital roof growing fractures are potentially important cause of orbital problems. The dural repair alone, usually provides satisfactory outcome, while calvarial bone graft may be of help in cases with large bony defects. Early diagnosis and management of such cases may prevent permanent neurological deficits.

Decompressive surgery for acute subdural haematoma leading to contralateral extradural haematoma: a report of two casesand review of literature

Development of a contralateral epidural haematoma during or immediately after cranial surgery is a well-described entity. However, in a case of acute subdural haematoma where the brain is usually tense, postoperative development of contralateral extradural haematoma is uncommon. We report two cases of contralateral extradural haematoma after decompressive surgery for acute subdural haematoma. We recommend routine postoperative CT immediately after cranial surgery for head trauma. This would help in timely detection and treatment of such a complication.

Brainstem abscess: the nonsurgical management

The brainstem is an unusual location for a pyogenic abscess. Stereotactic aspiration or microsurgical drainage may be required in antibiotic refractory cases. Prolonged antibiotic therapy, along with symptomatic treatment may provide successful outcome. We report a case of cerebellar and brainstem abscess, managed successfully with prolonged antibiotic administration.

Subgaleal suction drain leading to fatal sagittal sinus haemorrhage

The use of wound drains in surgical practice, very often falls into the realm of habit, rather than science. The utility of a prophylactic drain in surgical wounds may be questionable, but this practice is not uncommon, despite complications. We report a case of fatal haemorrhage from the superior sagittal sinus, due to a closed negative suction drain of the craniotomy wound in an infant operated upon for a growing fracture skull.

Calvarial malignant fibrous histiocytoma

Primary malignant fibrous histiocytoma (MFH) of the central nervous system (CNS) is uncommon. We report cases of two young patients of MFH arising from the cranial meninges and involving the adjacent skull and scalp. There was infiltration of the brain in one case. Both the lesions were excised and primary scalp repair was performed.

Vertebral cryptococcosis simulating tuberculosis

Infection with the fungus Cryptococcus neoformans is seen predominantly in two forms: (a) pulmonary and (b) cerebromeningeal. Skeletal cryptococcosis is uncommon. There have been only occasional case reports of thoracic vertebral cryptococcosis presenting as cord compression. A young female had cervical lymphadenopathy diagnosed as tuberculosis by fine needle aspiration cytology (FNAC) and was on antitubercular therapy (ATT) for 5 months. She developed rapidly progressive paraparesis and imaging demonstrated a destructive vertebral body lesion involving T2-3 with a paraspinal abscess producing cord compression. A costotransversectomy with excision of the diseased bone and bone grafting was done. Histopathological examination revealed cryptococcosis. The patient was put on antifungal medication, but expired 2 weeks after surgery. Radiological, magnetic resonance imaging and surgical finding of vertebral cryptococcosis can mimic tuberculosis. The definite diagnosis of cryptococcosis depends upon microscopic identification of the organism. A high index of suspicion leading to early surgical confirmation and institution of anti fungal therapy is necessary to reduce the mortality and morbidity.

Raised intracranial pressure in hepatic encephalopathy

Intracranial hypertension secondary to cerebral edema is the cause of death in 50%-80% of patients with fulminant hepatic failure (FHF). This is rarely seen in chronic hepatic failure. The genesis of cerebral edema in FHF is poorly understood. The grade of encephalopathy and coagulopathy are the most important predictors of outcome in FHF. However, it is important to emphasize that intracranial pressure (ICP) may not reflect clinical course. Decerebrate posturing may be seen with ICP recording of 16 mmHg, while a quarter of the patients may have brain damage without clinical signs of raised ICP. ICP monitoring is therefore vital. The gold standard for ICP monitoring is the intraventricular method. Non-invasive methods like computerized tomography scan and magnetic resonance imaging have poor correlation with ICP. Other methods like transcranial Doppler and jugular venous oximetry measurement of brain metabolites need evaluation. The main indications for ICP monitoring in FHF are (a) patients in grade III or IV encephalopathy and (b) patients undergoing liver transplantation. Generally, patients with an ICP >40 mmHg with cerebral perfusion pressure <50 mmHg for over 2 hours are poor subjects for liver transplant.

Recurrent intramedullary cervical ependymal cyst

We report a rare case of high cervical intramedullary ependymal cyst in a young boy. This was associated with atlantoaxial dislocation. After partial removal and marsupialization, the cyst recurred and needed radical total resection.

Traumatic subarachnoid haemorrhage: a clinicoradiological and TCD correlation

Twenty five consecutive patients with CT proven pure traumatic subarachnoid haemorrhage (tSAH) were studied, prospectively over a 6 month period. They constituted 2% of all head injuries. Most of the patients (88%) had a mild or moderate head injury at the time of admission, with a mean glasgow comma scale (GCS) of 10.68. The CT scan findings were divided into 3 grades. Grade 1 - blood in hemispheric region only (n=4), grade 2 - blood in basal region only (n=11), grade 3 - blood in both hemispheric as well as basal region (n=10). Transcranial doppler ultrasound (TCD) velocities were recorded in all patients by insonating the middle cerebral artery, internal carotid artery and anterior cerebral artery on both sides. All patients were also subjected to digital substraction angiography (DSA). All patients with mild head injury had normal TCD velocity (<100 cm/sec), while TCD velocities of more than 150 cm/sec were seen only in one patient with severe head injury. Patients with severe head injury were found to have grade 3 tSAH on CT. No statistically significant correlation was found between the CT grade and TCD velocities. Angiographic vasospasm was found in 2 patients with severe head injury only. 90.2% of patients had good outcome at discharge.

Fatal posterior fossa pneumocephalus due to hydrogen peroxide irrigation of lumbar wound

Fatal brain stem failure developed suddenly in a 40-year-old male undergoing irrigation of an infected wound consequent to lumbar disc space infection. CT of head revealed posterior fossa pneumacephalus compressing the brain stem, which most likely developed from ingress of nascent oxygen under pressure through a defect in the thecal sac.

Housing status and health care service utilization among low-income persons with HIV/AIDS

OBJECTIVE

To examine the impact of housing status on health service utilization patterns in low-income HIV-infected adults.

DESIGN

A survey of 1,445 HIV-infected Medicaid recipients in New York State between April 1996 and March 1997.

MAIN RESULTS

Six percent of study participants were homeless, 24.5% were "doubled-up," and 69.5% were stably housed. Compared with the stably housed, doubled-up and homeless participants were less likely to be seeing a physician regularly (P = .0001), and if seeing a physician, they were likely to have been doing so for a significantly shorter time (P = .02). The homeless were also less likely than either stably housed or doubled-up individuals to see the same physician or group of physicians at each ambulatory visit (P = .007). In addition, a higher proportion of the homeless had made one or more hospital visits over the prior 3 months than the nonhomeless. After multivariate adjustment, doubled-up participants were found to make more emergency room visits, the homeless were less likely to be taking prophylaxis for Pneumocystis carinii pneumonia, and both the doubled-up and the homeless were shown to use slightly more outpatient care than the stably housed.

CONCLUSION

Our study documents differences in health care utilization patterns across stably housed, doubled-up, and homeless HIV-infected persons after controlling for health insurance coverage. These differences, especially those pertaining to outpatient services, suggest that the unstably housed may be receiving less adequate health care than the stably housed, and hence may be more likely to experience adverse clinical outcomes.

Use of midline catheters in low birth weight infants

Prolonged intravenous access is an important consideration in the treatment of premature neonates. Because peripheral intravenous catheters have short dwell times, centrally positioned percutaneous catheters have been used increasingly in neonatal intensive care. Midline catheters are peripherally inserted long catheters advanced only to the proximal portion of a limb or to the neck, with the tip remaining outside the thoracic and abdominal cavities. Midline catheters were placed with use of an innovative technique via a 24-gauge Angiocath catheter (Becton Dickinson, Sandy, Utah). This study compared dwell time and reason for removal of midline catheters with respective data for peripheral intravenous catheters. Dwell time was found to be 9.0 +/- 1.4 days for the midline catheters versus 3.1 +/- 0.5 days for peripheral intravenous catheters placed in the same patients (p < 0.05). No significant complications occurred with the use of midline catheters. These data suggest that midline catheters may be useful in neonates who require a limited duration of intravenous therapy.

Tumors of the bladder, kidney, and intestine of F344 rats and liver of B6C3F1 mice administered o-nitroanisole in feed

o-Nitroanisole, a mutagenic intermediate used in the manufacture of azo dyes, was administered in feed for 2 years at concentrations of 0, 222, 666, or 2000 ppm to groups of 60 male and 60 female F344 rats. No significant increase in neoplasms occurred in these groups of rats. Additional (stop exposure) groups of 60 male and 60 female F344 rats received diets containing 0, 6000, or 18,000 ppm for 27 weeks followed by maintenance on control diets for up to an additional 77 weeks. Survival of the stop exposure groups was reduced because of the development of chemical related neoplasms of the urinary bladder. After 13, 28, 40, and 65 weeks on study, 10 rats per group were necropsied and evaluated for the presence of chemical associated lesions. Hyperplasia of the epithelium of the urinary bladder was significantly increased at all interim evaluations. A transitional cell carcinoma was observed at the 13-week evaluation in one male rat that received 18,000 ppm and thereafter transitional cell neoplasms of the bladder were present in male and female rats at each interim evaluation. Adenomatous polyps of the large intestine were significantly increased in groups that received 6000 or 18,000 ppm. In addition carcinomas of the large intestine were present in four males and two females that received 18,000 ppm. Hyperplasia of the transitional epithelium of the renal pelvis was significantly increased in groups of rats that received 6000 or 18,000 ppm and transitional cell papillomas were observed in three males and one female that received 18,000 ppm. Transitional cell carcinomas of the kidney occurred in one male that received 6000 ppm and six males and one female that received 18,000. Groups of 60 male and 60 female B6C3F1 mice received dietary concentrations of 0, 666, 2000, or 6000 ppm o-nitroanisole for 2 years. No stop exposure study was conducted with mice. The only neoplastic response observed in mice was in the liver of males; hepatocellular adenomas or carcinomas were increased in groups of male mice that received 2000 or 6000 ppm. No increase in neoplasms associated with chemical exposure occurred in female mice.