By S. Redge. Texas State University.

Visual Acuity Visual acuity should dutasteride 0.5 mg overnight delivery hair loss in men kind, at a minimum generic 0.5mg dutasteride mastercard hair loss postpartum, be measured, with the patient’s corrective lenses in place, if corrective lenses are used, and in a well-lighted area. Testing the visual acuity assesses a patient’s central vision and should be performed one eye at a time and then with both eyes simultaneously. Visual acuity is typically assessed with a Snellen chart, with the patient standing 20 feet from the chart. There are times when the patient cannot read even the top line of the Snellen chart from 20 feet. In this case, you may have the patient move progressively closer to the chart and record the distance at which the top line can be read, if needed. If the patient cannot read the chart at a near distance, record whether the patient can count fingers, identify gross hand motion, or detect light. Near vision is tested using a hand-held chart, such as a Rosenbaum chart, typically held 14 inches from the eyes. Color vision can be grossly tested using the color strips (green and red) on the Snellen chart or by asking the patient to identify the colors of other objects. Ishihara plates can be used for a more thorough assessment of color vision. Carefully identify the location of any visual defects. Alternatively, peripheral vision can be measured much more objectively using equipment designed specifically for this purpose. Alignment Observe the position of the eyes as the patient follows an object as it is moved smoothly through the six cardinal positions, approximately 12 inches in front of the face. Perform the cover/uncover test observing for movement as an eye is covered and uncovered. Ask the patient to focus on a distant object and observe one eye, as the opposite eye is covered. If the visible eye, which is uncovered, moves as it fixates on the distant object as the opposite eye is covered, this is an abnormal finding, indicating that the eye was not aligned prior to the opposite eye being covered. Next, uncover the opposite eye, as the patient continues to focus on the distant object. If this eye moves as it is uncovered, it indicates that the eye did not maintain alignment as it was covered and unable to focus on an object. Repeat the same process, as you cover and uncover the opposite eye. Later, as pupillary responses are assessed, alignment can be further evaluated as a penlight beam is directed toward the bridge of the nose as the patient looks straight ahead and the examiner observes for sym- metry of light reflex. Accessory Structures Inspect the eyebrows and lashes for symmetry and orientation. Inspect for symmetry and placement; palpate the lids for masses or tenderness, observe for ptosis. Observe for areas of discoloration, masses, and xanthomas. External Eye Structures Inspect the conjunctiva, cornea, and sclera, noting the condition of the surface, clarity, color, and vascularity. Examples of several abnormalities are identified in Table 4-1. Box 4-2 reviews the procedure for performing a fluorescein stain, to assess for potential corneal lesions. Pupils Observe the shape and symmetry of the pupils, including the response to light and accom- modation. The pupils provide important indications of the cause for vision change. Examples of abnormal findings and causes are noted in Table 4-2. The cornea is also assessed during the pupil examination. Anterior Chamber and Lens Determine the approximate depth and clarity of the anterior chamber using oblique light- ing. Also with the oblique lighting, assess the clarity of the lens. During the funduscopic exam, the clarity of the lens is also identified when the red reflex is noted. Cranial Nerves The eye examination includes an assessment of cranial nerves II, III, IV, and VI, which is accomplished during assessment of visual acuity, accessory structures, and pupils. The optic nerve is finally directly observed during the funduscopic examination. Nursing health assessment: A critical thinking, case studies approach.

J Neurol 248: 903–904 Orwitz JI generic dutasteride 0.5 mg line hair loss supplements, Galetta SL purchase 0.5mg dutasteride visa hair loss youtube, Teener JW (1997) Bilateral trochlear nerve palsy and downbeat nystagmus in a patient with cephalic tetanus. Neurology 49: 894–895 357 Muscle and myotonic diseases 359 Fig. Human Skeletal Muscle showing the gross and microscopic structure. The sacroplasmic reticulum (SR) is an intracellular membrane system. The T tubules are invaginations of the sarcolem- ma, and communicate with the extracellular space. Ultrastructurally several components of the muscle can be identified. The sarcomere (SA) represents the space between the Z discs. The A band comprises thick filaments of myosin, with an overlap of actin at the edges. The H band represents pure myosin, with a thickening in the center called the M line. The I band on either side of the Z line, comprises thin filaments. The Z disc helps to stabilize the actin filaments Although the history and clinical examination remain the most effective way of Introduction diagnosing the presence of myopathy, increasingly the clinician has to rely on an understanding of muscle electrophysiology, pathology, and genetics to differentiate between an ever-increasing number of complex disorders of mus- cle. The motor unit consists of the Electrophysiology anterior horn cell, axon, muscle membrane and muscle fiber, and is the final common pathway leading to activation of the muscle. The number of motor units in individual muscles varies depending on size from 10 in extraocular muscles to more than 1000 in lower limb muscles. Electromyography allows us to determine if the abnormality of the motor unit points to a disorder of the axon, muscle membrane, or muscle fiber and allows accurate diagnosis. Acti- vation of the motor unit results in firing of muscle fibers and leads to muscle contraction. Striated muscle is made up of interdigitating thick filaments com- prising myosin, and thin filaments comprising actin, and dividing the sarcomere into A and I bands (Fig. Myosin is composed of light and heavy meromyosin and acts as an ATPase, hydrolyzing ATP. Actin filaments comprise actins, 360 troponins, and tropomyosin. ATPase hydrolysis in the presence of calcium ions activates the troponin-tropomyosin system and permits sliding of actin on myosin filaments as predicted by the “sliding filament theory”. The force generated by a muscle is critically depended on its length. The more cross bridges between the filaments, the larger the force generated. In order to induce contraction there is first an increase in calcium ions in the sarcoplasmic reticulum following depolarization of the muscle membrane. The degree of increase in calcium ions equates with increased muscle tension, and is maxi- mal at 10–5 to 10–4 M. Between contractions calcium is sequestered in the sarcoplasmic reticulum. Electrodiagnosis is useful in diagnosing the myopa- thies. Firstly, it helps distinguish between primarily myopathic compared to neurogenic disorders, secondly it allows the distribution of the myopathy to be determined, and finally it gives some information about severity and prognosis. Although electromyography can distinguish broad types of myopathic disor- ders, it cannot diagnose the specific myopathy. This requires analysis of the muscle pathology often coupled with biochemical and genetic analysis. Fur- thermore, some myopathies show evidence of both myopathic as well as neurogenic types of motor units, for example the inflammatory myopathies and disorders of fatty acid metabolism. Muscle histology and The second critical diagnostic evaluation in myopathic disorders is the muscle immunohistochemistry biopsy. Regular histology may diagnose many of the disorders listed in the following sections, and can recognize distinct histological patterns such as those seen in dermatomyositis, or some infective or toxic myopathies. How- ever, increasingly we rely on specific immunohistochemical studies to make an accurate diagnosis. Thus, in the dystrophinopathies antibodies to certain mus- cle proteins allow us to determine the specific muscle disease, or in mitochon- drial myopathies and other metabolic diseases the pathogenic enzyme system can be determined. Increasingly, patients with a metabolic myopathy present with significant symptoms of myalgia or myoglobinuria and have normal or minimally abnormal basic muscle histology, yet biochemical tests reveal signif- icant enzyme abnormalities that would otherwise be missed. However, even the most astute muscle pathologist is dependent on accurate clinical informa- tion to decide which of the numerous biochemical studies are most appropri- ate.

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