The cause is thought to be predominantly related to abnormal ammonia metabolism. Asterixis is seen most often in drowsy or stuporous patients with metabolic encephalopathies, especially in decompensated cirrhosis or acute liver failure. It is also seen in some patients with kidney failure and azotemia. It can also be a feature of Wilsons disease. Asterixis is also seen in respiratory failure due to carbon dioxide toxicity (hypercapnia). Some drugs are known to cause asterixis, particularly phenytoin (when it is known as phenytoin flap). Other drugs implicated include benzodiazepines, salicylates, barbiturates, valproate, gabapentin, lithium, ceftazidime, and metoclopramide. History
R.D. Adams and J.M. Foley first described asterixis in 1949 in patients with severe liver failure and encephalopathy. Initially Foley and Adams referred to asterixis simply as "tremor" but realized that they needed a more appropriate term. On a literature search they found a poorly described phenomenon in similar patients mentioned by German physicians called “jactitations” but the reference was vague. Foley consulted Father Cadigan, a Jesuit classics scholar, who suggested “anisosterixis” (an "negative"–iso "equal"–sterixis "firmness") but Foley shortened this to asterixis due to the former being too difficult to pronounce. They introduced the term in 1953 by way of a medical abstract and later Adams solidified its medical use as he was an author and editor of the widely influential Harrisons Principles of Internal Medicine. References
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Umbilical cord prolapse is when the umbilical cord comes out of the uterus with or before the presenting part of the baby. The concern with cord prolapse is that pressure on the cord from the baby will compromise blood flow to the baby. It usually occurs during labor but can occur anytime after the rupture of membranes.The greatest risk factors are an abnormal position of the baby within the uterus and a premature or small baby. Other risk factors include a multiple pregnancy, more than one previous delivery, and too much amniotic fluid. Whether medical rupture of the amniotic sac is a risk is controversial. The diagnosis should be suspected if there is a sudden decrease in the babys heart rate during labor. Seeing or feeling the cord confirms the diagnosis.Management focuses on quick delivery, usually by cesarean section. Filling the bladder or pushing up the baby by hand is recommended until this can take place. Sometimes women will be placed in a knee-chest position or the Trendelenburg position in order to help prevent further cord compression. With appropriate management, the majority of cases have good outcomes.Umbilical cord prolapse occurs in about 1 in 500 pregnancies. The risk of death of the baby is about 10%. However, much of this risk is due to congenital anomalies or prematurity. It is considered an emergency. Signs and symptoms
The first sign of umbilical cord prolapse is usually a sudden and severe decrease in fetal heart rate that does not immediately resolve.