The role of nucleoside and nucleotide analogues in nodular regenerative hyperplasia in HIV-infected patients: a case control study

[Portosinusoidal vascular disorder: A paradigm shift]

The term portosinusoidal vascular disorder (PSVD) refers to a clinical-pathological entity that encompasses those patients with intrahepatic vascular damage without cirrhosis at risk of developing severe complications of portal hypertension. Numerous systemic diseases, genetic disorders, and toxic agents have been associated with this pathology, making its diagnosis an important clinical challenge. The recent description of uniform diagnostic criteria and a better understanding of its pathophysiology will allow for better identification of patients, even in early stages of the disease. Although there is currently no effective etiological treatment available, early diagnosis allows for the development of preventive strategies for some severe complications of portal hypertension.

Molecular Mechanisms Underlying Vascular Liver Diseases: Focus on Thrombosis

Vascular liver disorders (VLDs) comprise a wide spectrum of clinical-pathological entities that primarily affect the hepatic vascular system of both cirrhotic and non-cirrhotic patients. VLDs more frequently involve the portal and the hepatic veins, as well as liver sinusoids, resulting in an imbalance of liver homeostasis with serious consequences, such as the development of portal hypertension and liver fibrosis. Surprisingly, many VLDs are characterized by a prothrombotic phenotype. The molecular mechanisms that cause thrombosis in VLD are only partially explained by the alteration in the Virchow's triad (hypercoagulability, blood stasis, and endothelial damage) and nowadays their pathogenesis is incompletely described and understood. Studies about this topic have been hampered by the low incidence of VLDs in the general population and by the absence of suitable animal models. Recently, the role of coagulation imbalance in liver disease has been postulated as one of the main mechanisms linked to fibrogenesis, so a novel interest in vascular alterations of the liver has been renewed. This review provides a detailed analysis of the current knowledge of molecular mechanisms of VLD. We also focus on the promising role of anticoagulation as a strategy to prevent liver complications and to improve the outcome of these patients.

Porto-sinusoidal vascular disorder

It is well established that portal hypertension can occur in the absence of cirrhosis, as reported in patients with immune disorders, infections and thrombophilia. However, similar histological abnormalities primarily affecting the hepatic sinusoidal and (peri)portal vasculature have also been observed in patients without portal hypertension. Thus, the term porto-sinusoidal vascular disorder (PSVD) has recently been introduced to describe a group of vascular diseases of the liver featuring lesions encompassing the portal venules and sinusoids, irrespective of the presence/absence of portal hypertension. Liver biopsy is fundamental for PSVD diagnosis. Specific histology findings include nodular regenerative hyperplasia, obliterative portal venopathy/portal vein stenosis and incomplete septal fibrosis/cirrhosis. Since other conditions including alcohol-related and non-alcoholic fatty liver disease, or viral hepatitis, or the presence of portal vein thrombosis may occur in patients with PSVD, their relative contribution to liver damage should be carefully assessed. In addition to histology and clinical diagnostic criteria, imaging and non-invasive tests such as liver and spleen stiffness measurements could aid in the diagnostic workup. The introduction of PSVD as a novel clinical entity will facilitate collaborative studies and investigations into the underlying molecular pathomechanisms encompassed by this term.

Mechanistic insights into antiretroviral drug-induced liver injury

All classes of antiretroviral therapy (ART) have been implicated to induce adverse drug reactions such drug-induced liver injury (DILI) and immune-mediated adverse reactions in Human Immunodeficiency Virus (HIV) infected individuals. Patients that develop adverse drug reactions tend to have prolonged stays in hospital and may require to change to alternative regimens if reactions persist upon rechallenge or if rechallenge is contraindicated due to severity of the adverse reaction. Diagnosis of DILI remains a huge obstacle that delays timely interventions, since it is still based largely on exclusion of other causes. There is an urgent need to develop robust diagnostic and predictive biomarkers that could be used alongside the available tools (biopsy, imaging, and serological tests for liver enzymes) to give a specific diagnosis of DILI. Crucial to this is also achieving consensus in the definition of DILI so that robust studies can be undertaken. Importantly, it is crucial that we gain deeper insights into the mechanism of DILI so that patients can receive appropriate management. In general, it has been demonstrated that the mechanism of ART-induced liver injury is driven by four main mechanisms: mitochondrial toxicity, metabolic host-mediated injury, immune reconstitution, and hypersensitivity reactions. The focus of this review is to discuss the type and phenotypes of DILI that are caused by the first line ART regimens. Furthermore, we will summarize recent studies that have elucidated the cellular and molecular mechanisms of DILI both in vivo and in vitro.

Porto-sinusoidal vascular disease: proposal and description of a novel entity

Portal hypertension in the absence of portal vein thrombosis and without cirrhosis, but with mild or moderate alterations of liver histology (eg, obliterative venopathy, nodular regenerative hyperplasia, or incomplete septal cirrhosis) is being increasingly recognised. Owing to the heterogeneity of causes and histological findings, a substantial number of terms have been used to describe such idiopathic non-cirrhotic portal hypertension. Patients with the same clinical and histological features exist, but without portal hypertension at the time of diagnosis. Therefore, improved criteria are needed to define this form of liver disease. Here, we propose the term porto-sinusoidal vascular disease, since all lesions found involve the portal venules or sinusoids. The definition of this entity is based on the characteristic absence of cirrhosis with or without signs of portal hypertension or histological lesions. The presence of known causes of liver disease does not rule out porto-sinusoidal vascular disease, but specific causes of vascular liver disease are excluded from its definition. The diagnosis of porto-sinusoidal vascular disease is based on liver biopsy and might include signs specific for portal hypertension with normal or mildly elevated liver stiffness values and no complete portal vein thrombosis. We provide simple diagnostic criteria, because agreement on a uniform nomenclature is an essential requirement for future collaborative studies.

Noncirrhotic Portal Hypertension Secondary to Nodular Regenerative Hyperplasia Postrenal Transplant

Noncirrhotic portal hypertension (NCPH) is a well-known clinical entity, but often underdiagnosed. One of the common causes of NCPH is nodular regenerative hyperplasia (NRH) that presents as nodularity with features of portal hypertension and thus often diagnosed as cirrhosis. Although NRH has no histologic fibrosis, the liver synthetic function remains intact; thus, clinical diagnosis is essential because management may differ from cirrhosis. We were asked to consult in this series of 4 patients who had new-onset ascites after kidney transplantation and were diagnosed with NCPH from NRH.

Nodular Regenerative Hyperplasia: A Case of Rare Prognosis

Introduction: Nodular regenerative hyperplasia (NRH) is a known etiology of noncirrhotic portal hypertension. Cases of biopsy-proven NRH in human immunodeficiency virus (HIV)-positive patients have been described. While these patients often have normal synthetic liver function, several reports described disease progression to liver failure. Case: We here present a 26-year-old woman with history of congenital HIV on antiretroviral therapy complicated by Pneumocystis carinii pneumonia at age 14. CD4 counts have been >300 with undetectable viral load. She was referred to our Hepatology service for evaluation of splenomegaly, elevated liver tests, and thrombocytopenia. On initial presentation, she reported easy bruising and gingival bleeding, and abdominal imaging showed evidence of portal hypertension without associated cirrhosis. Upper endoscopy was significant for large esophageal varices without bleeding stigmata. Liver biopsy showed minimal fibrosis around the portal areas without significant inflammation. The lobules showed focal zones of thin hepatocyte plates on reticulin stain with adjacent areas showing mild regenerative changes. The diagnosis of NRH was made and patient was placed on propranolol for variceal bleeding prophylaxis. Two years later, the patient presented with bleeding gastric varices warranting transjugular intrahepatic portosystemic shunt. Postprocedure course was complicated by mild encephalopathy. Subsequent magnetic resonance imaging showed a 1.7 × 1.3 cm lesion suggestive of hepatocellular carcinoma (HCC). The patient was deemed to be a candidate for liver transplantation, and she is now delisted due to ongoing pregnancy. Conclusion: This report describes the first case of HCC in an HIV patient with NRH. The possible association of NRH with HCC warrants further investigation.

Prevalence of significant liver disease in human immunodeficiency virus-infected patients exposed to Didanosine: A cross sectional study

AIM

To identify significant liver disease [including nodular regenerative hyperplasia (NRH)] in asymptomatic Didanosine (DDI) exposed human immunodeficiency virus (HIV) positive patients.

METHODS

Patients without known liver disease and with > 6 mo previous DDI use had liver stiffness assessed by transient elastography (TE). Those with alanine transaminase (ALT) above upper limit normal and/or TE > 7.65 kPa underwent ultrasound scan (U/S). Patients with: (1) abnormal U/S; or (2) elevated ALT plus TE > 7.65 kPa; or (3) TE > 9.4 kPa were offered trans-jugular liver biopsy (TJLB) with hepatic venous pressure gradient (HVPG) assessment.

RESULTS

Ninety-nine patients were recruited, median age 50 years (range 31-70), 81% male and 70% men who have sex with men. Ninety-five percent with VL < 50 copies on antiretroviral therapy with median CD4 count 639 IU/L. Median DDI exposure was 3.4 years (range 0.5-14.6). Eighty-one had a valid TE readings (interquartile range/score ratio < 0.3): 71 (88%) < 7.65 kPa, 6 (7%) 7.65-9.4 kPa and 4 (6%) > 9.4 kPa. Seventeen (17%) met criteria for TJLB, of whom 12 accepted. All had HVPG < 6 mmHg. Commonest histological findings were steatosis (n = 6), normal architecture (n = 4) and NRH (n = 2), giving a prevalence of previously undiagnosed NRH of 2% (95%CI: 0.55%, 7.0%).

CONCLUSION

A screening strategy based on TE, liver enzymes and U/S scan found a low prevalence of previously undiagnosed NRH in DDI exposed, asymptomatic HIV positive patients. Patients were more likely to have steatosis highlighting the increased risk of multifactorial liver disease in this population.

Noncirrhotic Portal Hypertension in Perinatally HIV-infected Adolescents Treated With Didanosine-containing Antiretroviral Regimens in Childhood

BACKGROUND

Noncirrhotic portal hypertension (NCPH) has been reported in HIV-infected adults. Antiretroviral drugs, as well as genetic and thrombophilic predisposition, have been suggested as possible etiologic factors.

METHODS

Clinical data were collected from 6 HIV-infected patients attending the Infectious Diseases Departments at respectively Emma Children's Hospital Academic Medical Centre in Amsterdam, The Thai Red Cross AIDS Research Centre, Bangkok, Imperial College Healthcare NHS Trust, London who were diagnosed with NCPH. All underwent extensive blood analysis, liver ultrasound, liver elastography, esophagogastroduodenoscopy and percutaneous needle liver biopsy for histological evaluation.

RESULTS

We describe 6 perinatally HIV-infected adolescents, all female, who developed NCPH after prolonged exposure during childhood to a didanosine-containing antiretroviral regimen. Histology and electron microscopy showed periportal fibrosis and mitochondrial damage as key findings in their liver biopsies. One of these 6 patients required surgical intervention, the remainder have been managed conservatively to date.

CONCLUSIONS

Thus, symptomatic NCPH may present in adolescence after perinatally acquired HIV-1 infection. In this case series, risk factors included female sex and prolonged exposure to antiretroviral regimens that included the nucleoside-analogue didanosine in childhood.

Epidemiological Distribution and Genotype Characterization of the Hepatitis C Virus Among HIV Patients in Kashan, Iran

BACKGROUND

Parenteral transmission is a common route of transmission for both human immunodeficiency virus (HIV) and hepatitis C virus (HCV); therefore, hepatitis C viral infection is highly prevalent among people infected with HIV.

OBJECTIVES

This study was designed to examine the epidemiology and describe the clinical manifestation as well as the HCV genotypes in patients from the city of Kashan, Iran, who are coinfected with HIV and HCV.

PATIENTS AND METHODS

This descriptive study was conducted in 2014 in the city of Kashan. The population consisted of all the HIV-infected patients who were referred to the behavioral counseling center and jail in Kashan. Demographic information and HCV- and HIV-related risk behaviors were obtained through the use of an interviewer-assisted questionnaire. After the participants gave written informed consent to participate, 10 cc venous blood samples were collected. The serum samples were screened for HCV infection using an enzyme-linked immunosorbent assay (ELISA). In the event of a positive test for HCV, the RNA was then amplified by polymerase chain reaction (PCR) amplification. The HCV subtypes were determined via the direct sequencing of the amplicons. All data analysis was performed using SPSS version 16.0 for the descriptive statistics, and then the chi-square test and Pearson coefficient were performed for additional analysis.

RESULTS

The results of the analysis indicated that 54 (85%) of the 63 HIV-infected patients were males who were also HCV positive and who had less than a high school level education. There was a significant association between HCV infection and both occupation (P < 0.0001) and level of education (P < 0.05). All the HIV/HCV coinfected cases had a history of illicit drug use, while 92.6% had a history of imprisonment and 40.7% had high risk sexual contacts. Overall, genotype 1 was found in 75.9% of HCV patients, while genotype 3 was found in 24.1%. Some 94.4% of HCV patients had subtype A. There were no clinical symptoms of chronic hepatitis C.

CONCLUSIONS

The majority of HIV-infected persons in the city of Kashan were also HCV positive. Genotype 1 was the predominant type, alongside subtype A. Considering the high prevalence of HCV among the HIV-infected persons, as well as the impact of occupation, education, illicit drug use, and imprisonment on the incidence of both infections, health policy makers must introduce health programs and plans to reduce the prevalence of these infections.

Impact of Obliterative Portal Venopathy Associated With Human Immunodeficiency Virus

HIV-associated obstructive portopathy (HIVOP) is an obstruction of the hepatic microvasculature of unknown origin. The purpose of this study was to describe the clinical and paraclinical presentation of the disease and its impact in terms of morbidity. Twenty-nine HIV1-infected patients (average 12 years of infection, nadir of CD4 210/mm, including 7 patients with a history of opportunistic infection) with a biopsy-proven or likely HIVOP have been followed up for an average of 6.1 years. Modes of revelation of the HIVOP were: cytolysis and/or cholestasis (60%), occult (14%) or symptomatic (37%) portal hypertension (esophageal varices 17%, ascites 10%, cytopenia 10%), or fortuitous (8%). Hypoalbuminemia (≤35 g/L) was present in (31%), thrombocytopenia (<150,000 platelets) in 52% and prothrombin rate <70% in 10%. Esophageal varices were detected in 71%. Thrombophilia was present in 23 patients (80%): in head, protein S deficiency (87%). MRI showed in 82% at least 1 morphological abnormality. The average value of the liver stiffness by Fibroscan was 8.3 kPa. During follow-up, there was no radiological improvement, 15 (52%) patients presented with variceal hemorrhage, 10 patients (34%) ascites, 10 (34%) portal vein thrombosis, 7 (24%) an iron deficiency, and 2 (7%) with a protein-losing enteropathy, including 14 patients (48%) with several events. Four patients (14%) were transplanted, 1 (25%) recurred the HIVOP on the graft, and 1 patient is waiting for a transplant. HIVOP is a severe disease associated with high morbidity related to symptomatic portal hypertension, which occurred in 50% and required liver transplantation in 14%.

Diagnosing Nodular Regenerative Hyperplasia of the Liver Is Thwarted by Low Interobserver Agreement

Background and Aims

Nodular regenerative hyperplasia (NRH) of the liver is associated with several diseases and drugs. Clinical symptoms of NRH may vary from absence of symptoms to full-blown (non-cirrhotic) portal hypertension. However, diagnosing NRH is challenging. The objective of this study was to determine inter- and intraobserver agreement on the histopathologic diagnosis of NRH.

Methods

Liver specimens (n=48) previously diagnosed as NRH, were reviewed for the presence of NRH by seven pathologists without prior knowledge of the original diagnosis or clinical background. The majority of the liver specimens were from thiopurine using inflammatory bowel disease patients. Histopathologic features contributing to NRH were also assessed. Criteria for NRH were modified by consensus and subsequently validated. Interobserver agreement was evaluated by using the standard kappa index.

Results

After review, definite NRH, inconclusive NRH and no NRH were found in 35% (23-40%), 21% (13-27%) and 44% (38-56%), respectively (median, IQR). The median interobserver agreement for NRH was poor (κ = 0.20, IQR 0.14-0.28). The intraobserver variability on NRH ranged between 14% and 71%. After modification of the criteria and exclusion of biopsies with technical shortcomings, the interobserver agreement on the diagnosis NRH was fair (κ = 0.45).

Conclusions

The interobserver agreement on the histopathologic diagnosis of NRH was poor, even when assessed by well-experienced liver pathologists. Modification of the criteria of NRH based on consensus effort and exclusion of biopsies of poor quality led to a fairly increased interobserver agreement. The main conclusion of this study is that NRH is a clinicopathologic diagnosis that cannot reliably be based on histopathology alone.

Idiopathic Non-Cirrhotic Intrahepatic Portal Hypertension (NCIPH)-Newer Insights into Pathogenesis and Emerging Newer Treatment Options

Chronic microangiopathy of portal venules results in idiopathic non-cirrhotic intrahepatic portal hypertension (NCIPH). Recent data suggest a role for vasoactive factors of portal venous origin in the pathogenesis of this 'pure' vasculopathy of the liver. Enteropathies (often silent), are an important 'driver' of this disease. NCIPH is under-recognized and often mis-labeled as cryptogenic cirrhosis. Liver biopsy is needed to prove the diagnosis of NCIPH. In these patients, with advancing disease and increased porto-systemic shunting, the portal venous vasoactive factors bypass the liver filter and contribute to the development of pulmonary vascular endothelial disorders-porto-pulmonary hypertension and hepato-pulmonary syndrome as well as mesangiocapillary glomerulonephritis. Prognosis in NCIPH patients is determined by presence, recognition and management of associated disorders. With better understanding of the pathogenesis of NCIPH, newer treatment options are being explored. Imbalance in ADAMTS 13 (a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13): vWF (von-Willebrand factor) ratio is documented in NCIPH patients and may have a pathogenic role. Therapeutic interventions to correct this imbalance may prove to be important in the management of NCIPH.

A woman with didanosine retinopathy and non-cirrhotic portal hypertension

We present a case of structural and functional changes compatible with didanosine retinopathy in a patient who also developed non-cirrhotic portal hypertension.

Human immunodeficiency virus and nodular regenerative hyperplasia of liver: A systematic review

AIM: To investigate the diagnosis, pathogenesis, natural history, and management of nodular regenerative hyperplasia (NRH) in patients with human immunodeficiency virus (HIV).

METHODS: We performed a systematic review of the medical literature regarding NRH in patients with HIV. Inclusion criteria include reports with biopsy proven NRH. We studied the clinical features of NRH, in particular, related to its presenting manifestation and laboratory values. Combinations of the following keywords were implemented: “nodular regenerative hyperplasia”, “human immunodeficiency virus”, “noncirrhotic portal hypertension”, “idiopathic portal hypertension”, “cryptogenic liver disease”, “highly active antiretroviral therapy” and “didanosine”. The bibliographies of these studies were subsequently searched for any additional relevant publications.

RESULTS: The clinical presentation of patients with NRH varies from patients being completely asymptomatic to the development of portal hypertension – namely esophageal variceal bleeding and ascites. Liver associated enzymes are generally normal and synthetic function well preserved. There is a strong association between the occurrence of NRH and the use of antiviral therapies such as didanosine. The management of NRH revolves around treating the manifestations of portal hypertension. The prognosis of NRH is generally good since liver function is preserved. A high index of suspicion is required to make a identify NRH.

CONCLUSION: The appropriate management of HIV-infected persons with suspected NRH is yet to be outlined. However, NRH is a clinically subtle condition that is difficult to diagnose, and it is important to be able to manage it according to the best available evidence.

Histological features in western patients with idiopathic non-cirrhotic portal hypertension

AIMS

In the western world, idiopathic non-cirrhotic portal hypertension (INCPH) is a rare disease. This study aimed to investigate the histopathological features in western INCPH patients and to assess pathological differences between liver specimens of INCPH with and without HIV.

METHODS AND RESULTS

Biopsies of 70 INCPH patients (of which 15 were HIV-infected) were compared to 23 patients with non-cirrhotic portal vein thrombosis (PVT), which served as a control group for non-cirrhotic portal hypertension. Phlebosclerosis, nodular regeneration (NR), sinusoidal dilatation, paraportal shunting vessels, perisinusoidal fibrosis and portal tract remnants were the most prevalent morphological features of INCPH. There were significant (P < 0.01) morphological differences between INCPH and PVT liver specimens with regard to portal tract remnants (46% versus 0%), phlebosclerosis (95% versus 65%), portal vein dilatation (34% versus 78%) and NR (56% versus 22%). The degree of NR correlated with the severity of phlebosclerosis (P < 0.01). NR was seen more frequently in the HIV-INCPH group, compared to the non-HIV-infected patients (P < 0.001).

CONCLUSION

Portal tract remnants, phlebosclerosis and nodular regeneration are typical features of INCPH. Sinusoidal dilatation, paraportal shunting vessels and increased portal and parenchymal vessels might represent pressure-related morphological signs of portal hypertension. Finally, more nodular regeneration was observed in HIV-associated INCPH.

Genetic determinants of idiopathic noncirrhotic portal hypertension in HIV-infected patients

BACKGROUND

Noncirrhotic portal hypertension (NCPH) is a rare but potentially life-threatening complication in patients with human immunodeficiency virus (HIV). Cases of NCPH have been reported in HIV-negative individuals as result of treatment with thiopurines for leukemia or inflammatory bowel disease. Exposure to didanosine, which is also a purine analogue, predisposes to NCPH in the HIV setting. However, it is unclear why NCPH only develops in a small subset of didanosine-treated patients.

METHODS

A multicenter, case-control study was conducted to investigate the role of pharmacogenomics in NCPH in HIV patients with prior didanosine exposure. Three controls were chosen for each case, adjusted for sex, age, CD4 counts, plasma HIV-RNA, and site. Tagging 36 single-nucleotide polymorphisms (SNPs) at enzymes involved in the purine metabolism (inosine triphosphatase, 5'-nucleotidase cytosolic-II, purine nucleoside phosphorylase and xanthine oxidase) was performed using SNPlex microarray technology.

RESULTS

Eighty individuals were examined; 22 with NCPH and 58 matched controls. Two SNPs at the 5'-nucleotidase gene were associated with NCPH: rs11191561 (48% CG/GG vs 17% CC; P=.003) and rs11598702 (40% CC/CT vs 9% TT; P=.003). SNPs at another 2 loci at the xanthine oxidase gene were also associated with NCPH: rs1429376 (71% AA vs 23% CC/AC; P=.015) and rs1594160 (71% AA vs 23% CC/AC; P=.015). There was a cumulative risk of NCPH for these 4 SNPs: 7%, 26%, 42%, 50%, and 100%, respectively, for 0, 1, 2, 3, or all SNPs (P=.001).

CONCLUSIONS

SNPs at the 5'-nucleotidase and xanthine oxidase genes influence the risk of NCPH in HIV patients treated with didanosine.

Use of serum vitamin B12 level as a marker to differentiate idiopathic noncirrhotic intrahepatic portal hypertension from cryptogenic cirrhosis

BACKGROUND AND AIMS

Idiopathic non-cirrhotic intrahepatic portal hypertension (NCIPH) is often mis-diagnosed as cryptogenic cirrhosis. Serum vitamin B12 levels can be raised in cirrhosis, probably because of excess release or reduced clearance. Because NCIPH is characterised by long periods of preserved liver function, we examined whether serum B12 level could be used as a marker to differentiate NCIPH from cryptogenic cirrhosis.

METHODS

We analysed serum B12 levels in 45 NCIPH and 43 cryptogenic cirrhosis patients from January 2009 to September 2011.

RESULTS

Serum B12 levels were significantly lower in NCIPH patients than in cryptogenic cirrhosis patients (p < 0.001) and were useful in differentiating the two disorders (area under ROC: 0.84; 95% C.I: 0.76-0.93). Low serum B12 level (≤250 pg/ml) was noted in 25/72 (35%) healthy controls, 14/42 (33%) NCIPH patients, and 1/38 (3 %) cryptogenic cirrhosis patients. In patients with intrahepatic portal hypertension of unknown cause, serum B12 level ≤ 250 pg/ml was useful for diagnosing NCIPH (positive predictive value: 93 %, positive likelihood ratio 12.7), and serum B12 level >1,000 pg/ml was useful in ruling out NCIPH (negative predictive value: 86 %, negative likelihood ratio: 6.67). Low serum B12 levels (≤250 pg/ml) correlated with diagnosis of NCIPH after adjusting for possible confounders (O.R: 13.6; 95% C.I:1.5-126.2). Among patients in Child's class A, serum B12 level was ≤250 pg/ml in 14/35 NCIPH patients compared with 1/21 cryptogenic cirrhosis patients (O.R: 13.3; 95% C.I: 1.6-111).

CONCLUSION

Serum vitamin B12 level seems to be a useful non-invasive marker for differentiation of NCIPH from cryptogenic cirrhosis.

Risk factors and outcome of HIV-associated idiopathic noncirrhotic portal hypertension

BACKGROUND

Idiopathic noncirrhotic portal hypertension (INCPH) has been reported increasingly in patients with HIV infection.

AIM

To evaluate the number of nationwide diagnosed HIV-associated INCPH cases and to assess its clinical features, risk factors and outcome.

METHODS

All HIV centres in the Netherlands were contacted and requested to notify INCPH cases diagnosed in their population. A case–control study was performed to identify the risk factors of INCPH. The cases were group-matched for duration of follow-up after HIV diagnosis to controls. Controls were selected from a database of HIV patients with negative screening for signs of portal hypertension on abdominal ultrasound. Univariate and multivariate conditional logistic regression analyses were performed.

RESULTS

On 1st of July 2011, 18.085 individuals were infected with HIV in the Netherlands. Within this population, sixteen patients with clinically overt INCPH were identified. At the time of INCPH diagnosis, cases had a lower platelet count and a higher ALT level. In univariate and multivariate analyses, didanosine [OR: 1.9 (1.3–2.8)], concomitant didanosine and stavudine treatment [OR: 6.3 (2.1–19.1)] and concomitant didanosine and tenofovir treatment [OR: 5.1 (1.2–22.6)] were independently associated INCPH. During follow-up, 4 patients died [malignancy (n = 3), liver failure (n = 1)]. A significant decline in platelets was observed after didanosine discontinuation (P = 0.003).

CONCLUSIONS

HIV-associated clinically relevant idiopathic noncirrhotic portal hypertension appears to be a rarely diagnosed disease. Long-term exposure to didanosine and short-term combination of didanosine and stavudine or tenofovir exposure are associated with idiopathic noncirrhotic portal hypertension. Mortality in HIV-associated idiopathic noncirrhotic portal hypertension is mainly related to HIV-associated disorders. Portal hypertension continues despite didanosine discontinuation

An Update on Drug-induced Liver Injury

Idiosyncratic drug-induced liver injury (DILI) is an important cause of morbidity and mortality following drugs taken in therapeutic doses. Hepatotoxicity is a leading cause of attrition in drug development, or withdrawal or restricted use after marketing. No age is exempt although adults and the elderly are at increased risk. DILI spans the entire spectrum ranging from asymptomatic elevation in transaminases to severe disease such as acute hepatitis leading to acute liver failure. The liver specific Roussel Uclaf Causality Assessment Method is the most validated and extensively used for determining the likelihood that an implicated drug caused DILI. Asymptomatic elevation in liver tests must be differentiated from adaptation. Drugs producing DILI have a signature pattern although no single pattern is characteristic. Antimicrobial and central nervous system agents including antiepileptic drugs are the leading causes of DILI worldwide. In the absence of a diagnostic test or a biomarker, the diagnosis rests on the evidence of absence of competing causes such as acute viral hepatitis, autoimmune hepatitis and others. Recent studies show that antituberculosis drugs given for active or latent disease are still a major cause of drug-induced liver injury in India and the West respectively. Presence of jaundice signifies a severe disease and entails a worse outcome. The pathogenesis is unclear and is due to a mix of host, drug metabolite and environmental factors. Research has evolved from incriminating candidate genes to genome wide analysis studies. Immediate cessation of the drug is key to prevent or minimize progressive damage. Treatment is largely supportive. N-acetylcysteine is the antidote for paracetamol toxicity. Carnitine has been tried in valproate injury whereas steroids and ursodeoxycholic acid may be used in DILI associated with hypersensitivity or cholestatic features respectively. This article provides an overview of the epidemiology, the patterns of hepatotoxicity, the pathogenesis and associated risk factors besides its clinical management.

Non-cirrhotic portal hypertension in HIV mono-infected patients

BACKGROUND AND AIM

Unexplained liver injury including fibrosis and portal hypertension has rarely been reported among patients with HIV in the absence of co-infection with hepatitis B (HBV) or hepatitis C (HCV). We describe a series of HIV mono-infected patients with evidence of non-cirrhotic portal hypertension.

METHODS

HIV-infected patients with evidence of portal hypertension who were anti-HBV and anti-HCV negative and HBV and HCV RNA polymerase chain reaction (PCR) negative were identified from patients managed by the Victorian statewide HIV referral service located at The Alfred Hospital, Melbourne. Portal hypertension was defined as either radiological or endoscopic evidence of varices, portal vein flow obstruction, or elevated hepatic venous pressure gradient (HPVG).

RESULTS

Five patients were found to have portal hypertension. These patients were male, aged 41 to 65 years, with known duration of HIV infection between 11 to 25 years. All had been treated with antiretroviral therapy, including didanosine. Tests for metabolic, autoimmune, and hereditary causes of liver disease failed to establish an etiology for the liver injury. All had radiological or endoscopic findings of varices, and four patients had radiological features of portal vein obstruction or flow reversal. Only one patient underwent HPVG measurement, which was elevated. Non-invasive fibrosis assessment revealed increased liver stiffness in three (out of four) patients, and no cirrhotic features were found on those who underwent liver biopsy.

CONCLUSIONS

To our knowledge, this is the largest published series of non-cirrhotic portal hypertension in HIV mono-infected patients in Australia. Further research is needed to understand what relationship, if any, HIV or its treatments might have on liver injury over time.

Management of hepatic vascular diseases

Primary damage to hepatic vessels is rare. (i) Hepatic arterial disorders, related mostly to iatrogenic injury and occasionally to systemic diseases, lead to ischemic cholangiopathy. (ii) Hepatic vein or inferior vena cava thrombosis, causing primary Budd-Chiari syndrome, is related typically to a combination of underlying prothrombotic conditions, particularly myeloproliferative neoplasms, factor V Leiden, and oral contraceptive use. The outcome of Budd-Chiari syndrome has markedly improved with anticoagulation therapy and, when needed, angioplasty, stenting, TIPS, or liver transplantation. (iii) Extrahepatic portal vein thrombosis is related to local causes (advanced cirrhosis, surgery, malignant or inflammatory conditions), or general prothrombotic conditions (mostly myeloproliferative neoplasms or factor II gene mutation), often in combination. Anticoagulation at the early stage prevents thrombus extension and, in 40% of the cases, allows for recanalization. At the late stage, gastrointestinal bleeding related to portal hypertension can be prevented in the same way as in cirrhosis. (iv) Sinusoidal obstruction syndrome (or venoocclusive disease), caused by agents toxic to bone marrow progenitors and to sinusoidal endothelial cells, induces portal hypertension and liver dysfunction. Decreasing the intensity of myeloablative regimens reduces the incidence of sinusoidal toxicity. (v) Obstruction of intrahepatic portal veins (obliterative portal venopathy) can be associated with autoimmune diseases, prothrombotic conditions, or HIV infection. The disease can eventually be complicated with end-stage liver disease. Extrahepatic portal vein obstruction is common. Anticoagulation should be considered. (vi) Nodular regenerative hyperplasia is induced by the uneven perfusion due to obstructed sinusoids, or portal or hepatic venules. It causes pure portal hypertension.

Fatal cumulative toxicities of HAART in a stable, AIDS-free, HIV-infected patient

The authors describe the case of fatal cumulative toxicities in a 58-year-old AIDS-free, HIV-infected patient, who successively developed under highly active antiretroviral therapy (HAART): severe lipodystrophy, complicated osteoporosis, complicated non-cirrhotic portal hypertension of the liver (with ascites, portal thrombosis, oesophageal varices and protein-losing enteropathy) due to nodular regenerative hyperplasia. These cumulative HAART-related toxicities led to death, despite symptomatic treatment and the switch of antiretrovirals (especially didanosine) putatively involved in the process in these drug-mediated diseases. As morbidity and mortality in HIV infection continue to improve, it appears important to recognise such rare HAART-associated toxicities. This case illustrates the absolute necessity of investigating the long-term side effects of HAART in HIV infection, particularly in patients treated with first generation molecules. The switch strategy (switching old molecules to newer ones) is crucial in case of severe suspected toxicity and has to be discussed in asymptomatic patients largely exposed to first generation molecules, in order to prevent long-term toxicity.