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The cache acts as an intermediate store image manipulation and compression in radiology order v-gel online herbal. Some means must be available to store the examinations’ images buy v-gel 30 gm line quality herbals, perhaps on a semi- however buy generic v-gel 30 gm herbals used for abortion, volatile (it loses stored information when permanent basis, for viewing and for making hard- the power supply is removed). The earliest storage devices were punched paper cards, which were used as early the important features to be considered when as 1804 to control silk-weaving looms. Modern mass choosing and specifying a digital auxiliary storage storage devices include all types of disk drives and device are: tape drives. Mass storage is Transfer time, the rate (M-bits s 1) at which the distinct from memory, which refers to temporary • information can be moved from main memory to storage areas within the computer. Unlike main storage device and vice versa memory, mass storage devices retain data even when • Access time, the time required to retrieve a stored the computer is turned off. The main types of mass piece of information storage are: Typical values for these characteristics are shown in • Hard disks : very fast and with more capacity than Table 11. Some hard account are the relative cost of storage per image, disk systems are portable (removable cartridges), ease of operation and avoidance of any errors which but most are not. Fast access, short-term storage is always disks have quite large storage capacity (4. Track • Flash storage: this is a type of semiconductor mem- ory which retains information when removed from its power source. An example of this design the performance of a hard disk is crucial to the is shown in Fig. Hard disks offer the cheapest 80 ms for slow disks to 10 to 12 ms for the large fast storage medium for archiving information. The position of each point accurate view of a hard disk performance both access is decided by the disk format so the disks need to be time and transfer rate should be considered. Accessing the data access rate with a slow transfer rate produces a slow in any reasonable time requires the disk to spin very drive. Hard disks spin at between 5400 and 10 000 rpm defines the amount of time it takes the hard drive’s yielding very fast data storage and retrieval. Such a store would be capable of holding many tens of thousands of 512 512 images. However, it is a relatively (a) cheap storage medium and its portability has made it a popular medium of image data transfer. There are two types of technology used for tape streamers: helical scan recording and linear (or longitudinal) recording. The linear type offers a better performance over the helical but has lower capacities. Helical scan recording uses the same principle as video tape recorders and is inherently slower than the linear type. The read/write heads are attached to a helical scanning drum and data are recorded in a stripe pattern. When data is medium because of their very large storage capaci- recorded onto linear tape the tape heads are stationary ties, typically in the gigabyte range, and slow transfer and the tape moves past at about 100 to 125 inches per 1 rate (mega-bits per second (Mb s )) which is much second. The 1 1 of magnetic and optical storage media is shown in 800 kB s can be increased to 1. The information is physically stored on the disk surface by burning a tiny indentation, using a laser. These devices are well suited as an archival the disk can be erased and overwritten by new data. This brings the mag- metallic film consisting of an alloy of silver, indium, netic layer to its Curie point when new magnetic antimony, and tellurium, initially in a clear crys- information can then be written. Heated heating step takes time and consequently slows the for a longer period and this metallic layer becomes writing speed. These Data access is as fast as the optical disk and relies on ‘phase change’ materials are not fully stable so there the polarization of laser light by the magnetic polarity is usually a fixed read/write limit of about 1000 times. The main drawback of magneto-optic However, their record can be archived more success- disks is the extra time to write information. This was initially called digital video disk but eventu- the edge of each pit represents only 1 bit of data. It surface covered by a thin layer of metal to reflect laser first appeared in 1997 having a capacity of 3. Each signal transition (pit to land, or nique to maximize the storage density on the disk sur- land to pit) corresponds to a binary 1, while a period face. This results in a variable number of revolutions with no change corresponds to a zero. If both sides are needed for recording, then memory cells are erased in a single action or ‘flash’. In this Flash memory uses in-circuit wiring to apply the elec- case each side must be read directly by turning the tric field either to the entire chip or to predetermined disc over, as dual layer technology is not currently sections known as blocks. A ‘land groove’ for- outside world by exchanging information very much mat allows signals to be recorded on both the grooves as do human beings. There are input ‘sensory’ signals formed on the disk and in the lands between the in the form of image data or keyboard instructions grooves. The mouse is the most common form of pointing device using a serial port along with the keyboard. The computer keyboard has special keys which are not found on a typewriter keyboard. Modifier keys are used in combination with other keys to change commands, the most useful key being the control key or ‘Ctrl’. Other keys are the function keys F1 through to F12 which represent macro functions (small programs) or specific commands that launch an application that would otherwise require a set of Figure 11. Gray-scale monitors in coded words or blocks recognizable by either the are able to display a wide range of grays. Some devices need confirmation mon monitor has 8 bit pixel depth so can display 256 or ‘handshakes’ after each data transfer so that gray levels but high brightness monitors are capable synchronization can be maintained. These could be mice, modems, keyboards, Software 287 printers, storage devices or scanners. It uses the same cables and con- gies provide higher download than upload band- nectors and supports data rates up to 480 Mbps (40 width. Latency is the delay to connect peripheral equipment such as displays, that occurs along the transmission path. The communication with factor with satellite connections because the data other equipment, including other computers, is more must travel over large distances. Therefore satellite complex since the speed of communication is most systems are not suitable for businesses that require important.
Among the 31 indigenously antigen in brain tissue using a direct fuores- acquired cases order v-gel online herbals essences, all but 4 were associated with cent antibody test buy v-gel 30 gm overnight delivery shahnaz herbals. Despite the large focus of rabies in rac- should be euthanized in a manner that pre- coons in the eastern United States order v-gel 30gm on line herbals for kidney function, only 3 serves brain tissue for appropriate laboratory human deaths have been attributed to the rac- diagnosis. Historically, 2 cases mice or in tissue culture from saliva, brain, of human rabies were attributable to probable and other specimens and can be detected by aerosol exposure in laboratories, and 2 unusual identifcation of viral antigens or nucleotide cases have been attributed to possible airborne sequences in afected tissues. Diagnosis in exposures in caves inhabited by millions of suspected human cases can be made post- bats, although alternative infection routes mortem by immunofuorescent or immuno- cannot be discounted. Transmission has also histochemical examination of brain tissue occurred by transplantation of organs, corneas, or by detection of viral nucleotide sequences. Ten people have survived detection of viral nucleotide sequences in rabies in association with incomplete rabies saliva, skin, or other tissues. Since 2004, 3 girls, each of is sufciently sensitive because of the unique whom had not received rabies postexposure nature of rabies pathobiology. A combination sonnel and state or local health departments of sedation and intensive medical intervention should be consulted before submission of may be valuable adjunctive therapy. This electron micrograph shows the rabies virus, as well as Negri bodies or cellular inclusions. Courtesy of Centers for Disease rabies appear depressed, lethargic, and Control and Prevention/Dr makonnen Fekadu. When their throat and jaw muscles are paralyzed, the animals will drool and have diffculty swallowing. S minus is transmitted by bites of rats and Rat-bite fever is caused by Streptobacillus mice. S moniliformis most cases of rat-bite fever in the United States; infection (streptobacillary or Haverhill fever) S minus infections occur primarily in Asia. Tere is an abrupt Incubation Period onset of fever, chills, muscle pain, vomiting, For S moniliformis, usually less than 7 days headache, and, rarely (unlike S minus), lymph- (range, 3 days–3 weeks); for S minus, 7 to adenopathy. The bite site usually heals promptly organism isolated from specimens of blood, and exhibits no or minimal infammation. Cultures should be held resolve within 2 weeks, but fever can occa- up to 3 weeks if S moniliformis is suspected. Com- Sodium polyanethol sulfonate, present in plications include sof tissue and solid-organ most blood culture media, is inhibitory to abscesses, septic arthritis, pneumonia, endo- S moniliformis; therefore, sodium polyanethol carditis, myocarditis, and meningitis. S minus fatality rate is 7% to 13% in untreated patients, has not been recovered on artifcial media but and fatal cases have been reported in young can be visualized by darkfeld microscopy in children. With S minus infection (sodoku), a wet mounts of blood, exudate of a lesion, and period of initial apparent healing at the site of lymph nodes. Blood specimens should also be the bite is usually followed by fever and ulcer- viewed with Giemsa or Wright stain. S minus ation at the site, regional lymphangitis and can be recovered from blood, lymph nodes, or lymphadenopathy, and a distinctive rash of local lesions by intraperitoneal inoculation of red or purple plaques. The causes of rat-bite fever are S moniliformis, Treatment a microaerophilic, gram-negative, pleomorphic Penicillin administered intravenously or intra- bacillus, and S minus, a small, gram-negative, muscularly for 7 to 10 days is the treatment for spiral organism with bipolar fagellar tufs. Initial Epidemiology intravenous penicillin for 5 to 7 days followed by oral penicillin for 7 days has also been Rat-bite fever is a zoonotic illness. Limited experience exists for ral habitat of S moniliformis and S minus ampicillin, cefuroxime, and cefotaxime. Doxycycline or streptomycin can be substi- S moniliformis is transmitted by bites or tuted when a patient has a serious allergy to scratches from or exposure to oral secretions penicillin. Patients with endocarditis should of infected rats (eg, kissing pet rodents); other receive intravenous high-dose penicillin G for rodents (eg, mice, gerbils, squirrels, weasels) at least 4 weeks. The addition of streptomycin and rodent-eating animals, including cats and or gentamicin for initial therapy may be useful. Streptobacillus moniliformis was isolated from blood cultures, and the patient responded to intravenous penicillin therapy without complication. Because of fever, chills, headache, and rash 5 days later, blood cultures were obtained that grew Streptobacillus moniliformis. Sodoku, or rat-bite fever caused by Spirillum minus, rarely occurs in the united States. The virus uses to 30% develop lower respiratory tract disease attachment (G) and fusion (F) surface glyco- (eg, bronchiolitis, pneumonia) with the frst proteins for virus entry; these surface proteins infection. Signs and symptoms of bronchiolitis lack neuraminidase and hemagglutinin activ- typically begin with rhinitis and cough, which ities. Only one serotype is known, but progress to increased respiratory efort with variations in the surface proteins (especially tachypnea, wheezing, rales, crackles, inter- attachment protein G) result in the classifca- costal or subcostal retractions, grunting, and tion of viruses in 2 major subgroups, desig- nasal faring. Approximately surfaces for several hours and for 30 minutes 1% to 3% of all infants in the frst 12 months of or more on hands. Spread among household can be associated with short-term or long-term and child care contacts, including adults, complications that include recurrent wheezing is common. However, these tests should be interpreted with caution, especially Incubation Period when a multiplex assay identifes the presence 4 to 6 days; range, 2 to 8 days. In children, the sensitivity of these assays in comparison Respiratory syncytial virus isolation from with culture varies between 53% and 96%, with respiratory tract secretions in cell culture most in the 80% to 90% range. Experienced viral laboratory per- detection assays, the predictive value is high sonnel should be consulted for optimal during the peak season, but false-positive methods of collection and transport of speci- test results are more likely to occur when mens, which include keeping the specimen the incidence of disease is low, such as in the cold but unfrozen during transport, rapid summer in temperate areas. Terefore, antigen specimen processing, and stabilization in detection assays should not be the only basis virus transport media. Conventional sero- on which the beginning and end of monthly logic testing of acute and convalescent serum immunoprophylaxis is determined. In most specimens cannot be relied on to confrm outpatient and inpatient settings, specifc viral infection in young infants, in whom sensitiv- testing has little efect on management and ity may be low. Clinicians may choose not to adminis- such as human metapneumovirus, rhinovirus, ter supplemental oxygen if the oxyhemoglobin bocavirus, adenovirus, coronavirus, infuenza saturation exceeds 90% in infants and children virus, or parainfuenza virus. Continuous with bronchiolitis who are coinfected with measurement of oxygen saturation may detect more than one virus experience more severe transient fuctuations in oxygenation that are disease is not clear. Many commercial tests signifcant increase in oxygen saturation dur- are designed as multiplex assays to facilitate ing the acute infection in several small studies. Evidence does not support the use of efective at improving the symptoms of mild nebulized epinephrine in hospitalized chil- to moderate bronchiolitis afer 24 hours of dren with bronchiolitis or for outpatient use and in reducing hospital length of stay in management of children with bronchiolitis. Controlled clinical been shown to be efective over the short trials among children with bronchiolitis term for patients managed in the emergency have demonstrated that corticosteroids do department or when length of hospitaliza- not reduce hospital admissions or length of tion is brief. The virion is variable in shape and size (average diameter between 120 and 300 nm). Note the wide intercostal spaces, hyperaeration of the lung felds, and fattening of the diaphragm.
Roughly half the cases gations the first case will present a sensitivity of 98% in the image set have no objects effective v-gel 30gm herbals for ed. A ranking/scoring and a specificity of 54% and the second case will system from 1 to 5 would be: present a sensitivity of 72% and a specificity of 96% trusted 30gm v-gel rajasthan herbals international. So combining the results from carefully chosen 1 Definitely normal (only obvious normals scored) investigations markedly improves overall sensitivity where false positive rate would be high and the and specificity order v-gel in united states online herbs paint and body. The sec- (a) False positive fraction ond and third methods require electronic handling of the image information to produce a video signal 1. Since a video False positive fraction camera is commonly restricted to an 8 10 film size it is not possible to hold more than about six images 1. The main action of a laser imager is to capture the incoming digitized video signal which then modu- 2 Probably normal (probably no lesion) lates a laser beam scanning a film surface. The critical false negative would be high design concerns the prism and mirror scanning Hard-copy devices 223 Spinning penta-prism Lens Acoustic–Optical modulator Film surface Laser (a) 80 m (b) (c) Figure 8. Each line of pixels (4096) by a constantly rotating prism in the laser light beam is exposed in approximately 3. The He–Ne laser produces red light (630 nm) so beam is shifted down until the entire sheet of film has special red-sensitive film is necessary. An electrical signal is converted contrast detail diagram: graphic display comparing into an acoustic signal which changes the refractive contrast and resolution index of the crystal scattering the light at different contrast improvement factor: improvement of con- angles from the main beam, so reducing the main trast when grid is used beam intensity. The scatter intensity depends on the contrast: film: the slope of the characteristic curve: size of the acoustic signal. The main beam passes film gamma through a small slot which blocks the scattered light contrast: image: relative measure of density differ- from reaching the film surface. The laser beam passes through a film speed: film sensitivity measured for an optical lens system which gives a typical beam diameter of density of 1 85 m giving an image matrix size of typically grid factor: increase in exposure when grid is used 4096 5120 pixels, representing 12 pixels mm 1. The mechanical catter grid per centimeter precision is therefore very high and vibration must grid ratio: ratio of grid height to interspace distance be prevented over the exposure 20 s exposure time. Fields are interlaced the disadvantage of the laser imager is the to give each frame fixed image matrix size. Multiple images would share line pairs: resolution measurement using a grating of the total 4096 5120 matrix. High definition (1024/ paired light and dark lines 1249 line) video images in multi-format (4 5 line spread function: a count profile taken through a image set) would only just be faithfully recorded. Projection imaging delivers a great deal of ensure that photoelectric events are dominant, even in information compression, because anatomy that spans soft tissues giving maximum subject contrast. It is very the entire thickness of the patient is presented in one effective for differentiating soft tissue detail but is only image. A single chest radiograph can reveal impor- practical for tissue thicknesses of a few centimeters; tant diagnostic information concerning the lungs, its most important application is mammography. They are provided using just one radiograph, the position along the tra- in constant-potential and most high frequency genera- jectory of the X-ray beam of a specific radiographic tors. Both the tube loadability and the focus size are shadow, such as that of a pulmonary nodule, is not important for this application and a balance must be known. X-rays emerge from the X-ray rube, which is posi- tioned on one side of the patient’s body, they then 9. Both the tube loadability and the focus size are important for this application and a balance must be struck between these two parameters. Tube voltages are typically in the region of 50 specialized examinations performed on specialized to 85 kV; the most common range is between 60 and equipment. This is needed in order to provide sufficient Conventional radiography commonly employs low contrast detail in the radiograph. The higher kVp X-ray energies between 50 and 80 kVp but special values are almost exclusively used for regions with imaging requirements sometimes utilize the particular high X-ray attenuation, such as oblique projections 228 Basic projection X-ray imaging systems of the abdomen or lateral projections of the spine. Depending on the type of the range between 65 and 70 kV, which is used for examination, it is important to determine whether the urography and examinations involving the bones of loadability of the tube, and hence the shortness of the exposure, have the higher priority, or whether it should be the smallness of the focus, and hence the reduced geometric unsharpness. Due to this inter-relationship, double- focus tubes are particularly common in this type of application. The minimum anode angle for coverage of a Slit format length of 43 cm at 100 cm can be calculated 80 to 100 mm diameter 150 to 200mm diameter as 13°. As a heavy tube load should be available to reduce exposure times and movement unsharpness Conventional dual focus Stress-relieved anode to the minimum, a loadability of 50 or even 100 kW (a) is required. Specification Low power Medium power High power Maximum voltage 150 150 150 Anode heat capacity 111kJ 260kJ 600kJ Anode construction Tungsten/molybdenum Tungsten/molybdenum Tungsten/graphite Focal spot 1mm 0. The operating frequency of 5 kHz is commonly increased to values above 20 kHz in order to reduce size, eliminate audible hum from the generator and improve generator efficiency. Their number depends on the firing frequency of the inverter system, consequently high frequency generators are sometimes called multi- 9. The high frequency generator com- bines the advantages of a constant-potential generator the high frequency generator combines the advantages but at less cost (about 30% less). The reproducibility rate than guessing the milliampere–second reference and consistency of tube voltage is enhanced by a rela- value required for a specific patient. Additional features include the following: • Fast tube voltage closed-loop control with about • the line supply can be either single phase or 200 s response 3-phase (220 to 440 V). This allows reduction of 20% the cross-section A of the core and the number of turns n on the coils (kV A n f). The response time of the closed loop control circuit depends on the trigger frequency. It is approximately 250 s, which is slower than that of a direct-current generator but is by far faster than the response time of a conventional generator. This method of (10 to 20 kHz) construction is called a ‘single-tank generator’, does Figure 9. Image surface the timing is controlled by the reference value which Comparator Integrator depends on detector sensitivity (film-screen speed) and dose registered Reference value by the ion chamber. D depends on the recording sys- are used: Ref tem sensitivity and desired image quality. The region of an object which is of diagnostic inter- • A semiconductor detector is placed behind the est is called the dominant. The measuring field of the sensor (either ion- the ionization chamber should be as narrow as ization chamber or semiconductor radiation detector) possible, and should not create a shadow on the film. Automatic exposure control sys- ionization events in the chamber which is charged to tems are designed for all types of exposures allowing 300 or 1000 V. The magnitude of the ionization cur- alignment of the light beam measuring diaphragm and rent is extremely small (picoampere range 10 12). This technique is applied in behind the film cassette or in film changers behind conventional Bucky, mammography, and fluoroscopy. Signal integration is advantage over the ionization chamber is that the 232 Basic projection X-ray imaging systems Figure 9. The current of this detector is proportional to the dose rate received behind the cas- sette and not in the plane of the film. Movement unsharpness or kinetic Conventional imaging (60 to 80kVp) 233 blurring is influenced by the generator power rating. It includes the scattered radiation, and tube peak value U (kVp), the tube current in mA and therefore the reference dose value is reached sooner in exposure time as: the case of thick objects.
Of the patients who survive the ictal bleed discount v-gel 30 gm free shipping herbs to grow indoors, about one-third die in the hospital order v-gel 30 gm greenridge herbals, one-third live with significant disability order 30gm v-gel with mastercard jeevan herbals, and one-third recover with little disability. Very specific but variable sensitivity for vasospasm and is proceduralist dependent. There is relatively weak evidence for this particular therapeutic approach, however. A target Hgb of 8 g/dl to 10 g/dl is considered by expert opinion to be most beneficial; however, increased phlebotomy to drop hemoglobin is not advised. Fluid balance should be closely monitored, and routine placement of pulmonary artery catheters or other invasive methods should be avoided unless the balance is difficult to ascertain. The improved outcomes related to oral nimodipine are now thought to be possibly secondary to protective effects on the neurovascular unit. Consists of multiple arteries and veins, connecting at a nidus without an interven- ing normal capillary bed. Pathogenesis is not well understood, but they are consid- ered sporadic congenital developmental vascular lesions 2. After an initial hemorrhage, annual hemorrhage rates are approximately 6% to 17% in the first year, but then decrease. Important considerations in the decision to treat and the choice of treatment are age, lesion size and location, and prior history of intracerebral hemorrhage. Surgery is the mainstay of treatment; radiosurgery is a useful option in lesions deemed at high risk for surgical therapy, and endovascular embolization can be a useful adjunct to these techniques. They can occur throughout the brain but are most common in the subcortical Rolandic and temporal areas. Clinical presentation can include hemorrhage, seizures, and/or progressive neuro- logic deficits. Annual bleeding rates are up to 1% per year for supratentorial lesions and up to 3% per year for brainstem lesions. Surgical resection may be indicated for progressive neurologic deficits, intractable epilepsy, and/or hemorrhage. As the duration of seizures increases, so does the number of neurons lost, and the likelihood of a successful treatment decreases. If true seizure activity occurs for longer than 5 to 10 minutes, the likelihood of cessation of activity is unlikely without intervention. The rise in creatine kinase and rhabdomyolysis, however, pose a threat to other organ systems and should be monitored. Bacterial meningitis: treated with empiric antibiotics followed by de- escalated antibiotic therapy based on cultures. Treatment is related to immune suppression combined with plasmapheresis and/or intravenous immunoglobulin ther- apy and steroids in addition to escalated anti-epileptic medication therapy. Coma: There are some subtle semantic differences in the exact definition of coma; however, most describe a coma as a profound unarousable state of unresponsiveness and unconsciousness with little or no response to pain, voice, or other external stim- ulation and no spontaneous eye opening. Etiologies for coma include severe bilateral hemispheric brain damage, injury to vital areas of the reticular activation system (brainstem, basal forebrain, thalamus and hypothalamus), and metabolic, septic, or drug effect. It is important to note that arousal requires an intact brainstem and subcortical function, whereas awareness requires an intact cerebral cortex. Management of coma requires standard airway, breathing, and circulation sup- portive therapy while determining etiology and the potential for reversibility. Glasgow Coma Scale Spontaneous 4 To voice 3 Eye opening To pain 2 None 1 Obeys commands 6 Localizes pain 5 Withdraws to pain 4 Best motor response Flexor posturing 3 Extensor posturing 2 None 1 Conversant and oriented 5 Conversant and disoriented 4 Best verbal response Inappropriate words 3 Incomprehensible words 2 None 1 7. The difference between coma and brain death is that brain death is characterized by the total irreversible loss of all brain function to sustain life. The term serves as a second legal declaration of death, the only other currently being cardiac death. Certain conditions must be met to make the declaration of death by neurological criterion: a. There must be no severe overlying medical condition (electrolytes, acid/base disturbances, endocrine abnormalities). There should be no recent administration or continued presence of neuromus- cular blocking agents. No caloric vestibular reflex (“cold calorics”): using 50 mL of cold water, instill water for 1 minute into each ear and allow for at least 5 minutes between ears. Eyes should turn slowly toward the ear being stimulated in the patient with intact reflexes. Cannulated 100% oxygen can be delivered down the endotracheal tube to provide oxygenation. Patient will pass the apnea test (not deemed brain dead) if there are any respiratory movements. If the patient meets all of the previous criteria, generally on two separate occasions at least 6 hours apart, patient meets the legal definition of death by neurological criteria posed by most states. There are several confirmatory tests that can assist with the clinical examination if there is uncertainty of brain death: a. Digital subtraction angiography can be done, which in the brain-dead pa- tient will demonstrate no filling above the level of carotid bifurcation (internal carotid artery), the intracranial vertebral arteries, or the circle of Willis. There should also be no electroencephalographic reactivity to somatosensory or audiovisual stimuli. This will be indicated by a lack of diastolic flow and small sharp systolic peaks in early systole. It will show no radiotracer uptake within the cerebral vessels or parenchyma in the brain-dead patient. Somatosensory evoked potentials: no response of N20 to P22, indicating a lack of communication between the body and the cortex. Delirium: an acute confusional state, marked by decreased attention and prominent alterations in perception and consciousness and associated with vivid hallucinations, delusions, heightened alertness, and agitation; hyperactivity of psychomotor and autonomic functions; insomnia; and so forth. Dementia: a syndrome characterized by a progressive deterioration of function in memory, plus two other cognitive domains (e. Etiologies of dementia (cont’d) Benign and malignant tumors Neoplastic Paraneoplastic limbic encephalitis Hypothyroid Vitamin B1 deficiency (Wernicke-Korsakoff) (acute to subacute) Vitamin B12 deficiency Vitamin E deficiency (neuropathy, ataxia, encephalopathy) Nicotinic acid (niacin or vitamin B3) deficiency (pellagra) Metabolic Uremia/dialysis dementia Chronic hepatic encephalopathy Chronic hypoglycemic encephalopathy Chronic hypercapnia/hyperviscosity/hypoxemia Chronic hypercalcemia/electrolyte imbalance Cushing’s disease (usually behavior change or psychosis) Multi-infarct dementia Binswanger’s encephalopathy Specific vascular syndromes (thalamic, inferotemporal, bifrontal) (post-acute) Triple border-zone watershed infarction (post-acute) Vascular Diffuse hypoxic/ischemic injury (post-acute) Mitochondrial disorders (e. Alzheimer’s dementia: the most common degenerative disease of the brain; incidence increases sharply with age after 65; age is the most important and common risk factor (10% of people >65 years old [y/o], 50% of people >85 y/o); other risk factors: Down syndrome (patient 30–45 y/o shows similar pathologic changes), midlife obesity, dia- betes mellitus, current tobacco use, head injury, apolipoprotein E4 genotype; reported protective factors: education, Mediterranean-type diet, low or moderate alcohol in- take, physical activity, inheritance of apolipoprotein E2 allele. Alzheimer’s dementia—clinical features: characteristically impaired recall, re- peated questions to family. Alzheimer’s dementia—clinical features (cont’d) changes; parkinsonian look; rigidity and fine tremor; myoclonus (late). Pathology: brain volume is decreased in advanced case up to 20% or more; ven- tricles enlarge proportionally; extreme hippocampal atrophy; atrophic process involves temporal, parietal, and frontal, but cases vary a lot; microscopically: senile or neuritic plaques, neurofibrillary tangles, granulovacuolar degeneration of neu- rons most prominent in pyramidal cell layer of hippocampus; Hirano bodies. Cholinergic neurons of the nucleus basalis of Meynert (substantia innominata), medial septal nuclei, and diagonal band of Broca are reduced; with resulting deficiency of acetylcholine.
