Intrahepatic cholestasis of pregnancy | |
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High magnification micrograph showing liver cholestasis. | |
Specialty | Obstetrics |
Intrahepatic cholestasis of pregnancy (ICP), also known as obstetric cholestasis, cholestasis of pregnancy, jaundice of pregnancy, and prurigo gravidarum, [1] is a medical condition in which cholestasis occurs during pregnancy. [2] It typically presents with itching and can lead to complications for both mother and fetus. [2]
Itching is a common symptom of pregnancy, affecting around 23% of women. [3] The majority of times, itching is a minor annoyance caused by changes to the skin, especially that of the abdomen. However, there are instances when itching may be a symptom of ICP. Although typically noticed on the palms of the hands and the soles of the feet, the itching can occur anywhere on the body.
Onset is mostly in the third trimester, but may begin earlier. [4]
Most women with this condition present in the third trimester (although it can present as early as seven weeks) with itching without a rash. Typically, the itching is localized to the palms of the hands and soles of the feet, but can be anywhere on the body.
Hallmarks of ICP include the following symptoms: [5]
Most common:
Less common:
Not all ICP sufferers have all of the above symptoms.
The causes of intrahepatic cholestasis of pregnancy are still not fully understood, but are thought to be caused through a combination of genetics, [6] [7] hormones and environment. [8] Hormones, environmental and genetic factors are all thought to contribute to the condition. [9]
Estrogens, and particularly glucuronides such as estradiol-17β-D-glucuronide, have been shown to cause cholestasis in animal studies, by reducing bile acid uptake by hepatocytes. [11]
Treatment with progesterone in the third trimester of pregnancy has been shown to be associated with the development of ICP, and levels of metabolites of progesterone, particularly sulfated progesterone, [12] are higher in patients with ICP than unaffected women, suggesting that progesterone may have a bigger role than estrogen in ICP. [13]
Clustering of cases of ICP in families, geographic variation in rates of ICP, and recurrence of ICP in 45-70% of subsequent pregnancies all suggest a genetic component to the disease. [9] Genetic mutations in the hepatocellular transport protein ABCB4 (MDR3), which controls secretion of phosphatidylcholine into bile, have been found in cases of ICP. [14]
Genetic mutations affecting hepatic bile salt transport molecules have also been found in patients with progressive familial intrahepatic cholestasis. It has been found that mothers of patients with this disease have a higher incidence of ICP, suggesting that heterozygote carriers of these mutations are also predisposed to ICP. [9]
In addition to genetic changes to bile salt transport molecules, high levels of estrogen glucuronides have been shown to inhibit the bile salt export pump (BSEP) ABCB11, [15] and high levels of progesterone to inhibit the ABCB4 (MDR3) phospholipid transporter. [16]
Consequently, both genetic mutations in hepatocyte proteins involved in bile secretion together with inhibition of those proteins by high levels of hormone metabolites in pregnancy may have roles in the pathogenesis of ICP. [8]
A number of features of ICP suggest that environmental factors also have a role in the disease:
ICP is diagnosed by blood tests including a serum bile acid test and liver function test. While most pregnant women experience some itch from time to time, itching without a visible rash, or persistent or extensive itch symptoms should be reported to the midwife or obstetrician. As the level of itch does not correlate with bile acid levels (shown to be the most likely cause of stillbirth in ICP), the itch in ICP can range from being mild to severe.[ citation needed ]
To obtain a diagnosis of ICP, a liver function test and a serum bile acid test should be requested. Although the ALT level may be raised, 20% of women with ICP will always have a normal LFT test result. [20] This, plus pruritus of palms and soles, could be considered as potentially diagnostic of ICP but only with elevated bile acid levels (however LFTs are not always elevated in ICP patients). The serum bile acid blood test for ICP is a quantitative measurement of bile acids.
Other problems with the liver that occur in pregnancy should be considered by the treating clinician. These include preeclampsia, the HELLP syndrome, and acute fatty liver of pregnancy. Furthermore, other causes of hepatitis, like hepatitis viruses, cancer and certain medications, should also be considered.
Many providers will prescribe ursodeoxycholic acid. The most recent trial, PITCHES, [21] did not show an overall beneficial effect, but some researchers believe that it may still be useful to offer ursodeoxycholic acid to women whose bile acids are > 40 μmol/litre. While there is no cure for ICP, and no way to guarantee a successful outcome, studies have shown a slightly better fetal and maternal outcome from administration of ursodeoxycholic acid, whereas cholestyramine appears to only relieve itching. [11] [22]
There is no evidence that giving oral water-soluble Vitamin K may help to avoid the risk of hemorrhage at delivery. However, experts in ICP will prescribe this if the woman reports pale stools, has very severe ICP (bile acids > 100 μmol/litre) or has a known clotting problem.
Delivery from 34 weeks may be important to reduce the risk of stillbirth, as a recent study identified the level of bile acids at which stillbirth risk rises. This research, published in The Lancet, also suggests that around 90% of women with ICP could wait until 39 weeks of pregnancy to be induced. However, this relies on regular bile acid testing with rapid return of results. [23]
Maternal consequences include the following:
Fetal consequences include:
In most cases induction is typically recommended anywhere from 34 to 39 weeks. [23] [25] [26] [27] [28] [29]
In the United States, some researchers have suggested that the risk of stillbirth is lower if induction occurs at 36 weeks. Whilst Ovadia's research [23] suggests differently, in the United States bile acid tests can take up to seven days to be processed, and this means that it may be more prudent to base delivery on the US research. [30]
Estrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3). Estradiol, an estrane, is the most potent and prevalent. Another estrogen called estetrol (E4) is produced only during pregnancy.
Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the major progestogen in the body. Progesterone has a variety of important functions in the body. It is also a crucial metabolic intermediate in the production of other endogenous steroids, including the sex hormones and the corticosteroids, and plays an important role in brain function as a neurosteroid.
An itch is a sensation that causes a strong desire or reflex to scratch. Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itches leads to a scratch reflex.
Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune disease of the liver. It results from a slow, progressive destruction of the small bile ducts of the liver, causing bile and other toxins to build up in the liver, a condition called cholestasis. Further slow damage to the liver tissue can lead to scarring, fibrosis, and eventually cirrhosis.
Lipoid congenital adrenal hyperplasia is an endocrine disorder that is an uncommon and potentially lethal form of congenital adrenal hyperplasia (CAH). It arises from defects in the earliest stages of steroid hormone synthesis: the transport of cholesterol into the mitochondria and the conversion of cholesterol to pregnenolone—the first step in the synthesis of all steroid hormones. Lipoid CAH causes mineralocorticoid deficiency in affected infants and children. Male infants are severely undervirilized causing their external genitalia to look feminine. The adrenals are large and filled with lipid globules derived from cholesterol.
Ursodeoxycholic acid (UDCA), also known as ursodiol, is a secondary bile acid, produced in humans and most other species from metabolism by intestinal bacteria. It is synthesized in the liver in some species, and was first identified in bile of bears of genus Ursus, from which its name derived. In purified form, it has been used to treat or prevent several diseases of the liver or bile ducts.
Alagille syndrome (ALGS) is a genetic disorder that affects primarily the liver and the heart. Problems associated with the disorder generally become evident in infancy or early childhood. The disorder is inherited in an autosomal dominant pattern, and the estimated prevalence of Alagille syndrome is 1 in every 30,000 to 1 in every 40,000 live births. It is named after the French pediatrician Daniel Alagille, who first described the condition in 1969. Children with Alagille syndrome live to the age of 18 in about 90% of the cases.
The hypothalamic–pituitary–gonadal axis refers to the hypothalamus, pituitary gland, and gonadal glands as if these individual endocrine glands were a single entity. Because these glands often act in concert, physiologists and endocrinologists find it convenient and descriptive to speak of them as a single system.
Cholestasis is a condition where the flow of bile from the liver to the duodenum is impaired. The two basic distinctions are:
Bile acids are steroid acids found predominantly in the bile of mammals and other vertebrates. Diverse bile acids are synthesized in the liver. Bile acids are conjugated with taurine or glycine residues to give anions called bile salts.
Progressive familial intrahepatic cholestasis (PFIC) is a group of familial cholestatic conditions caused by defects in biliary epithelial transporters. The clinical presentation usually occurs first in childhood with progressive cholestasis. This usually leads to failure to thrive, cirrhosis, and the need for liver transplantation.
Pruritic urticarial papules and plaques of pregnancy (PUPPP), known in the United Kingdom as polymorphic eruption of pregnancy (PEP), is a chronic hives-like rash that strikes some women during pregnancy. Some skin changes are known to occur in people who are pregnant while other skin conditions, or dermatoses, that people have prior to getting pregnant will become altered or symptoms will increase. Pruritic urticarial papules and plaques of pregnancy (PUPPP) is one of many skin conditions that is specific to pregnancy and occurs in about 1 in every 160 (0.625%) of pregnancies.
ATP-binding cassette, sub-family B member 11 (ABCB11), also known as the bile salt export pump (BSEP), is a protein which in humans is encoded by the ABCB11 gene.
The ATP-binding cassette 4 (ABCB4) gene encodes multidrug resistance protein 3. ABCB4 is associated with progressive familial intrahepatic cholestasis type 3 and intrahepatic cholestasis of pregnancy.
Pruritic folliculitis of pregnancy is a skin condition that occurs in one in 3000 people, about 0.2% of cases, who are in their second to third trimester of pregnancy where the hair follicle becomes inflamed or infected, resulting in a pus filled bump. Some dermatologic conditions aside from pruritic folliculitis during pregnancy include "pruritic urticarial papules and plaques of pregnancy, atopic eruption of pregnancy, pemphigoid gestationis, intrahepatic cholestasis of pregnancy, and pustular psoriasis of pregnancy". This pruritic folliculitis of pregnancy differs from typical pruritic folliculitis; in pregnancy, it is characterized by sterile hair follicles becoming inflamed mainly involving the trunk, contrasting how typical pruritic folliculitis is mainly localized on "the upper back, shoulders, and chest." This condition was first observed after some pregnant individuals showed signs of folliculitis that were different than seen before. The inflammation was thought to be caused by hormonal imbalance, infection from bacteria, fungi, viruses or even an ingrown hair. However, there is no known definitive cause as of yet. These bumps usually begin on the belly and then spread to upper regions of the body as well as the thighs.
Epomediol is a synthetic terpenoid with choleretic effects. It has been used in the symptomatic treatment of itching due to intrahepatic cholestasis of pregnancy.
Cholestatic pruritus is the sensation of itch due to nearly any liver disease, but the most commonly associated entities are primary biliary cholangitis, primary sclerosing cholangitis, obstructive choledocholithiasis, carcinoma of the bile duct, cholestasis, and chronic hepatitis C viral infection and other forms of viral hepatitis.
Vanishing bile duct syndrome is a loose collection of diseases leading to hepatic bile duct injury and eventual ductopenia.
Obeticholic acid (OCA), sold under the brand name Ocaliva, is a semi-synthetic bile acid analogue which has the chemical structure 6α-ethyl-chenodeoxycholic acid. It is used as a medication used to treat primary biliary cholangitis. Intercept Pharmaceuticals Inc. hold the worldwide rights to develop OCA outside Japan and China, where it is licensed to Dainippon Sumitomo Pharma.
Odevixibat, sold under the brand name Bylvay among others, is a medication for the treatment of progressive familial intrahepatic cholestasis. It is taken by mouth. Odevixibat is a reversible, potent, selective inhibitor of the ileal bile acid transporter (IBAT). It was developed by Albireo Pharma.
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