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Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
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Not smoking is a common suggestion in the literature. Apart from smoking cessation, there is little definitive research in this area. In addition to the selenium studies above, some recent research also is suggestive that statin use may assist.
Graves' ophthalmopathy is diagnosed clinically by the presenting ocular signs and symptoms, but positive tests for antibodies (anti-thyroglobulin, anti-microsomal and anti-thyrotropin receptor) and abnormalities in thyroid hormones level (T3, T4, and TSH) help in supporting the diagnosis.
Orbital imaging is an interesting tool for the diagnosis of Graves' ophthalmopathy and is useful in monitoring patients for progression of the disease. It is, however, not warranted when the diagnosis can be established clinically. Ultrasonography may detect early Graves' orbitopathy in patients without clinical orbital findings. It is less reliable than the CT scan and magnetic resonance imaging (MRI), however, to assess the extraocular muscle involvement at the orbital apex, which may lead to blindness. Thus, CT scan or MRI is necessary when optic nerve involvement is suspected. On neuroimaging, the most characteristic findings are thick extraocular muscles with tendon sparing, usually bilateral, and proptosis.
Von Graefe's sign is the lagging of the upper eyelid on downward rotation of the eye, indicating exophthalmic goiter (Graves' Disease). It is a dynamic sign, whereas lid lag is a static sign which may also be present in cicatricial eyelid retraction or congenital ptosis.
A pseudo Graefe's sign (pseudo lid lag) shows a similar lag, but is due to aberrant regeneration of fibres of the oculomotor nerve (III) into the elevator of the upper lid. It occurs in paramyotonia congenita.
A pseudo Graefe's sign is most commonly manifested in just one eye but can occasionally be observed in both. The reason only one eye is affected is not yet clear.
Prior to any physical examination, the diagnosis of keratoconus frequently begins with an ophthalmologist's or optometrist's assessment of the person's medical history, particularly the chief complaint and other visual symptoms, the presence of any history of ocular disease or injury which might affect vision, and the presence of any family history of ocular disease. An eye chart, such as a standard Snellen chart of progressively smaller letters, is then used to determine the person's visual acuity. The eye examination may proceed to measurement of the localized curvature of the cornea with a manual keratometer, with detection of irregular astigmatism suggesting a possibility of keratoconus. Severe cases can exceed the instrument's measuring ability. A further indication can be provided by retinoscopy, in which a light beam is focused on the person's retina and the reflection, or reflex, observed as the examiner tilts the light source back and forth. Keratoconus is amongst the ophthalmic conditions that exhibit a scissor reflex action of two bands moving toward and away from each other like the blades of a pair of scissors.
If keratoconus is suspected, the ophthalmologist or optometrist will search for other characteristic findings of the disease by means of slit lamp examination of the cornea. An advanced case is usually readily apparent to the examiner, and can provide for an unambiguous diagnosis prior to more specialized testing. Under close examination, a ring of yellow-brown to olive-green pigmentation known as a Fleischer ring can be observed in around half of keratoconic eyes. The Fleischer ring, caused by deposition of the iron oxide hemosiderin within the corneal epithelium, is subtle and may not be readily detectable in all cases, but becomes more evident when viewed under a cobalt blue filter. Similarly, around 50% of subjects exhibit Vogt's striae, fine stress lines within the cornea caused by stretching and thinning. The striae temporarily disappear while slight pressure is applied to the eyeball. A highly pronounced cone can create a V-shaped indentation in the lower eyelid when the person's gaze is directed downwards, known as Munson's sign. Other clinical signs of keratoconus will normally have presented themselves long before Munson's sign becomes apparent, and so this finding, though a classic sign of the disease, tends not to be of primary diagnostic importance.
A handheld keratoscope, sometimes known as "Placido's disk", can provide a simple noninvasive visualization of the surface of the cornea by projecting a series of concentric rings of light onto the cornea. A more definitive diagnosis can be obtained using corneal topography, in which an automated instrument projects the illuminated pattern onto the cornea and determines its topography from analysis of the digital image. The topographical map indicates any distortions or scarring in the cornea, with keratoconus revealed by a characteristic steepening of curvature which is usually below the centreline of the eye. The technique can record a snapshot of the degree and extent of the deformation as a benchmark for assessing its rate of progression. It is of particular value in detecting the disorder in its early stages when other signs have not yet presented.
Once keratoconus has been diagnosed, its degree may be classified by several metrics:
- The steepness of greatest curvature from 'mild' ( 52 D);
- The morphology of the cone: 'nipple' (small: 5 mm and near-central), 'oval' (larger, below-center and often sagging), or 'globus' (more than 75% of cornea affected);
- The corneal thickness from mild (> 506 μm) to advanced (< 446 μm).
Increasing use of corneal topography has led to a decline in use of these terms.
Lid lag is the static situation in which the upper eyelid is higher than normal with the globe in downgaze. It is most often a sign of thyroid eye disease, but may also occur with cicatricial changes to the eyelid or congenital ptosis. Lid lag differs from Von Graefe's sign in that the latter is a dynamic process.It can also be the manifestaition of chemosis (swelling (or edema) of the conjunctiva)
The detection of tumours specific to VHL disease is important in the disease's diagnosis. In individuals with a family history of VHL disease, one hemangioblastoma, pheochromocytoma or renal cell carcinoma may be sufficient to make a diagnosis. As all the tumours associated with VHL disease can be found sporadically, at least two tumours must be identified to diagnose VHL disease in a person without a family history.
Genetic diagnosis is also useful in VHL disease diagnosis. In hereditary VHL, disease techniques such as southern blotting and gene sequencing can be used to analyse DNA and identify mutations. These tests can be used to screen family members of those afflicted with VHL disease; "de novo" cases that produce genetic mosaicism are more difficult to detect because mutations are not found in the white blood cells that are used for genetic analysis.
In overt primary hyperthyroidism, TSH levels are low and T and T levels are high. Subclinical hyperthyroidism is a milder form of hyperthyroidism characterized by low or undetectable serum TSH level, but with a normal serum free thyroxine level. Although the evidence for doing so is not definitive, treatment of elderly persons having subclinical hyperthyroidism could reduce the incidence of atrial fibrillation. There is also an increased risk of bone fractures (by 42%) in people with subclinical hyperthyroidism; there is insufficient evidence to say whether treatment with antithyroid medications would reduce that risk.
When vWD is suspected, blood plasma of a patient must be investigated for quantitative and qualitative deficiencies of vWF. This is achieved by measuring the amount of vWF in a vWF antigen assay and the functionality of vWF with a glycoprotein (GP)Ib binding assay, a collagen binding assay, or a ristocetin cofactor activity (RiCof) or ristocetin induced platelet agglutination (RIPA) assays. Factor VIII levels are also performed because factor VIII is bound to vWF which protects the factor VIII from rapid breakdown within the blood. Deficiency of vWF can then lead to a reduction in factor VIII levels, which explains the elevation in PTT. Normal levels do not exclude all forms of vWD, particularly type 2, which may only be revealed by investigating platelet interaction with subendothelium under flow, a highly specialized coagulation study not routinely performed in most medical laboratories. A platelet aggregation assay will show an abnormal response to ristocetin with normal responses to the other agonists used. A platelet function assay may give an abnormal collagen/epinephrine closure time, and in most cases, a normal collagen/ADP time. Type 2N may be considered if factor VIII levels are disproportionately low, but confirmation requires a "factor VIII binding" assay. Additional laboratory tests that help classify sub-types of vWD include von-willebrand multimer analysis, modified ristocetin induced platelet aggregation assay and vWF propeptide to vWF antigen ratio propeptide. In cases of suspected acquired von-Willebrand syndrome, a mixing study study (analysis of patient plasma along with pooled normal plasma/PNP and a mixture of the two tested immediately, at one hour, and at two hours) should be performed. Detection of vWD is complicated by vWF being an acute phase reactant with levels rising in infection, pregnancy, and stress.
Other tests performed in any patient with bleeding problems are a complete blood count-CBC (especially platelet counts), activated partial thromboplastin time-APTT, prothrombin time with International Normalized Ratio-PTINR, thrombin time-TT, and fibrinogen level. Testing for factor IX may also be performed if hemophilia B is suspected. Other coagulation factor assays may be performed depending on the results of a coagulation screen. Patients with von Willebrand disease typically display a normal prothrombin time and a variable prolongation of partial thromboplastin time.
The testing for vWD can be influenced by laboratory procedures. Numerous variables exist in the testing procedure that may affect the validity of the test results and may result in a missed or erroneous diagnosis. The chance of procedural errors are typically greatest during the preanalytical phase (during collecting storage and transportation of the specimen) especially when the testing is contracted to an outside facility and the specimen is frozen and transported long distances. Diagnostic errors are not uncommon, and the rate of testing proficiency varies amongst laboratories, with error rates ranging from 7 to 22% in some studies to as high as 60% in cases of misclassification of vWD subtype. To increase the probability of a proper diagnosis, testing should be done at a facility with immediate on-site processing in a specialized coagulation laboratory.
Given the anatomic site, a spindle cell lipoma, nuchal-type fibroma and fibromatosis colli are all included in the differential diagnosis.
In those without symptoms who are not pregnant there is little evidence for or against screening.
Simple excision is the treatment of choice, although given the large size, bleeding into the space can be a potential complication. Isolated recurrences may be seen, but there is no malignant potential.
The differential diagnosis for Bernard–Soulier syndrome includes both Glanzmann thrombasthenia and pediatric Von Willebrand disease. BSS platelets do not aggregate to ristocetin, and this defect is not corrected by the addition of normal plasma, distinguishing it from von Willebrand disease.
There is no way to reverse VHL mutations, but early recognition and treatment of specific manifestations of VHL can substantially decrease complications and improve quality of life. For this reason, individuals with VHL disease are usually screened routinely for retinal angiomas, CNS hemangioblastomas, clear-cell renal carcinomas and pheochromocytomas. CNS hemangioblastomas are usually surgically removed if they are symptomatic. Photocoagulation and cryotherapy are usually used for the treatment of symptomatic retinal angiomas, although anti-angiogenic treatments may also be an option. Renal tumours may be removed by a partial nephrectomy or other techniques such as radiofrequency ablation.
In terms of treatment/management, bleeding events can be controlled by platelet transfusion.
Most heterozygotes, with few exceptions, do not have a bleeding diathesis. BSS presents as a bleeding disorder due to the inability of platelets to bind and aggregate at sites of vascular endothelial injury. In the event of an individual with mucosal bleeding tranexamic acid can be given.
The affected individual may need to avoid contact sports and medications such as aspirin, which can increase the possibility of bleeding. A potential complication is the possibility of the individual producing antiplatelet antibodies
Some cases of myotonia congenita do not require treatment, or it is determined that the risks of the medication outweigh the benefits. If necessary, however, symptoms of the disorder may be relieved with quinine, phenytoin, carbamazepine, mexiletine and other anticonvulsant drugs. Physical therapy and other rehabilitative measures may also be used to help muscle function. Genetic counseling is available.
A Cushing ulcer, named after Harvey Cushing, is a gastric ulcer associated with elevated intracranial pressure. It is also called von Rokitansky-Cushing syndrome. Apart from in the stomach, ulcers may also develop in the proximal duodenum and distal esophagus.
The mechanism of development of Cushing ulcers is thought to be due to direct stimulation of vagal nuclei as a result of increased intracranial pressure. Alternatively, it may also be a direct result of Cushing reaction. Efferent fibers of the vagus nerve then release acetylcholine onto gastric parietal cell M receptors, causing insertion of hydrogen potassium ATPase vesicles into the apical plasma membrane. The end result is increased secretion of gastric acid with eventual ulceration of the gastric mucosa.
The diagnosis can be established by measuring catecholamines and metanephrines in plasma (blood) or through a 24-hour urine collection. Care should be taken to rule out other causes of adrenergic (adrenalin-like) excess like hypoglycemia, stress, exercise, and drugs affecting the catecholamines like stimulants, methyldopa, dopamine agonists, or ganglion blocking antihypertensives. Various foodstuffs (e.g. coffee, tea, bananas, chocolate, cocoa, citrus fruits, and vanilla) can also affect the levels of urinary metanephrine and VMA (vanillylmandelic acid).
Imaging by computed tomography or a T2 weighted MRI of the head, neck, and chest, and abdomen can help localize the tumor. Tumors can also be located using an MIBG scan, which is scintigraphy using iodine-123-marked metaiodobenzylguanidine. Even finer localization can be obtained in certain PET scan centers using PET-CT or PET-MRI with [18F] fluorodopamine or FDOPA.
Pheochromocytomas occur most often during young-adult to mid-adult life.
These tumors can form a pattern with other endocrine gland cancers which is labeled multiple endocrine neoplasia (MEN). Pheochromocytoma may occur in patients with MEN 2 and MEN 3 (MEN 2B). Von Hippel Lindau patients may also develop these tumors.
Patients experiencing symptoms associated with pheochromocytoma should be aware that it is rare. However, it often goes undiagnosed until autopsy; therefore patients might wisely choose to take steps to provide a physician with important clues, such as recording whether blood pressure changes significantly during episodes of apparent anxiety.
Acute GPP typically requires inpatient management including both topical and systemic therapy, and supportive measures. Systemic glucocorticoid withdrawal is a common causative agent. Withdrawal or administration of certain drugs in the patient's previous medication regimen may be required. Oral retinoids are the most effective treatment, and are considered first line. Cyclosporine or infliximab may be required for particularly acute cases.
Kogoj's spongiform pustules can be observed via histopathology to confirm acute GPP.
Cruveilhier–Baumgarten disease or Pégot-Cruveilhier–Baumgarten disease is a rare medical condition in which the umbilical or paraumbilical veins are distended, with an abdominal wall bruit (the Cruveilhier-Baumgarten bruit) and palpable thrill, portal hypertension with splenomegaly, hypersplenism and oesophageal varices, with a normal or small liver.
It was first described by Pégot in 1833, and then by Jean Cruveilhier (1835) and Paul Clemens von Baumgarten (1907).
Armstrong "et al." (1942) and Steinburg and Galambos (1967) described two different types of the condition:
- Cruveilhier-Baumgarten syndrome: liver cirrhosis or portal hypertension is the cause of the distension of the paraumbilical veins (i.e. an "acquired" condition in which the veins reopen due to high portal pressure).
- Cruveilhier–Baumgarten disease: the distension of the paraumbilical veins is due to failure of umbilical vein closure, with little or no evidence of liver disease found on liver biopsy (i.e. a "congenital" patency of the umbilical vein leading to portal hypertension).
Phakomatoses are inconsistently defined, and there is a lack of consensus about what conditions are included in this category.
Conditions included are:
- Ataxia telangiectasia
- Incontinentia pigmenti
- Neurofibromatosis
- Nevoid basal cell carcinoma syndrome
- Sturge-Weber syndrome
- Tuberous sclerosis
- Wyburn-Mason syndrome (Bonnet–Dechaume–Blanc syndrome)
- von Hippel-Lindau disease
The four hereditary types of vWD described are type 1, type 2, type 3, and pseudo- or platelet-type. Most cases are hereditary, but acquired forms of vWD have been described. The International Society on Thrombosis and Haemostasis's classification depends on the definition of qualitative and quantitative defects.
Trousseau sign of latent tetany is a medical sign observed in patients with low calcium. From 1 to 4 percent of normal patients will test positive for Trousseau's sign of latent tetany. This sign may be positive before other manifestations of hypocalcemia such as hyperreflexia and tetany, as such it is generally believed to be more sensitive (94%) than the Chvostek sign (29%) for hypocalcemia.
To elicit the sign, a blood pressure cuff is placed around the arm and inflated to a pressure greater than the systolic blood pressure and held in place for 3 minutes. This will occlude the brachial artery. In the absence of blood flow, the patient's hypocalcemia and subsequent neuromuscular irritability will induce spasm of the muscles of the hand and forearm. The wrist and metacarpophalangeal joints flex, the DIP and PIP joints extend, and the fingers adduct. The sign is also known as main d'accoucheur (French for ""hand of the obstetrician"") because it supposedly resembles the position of an obstetrician's hand in delivering a baby.
The sign is named after French physician Armand Trousseau who described the phenomenon in 1861. It is distinct from the Trousseau sign of malignancy.