Analysis of an adult Duchenne muscular dystrophy population

BACKGROUND

Advances in management have led to increasing numbers of patients with Duchenne muscular dystrophy (DMD) reaching adulthood. Older patients with DMD are necessarily severely disabled, and their management presents particular practical issues.

AIM

To review the management of a late adolescent and adult DMD population, and to identify areas in which the present service provisions may be inadequate to their needs.

DESIGN

Retrospective review.

METHODS

We studied 25 patients with DMD referred to an adult neuromuscular clinic over a 7-year period. Clinical details were obtained retrospectively, from case notes or direct observations.

RESULTS

There were 24 males and one symptomatic female carrier. Nine patients died during the observation period. There was no significant correlation between age of wheelchair confinement and age of death. Sixteen patients received non-invasive positive pressure support. Twelve attended mainstream schools and 12, residential special schools. All the patients lived at home for some or all of the time, when their main carers were either one or both of the parents. The most striking difficulties were with the provision of practical aids, including appropriate hoists and belts, feeding and toileting aids, and the conversion of accommodation. Patients rarely wished to discuss the later stages of their disease, and death was often more precipitate than expected. Death usually occurred outside hospital and the final cause was often difficult to establish.

DISCUSSION

Adult patients with DMD develop progressive impairment, due to respiratory, orthopaedic and general medical factors. However, the particular areas of difficulty in this study often reflected inadequate and poorly directed social and medical support, illustrating the need for improvements in the structure, co-ordination and breadth of rehabilitation services for adult patients with DMD.

Factors influencing PCR detection of viruses in cerebrospinal fluid of patients with suspected CNS infections

BACKGROUND

Polymerase chain reaction (PCR) is used to detect viruses in the cerebrospinal fluid (CSF) of patients with neurological disease. However, data to assist its use or interpretation are limited.

OBJECTIVE

We investigated factors possibly influencing viral detection in CSF by PCR, which will also help clinicians interpret positive and negative results.

METHODS

CSF from patients with was tested for human herpesviruses types 1-6, JC virus, enteroviruses, and Toxoplasma gondii. The likelihood of central nervous system (CNS) infection was classified as likely, possible, or unlikely. PCR findings in these categories were compared using single variable and logistic regression analysis.

RESULTS

Of 787 samples tested, 97 (12%) were PCR positive for one or more viruses. Of episodes likely to be CNS viral infections, 30% were PCR positive compared to 5% categorised as unlikely. The most frequent positive findings were Epstein Barr virus (EBV), enteroviruses, and herpes simplex virus (HSV). Enteroviruses and HSV were found predominantly in the likely CNS viral infection group, whereas EBV was found mainly in the unlikely group. Positive PCR results were more likely when there were 3-14 days between symptom onset and lumbar puncture, and when CSF white cell count was abnormal, although a normal CSF did not exclude a viral infection.

CONCLUSIONS

The diagnostic yield of PCR can be maximised by using sensitive assays to detect a range of pathogens in appropriately timed CSF samples. PCR results, in particular EBV, should be interpreted cautiously when symptoms cannot readily be attributed to the virus detected.

Frontotemporal lobar degeneration with ubiquitin-only-immunoreactive neuronal changes: broadening the clinical picture to include progressive supranuclear palsy

The frontotemporal lobar degenerations (FTLDs) are a group of disorders in which the clinical picture is not necessarily predictive of the underlying neuropathology. The FTLD with ubiquitin-only-immunoreactive neuronal changes (FTLD-U) subtype is pathologically characterized by ubiquitin-positive, tau and alpha-synuclein-negative neuronal cytoplasmic inclusions in the frontotemporal cortex and hippocampal dentate fascia. When similar pathological changes are accompanied by histological features of motor neuron disease (MND), the term FTLD-MND is used. The latter pathological changes may be found in patients with or without clinical evidence of MND. We retrospectively reviewed the clinical details of three patients with a rapidly progressive, levodopa-unresponsive bradykinetic-rigid syndrome and frontal cognitive impairment. A diagnosis of progressive supranuclear palsy (PSP) had been considered in all three cases at initial presentation. Two of the cases fulfilled clinical diagnostic criteria for PSP, which was the final clinical diagnosis during life. Pathological analysis showed typical histological appearances of FTLD-MND in two cases and of FTLD-U in one case. Semi-quantitative analysis of pathological load seemed to correlate with the clinical phenotype. FTLD-U or FTLD-MND should be considered in the differential diagnosis of progressive frontal dementia with an akinetic rigid syndrome and supranuclear gaze palsy or Steele-Richardson-Olszewski disease.

Herpes simplex encephalitis: an audit of the use of laboratory diagnostic tests

BACKGROUND

The combination of both PCR and intrathecal antibody studies is recommended to confirm or refute the diagnosis of herpes simplex encephalitis (HSE).

AIM

To investigate the pattern of use of laboratory tests in the diagnosis of suspected cases of HSE, and to determine the final diagnosis in cases proven not to be HSE.

DESIGN

Structured audit.

METHODS

We reviewed the case-notes of all patients who, over a five-year time period, presented with suspected encephalitis; and/or were prescribed aciclovir. Clinical and laboratory criteria were used to categorize the likelihood of HSE.

RESULTS

We identified 222 patients: 10 (5%) had definite HSE, 24 (10%) possible HSE, and 144 (65%) a definite alternative diagnosis. In 44 (20%), no final diagnosis was made, but the diagnosis of HSE was excluded. PCR was performed in 68 (31%), intrathecal antibody studies in 24 (11%), and brain biopsy in 17 (8%). A wide range of diseases mimicked HSE, but most common were inflammatory diseases and other infections of the central nervous system.

DISCUSSION

Laboratory tests, particularly intrathecal antibody assays, are under-used in the diagnosis of HSE. Although early empirical treatment of suspected HSE is essential, confirmation or exclusion of the diagnosis is equally important to avoid overlooking alternative diagnoses. Identification of the aetiology of encephalitis is of particular importance, given the current concerns of emerging infections and bioterrorism.

Passive transfer of purified IgG from patients with amyotrophic lateral sclerosis to mice results in degeneration of motor neurons accompanied by Ca2+ enhancement

It has been reported that immunoglobulins (IgG) in sera of patients with amyotrophic lateral sclerosis (ALS) kill cultured motoneurones (MN), but whether they also cause MN degeneration in vivo is unclear. To test this, protein-A affinity purified and dialysed IgGs were prepared from sera of 44 ALS patients without paraproteinemias, 20 healthy controls and 15 disease controls. Control and ALS-IgGs were injected intraperitoneally into groups of mice for 5 consecutive days and examined at day 8. IgG was localised immunocytochemically and spinal MN were characterised histologically and ultrastructurally and by comparative counts of Ca(2+) containing organelles revealed with oxylate-pyroantimonate histochemistry. ELISA revealed no differences in IgG concentration between ALS patients and control subjects. Immunocytochemistry showed IgG was present in MN of mice injected with control or ALS-IgG, but densitometry showed immunostaining in MN was stronger in mice injected with ALS-IgG. Compared to MN of non-injected mice, control-IgG-treated mice showed near normal MN morphology and numbers of Ca(2+)-containing organelles. Disease control IgGs evoked negligible or minor morphological changes according to disease, but normal numbers of Ca(2+) containing organelles. Ultrastructurally, about 70% of ALS-derived IgGs induced a population of MN with electron lucent cytoplasm, distended Golgi, disrupted Nissl and mitochondria (i.e., necrosis). However 30% of ALS-IgGs additionally induced electron-dense degeneration in 40% of the MN. These MN exhibited shrinkage, condensed nuclear chromatin and ill-defined nuclear membranes and resembled preliminary stages of apoptosis. We conclude that passive transfer of ALS-derived, but not control IgGs, does result in MN degeneration in the recipient mice. This appears to be associated with abnormal calcium homeostasis, but the exact target of ALS-IgG remains conjectural, and the possibilities are discussed.

Opposites attract? Mate choice for parasite evasion and the evolutionary stability of sex

If sex is naturally selected as a way to combat parasites, then sexual selection for disease resistance might increase the overall strength of selection for outcrossing. In the present study, we compared how two forms of mate choice affect the evolutionary stability of outcrossing in simultaneous hermaphrodites. In the first form, individuals preferred to mate with uninfected individuals (condition-dependent choice). In the second form, individuals preferred to mate with individuals that shared the least number of alleles in common at disease-resistance loci. The comparisons were made using individual-based computer simulations in which we varied parasite virulence, parasite transmission rate, and the rate of deleterious mutation at 500 viability loci. We found that alleles controlling both forms of mate choice spread when rare, but their effects on the evolutionary stability of sex were markedly different. Surprisingly, condition-dependent choice for uninfected mates had little effect on the evolutionary stability of sexual reproduction. In contrast, active choice for mates having different alleles at disease-resistance loci had a pronounced positive effect, especially under low rates of deleterious mutation. Based on these results, we suggest that mate choice that increases the genetic diversity of offspring can spread when rare in a randomly mating population, and, as an indirect consequence, increase the range of conditions under which sexual reproduction is evolutionarily stable.

Mutation accumulation in growing asexual lineages

The stochastic loss of entire classes of individuals bearing the fewest number of mutations-a process known as Muller's ratchet-is studied in asexual populations growing unconstrained from a single founder. In the neutral regime, where mutations have zero effect on fitness, we derive a recursion equation for the probability distribution of the minimum number of mutations carried by individuals in the least-loaded class, and obtain an explicit condition for the halting of the ratchet. Next, we consider the case of deleterious mutations, and show that weak selection can actually accelerate the ratchet beyond that achieved for the neutral regime. This effect is transitory, however, as our results suggest that even weak purifying selection will eventually lead to the complete cessation of the ratchet. These results may have important implications for problems in biology and the medical sciences.

Brain stem encephalitis caused by primary herpes simplex 2 infection in a young woman

A 27 year old woman developed a vesicular genital rash and cerebellar dysfunction with progressive neurological deterioration suggesting brain stem encephalitis. Respiratory support was required. Magnetic resonance imaging (MRI) of the brain on day 7 showed signal hyperintensity in the central medulla and ventral pons, typical of acute inflammation. The course was severe and relapse occurred. MRI on day 33 showed a haemorrhagic area in the medulla. Treatment with aciclovir/valaciclovir eventually led to gradual recovery. Herpes simplex virus 2 (HSV-2) DNA was detected in CSF on days 11 and 14. HSV-2 was also detected in vesicle fluid from the genital rash. Serum was initially negative for HSV-1 and HSV-2 antibodies, but convalescent samples showed seroconversion to HSV-2, indicating primary infection. Intrathecal synthesis of oligoclonal IgG bands specific for HSV was identified in the CSF. It is important to differentiate HSV-2 from HSV-1, and primary from initial or reactivated infection, so that prolonged aciclovir treatment followed by prophylaxis is instituted to prevent the high likelihood of symptomatic relapse in primary HSV-2 infection.

Diffusion tensor imaging detects corticospinal tract involvement at multiple levels in amyotrophic lateral sclerosis

BACKGROUND

Histopathological studies of amyotrophic lateral sclerosis (ALS) are of end stage disease. Diffusion tensor imaging (DTI) provides the opportunity to investigate indirectly corticospinal tract pathology of ALS in vivo.

METHODS

DTI was used to study the water diffusion characteristics of the corticospinal tracts in 21 patients with ALS and 14 normal controls. The authors measured the fractional anisotropy (FA) and mean diffusivity (MD) along the pyramidal tracts from the internal capsules down to the pyramids. A mixed model regression analysis was used to compare FA and MD between the ALS and control groups.

RESULTS

FA showed a downward linear trend from the cerebral peduncles to the pyramids and was lower in the ALS group than controls at multiple levels of the corticospinal tract. At the internal capsules, FA was higher on the right. MD showed an upward trend, progressing caudally from the internal capsules to the pyramids. MD was higher at the level of the internal capsule in the ALS group, but caudally this difference was not maintained. No correlations were found between clinical markers of disability and water diffusion indices.

CONCLUSIONS

These findings provide insights into the pathological processes of ALS. Differences in diffusion characteristics at different anatomical levels may relate to underlying tract architecture or the distribution of pathological damage in ALS. Further development may permit monitoring of progression and treatment of disease.

Androgen deprivation in men with prostate cancer is associated with an increased rate of bone loss

The objective of this work was to determine the effect of androgen deprivation therapy (ADT) on rates of bone mineral density (BMD) loss in men with prostate cancer. It was a prospective study comparing men receiving ADT to age matched controls for 2 y. Subjects received a history, physical exam, bone mineral density measurement, and laboratory evaluation every 6 months. Thirty-nine subjects receiving continuous ADT for prostate cancer (subjects) were compared to 39 age-matched controls not receiving ADT (controls). Twenty-three subjects and 30 controls completed the study through 24 months. Men in the ADT group demonstrated greater rates of bone mineral density loss than men in the control group at every site except the lumbar spine. Twenty-four month per cent of bone mineral density loss is presented as mean+/-standard error (s.e.). At the distal forearm, the ADT group value was -9.4%+/-1.0% and -4.4%+/-0.3% for controls (P<0.0005). The ADT group femoral neck values were -1.9%+/-0.7% and 0.6%+/-0.5% in the control group (P=0.0016). The ADT group total hip value was -1.5%+/-1.0% and 0.8%+/-0.5% in the control group (P=0.0018). The ADT group trochanter value was -2.0%+/-1.3% and -0.1%+/-0.5% in the control group (P=0.0019). The ADT group lumbar spine value was -0.2%+/-0.8 % and 1.1%+/-0.6% in the control group (P=0.079). Our data demonstrate greater rates of bone mineral density loss in men receiving androgen deprivation therapy for prostate cancer.

Hypocretin (orexin) deficiency in narcolepsy and primary hypersomnia

The discovery that hypocretins are involved in narcolepsy, a disorder associated with excessive daytime sleepiness, cataplexy, and unusually rapid transitions to rapid eye movement sleep, opens a new field of investigation in the area of disorders of sleep and activation. Hypocretin-1 (hcrt-1) and hypocretin-2 (hcrt-2) (also called orexin-A and orexin-B) are newly discovered neuropeptides processed from a common precursor. Hypocretin containing cells are located exclusively in the lateral hypothalamus, with widespread projections within the central nervous system. The role of the hypocretin system in other disorders causing excessive daytime sleepiness is more uncertain. This study reports the findings of a prospective study measuring cerebrospinal fluid concentrations of hypocretin-1 and hypocretin-2 in HLA DQB1*0602 positive narcolepsy with cataplexy, monosymptomatic narcolepsy, and primary hypersomnia. The results confirmed the previous observations, that hcrt-1 is deficient in narcolepsy and for the first time report very low levels of hcrt-1 in primary hypersomnia. It is also reported for the first time that there is a generalised defect in hcrt-2 transmission in all three of these clinical entities compared with controls.

Management of motor neurone disease

Motor neurone disease is a progressive neurodegenerative disorder leading to severe disability and death. It is clinically characterised by mixed upper and lower motor neurone involvement affecting bulbar, limb, and respiratory musculature. Recent guidelines have established diagnostic criteria and defined management of the condition. In a proportion of familial amyotrophic lateral sclerosis there is a mutation in the gene encoding the enzyme copper/zinc superoxide dismutase 1; this has allowed mutation screening and generated considerable laboratory based research. The diagnosis must be given with care and consideration and close follow up is essential. Management involves a multidisciplinary team based in the hospital and the community. Riluzole is the only drug shown to have a disease modifying effect and has been approved by the National Institute for Clinical Excellence. The essence of care is good symptomatic management, including nutritional support with percutaneous endoscopic gastrostomy and ventilatory care with non-invasive ventilation. Palliative care should be introduced before the terminal stages after careful discussion with the patient and carers. Knowledge of this condition has grown dramatically recently with a parallel improvement in treatment and ability to deal with the most troublesome problems.

Outcome of ventilatory support for acute respiratory failure in motor neurone disease

OBJECTIVES

To review the outcome of acute ventilatory support in patients presenting acutely with respiratory failure, either with an established diagnosis of motor neurone disease (MND) or with a clinical event where the diagnosis of MND has not yet been established.

METHODS

Outcome was reviewed in 24 patients with respiratory failure due to MND who received endotracheal intubation and intermittent positive pressure ventilation either at presentation or as a result of the unexpected development of respiratory failure. Patients presenting to local hospitals with acute respiratory insufficiency and requiring tracheal intubation, ventilatory support, and admission to an intensive therapy unit (ITU) before transfer to a regional respiratory care unit were selected. Clinical features of presentation, management, and outcome were studied.

RESULTS

24 patients with MND were identified, all being intubated and ventilated acutely within hours of presentation. 17 patients (71%) were admitted in respiratory failure before the diagnosis of MND had been made; the remaining seven patients (29%) were already known to have MND but deteriorated rapidly such that intubation and ventilation were initiated acutely. Seven patients (29%) died on ITU (between seven and 54 days after admission). 17 patients (71%) were discharged from ITU. 16 patients (67%) received long term respiratory support and one patient required no respiratory support following tracheal extubation. The daily duration of support that was required increased gradually with time.

CONCLUSION

When a patient with MND is ventilated acutely, with or without an established diagnosis, independence from the ventilator is rarely achieved. Almost all of these patients need long term ventilatory support and the degree of respiratory support increases with time as the disease progresses. The aim of management should be weaning the patient to the minimum support compatible with symptomatic relief and comfort. Respiratory failure should be anticipated in patients with MND when the diagnosis has been established.

Brain excitatory amino acid concentrations are lower in the neonatal pig: a buffer against excitotoxicity?

Hypoglycemic brain damage has been associated with high levels of the excitatory amino acids (EAA) aspartate and glutamate in the newborn and adult. We hypothesized that newborn piglet EAA would be different from those of older pigs when stressed with severe insulin-induced hypoglycemia (<30 mg/dl). Brain EAA were measured in piglets and adolescent pigs via microdialysis. Eleven of 12 newborn normoglycemic piglets had no detectable baseline levels (<0.5 microM) of EAA, while pigs had aspartate and glutamate concentrations of 1.78 +/- 0.44 and 3.43 +/- 1.14 microM (mean +/- SEM), respectively. Piglet aspartate and glutamate concentrations reached but did not significantly exceed normoglycemic pig levels after 2 h with plasma glucose values < or =20 mg/ml. Elevations in EAA were only detected in piglets whose EEG activity ceased. Aspartate and glutamate concentrations did not increase in insulin-treated pigs nor in control animals. We speculate that newborns with blood glucose less than clinically acceptable values (35 mg/dl) may be protected from EAA-associated neuronal damage during acute hypoglycemia. Lower normoglycemic and hypoglycemic levels of EAA in newborns when compared to older pigs provide this protection.

Measurement of isolated subtalar range of motion: a cadaver study

Fifteen fresh-frozen cadaveric lower extremities were studied to evaluate the reliability of measuring subtalar motion using a bubble inclinometer. There was high intra-observer reliability for manual inversion and eversion of the subtalar joint with the tibiotalar joint locked and unlocked. Poor correlation of radiographic and clinical measurements questioned the validity of bubble inclinometer measurements. The contribution of the tibiotalar joint to apparent subtalar motion, as measured clinically and radiographically, was found to be one-third of the arc of motion, as compared to motion measured clinically and radiographically with the tibiotalar joint locked.

Rituximab using a thrice weekly dosing schedule in B-cell chronic lymphocytic leukemia and small lymphocytic lymphoma demonstrates clinical activity and acceptable toxicity

PURPOSE

Rituximab has been reported to have little activity in small lymphocytic lymphoma (SLL)/chronic lymphocytic leukemia (CLL) and to be associated with significant infusion-related toxicity. This study sought to decrease the initial toxicity and optimize the pharmacokinetics with an alternative treatment schedule.

PATIENTS AND METHODS

Thirty three patients with SLL/CLL received dose 1 of rituximab (100 mg) over 4 hours. In cohort I (n = 3; 250 mg/m(2)) and cohort II (n = 7; 375 mg/m(2)) rituximab was administered on day 3 and thereafter three times weekly for 4 weeks using a standard administration schedule. Cohort III (n = 23; 375 mg/m(2)) administered rituximab similar to cohort II for the first two treatments and then over 1 hour thereafter.

RESULTS

A total of 33 CLL/SLL patients were enrolled; only one patient discontinued therapy because of infusion-related toxicity. Thirteen patients developed transient hypoxemia, hypotension, or dyspnea that were associated with significant changes in baseline interleukin-6, interleukin-8, tumor necrosis factor alpha, and interferon gamma compared with those not experiencing such reactions. Infusion-related toxicity occurred more commonly in older (median age 73 v 62 years; P =.02) patients with no other pretreatment clinical or laboratory features predicting occurrence of these events. The overall response rate was 45% (3% CR, 42% PR; 95% CI 28% to 64%). Median response duration for these 15 patients was 10 months (95% CI, 6.8-13.2; range, 3 to 17+).

CONCLUSION

Rituximab administered thrice weekly for 4 weeks demonstrates clinical efficacy and acceptable toxicity. Initial infusion-related events seem to be cytokine mediated and resolve by the third infusion making rapid administration possible. Future combination studies of rituximab with other therapies in CLL seem warranted.

Outcome of sulcus fixation of dislocated posterior chamber intraocular lenses using temporary externalization of the haptics

OBJECTIVE

This study evaluated the visual outcome and complications of repositioning and sulcus fixation of a dislocated posterior chamber intraocular lens (PC IOL) using a technique in which the haptics of the IOL are temporarily externalized for suture placement.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Seventy-eight patients with a dislocated PC IOL.

INTERVENTION

All patients underwent surgery to fixate the PC IOL using this technique.

MAIN OUTCOME MEASURES

Patients were evaluated for visual acuity, refractive error, and surgical complications associated with the procedure.

RESULTS

The average visual acuity before surgery was 20/205 (range, 20/20 to light perception), with a median refractive error of -1.00 diopters (D; range, -7.25-+15.00 D). After surgery, the average visual acuity improved to 20/72 (range, 20/20 to no light perception), with a median refractive error of -0.75 D (range, -5.50-+3.50 D). Patients were observed for a median of 15.5 months (range, 6-57 months). Twenty patients had postoperative cystoid macular edema (26%), 7 patients had an epiretinal membrane (ERM) (9%), and 5 patients had a retinal detachment (6%). Eight patients (10%) experienced iris capture of the sutured IOL, and in three patients (4%) the PC IOL dislocated again after surgery.

CONCLUSIONS

This technique is an effective method for securing a dislocated PC IOL.