Signs and seasons.

Mode of access: Internet.

Clinical signs and duration of cyanide toxicosis delivered by the M-44 ejector in wild dogs

Sodium cyanide poison is potentially a more humane method to control wild dogs than sodium fluoroacetate (1080) poison. This study quantified the clinical signs and duration of cyanide toxicosis delivered by the M-44 ejector. The device delivered a nominal 0.88 g of sodium cyanide, which caused the animal to loose the menace reflex in a mean of 43 s, and the animal was assumed to have undergone cerebral hypoxia after the last visible breath. The mean time to cerebral hypoxia was 156 s for a vertical pull and 434 s for a side pull. The difference was possibly because some cyanide may be lost in a side Pull. There were three distinct phases of cyanide toxicosis: the initial phase was characterised by head shaking, panting and salivation; the immobilisation phase by incontinence, ataxia and loss of the righting reflex; and the cerebral hypoxia phase by a tetanic seizure. Clinical signs that were exhibited in more than one phase of cyanide toxicosis included retching, agonal breathing, vocalisation, vomiting, altered levels of ocular reflex, leg paddling, tonic muscular spasms, respiratory distress and muscle fasciculations of the muzzle.

Utility of signs and symptoms of chronic cough in predicting specific cause in children

Background: Paediatricians rely on cough descriptors to direct them to the level of investigations needed for a child presenting with chronic cough, yet there is a lack of published data to support this approach. A study was undertaken to evaluate ( 1) whether historical cough pointers can predict which children have a specific cause for their cough and ( 2) the usefulness of chest radiography and spirometry as standard investigations in children with chronic cough. Methods: This was a prospective cohort study of children referred to a tertiary hospital with a cough lasting 3 weeks between June 2002 and July 2004. All included children completed a detailed history and examination using a standardised data collection sheet and followed a pathway of investigation until a diagnosis was made. Results: In 100 consecutively recruited children of median age 2.8 years, the best predictor of specific cough observed was a moist cough at the time of consultation with an odds ratio ( OR) of 9.34 (95% CI 3.49 to 25.03). Chest examination or chest radiographic abnormalities were also predictive with OR 3.60 ( 95% CI 1.31 to 9.90) and 3.16 (95% CI 1.32 to 7.62), respectively. The most significant historical pointer for predicting a specific cause of the cough was a parental history of moist cough ( sensitivity 96%, specificity 26%, positive predictive value 74%). Conclusions: The most useful clinical marker in predicting specific cough is the presence of a daily moist cough. Both chest examination and chest radiographic abnormalities are also useful in predicting whether children have a specific cause of their cough.

Visual signs and symptoms of Creutzfeldt-Jakob disease

A number of neurodegenerative diseases caused by prions have been described recently. These include Creutzfeldt-Jakob disease (CJD) in humans, scrapie in sheep and BSE in cows. Patients with CJD may suffer a range of visual problems including eye movement deficits and visual hallucinations. In addition, it is possible that CJD may be acquired via corneal transplant and that prions may be transmitted by reusable contact lenses.

Visual signs and symptoms of Alzheimer's disease

Alzheimer's disease is the commonest degenerative disease of the nervous system to affect elderly people. It is characterised by 'dementia', a global cognitive decline involving loss of short term memory, judgement and emotional control. In addition, patients may suffer a range of visual problems including impairment of visual acuity, colour vision, eye movement problems and complex visual disturbances.

Visual signs and symptoms of Parkinson's disease

Parkinson's disease (PD) is a common disorder of middle-aged and elderly people, in which there is degeneration of the extra-pyramidal motor system. In some patients, the disease is associated with a range of visual signs and symptoms, including defects in visual acuity, colour vision, the blink reflex, pupil reactivity, saccadic and smooth pursuit movements and visual evoked potentials. In addition, there may be psychophysical changes, disturbances of complex visual functions such as visuospatial orientation and facial recognition, and chronic visual hallucinations. Some of the treatments associated with PD may have adverse ocular reactions. If visual problems are present, they can have an important effect on overall motor function, and quality of life of patients can be improved by accurate diagnosis and correction of such defects. Moreover, visual testing is useful in separating PD from other movement disorders with visual symptoms, such as dementia with Lewy bodies (DLB), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). Although not central to PD, visual signs and symptoms can be an important though obscure aspect of the disease and should not be overlooked.

Progressive supranuclear palsy (PSP): general pathology and visual signs and symptoms

Progressive supranuclear palsy (PSP) is a rare, degenerative disorder of the brain believed to affect between 1.39 and 6.6 individuals per 100,000 of the population. The disorder is likely to be more common than suggested by these data due to difficulties in diagnosis and especially in distinguishing PSP from other conditions with similar symptoms such as multiple system atrophy (MSA), corticobasal degeneration (CBD), and Parkinson’s disease (PD). PSP was first described in 1964 by Steele, Richardson and Olszewski and originally called Steele-Richardson-Olszewski syndrome. The disorder is the second commonest syndrome in which the patient exhibits ‘parkinsonism’, viz., a range of problems involving movement most typically manifest in PD itself but also seen in PSP, MSA and CBD. Although primarily a brain disorder, patients with PSP exhibit a range of visual clinical signs and symptoms that may be useful in differential diagnosis. Hence, the present article describes the general clinical and pathological features of PSP, its specific visual signs and symptoms, discusses the usefulness of these signs in differential diagnosis, and considers the various treatment options.

Visual signs and symptoms of Parkinson's disease

There are two aspects of PD of particular interest to optometrists. First, PD patients can develop a range of visual problems including those affecting eye movement, pupillary function, and in complex visual functions involving the ability to judge distance or make out the shape of an object. Second, the symptoms of PD can be treated successfully using a variety of drugs, some of which have significant ocular adverse reactions (OAR). This article describes the general features of PD, the dopamine neurotransmitter system and its relevance to eye symptoms, the visual symptoms reported in PD, and the OAR that have been reported.

Visual signs and symptoms of progressive supranuclear palsy

Progressive supranuclear palsy is a rare, degenerative brain disorder and the second most common syndrome in which the patient exhibits 'parkinsonism', that is, a variety of symptoms involving problems with movement. General symptoms include difficulties with gait and balance; the patient walking clumsily and often falling backwards. The syndrome can be difficult to diagnose and visual signs and symptoms can help to separate it from closely related movement disorders such as Parkinson's disease, multiple system atrophy, dementia with Lewy bodies and corticobasal degeneration. A combination of the presence of vertical supranuclear gaze palsy, fixation instability, lid retraction, blepharospasm and apraxia of eyelid opening and closing may be useful visual signs in the identification of progressive supranuclear palsy. As primary eye-care practitioners, optometrists should be able to identify the visual problems of patients with this disorder and be expected to work with patients and their carers to manage their visual welfare.

Visual signs and symptoms of Multiple System Atrophy

Multiple system atrophy (MSA) is a rare movement disorder and a member of a group of neurodegenerative diseases, which include Parkinson’s disease (PD) and progressive supranuclear palsy (PSP), and referred to as the ‘parkinsonian syndromes’. Although primarily a neurological disorder, patients with MSA may also develop visual signs and symptoms that could be useful in differential diagnosis. In addition, the eye-care practitioner may contribute to the management of visual problems of MSA patients and therefore, help to improve quality of life. This second article in the series considers the visual signs and symptoms of MSA with special reference to those features most useful in differential diagnosis of the parkinsonian syndromes.

Visual signs and symptoms of dementia with Lewy bodies

Dementia with Lewy bodies ('Lewy body dementia' or 'diffuse Lewy body disease') (DLB) is the second most common form of dementia to affect elderly people, after Alzheimer's disease. A combination of the clinical symptoms of Alzheimer's disease and Parkinson's disease is present in DLB and the disorder is classified as a 'parkinsonian syndrome', a group of diseases which also includes Parkinson's disease, progressive supranuclear palsy, corticobasal degeneration and multiple system atrophy. Characteristics of DLB are fluctuating cognitive ability with pronounced variations in attention and alertness, recurrent visual hallucinations and spontaneous motor features, including akinesia, rigidity and tremor. In addition, DLB patients may exhibit visual signs and symptoms, including defects in eye movement, pupillary function and complex visual functions. Visual symptoms may aid the differential diagnoses of parkinsonian syndromes. Hence, the presence of visual hallucinations supports a diagnosis of Parkinson's disease or DLB rather than progressive supranuclear palsy. DLB and Parkinson's disease may exhibit similar impairments on a variety of saccadic and visual perception tasks (visual discrimination, space-motion and object-form recognition). Nevertheless, deficits in orientation, trail-making and reading the names of colours are often significantly greater in DLB than in Parkinson's disease. As primary eye-care practitioners, optometrists should be able to work with patients with DLB and their carers to manage their visual welfare.

Visual signs and symptoms of multiple system atrophy

Multiple system atrophy (MSA) is a rare movement disorder and a member of the 'parkinsonian syndromes', which also include Parkinson's disease (PD), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB) and corticobasal degeneration (CBD). Multiple system atrophy is a complex syndrome, in which patients exhibit a variety of signs and symptoms, including parkinsonism, ataxia and autonomic dysfunction. It can be difficult to separate MSA from the other parkinsonian syndromes but if ocular signs and symptoms are present, they may aid differential diagnosis. Typical ocular features of MSA include blepharospasm, excessive square-wave jerks, mild to moderate hypometria of saccades, impaired vestibular-ocular reflex (VOR), nystagmus and impaired event-related evoked potentials. Less typical features include slowing of saccadic eye movements, the presence of vertical gaze palsy, visual hallucinations and an impaired electroretinogram (ERG). Aspects of primary vision such as visual acuity, colour vision or visual fields are usually unaffected. Management of the disease to deal with problems of walking, movement, daily tasks and speech problems is important in MSA. Optometrists can work in collaboration with the patient and health-care providers to identify and manage the patient's visual deficits. A more specific role for the optometrist is to correct vision to prevent falls and to monitor the anterior eye to prevent dry eye and control blepharospasm.