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If you want to review some normal neurohistology cheap provera 10mg overnight delivery womens health warner robins ga, there is an interesting “virtual slide box of histology” at www order 10 mg provera otc women's health clinic bray. Finally buy cheap provera 2.5 mg online breast cancer grade 3, constructive criticism and comments are welcome and should be referred to the course director. Phone and office numbers are given for the preceptors and we encourage you to make use of this resource outside of our formal teaching plan. Introduction to Cellular Neuropathology/Cerebral Edema Cerebrovascular Diseases R eview Weds. Dementia and Degenerative Diseases & M etabolic D iseasesR eview Case 2: Dementia Fri. You will discover that these alterations are common to a variety of neuropathological disorders. Acute ischemic or hypoxic damage produces a shrinkage of the cell body and a hypereosinophilia. The neuron may be involved directly or indirectly, through retrograde (via efferents) or anterograde (via afferents) transneuronal or transynaptic degeneration. Chromatolysis may be followed by regrowth of the axon from the point of damage, a phenomenon more often seen in the peripheral than in the central nervous system. In neuronal storage diseases, excessive amounts of lipids, carbohydrates, glycosaminoglycans, or glycoproteins accumulate within neurons, enlarging and distorting the normal geometry of the cell body and proximal processes. These are usually seen in the context of inherited disorders of lipid or glycosaminoglycan catabolism (eg. Some reflect the focal storage of metabolites, some the presence of viral proteins or nucleoproteins, and some the abnormal accumulation of structural proteins (eg. Lipofuscin is an insoluble mix of proteins, lipids, and minerals that accumulates in neurons and astrocytes during the normal aging process. Neuronophagia is the phagocytosis of degenerating neurons, usually by macrophages. This is commonly seen after hypoxic or ischemic insults or during viral infections. Dying back degeneration, a degeneration of the most distal axon, followed by the progressive loss of more and more proximal regions, is often seen in toxic peripheral neuropathies. Demyelination refers to the primary loss of myelin with relative preservation of the axon (eg. Spheroids contain mixtures of lysosomes, mitochondria, neurofilaments, and other cytoplasmic constituents. Slowing or cessation of axoplasmic transport at sites of damage presumably account for spheroids. This is seen in many types of mental retardation, including congenital hypothyroidism (cretinism). Atrophy is a reduction in the volume and surface area of dendritic branches, commonly seen in neurodegenerative diseases. Neuritic plaques are collections of degenerating axons and dendrites, mixed with microglia and astrocytes and associated with the extracellular deposition of amyloid (beta-amyloid, see lecture on Neurodegenerative diseases). Status spongiosis refers to a spongy state of the neuropil, the formation of fine to medium sized vacuoles representing swollen neuronal and astrocytic processes. This change is typical of transmissible spongiform encephalopathies, such as Creutzfeldt- Jacob disease. They contact blood vessels, pial surfaces, and enfold synapses in their functions to maintain the concentration of ions, neurotransmitters, and other metabolites within normal levels in the extracellular space. Astrocytes undergo hypertrophy (enlargement) and hyperplasia (proliferation) in response to a great many pathological processes, including hypoxic-ischemic damage and trauma. Astrocytes develop abundant pink cytoplasm, either due to imbibing plasma proteins and fluid in the short-term (when the blood-brain-barrier is broken) or filling up with intermediate filaments (in long-term scarring). The descriptive term of reactive, hypertrophic or gemistocytic is often used to describe this change. They are thought to be related to the hyperammonemia of hepatic failure (see notes on Metabolic diseases). Corpora amylacea are spherical accumulations of polyglucosan (branched-chain glucose polymers), which increase in numbers with age, particularly in a subventricular and subpial locations, and in glial scars. Neoplasia: Astrocytomas represent a common form of brain tumor (see notes on neoplasia) 5. Note that oligodendrocytes or progenitors of oligodendrocytes are able to remyelinate demyelinated axons, and thus help to repair demyelinated lesions. Myelin edema: In certain toxic and metabolic settings, fluid accumulates within myelin sheaths, leading to intramyelinic edema. Cell loss of oligodendrocytes occurs in a variety of disorders, including immune mediated (multiple sclerosis), viral (papova virus of progressive multifocal leukoencephalopathy), and toxic (e. Viral inclusions form in oligodendrocytes in progressive multifocal leukoencephalopathy. Hypertrophy and hyperplasia of endothelial cells is commonly seen in ischemia and in the vicinity of primary and metastatic neoplasms. Schwannomas are common, usually benign, neoplasms of peripheral nerves (see notes on neoplasia). It is important to review gross neuroanatomy and appreciate the anatomic relationships among the medial temporal lobe, tentorium cerebelli, the brain stem and upper cranial nerves, and the vertebro-basilar artery system (posterior circulation). The falx cerebri acts as an incomplete partition separating the hemispheres in the sagittal plane, stopping just above the corpus callosum. The tentorium cerebelli, a horizontal reflection, which lies on the superior surface of the cerebellum, separates supra- from infra-tentorial spaces. The tentorium is open in the ventral midline to allow the midbrain to pass through (tentorial notch). Thus, each free edge of the tentorium lies adjacent to either side of the midbrain. Small increases in volume of the brain may be tolerated, since there is some room for expansion (compression of ventricles and subarachnoid space). Large increases in volume cannot be tolerated, as they may be in visceral organs, without serious consequences. Should rapid expansion occur in one part of the brain, there will be compromise of adjacent tissue. Local expansion leads to local increase in pressure, and consequently to pressure gradients within the brain. Thus, structures at a distance from the main focus of a lesion can also be compromised. Some of the important types of shifts, their pathological consequences, and clinical manifestations will be outlined below. Thus, most substances do not pass readily from blood vessels into the brain parenchyma. This is defined as an increase in volume and weight of the brain due to fluid accumulation.
Logarithmic multiplication of the mycobacteria takes place within the macrophage at the primary infection site provera 5mg lowest price african american women's health social issues. Thereafter order provera on line amex women's health free trial raspberry ketone, trans- portation of the infected macrophages to the regional lymph nodes occurs leading to the lymphohematogenous dissemination of the mycobacteria to other lymph nodes and organs such as kidneys buy provera 2.5 mg line womens health 2014 covers, epiphyses of long bones, vertebral bodies, jux- 16. Etiology, transmission and pathogenesis 527 taependymal meninges adjacent to the subarachnoid space, and, occasionally, to the apical posterior areas of the lungs. In addition, chemotactic factors released by the macrophages attract circulating monocytes to the infection site, leading to their differentiation into mature macrophages with increased capacity to ingest and kill free bacteria (Correa 1997, Starke 1996, Vallejo 1994). Due to the fact that myco- bacteria are not able to grow under the adverse conditions of the extracellular envi- ronment, most infections are controlled by the host immune system. However, the initial pulmonary infection site, which is denominated “primary complex or Ghon focus” and its adjacent lymph nodes, sometimes reach sufficient size to develop necrosis and calcification demonstrable by radiographs (Feja 2005, Schluger 1994). It is generally associ- ated with close contact with cattle, and is variable from one country to another and even from region to region inside the same country (see Chapter 8). This situation oc- curs when repetitive or constant contact with the infectious source - generally fam- 528 Tuberculosis in Children ily members - takes place. Therefore, when a child is diagnosed, a search should be performed for an adult case with a high bacillary load in the respiratory tract (Alet 1986). On the other hand, older children may become infected from an external source, such as schoolmates, team leaders or young adults outside the home. The presence of extensive pulmonary lesions, such as cavities, is the most impor- tant individual human factor in determining the infectious power, since these le- sions are associated not only with an important concentration of oxygen that allows active bacillary multiplication, but also with a rapid pathway to the external envi- ronment. The amount of bacilli released into the atmosphere under these conditions is enough to produce the transmission from person to person (Correa 1997, Schluger 1994). The degree of pulmonary involvement is another important factor, since the exten- sion of the lesions is related to the bacillary load, the intensity and frequency of coughing, and the number of cavities that may propagate these bacilli. Rarely, non- pulmonary localization of the disease with high infectious power, such as the la- ryngeal form, becomes an infectious source. In this case, simple actions such as talking can cause the elimination of an important amount of mycobacteria (Correa 1997). Socioeconomic factors as well as the overcrowded living places in urban areas increase the risk of infection allowing larger contacts with infected persons. The concentration of bacilli depends on ventilation of the surroundings and expo- sure to ultraviolet light. From a public health point of view, these stages have absolutely different transmission implications and epidemiologic consequences. Household is the most frequent setting for exposure although several places that allow a close con- tact with potentially contagious adults such as school, day care centers and other th environments become occasional exposure places. During the 18 century, the “familial hypothesis” raised by the occurrence of familial clustering, dominated medical thinking. In adults, the dis- tinction between infection and disease becomes less difficult because the latter may 530 Tuberculosis in Children be the result of dormant bacilli acquired during a past infection. In children, the distinction may not be so clear because the disease more often progresses from an initial or primary infection. Asymptomatic presentations are more common among school-age children (80-90 %) than in infants less than one year old (40-50 %) (Correa 1997, Vallejo 1996). Erythema nodosum is a toxic allergic erythema with nodular lesions in the skin or under it, 2 to 3 cm large. These lesions are spontaneously painful and very painful under pressure, and are usually located bilaterally in feet and legs. The erythema nodosum is usually accompanied by pharyngitis, fever and joint inflam- mation and is more frequent in girls over six years. Phlyctenular conjunctivitis is an allergic keratoconjunctivitis characterized by the presence of small vesicles that usually evolve to ulcers and resolve without scars. Primary pulmonary tuberculosis 531 associated to the phlyctenular conjunctivitis are photophobia and an excessive lacrimation (Peroncini 1977). Progression of the primary infectious complex may lead to enlargement of hilar and mediastinal lymph nodes with resultant bronchial collapse. Tubercular me- ningoencephalitis may also result from hematogenous dissemination (Newton 1994, Smith 1992). When the disease is controlled by the host immune system, those bacilli spread by the bloodstream may remain dormant in all areas of the lung or other organs for several months or years. Enlargement of lymph nodes may result in signs suggestive of bronchial obstruction or hemidiaphragmatic paralysis. Obstructive hyperaeration of a lobar segment or a complete lobe is less common in pediatric patients while cavi- ties, bronchiectasis and bullous emphysema are occasionally seen. Even in the presence of extensive pulmonary disease, many older children are asymptomatic at the time of diagnosis. In general, however, children are more likely to present with wheezing, cough, fever, and anorexia as part of the symptoms (Lincoln 1958, Starke 1996, Vallejo 1995). Persistent cough may be indicative of bronchial obstruction, while difficulty in swallowing may result from esophageal compression. Progressive primary pulmonary tuberculosis Progression of the pulmonary parenchymal component leads to enlargement of the caseous area and may lead to pneumonia, atelectasis, and air trapping. This form presents classic signs of pneumonia, including tachypnea, dullness to percussion, nasal flaring, grunting, egophony, decreased breath sounds, and crack- les. Typical history reveals an acute onset of fever, chest pain that increases in intensity on deep inspiration, and shortness of breath. The pain accom- panies the onset of the pleural effusion, but after that the pleural involvement is painless. The signs of pleural effusion include tachypnea, respiratory distress, decreased breath sounds, dullness to percussion, and occasionally, features of mediastinal shift. When the primary infection has not been treated properly, the lesion can reactivate from dormant bacilli in either lymph nodes or parenchymal nodules. In contrast to primary disease, the characteristic feature of reactivation is the parenchymal in- volvement, which usually evolves to cavities or diffuse infiltrates, without signifi- cant radiograph changes in pulmonary adenopathies (Peroncini 1979). Pericardial effusion can be an acute complication or can resemble chronic constric- tive pericarditis. Non-respiratory disease Non-respiratory disease implies the dissemination of the bacilli through the circu- latory and lymphatic systems. In the majority of these cases, the localization is intrathoracic affecting mainly the mediastinal lymph nodes. Close to 25-35 % of these forms have extrathoracic localizations, such as on the neck lymph nodes called scrofula. It has been estimated that 65 % to 80 % of children under 12 years old may be infected with Mycobacterium 534 Tuberculosis in Children avium complex; 10 % to 20 % with Mycobacterium scrofulaceum; and 10 % with M.
Typically cheap provera 5mg mastercard womens health focus harrisonburg va, the ap- proach to chronic pain is multidisciplinary in that pa- tients are assessed by a social worker generic 2.5mg provera with amex women's health clinic central coast, psychologist or psychiatrist buy cheapest provera womens health texas, orthopedic surgeon and physiotherapist. Most often, these very complicated patients are re- ferred to the clinic after seeing many other physicians. After taking a detailed history and performing a physi- cal exam, the anesthesiologist may institute a nerve block, using local anesthetic and/or steroids. Fentanyl can be used as an additive to spi- Respiratory depression which at the extreme leads to ap- nal and epidural anesthesia/analgesia. All of the depressant ef- fects of fentanyl are potentiated by concurrent use of sedatives, volatile anesthetics and nitrous oxide. Respiratory Mechanism of Action Respiratory depression, which at the extreme leads to ap- Acts at the mu-and kappa opioid receptors. All of the depressant effects of sufentanil are potentiated by concurrent use of sedatives, volatile anesthetics and nitrous oxide. The synthetic opioids are not direct myo- Mechanism of Action cardial depressants but they do reduce sympathetic Acts at the mu-and kappa opioid receptors. Not suitable for 5-10 minutes; context sensitive half time 3 minutes spinal or epidural use due to glycine additive. Rapid elimination requires initiation of post-operative analge- Elimination sia (usually morphine) prior to emergence. All of the depressant effects of al- fentanil are potentiated by concurrent use of sedatives, volatile anesthetics and nitrous oxide. The synthetic opioids are not direct myocardial depressants but they do reduce sympathetic drive, which may result in decreased car- diac output in patients who are relying on sympathetic tone to support their circulation, such as those in hypo- volemic or cardiogenic shock. Morphine is May cause hypotension, hypertension, bradycardia, ar- commonly used intravenously and for spinal or rhythmias. All of the depres- sant effects of morphine are potentiated by concurrent use of sedatives, volatile anesthetics, nitrous oxide and alcohol. Traditionally used for Respiratory postoperative pain but currently its use is restricted (in Respiratory depression which at the extreme leads to ap- many hospitals) to the treatment of postoperative shiver- nea. May cause sei- zures if used in large doses or over an extended time frame due to the accumulation of its excitatory metabo- lite, normeperidine. In this case, close monitoring Mechanism of Action is indicated and supplemental doses may be necessary. Muscle relaxants are the most common cause of anaphylactoid reactions under general Duration anesthesia. Competitive inhibitor at the acetylcholine receptors of Enhanced neuromuscular blockade is seen in patients the post-synaptic cleft of the neuromuscular junction. Muscle relaxants are the most common cause of anaphy- Duration lactoid reactions under general anesthesia. Increased risk of arrhythmias in patients receiving tricyclic antidepres- sants and volatile anesthetics. Mechanism of Action Histamine release may occur with rapid administration Competitive inhibitor at the acetylcholine receptors of or higher dosages. Muscle relaxants are the most com- Dose mon cause of anaphylactoid reactions under general an- Intubation : 0. Depolarizing muscle relaxant; ultra short-acting; Used Bradycardia, junctional rhythm and sinus arrest can oc- for rapid sequence induction. Succinylcholine (Sch) attaches to nicotinic cholinergic Respiratory receptors at the neuromuscular junction. There, it mim- Occasionally leads to bronchospasm and excessive sali- ics the action of acetylcholine thus depolarizing the vation due to muscarinic effects. Neuromuscular blockade increased thereby theoretically increasing the risk of re- (paralysis) develops because a depolarized post- gurgitation. Most of the other effects are secondary to the depolari- Dose zation and subsequent contraction of skeletal muscle. Deﬁciency can re- sult as a genetic defect, as a consequence of various medications or a result of liver disease. The latter two causes are usually relative while the genetic de- fect can produce a complete lack of pseudocholines- terase activity in homozygous individuals. The use of succinylcholine in a patient with pseudocholin- estersase deﬁciency leads to prolonged paralysis. In anesthesia practice, neostigmine ropine or more commonly glycopyrrolate) in order to is used for the reversal of neuromuscular blockade. Neostigmine Dose does not antagonize succinylcholine and may prolong For reversal of neuromuscular blockade: 0. Therefore, Has additive anticholinergic effects with antihistamines, atropine has an anti-parasympathetic effect. Contraindications Onset Contraindicated in patients with narrow-angle glau- Immediate coma, gastrointestinal or genitourinary obstruction. Duration 1-2 hours Elimination Hepatic, renal Effects Most effects result from the anticholinergic action of at- ropine. Can also be used for creases cerebral metabolic rate and intracranial pres- maintenance of anesthesia or for sedation, in each case sure. Maintenance of anesthesia:100-200 ug/kg/minute Respiratory Sedation: 40-100 ug/kg/minute Depression of respiratory centre leads to brief apnea. Propofol effectively blunts the airway’s response to ma- Onset nipulation thus hiccoughing and bronchospasm are Within one arm-brain circulation time (approximately rarely seen. Patients often experience pleasant dreams Offset of effect is more prolonged when administered under anesthesia followed by a smooth, clear-headed as a continuous infusion. Strict aseptic technique must be used when Elimination handling propofol as the vehicle is capable of support- Rapid redistribution away from central nervous system ing rapid growth of micro-organisms. May con- Decreases the rate of dissociation of the inhibitory neu- tribute to post-operative confusion and delirium. Onset Respiratory Within one arm-brain circulation time (approximately Depresses the rate and depth of breathing leading to 20 seconds). Does not blunt the airway’s re- sponse to manipulation therefore coughing, hiccough- Duration ing, laryngospasm and bronchospasm may be seen at Approximately 5-10 minutes after single induction light planes of anesthesia. Ketamine provides a state of uncon- agent (usually in hemodynamically-compromised pa- sciousness and intense analgesia however the patient’s tients) or for sedation during painful procedures. Cerebral metabolic rate and intrac- Acts at numerous central nervous system receptor sites, ranial pressure are increased. However, keta- Within one arm-brain circulation time (approximately mine does possess direct myocardial depressant effects 20 seconds). Approximately 10-15 minutes after single induction Respiratory dose, with full orientation occurring after 15-30 min- Some degree of airway protection is maintained. Apnea is rare as respiratory drive is inactive tissue sites accounts for termination of uncon- maintained.