Pathophysiology and current management of pruritus in liver disease

Pruritus is frequently reported by patients with cholestatic hepatobiliary diseases such as primary biliary cirrhosis, primary sclerosing cholangitis, intrahepatic cholestasis of pregnancy and hereditary cholestatic syndromes, but may accompany almost any other liver disease. Increased concentrations of bile salts, histamine, progesterone metabolites or endogenous opioids have been controversially discussed as potential pruritogens in cholestasis in the past. Most recently, novel insights unravelled lysophosphatidic acid (LPA), a potent neuronal activator, as a potential pruritogen in pruritus of cholestasis. Nevertheless, the pathogenesis of pruritus in cholestasis is still not clearly defined and current antipruritic treatment strategies provide relief only in a part of the affected patients. Based on recent experimental and clinical findings, this review outlines the actual insight in pathogenesis of pruritus in cholestasis and summarizes evidence-based and experimental therapeutic interventions for cholestatic patients suffering from itch.     

Pruritus in chronic liver disease: Mechanisms and treatment

Pruritus is a complication of liver disease. It can have a marked negative impact on quality of life; when intractable, it is an indication for liver transplantation. The cause of this type of pruritus is unknown. There is, however, evidence to suggest that the pruritus associated with liver disease is mediated, at least in part, by endogenous opioids. A central mechanism has been proposed. Therapeutic interventions have concentrated on the removal of presumed and unknown pruritogens from the circulation, hepatic enzyme induction, and, over the past decade, opiate antagonists, the first specific treatment for the pruritus of cholestasis. Other pharmacologic interventions that change neurotransmission have recently been reported to decrease the pruritus in patients with liver disease, as has a newly developed system that applies albumin-based dialysis. These interventions are promising, but they must be tested in properly controlled behavioral trials.     

Extracorporeal albumin dialysis: a procedure for prolonged relief of intractable pruritus in patients with primary biliary cirrhosis

BACKGROUND AND AIMS: Pruritus is a distressing symptom in patients with primary biliary cirrhosis, and when uncontrollable it is an indication for liver transplantation. Since pruritus can result from unknown substances that accumulate systemically as a consequence of impaired biliary secretion, we have assessed whether a new extracorporeal albumin dialysis (ECAD) procedure, the molecular-adsorbing recirculating system-MARS, has any effect on pruritus of cholestasis. METHODS: Four patients with primary biliary cirrhosis and resistant pruritus were treated with two 7-h ECAD sessions 1 day apart. Pruritus was recorded from 15 days before the first session, before and after each session, and during the follow-up using a visual analogue scale (VAS). Standard liver tests as well as serum bile acid levels were also measured. RESULTS: There was a clear association between ECAD treatment and relief of itching, which promptly disappeared in two patients, or decreased markedly in the other two. One patient was free of pruritus for 18 months except for short periods with mild pruritus. The second patient experienced amelioration of itching, which almost disappeared completely and recurred mildly 4 months later. In the other two patients pruritus was alleviated markedly after ECAD but gradually recurred. These two patients were treated again 9 and 7 months later with favorable effects on pruritus. The scratching skin lesions improved or disappeared in parallel with the alleviation of itching. The albumin dialysis procedure did not result in liver test changes, except for circulating bile acids, which decreased in all the patients. No significant adverse effects were observed. CONCLUSIONS: The ECAD procedure seems to be an effective alternative for the treatment of patients with pruritus of cholestasis who do not respond to other therapeutic methods.     

Evaluation of the role of bile acids and serotonin as markers of pruritus in children with chronic cholestatic liver disease

Background and study aimsPruritus is an annoying symptom with an unclear pathogenesis accompanied by chronic cholestasis. This cross-sectional study was conducted to define the relationship between serum levels of presumed pruritogens (bile acids (BAs) and serotonin) and severity of pruritus in pediatric patients with chronic cholestatic liver disease.Patients and methodsA total of 28 children suffering from pruritus due to chronic cholestatic liver disease and 29 age- and sex-matched healthy control subjects were examined. Scores obtained used the 5-D itch scale were evaluated among patients. Serum levels of BAs and serotonin were determined using enzymatic assays and high-performance liquid chromatography, respectively.ResultsPatients had higher serum BA levels and lower serotonin levels than control subjects. Serum BA levels were significantly elevated in 61% of patients. The 5-D itch scale scores were significantly higher in cholestatic individuals with normal γ-glutamyl transpeptidase levels. Neither BA nor serotonin levels correlated with the severity of the 5-Ditch scale score.ConclusionNeither BA nor serotonin levels correlated with the severity of pruritus, indicating that they may not be good laboratory markers for the intensity of itch in children with cholestasis. Our findings suggest that it is necessary to identify another potential pruritogenic mediator, most probably of a biliary origin.     

Extrahepatic manifestations of cholestasis

Pruritus, fatigue and metabolic bone disease represent three major extrahepatic manifestations of chronic cholestatic liver disease that considerably affect the patient's quality of life. The present article reviews pathogenetic aspects of and current therapeutic approaches to extrahepatic manifestations of cholestatic liver disease. Pathogenesis of pruritus of cholestasis remains poorly understood. The involvement of putative peripherally acting pruritogens, such as bile acids or endogenous opioids, is being discussed. More recently, central mechanisms, including an increased central opioidergic tone and pertubations in the serotonergic system have been proposed. Treatment of the underlying disease is beneficial also for the control of cholestasis-associated pruritus. Current therapeutic recommendations include ursodeoxycholic acid, cholestyramine, rifampicin and opioid antagonists. Liver transplantation may be indicated when severe pruritus is refractory to medical treatment. Fatigue is being recognized as the most frequent and one of the most disabling complaints in chronic cholestasis. Fatigue is presumably of central origin and its association with other neuropsychiatric disorders (e.g. depression, obsessive-compulsive disorders) is consistent with defective central neurotransmission. No specific therapies are currently available and a healthy lifestyle, regular sleep and avoidance of unnecessary stress and other precipiting factors are recommended. Antidepressant therapy may be warranted in selected patients. Osteopenia and osteoporosis are common in chronic cholestatic liver disease, whereas osteomalacia is rare. The pathophysiology of cholestasis-associated metabolic bone disease is regarded as multifactorial. Therapeutic recommendations include regular exercise, calcium and vitamin D supplementation in late stage disease, hormone replacement therapy in postmenopausal women and bisphosphonates.     

The multiple facets of ABCB4 (MDR3) deficiency

Opinion statement ABCB4 (MDR3), a lipid translocator, moves phosphatidylcholine from the inner to the outer leaflet of the canalicular membrane. Genetic mutations of ABCB4 lead to three distinct but related hepatobiliary diseases. Progressive familial intrahepatic cholestasis (PFIC) type 3 is a chronic cholestatic syndrome characterized by a markedly elevated γ-glutamyltranspeptidase. Patients present with jaundice, pruritus, and hepatosplenomegaly. Periportal inflammation progresses to biliary cirrhosis and causes portal hypertension. Ursodeoxycholic acid (UDCA) normalizes liver function tests in approximately one half of treated PFIC type 3 patients. Partial responders or nonresponders eventually will require liver transplantation. Gallstone patients with ABCB4 mutations may have low phospholipid-associated cholelithiasis syndrome, characterized by cholesterol gallstones and intrahepatic microlithiasis, along with recurrent biliary symptoms, despite cholecystectomy. Patients with ABCB4 mutations also may develop intrahepatic brown pigment stones. UDCA may improve biliary symptoms even before the dissolution of stones occurs. Additional therapies such as farnesoid X receptor ligands/agonists and benzfibrates show future therapeutic promise. Intrahepatic cholestasis of pregnancy affects pregnant women with abnormal ABCB4. These women suffer from disabling pruritus and also may experience steatorrhea. Fetuses are at high risk for prematurity and stillbirths. The definitive treatment is delivery of the baby. In the interim, limited fat intake, fat-soluble vitamin supplementation, and UDCA with or without S-adenosylmethionine can provide symptomatic relief. Additional hepatobiliary diseases related to ABCB4 mutations are likely to be identified. This may result in the discovery of additional therapies for PFIC type 3, gallstones, and intrahepatic cholestasis of pregnancy.     

Congenital cholestatic syndromes: what happens when children grow up?

Although advances in the management of children with congenital cholestasis have enabled many to survive into adulthood with their native livers, even the most common of these conditions remains rare in adult hepatology practice. Among four congenital cholestatic syndromes (biliary atresia, Alagille syndrome, Caroli disease and congenital hepatic fibrosis, and progressive familial intrahepatic cholestasis), the published data on outcomes of the syndromes into adulthood suggest that a spectrum of severity of liver disease can be expected, from cirrhosis (almost universal in adults with biliary atresia who have not required liver transplantation) to mild and subclinical (eg, in the previously undiagnosed affected parent of an infant with Alagille syndrome). Complications associated with portal hypertension and nutritional deficiencies are common, and other associated features of the cholestatic syndrome may require appropriate attention, such as congenital heart disease in Alagille syndrome. Indications for liver transplantation include synthetic failure, progressive encephalopathy, intractable pruritus, recurrent biliary sepsis and recurrent complications of portal hypertension. Improved understanding of biliary physiology will hopefully translate into improved therapy for children and adults with cholestasis.     

Drug-induced jaundice

A large number of drugs may be associated with impaired bile flow. Drug-associated cholestasis presents like other forms of cholestasis with pale stools, dark urine, pruritus and jaundice. Abdominal pain may be present in some instances and can be so severe as to lead to a false diagnosis of acute cholecystitis. Biochemically, drug-associated cholestasis resembles other forms of cholestasis although the presence of eosinophilia may suggest drug involvement. Many types of drug-induced cholestasis run a benign course with resolution of signs and symptoms within 3 months but occasionally the jaundice can take a year or more to resolve. Progression to cirrhosis is uncommon. Some patients may develop a syndrome resembling primary biliary cirrhosis. The mechanisms of drug-associated cholestasis are uncertain but may arise from alteration of bile formation within the hepatocyte or bile excretion at the level of the canaliculus or the extrahepatic ducts. Histological examination of the liver may be helpful in classifying the types of jaundice but the diagnosis of drug-induced cholestasis is usually one of temporal association and exclusion of other causes.     

Medical palliation of the jaundiced patient with pruritus

Cholestasis secondary to infiltration of the liver by malignant tumors or by obstruction of the biliary tree can be complicated by pruritus. The clinician and ancillary personal must recognize how debilitating pruritus is and identify the treatment of this symptom as a priority. Because robust clinical trials have not been conducted in patients who have pruritus with cholestasis, a network connecting the services that provide care for these patients (eg, hospices) may be useful for disseminating information.     

Benign recurrent intrahepatic cholestasis

Benign recurrent intrahepatic cholestasis is a rare autosomal recessive disorder characterized by repeated episodes of intense pruritus, profound elevations in serum alkaline phosphatase and bilirubin, with normal or nearly normal values for serum gamma-glutamyl transferase. Attack lasts from several weeks to months and resolve spontaneously. Between attacks patients remain asymptomatic for months to years. The disorder does not lead to progressive liver injury and is not fatal. Genetic studies have demonstrated that the disorder is the result of a mutation in ATP8BI, a gene that codes for the FIC1 (familial intrahepatic cholestasis) protein, which is also affected in other forms of familial intrahepatic cholestasis. It is believed this protein plays a role in bile acid secretion, in aminophospholid transport, and in maintaining fluidity of the cell membrane. Therapy is supportive and aimed at relieving pruritus and other complications of severe cholestasis until the episode resolves spontaneously.     

Treatment of primary biliary cirrhosis

Primary biliary cirrhosis is a chronic liver disease of unknown etiology, characterized by inflammation and destruction of the intrahepatic biliary ducts, resulting in chronic cholestasis and eventually cirrhosis. The main clinical manifestations consists of pruritus, jaundice, xanthomas, and the consequences of intestinal malabsorption, including vitamin deficiencies and osteodystrophy. Treatment of PBC is addressed at preventing or relieving the symptoms and clinical consequences of chronic cholestasis, and also at correcting the bile duct abnormalities by specific treatments. Pruritus is treated with cholestyramine, but in some cases other drugs, such as rifampicin or opioid antagonists are needed. Bisphosphanates are effective for increasing bone mass in osteopenic patients. Vitamin D and cAlcium supplements are also recommended, particularly in patients with severe cholestasis. Ursodeoxycholic acid (UDCA) has become the standard treatment (13-15 mg/kg/day), resulting in marked relieving of cholestasis. UDCA also prevents the histological progression of the disease, although the effects on survival are less apparent. Small trials of combination therapy using UDCA with methotrexate, colchicine, or prednisone, have been reported but have not shown any increased efficacy over UDCA therapy. Liver transplantation is the only treatment available when cholestasis progresses, with very good survival rates.     

Review: Treatment of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a slowly progressive chronic cholestatic disease of the liver thought to be caused by immune destruction of the interlobular bile ducts. One-third of patients are asymptomatic and one-third of these develop symptoms within 5 years. Therapeutic regimens should be directed at the control of symptoms, prevention of complications and specific therapy aimed at controlling progression of the disease. Symptoms may be secondary to cholestasis or due to other associated diseases. The cause of pruritus secondary to cholestasis remains unknown; the anion exchange resin cholestyramine generally brings relief. In patients resistant or intolerant to this therapy, rifampin may be helpful, as well as ultraviolet light without sunblock. Liver transplantation may rarely be the only option for uncontrollable pruritus. Clinical manifestations of keratoconjunctivitis sicca and xerostomia need constant attention to prevent corneal ulcers and dental caries. Preventative therapy includes regular screening for thyroid dysfunction and replacement therapy when necessary and the administration of the fat soluble vitamins A, D and K once hyperbilirubinaemia is present. Osteoporosis is a complication of all cholestatic liver disease. There is no satisfactory preventative therapy. It may be appropriate to give hormone replacement therapy to all post-menopausal women with PBC to reduce osteoporosis. Liver transplantation is the best option for those with fractures. Oesophageal varices may develop early in the course of PBC, non-selective beta-blocker therapy should be used as prophylaxis against variceal haemorrhage. The only specific therapy shown to cause both a biochemical and survival benefit in patients with PBC is ursodeoxycholic acid (UDCA). Treatment with UDCA delays progression, but does not result in a cure of this disease. Currently, liver transplantation is the only definitive treatment available for end-stage disease.     

Atypical causes of cholestasis

Cholestatic liver disease consists of a variety of disorders. Primary sclerosing cholangitis and primary biliary cirrhosis are the most commonly recognized cholestatic liver disease in the adult population, while biliary atresia and Alagille syndrome are commonly recognized in the pediatric population. In infants, the causes are usually congenital or inherited. Even though jaundice is a hallmark of cholestasis, it is not always seen in adult patients with chronic liver disease. Patients can have “silent” progressive cholestatic liver disease for years prior to development of symptoms such as jaundice and pruritus. In this review, we will discuss some of the atypical causes of cholestatic liver disease such as benign recurrent intrahepatic cholestasis, progressive familial intrahepatic cholestasis, Alagille Syndrome, biliary atresia, total parenteral nutrition induced cholestasis and cholestasis secondary to drug induced liver injury.     

Treatment of pruritus in primary biliary cirrhosis with rifampin. Results of a double-blind, crossover, randomized trial

The cause of pruritus of cholestasis is unknown. We have hypothesized that pruritus may be caused by an indirect effect of high hepatic concentrations of toxic bile acids. To test this hypothesis, we have conducted a double-blind, controlled, crossover clinical trial of rifampin, an agent that inhibits hepatic bile acid uptake and may detoxify hepatic bile acids by stimulation of mixed-function oxidases. Nine patients with primary biliary cirrhosis received 300-450 mg/day of rifampin and placebo sequentially, in random order. Each treatment was administered for 14 days, with a 14-day washout between treatments. Endpoints included patient preference, changes in a daily visual analogue scale pruritus score, and amount of cholestyramine ingested. Antipyrine elimination rates and serum bile acids were tested at the end of each treatment period. All 9 patients completed the trial and 8 of them preferred rifampin to placebo (p = 0.03). There were no adverse reactions. Visual analogue scale pruritus scores showed no significant placebo response or any effect from the order of treatment, but did show a highly significant reduction in pruritus in response to rifampin (p less than 0.002). This effect was evident within the first week of rifampin treatment. Rifampin produced a 33% reduction in antipyrine plasma half-life, but no change in fasting total serum bile acids. Cholestyramine usage did not change significantly. We conclude that rifampin is useful for short-term relief of pruritus in primary biliary cirrhosis; however, the mechanism of this effect is unknown. Longer trials are needed, as are trials in other cholestatic disorders.     

Pruritus and fatigue in primary biliary cirrhosis.

Pruritus is experienced by about 80% of patients with primary biliary cirrhosis. It can have a marked negative impact on the quality of life of patients, and it can be an indication for liver transplantation. There is evidence to suggest that the pruritus of cholestasis is mediated, at least in part, by endogenous opioids. A central component has been proposed. Behavioural data have shed light on the pathogenesis of this form of pruritus. Fatigue affects the majority of patients with primary biliary cirrhosis. It interferes with work performance and family life. An idea is emerging that suggests that fatigue in primary biliary cirrhosis also may be mediated centrally. Research tools need to be developed to study fatigue objectively in patients with primary biliary cirrhosis.     

Lipids and lipid-activated vitamins in chronic cholestatic diseases

Primary biliary cirrhosis, primary sclerosing cholangitis and autoimmune cholangiopathy are cholestatic liver diseases of unknown cause. Destruction of small to medium bile ducts (in primary biliary cirrhosis and autoimmune cholangiopathy) and large bile ducts (in primary sclerosing cholangitis) leads to progressive cholestasis, liver failure and end-stage liver disease. A variety of abnormalities in lipid metabolism have been described in primary biliary cirrhosis, and range from alterations in serum lipid levels and lipoprotein subsets to deranged metabolism of cholesterol. Progressive cholestasis and, consequently, decreased small intestinal bile acid concentrations in these cholestatic liver disease can also lead to impaired absorption of fats and fat-soluble vitamins, resulting in steatorrhea and deficiencies in vitamins A, D, E, and K. This article focuses on abnormalities in lipid metabolism in primary biliary cirrhosis and primary sclerosing cholangitis, and on lipid-activated vitamin deficiencies in these disorders.     

Idiopathic adulthood ductopenia: case report and review of the literature

The clinical and pathological findings of idiopathic ductopenia were studied in a 30-year-old woman who initially manifested jaundice and pruritus. Serum biochemical tests of liver function indicated severe and progressive cholestasis. Viral hepatitis markers and circulating autoantibodies were absent. The patient had a normal cholangiogram and lacked evidence of inflammatory bowel disease. Histological examination of a liver specimen showed severe cholestasis and absence of interlobular bile ducts. Severe jaundice and intractable pruritus developed in the patient and served as the indications for liver transplantation 4 months after initial examination. Transplantation resulted in prompt and complete resolution of the jaundice and pruritus. Two types of idiopathic adulthood ductopenia associated with different prognoses are recognized. Patients with type 1 idiopathic adulthood ductopenia are asymptomatic or manifest symptoms of cholestatic liver disease. They tend to have less destruction of the intrahepatic bile ducts on liver biopsy specimens. Their clinical course ranges from spontaneous improvement to progression to biliary cirrhosis. In contrast, patients with type 2 idiopathic adulthood ductopenia generally manifest initial symptoms of decompensated biliary cirrhosis, have extensive destruction of the intrahepatic bile ducts on liver biopsy, and frequently require orthotopic liver transplantation.     

Treatment of the pruritus of cholestasis

Opinion statement The etiology of the pruritus of cholestasis is unknown. It is inferred that the pruritogen( s) is produced in the liver, excreted in bile, and as a result of cholestasis it accumulates in plasma. It may follow, logically, that the removal of the substance(s) that mediate pruritus leads to its resolution. The problem with this approach, however, is that the substance(s) is unknown; thus, it is not possible to reduce its serum levels specifically. Oral cholestyramine, a resin that is not absorbed, is associated with increased fecal excretion of certain substances, including cholesterol and bile acids. Many patients respond to treatment with cholestyramine with a relief of pruritus, which unfortunately may be temporary, but is well tolerated in general and it seems reasonable to prescribe it as an initial therapy. When pruritus is not relieved by resins, the use of opiate antagonists (eg, naloxone and naltrexone) is supported by data from controlled clinical trials. Butorphanol is an agonist at the kappa opioid receptor and an antagonist at the mu opioid receptor with minimal or absent abuse potential. The use of butorphanol spray in selective patients may be a therapeutic alternative. In uncontrolled observations dronabinol, an agonist at the cannabinoid B1 receptor, and sertraline, a serotonin reuptake inhibitor, have been reported to be associated with the relief of pruritus. The cannabinoidergic and serotoninergic systems participate in the mediation of nociception; therefore, there appears to be a rationale for the use of these drugs to treat pruritus. Data from controlled clinical trials on the use of dronabinol and sertraline, however, are not available at present.     

Potential of ileal bile acid transporter inhibition as a therapeutic target in Alagille syndrome and progressive familial intrahepatic cholestasis

Alagille syndrome (ALGS) and progressive familial intrahepatic cholestasis (PFIC) are rare, inherited cholestatic liver disorders that manifest in infants and children and are associated with impaired bile flow (ie cholestasis), pruritus and potentially fatal liver disease. There are no effective or approved pharmacologic treatments for these diseases (standard medical treatments are supportive only), and new, noninvasive options would be valuable. Typically, bile acids undergo biliary secretion and intestinal reabsorption (ie enterohepatic circulation). However, in these diseases, disrupted secretion of bile acids leads to their accumulation in the liver, which is thought to underlie pruritus and liver‐damaging inflammation. One approach to reducing pathologic bile acid accumulation in the body is surgical biliary diversion, which interrupts the enterohepatic circulation (eg by diverting bile acids to an external stoma). These procedures can normalize serum bile acids, reduce pruritus and liver injury and improve quality of life. A novel, nonsurgical approach to interrupting the enterohepatic circulation is inhibition of the ileal bile acid transporter (IBAT), a key molecule in the enterohepatic circulation that reabsorbs bile acids from the intestine. IBAT inhibition has been shown to reduce serum bile acids and pruritus in trials of paediatric cholestatic liver diseases. This review explores the rationale of inhibition of the IBAT as a therapeutic target, describes IBAT inhibitors in development and summarizes the current data on interrupting the enterohepatic circulation as treatment for cholestatic liver diseases including ALGS and PFIC.     

Drug-induced cholestasis

The spectrum of drug-induced cholestasis ranges from 'bland' reversible cholestasis to chronic forms due to the vanishing bile duct syndrome. Agents known for many years to cause cholestasis include estrogens and anabolic steroids, chlorpromazine, erythromycin, and the oxypenicillins; structurally similar congeners of these drugs (tamoxifen, newer macrolides) may also cause cholestasis. Contemporary drugs linked to cholestastic liver injury include ticlopidine, terfenadine, terbinafine, nimesulide, irbesartan, fluoroquinolones, cholesterol-lowering 'statins,' and some herbal remedies (greater celandine, glycyrrhizin, chaparral). Amoxillin-clavulanate, ibuprofen, and pediatric cases of the vanishing bile duct syndrome are recent additions to a long list of drugs associated with the vanishing bile duct syndrome. Particular human leukocyte antigen profiles have recently been identified among those who have developed cholestasis with specific drugs (tiopronin and amoxicillin-clavulanate), and the mechanistic relevance of these genetic associations is being explored. The treatment of drug-induced cholestasis is largely supportive. The offending drug should be withdrawn immediately. Cholestyramine or ursodeoxycholic acid are used to alleviate pruritus, with rifampicin and opioid antagonists being reserved for those who fail first line therapy. Nutritional support is essential for those with prolonged cholestasis, a subgroup who are at risk of developing biliary cirrhosis and liver failure. Timely referral for liver transplant assessment is crucial in these patients.