While arrhythmias can occur at any time, in some forms of LQTS arrhythmias are more commonly seen in response to exercise or mental stress (LQT1), in other forms following a sudden loud noise (LQT2), and in some forms during sleep or immediately upon waking (LQT3).Some rare forms of long QT syndrome affect other parts of the body, leading to deafness in the Jervell and Lange-Nielsen form of the condition, and periodic paralysis in the Andersen–Tawil (LQT7) form. Risk for arrhythmias
While those with long QT syndrome have an increased risk of developing abnormal heart rhythms the absolute risk of arrhythmias is very variable. The strongest predictor of whether someone will develop TdP is whether they have experienced this arrhythmia or another form of cardiac arrest in the past. Those with LQTS who have experienced syncope without an ECG having been recorded at the time are also at higher risk, as syncope in these cases is frequently due to an undocumented self-terminating arrhythmia.In addition to a history of arrhythmias, the extent to which the QT is prolonged predicts risk. While some have QT intervals that are very prolonged, others have only slight QT prolongation, or even a normal QT interval at rest (concealed LQTS). Those with the longest QT intervals are more likely to experience TdP, and a corrected QT interval of greater than 500 ms is thought to represent those at higher risk. Despite this, those with only subtle QT prolongation or concealed LQTS still have some risk of arrhythmias.
Band keratopathy is a corneal disease derived from the appearance of calcium on the central cornea. This is an example of metastatic calcification, which by definition, occurs in the presence of hypercalcemia. Signs and symptoms
Signs and symptoms of band keratopathy include eye pain and decreased visual acuity. Causes
Band keratopathy has several causes. These causes include uveitis, interstitial keratitis, superficial keratitis, phthisis, sarcoidosis, trauma, intraocular silicone oil, systemic diseases (high levels of calcium in the blood, vitamin D intoxication, Fanconis Syndrome, low levels of phosphorus in the blood, gout, milk-alkali syndrome, myotonic dystrophy, and chronic mercury exposure). Pathology
Band keratopathy is seen when there is calcification of the epithelial basement membrane, Bowmans membrane, and the anterior stroma with destruction of Bowmans membrane. The calcium salts are intracellular when the process is due to alteration of systemic calcium metabolism, whereas they are extracellular when due to local disease. Diagnosis
Band keratopathy is diagnosed by slit lamp examination of the eye. Treatment
Treatment is indicated if vision is threatened or if the eye is uncomfortable. It is important to recognize and treat any underlying condition. Improvement of vision may be obtained by scraping off the opacity. Topical disodium EDTA can be used as a chelating agent. It can also be removed with the excimer laser (phototherapeutic keratectomy). Other modalities include diamond burr and lamellar keratoplasty. References


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