Key Points Dental caries: • occurs in plaque-covered areas frequently exposed to dietary carbohydrates; • the initial lesion is subsurface before the thin surface layer collapses; • the initial or pre-cavitation lesion is reversible; • saliva plays an essential part in caries prevention; • if all plaque is removed from the surface the carious process stops generic loratadine 10 mg with mastercard allergy symptoms vs asthma. The dotted line represents a typical pH value below which enamel will dissolve (the critical pH) discount loratadine american express allergy swollen eye. The body of the lesion shows marked radiolucency (loss of mineral) in contrast to sound enamel and the surface layer: ×70 purchase loratadine without prescription zocor allergy symptoms. One of the tasks of epidemiology is to record the level of disease and the variation between groups. A second task is to record changes in the levels of dental caries in populations over time, while a third task is to try to explain these variations. The United Kingdom has one of the best series of national statistics on dental caries. The dental health of adults and children has been recorded every 10 years, beginning with the Adult Dental Health Survey of 1968 (Table 6. They are national, using sound sampling methods to obtain representative samples of the populations. They include both clinical and sociological data, giving the interaction between knowledge, attitude, behaviour, and disease. The methods are well described and carefully standardized, resulting in meaningful longitudinal information. Data on children at the ages of 5, 12, and 14 are also available through the annual studies conducted under the auspices of the British Association for the Study of Community Dentistry. The ravages of dental caries were so severe in the past that the extent of disease in a population was measured by the proportion of the population with no natural teeth or edentulousness. A marked decrease in the per cent edentulous between 1968 and 1998 was recorded, especially in adults aged 35-54 years. For younger people, it is common to record the prevalence (the proportion of people affected), the severity (number of teeth affected per person) of dental caries and the percentage of carious teeth restored (Care Index). What is of concern is opinion that in the youngest age groups the improvement is not continuing, and indeed there are signs that caries experience is increasing in some areas. A decline in caries, first noticed during the 1970s, has been recorded in a large number of industrialized countries. The dental health of older children continued to improve in the 1980s but caries experience in primary teeth, measured at ages 5 or 6 years, had stayed fairly constant. The Nordic countries used to have very high caries experience and the drastic improvement in all five Nordic countries can be seen in Fig. Caries experience in Australian children has been well recorded indicating a dramatic improvement in dental health (Fig. Reports from North America indicate that caries prevalence and severity in the permanent dentition have continued to decline since 1982 in Canada and the United States, but that caries experience in the primary dentition may have stabilized since about 1986-7. While dental surveys of schoolchildren have been quite common, there is much less information on the dental health of preschool children mainly because access to them is more difficult (Table 6. The prevalence and severity of dental caries in British preschool children was reviewed by Holt (1990), and in preschool children around the world by Holm (1990). In most European countries, North America, and Australia, caries experience has declined in parallel with the increasing use of fluoride toothpastes, although this decline appears to have stopped in the United Kingdom. Caries experience of preschool children in South-East Asia, Central America, and parts of Africa is high and there are discernible trends of increasing prevalence in parallel with the rise in availability of sugar-containing snacks and drinks. While the state of the permanent dentition in children has improved dramatically in many countries, caries in primary teeth is still a considerable problem in preschool and school-aged children. In industrialized countries, caries experience is highest in the more deprived groups of society and often in ethnic minority groups. In developing countries, the reverse social trend is observed, with the well-off, urban children having the most caries experience. In adults, provision of dental services and patient preference for treatments can have a major effect on the state of the dentition, in addition to the aetiological and preventive roles of sugar, fermentable carbohydrates, and fluoride. Key Points Dental caries • Epidemiology indicates the size of the problem of caries and changes over time. Below the waterline lie the lesions which need the use of some form of additional aid to be identified. This can range from radiographs in the clinical situation to histopathology in the in vitro setting. The identification of caries depends on a systematic examination of clean dry teeth. The basic equipment consists of adequate lighting, compressed air for drying, dental mirror, and blunt or ball ended probe. The emphasis is on a visual examination, rather than a visual-tactile examination. A ball-ended or blunt probe may be used gently to confirm the presence of cavitation, sealants, and restorations. The first visible sign of caries is the white spot lesion, at first this can only be seen when the surface is dried (Fig. This is because when demineralized enamel becomes porous, these pores contain water, if dried, the water in the pores is replaced with air and the lesion becomes more obvious. Unfortunately active carious lesions are not the only causes of white areas on teeth; hypoplasia, fluorosis, and arrested hypermineralized carious lesions to name but a few can all mimic a white spot carious lesion. The decision as to the aetiology depends on factors such as site and surface characteristics. Caries tends to occur at predilection sites, therefore a white area at the gingival margin is much more likely to be caries than one of similar appearance at the incisal edge. Although large cavities are relatively easily identified dentine caries presents its own problems. On occlusal surfaces there may be no visible break in the surface, the evidence of caries being shadowing under the enamel. Therefore as even the most thorough visual clinical examination will detect only some of the enamel and dentine carious lesions present, the clinician needs to be helped by diagnostic aids. These provide information on both occlusal dentine caries and approximal enamel and dentine caries. Bimolars are not as useful a view as bitewings because there is often overlap of structures. Periapicals are as accurate as bitewings for caries diagnosis but obviously less information is available on any one film. As with the visual examination it is vital that the radiographs are viewed in a systematic way with appropriate illumination and ideal magnification. Although not all children will tolerate them, bitewing radiographs should be considered for all children from the age of 4 years and above who are at risk of caries. An interesting clinical phenomenon which may help the clinician decide if radiographs are warranted is the presence of a bleeding papilla, this suggesting the presence of an approximal cavity. This occurs because the cavity will be full of plaque, which together with driving the carious process on will cause gingivitis and thus the bleeding papilla.
Two to five days after classical dengue fever buy discount loratadine 10 mg allergy symptoms and treatment, patients go into shock generic 10mg loratadine overnight delivery allergy symptoms getting worse, develop hepatomegaly purchase loratadine 10mg on line allergy forecast naperville, liver enzyme elevations, and hemorrhagic manifestations. Ribavirin has been used for prophylaxis and treatment of Lassa fever, Sabia virus hemorrhagic fever, Argentine hemorrhagic fever, Bolivian hemorrhagic fever, Rift Valley fever, Crimean-Congo hemorrhagic fever, and Venezuelan hemorrhagic fever. Ribavirin has been used to treat Hantavirus hemorrhagic fever with renal syndrome but does not appear effective in treating Hantavirus pulmonary syndrome. There is no specific therapy for yellow fever, Ebola, or Marburg virus infections. The intravenous regimen recommended for the viral hemorrhagic fevers is as follows: 2 g loading dose, followed by 1 g every six hours for four days, followed by 0. Another intravenous regimen: 30 mg/kg loading dose, followed by 15 mg/kg every six hours for four days; followed by 7. Oral regimen: 2 g loading dose, followed by 4 g/day in four divided doses for four days; followed by 2 g/day for six days. Aerosolized virus is inactivated in 48 hours, but may remain viable in house dust for up to two years. Exposure to contaminated materials, clothing, and blankets can spread infection, and although rare, infection over long distances has been reported. Contagious period: Patients are not contagious during the incubation period but one to two days before the onset of symptoms or when the oral enanthema appears (24 hours prior to the rash). Viral shedding is greatest during the first 10 days of the rash, but persists until all scabs and crusts are shed. Bioterrorism Infections in Critical Care 477 Clinical disease: The prodrome begins with the sudden onset of fever, chills, back pain, headache, malaise, and sometimes nausea, vomiting, abdominal pain, and confusion. The typical patient develops a centrifugal rash two to three days after the onset of symptoms or very quickly after the enanthem. Early lesions are shotty and within 24 to 48 hours become vesicular then pustular. Flat malignant smallpox (10% to 20% of patients, usually unvaccinated children) present with a severe prodrome, poorly formed papules, and dusky erythema of the face followed by arms, back, and upper chest. Death (45% to 99% of patients) occurs in 7 to 15 days from encephalitis or hemorrhage. Hemorrhagic fulminate smallpox mimics hemorrhagic fever with most patients succumbing in seven days. The rash appears usually three to five days after the prodrome, but may appear later. Other mild forms of disease include an influenza-like illness and pharyngeal disease that is mild and presents without rash (variola sine eruptione, variola sine exanthemata). Complications include encephalopathy, eye complications (10–20% of patients), smallpox (viral) osteomyelitis (osteomyelitis variolosa), hemorrhagic disease particularly in pregnant women, fetal death, and premature delivery. Differential diagnosis: Includes acne, chickenpox, drug eruptions, generalized vaccinia or eczema vaccinatum, insect bites, monkeypox, secondary syphilis, vaccine reactions, and viral hemorrrhagic fever. Parenteral cidofovir and imatinib mesylate (Gleevec) may have a role in severe cases. Plague (25,26,29) Incubation period: Bubonic plague (from a fleabite or direct contact of the skin or mucous membrane): two to six days. Clinical disease: Patients present with one or more of five clinical syndromes: (i) classic bubonic plague; (ii) septicemic plague; (iii) upper respiratory infections; (iv) nonspecific febrile illnesses, and (v) gastrointestinal or urinary tract infections (95). Bubonic Plague Patients present with sudden onset of fever, chills, headache, and malaise. A papule, vesicle, pustule, ulcer, or eschar may be present at the inoculation site. Regional nodes enlarge within 24 hours (1 to 10 cm), are tender, inflamed, and become fluctuant. Septicemic Plague The symptoms (fever, chills, malaise, headache, and gastrointestinal symptoms) and signs (tachycardia, tachypnea, and hypotension) of septicemic plague are similar to those of other forms of gram-negative septicemia. Primary septicemic disease occurs from cutaneous exposure, but without regional lymphadenopathy. Gangrene in the extremities and tip of the nose from small vessel thrombosis occurs (The Black Death). Primary pneumonic plague from inhalation of infected droplets manifests itself with sudden onset of fever, chills, headache, chest pain, shortness of breath, hypoxia, and hemoptysis. Pharyngitis from inhalation or ingestion may be asymptomatic (colonization in contacts of patients with plague pneumonia) or present with swollen tonsils and/or inflamed cervical nodes. The differential diagnosis for plague pneumonia includes all causes of bilateral pneumonia, tularemia, Q fever, mycoplasma, Legionnaires’ disease (especially in the presence of diarrhea), tuberculosis, fungal infections, and viral pneumonias. Gentamicin, doxycycline, chlorampheni- col, and ciprofloxacin are alternate agents. Prophylaxis (adult dosing): Prophylaxis should be administered for seven days after the last exposure. Tularemia (1,30) Incubation period: The average incubation period after any of the exposures is three to six days (range a few hours to three weeks). Contagious period: Natural infection is acquired by contact with infected animals, especially rodents and rabbits, arthropod, insect and tick bites, inhalation, and ingestion. The laboratory must be notified so that no procedures are carried out at an open bench. Clinical disease: Patients present with an abrupt onset of fever, chills, myalgia, headache, and often a dry cough in all forms of the disease. Ulceroglandular or Glandular Tularemia Papule at site of entry progresses to a slow-healing crusting ulcer with the development of tender regional lymphadenopathy. Patients present with ulcerative tonsillitis or pharyngitis, often unilateral, with regional lymphadenopathy. Oculoglandular Tularemia This is similar to ulceroglandular disease except the primary lesion is in the conjunctivae. There is usually severe unilateral conjunctivitis with enlargement of the preauricular nodes. Typhoidal Tularemia Patients present with the same general symptoms, high fever with relative bradycardia, gastrointestinal symptoms, and pneumonia. Patients may have infiltrates, hilar adenopathy, pleural effusions, or necrotizing pneumonia. Typhoidal disease, especially if prolonged, must be differentiated from other forms of sepsis, including typhoid fever, enteric fever, brucellosis, Legionella, Q fever, disseminated mycobacterial or fungal disease, rickettsial disease, malaria, and endocarditis. Ulceroglandular disease may be mistaken for Mycobacterium marinum or sporotrichosis infections. Because lymphadenopathy may be present without the skin lesion and persist for long periods of time, bacterial infection, cat scratch disease, syphilis, chancroid, lymphogranu- loma venereum, tuberculosis, nontuberculous mycobacteria, toxoplasmosis, sporotrichosis, rat- bite fever, anthrax, plague, and herpes simplex must be included in the differential diagnosis. Oculoglandular disease with predominantly tender preauricular, submadibular, and cervical nodes may be mistaken for mumps. Pharyngeal tularemia may mimic other forms of exudative tonsillitis (streptococcal, infectious mononucleosis, adenovirus), and diphtheria. Fluoroquinolones appear to be efficacious for the subspecies holarctica (limited experience).
He/She can then correlate the images with the clinical ﬁndings with a considerable saving of time buy generic loratadine 10mg online allergy symptoms in 1 year old. Also buy 10 mg loratadine mastercard allergy medicine at night, the integrity of the system should be intact to avoid any medical errors in the patients’ information buy loratadine 10 mg mastercard allergy shots or pills. It should be always and easily accessible to all concerned to avoid delay in patient care. By virtue of teleradiology, a radiologist or a nuclear physician can retrieve and interpret diagnostic images from a distant hospital and send back the report to the original hospital. This type of practice has resulted in outsourcing practitioners at a lower cost from one country to interpret imaging scans performed in another country, where the practitioner’s pay is high. Describe the method and advantages and disadvantages of the list mode acquisition and the frame mode acquisition. Which mode would you use—byte mode or word mode—in static studies versus dynamic studies? What is the essential difference between the Anger type analog camera and the “all-digital” camera? Structural information in the third dimension, depth, is obscured by superimposition of all data along this direction. Although imaging of the object in different projections (posterior, anterior, lateral, and oblique) gives some information about the depth of a structure, precise assessment of the depth of a structure in an object is made by tomo- graphic scanners. The prime objective of these scanners is to display the images of the activity distribution in different sections of the object at dif- ferent depths. The principle of tomographic imaging in nuclear medicine is based on the detection of radiations from the patient at different angles around the patient. In contrast, in transmission tomography, a radi- ation source (x-rays or a radioactive source) projects an intense beam of radiation photons through the patient’s body, and the transmitted beam is detected by the detector and further processed for image formation. Single Photon Emission Computed Tomography 155 The detector head rotates around the long axis of the patient at small angle increments (3° to 10°) for collection of data over 180° or 360°. The data are collected in the form of pulses at each angular position and normally stored in a 64 × 64 or 128 × 128 matrix in the computer for later reconstruction of the images of the planes of interest. Transverse (short axis), sagittal (vertical long axis), and coronal (horizontal long axis) images can be gen- erated from the collected data. Multihead gamma cameras collect data in several projections simultaneously and thus reduce the time of imaging. For example, a three-head camera collects a set of data in about one third of the time required by a single-head camera for 360° data acquisition. Data Acquisition The details of data collection and storage such as digitization of pulses, use of frame mode or list mode, choice of matrix size, etc. Data are acquired by rotating the detector head around the long axis of the patient over 180° or 360°. Although 180° data collection is commonly used (particularly in cardiac studies), 360° data acquisition is preferred by some investigators, because it minimizes the effects of attenuation and vari- ation of resolution with depth. In some situations, the arithmetic mean (A1 + A2)/2 or the geometric mean (A × A )1/2 of the counts,A and A , of the two heads 1 2 1 2 are calculated to correct for attenuation of photons in tissue. However, in 180° collection, a dual-head camera with heads mounted at 90° angles to each other has the advantage of shortening the imaging time required to sample 180° by half (Table 12. Dual-head cameras with heads mounted at 90° or 180° angles to each other and triple-head cameras with heads ori- ented at 120° to each other are commonly used for 360° data acquisition and offer shorter imaging time than a one-head camera for this type of angular sampling. The sensitivity of a multihead system increases with the number of heads depending on the orientation of the heads and whether 180° or 360° acquisition is made. Older cameras were initially designed to rotate in circular orbits around the body. Relationship of sensitivity and time of imaging for 180° and 360° acqui- sitions for different camera head conﬁgurations. This causes loss of data and hence loss of spatial resolution in these projections. Data collection can be made in either continuous motion or “step-and- shoot” mode. In continuous acquisition, the detector rotates continuously at a constant speed around the patient, and the acquired data are later binned into the number of segments equal to the number of projections desired. In the step-and-shoot mode, the detector moves around the patient at selected incremental angles (e. Image Reconstruction Data collected in two-dimensional projections give planar images of the object at each projection angle. To obtain information along the depth of the object, tomographic images are reconstructed using these projections. Two common methods of image reconstruction using the acquired data are the backprojection method and the iterative method, of which the former is the more popular, although lately the latter is gaining more attention. Simple Backprojection The principle of simple backprojection in image reconstruction is illustrated in Figure 12. In the two-dimensional data acquisi- tion, each pixel count in a projection represents the sum of all counts along the straight-line path through the depth of the object (Fig. Recon- struction is performed by assigning each pixel count of a given projection in the acquisition matrix to all pixels along the line of collection (perpen- dicular to the detector face) in the reconstruction matrix (Fig. This Single Photon Emission Computed Tomography 157 is called simple backprojection. When many projections are backprojected, a ﬁnal image is produced as shown in Figure 12. Backprojection can be better explained in terms of data acquisition in the computer matrix. Suppose the data are collected in a 4 × 4 acquisition matrix, as shown in Figure 12. In this matrix, each row represents a slice, projection, or proﬁle of a certain thickness and is backprojected individu- ally. Counts in each pixel are considered to be the sum of all counts along the depth of the view. Similarly, counts from pixels B1,C, and D1 1 are added to each pixel of the second, third, and fourth columns of the reconstruction matrix, respectively. Next, suppose a lateral view (90°) of the same object is taken, and the data are again stored in a 4 × 4 acquisition matrix. The ﬁrst row of pixels (A2,B,C, and D2 2 2) in the 90° acquisition matrix is shown in Figure 12. Counts from pixel A2 are added to each pixel of the ﬁrst row of the same reconstruction matrix, counts from pixel B2 to the second row, counts from pixel C2 to the third row, and so on. If more views are taken at angles between 0° and 90°, or any other angle greater than 90° and stored in 4 × 4 acquisition matrices, then the ﬁrst row data of all these views can be Fig.
Seamus Cullen Long term follow up has dem onstrated an increased cardio- vascular m orbidity and m ortality follow ing repair of coarctation of the aorta loratadine 10mg for sale allergy symptoms dry eyes. Recoarctation m ay occur and produces upper body hypertension and pressure overload of the left ventricle cheapest generic loratadine uk allergy medicine that works quickly. Hypertension is a com m on com plication affecting 8–20% of patients w ho have undergone repair of coarctation of the aorta and is associated w ith increased m orbidity and m ortality buy cheap loratadine 10mg on line allergy symptoms chest pain. Indeed, patients w ho are norm otensive at rest m ay dem onstrate an abnorm ally high increase in systolic blood pressure in response to exercise, probably related to baroreceptor abnorm alities and/or reduced arterial com pliance. The bicuspid aortic valve is com m only seen in patients w ith coarctation and m ay predispose to infective endocarditis, aortic stenosis/regurgitation and to ascending aortic aneurysm. In addition, m itral valve abnorm alities have been detected in approxim ately 20% of patients. All patients w ho have undergone repair of aortic coarctation should be follow ed up on a regular basis w ith careful m onitoring of upper and low er lim b blood pressure. Cardiac exam ination is directed tow ards palpation of the fem oral pulses, m onitoring of blood pressure and auscultation. A plain chest x-ray picture m ay dem onstrate m ediastinal w idening related to aneurysm form ation. How ever, m agnetic resonance im aging is the gold standard for non-invasive diagnosis of recoarctation and/or aneurysm form ation. Cardiac catheterisation confirm s the presence of recoarctation and perm its transcatheter balloon dilatation w ith stenting of the aortic coarctation. This is probably the procedure of choice in suitable lesions because of the sm all but definite risk of neurological com plications associated w ith surgical correction of coarctation of the aorta. Persisting hypertension should be 100 100 Questions in Cardiology am enable to m edical therapy, e. Finally, patients w ho have had their coarctation repaired are at increased risk from infective endo- carditis and antibiotic prophylaxis is recom m ended. Arterial reactivity is significantly im paired in norm otensive young adults after successful repair of aortic coarctation in childhood. Survival patterns after cardiac surgery or interventional catheterization: a broadening base. This should include the construction of a fam ily tree w ith at least three generations. The clinical examination This should be aim ed specifically at excluding other causes of hypertrophy such as aortic stenosis or hypertension. Investigations to identify risk factors of sudden death The recognised risk factors are fam ily history of sudden deaths, recurrent syncope, non-sustained ventricular tachycardia and an 102 100 Questions in Cardiology abnorm al blood pressure response during exercise. The peak oxygen consum ption during the exercise also helps identify those w ith significant lim itation of exercise capacity. Additional investigations in patients with syncope In these patients, additional investigations should be aim ed at determ ining the m echanism. Other investigations that may be useful but not mandatory This includes electrophysiological studies and rarely a thallium scan for m yocardial ischaem ia. It is necessary to exclude significant coronary artery disease w ith a coronary angiogram in patients >40 years old, sm okers or those w ith severe chest pain. Asym ptom atic patients do not need treatm ent routinely unless they are at risk of sudden death. Treatment of symptoms Typical sym ptom s include dyspnoea, palpitations and chest pain. Dyspnoea is usually due to left ventricular diastolic dysfunction w hile chest pain is frequently due to m yocardial ischaem ia. The pain m ay how ever be atypical and occur in the absence of dem onstrable epicardial coronary disease. The treatm ent chosen w ill depend on w hether there is significant outflow tract obstruction (outflow gradient 30m m Hg). In those w ithout obstruction, the choice is betw een either a beta blocker or a calcium antagonist, such as high dose verapam il (up to 480m g/day). In those w ith obstruction a beta blocker w ith or w ithout disopyram ide is usually the first choice for those patients w ith outflow obstruction (~25% of patients). Both drugs reduce the outflow gradient and im prove diastolic function by their negative inotropism. Verapam il should only be used w ith caution as it m ay w orsen the outflow obstruction (through the increased vasodilatation and consequent ventricular em ptying w ith contraction). Supraventricular arrhythm ias including atrial fibrillation m ay be controlled w ith beta blockers, verapam il or am iodarone. Surgical septal m yectom y is long established and can be com bined w ith m itral valve replacem ent in patients w ith associated significant m itral regurgitation. W hen patients present w ith progressive ventricular dilatation and reduced systolic function, cardiac transplantation m ay need to be considered. O ral am iodarone and/or an im plantable cardiac defibrillator are the available options. Percutaneous translum inal septal m yocardial ablation in hypertrophic obstructive cardiom yopathy: acute results and 3-m onth follow -up in 25 patients. Niall G Mahon and W McKenna There are broadly tw o categories of indications for perm anent pace- m aker insertion in patients w ith hypertrophic cardiom yopathy: • Standard indications for pacing w hich apply to any patient. Indications for the use of dual cham ber pacing w ith a short program m ed atrioventricular delay for this purpose rem ain to be determ ined. Gradient reduction is thought to com e about through a variety of effects on septal and papillary m uscle m otion and contractility. In general outflow gradients can be reduced by approxim ately 50% but the translation of this benefit into clinical im provem ent is variable and unpredictable. A considerable placebo effect of the procedure has been observed in at least tw o random ised studies. The role of pacing in young patients is unclear and m ethods of identifying patients likely to benefit from the procedure have not been established. Dual cham ber pacing for hypertrophic cardiom yopathy: a random ised double blind crossover trial. Niall G Mahon and W McKenna Diagnostic criteria for the diagnosis of hypertrophic cardio- m yopathy in first degree relatives have been proposed as show n in Table 51. Relatives are considered affected in the presence of one m ajor criterion or tw o m inor echocardiographic criteria or one m inor echocardiographic plus tw o m inor electro- cardiographic criteria. These criteria do not apply w hen other potential causes such as athletic training, system ic arterial hyper- tension or obesity are present. Young children w ith no evidence of disease should be re-evaluated every 5 years until their teens and then annually until aged 21. Diagnosis in a child under 10 years requires a body surface area corrected left ventricular w all thickness of >10m m. Affected relatives should additionally undergo risk stratification, w hich includes 48 hour Holter m onitoring and exercise testing, looking especially for ventricular arrhythm ias and abnorm al blood pressure responses respectively.