Moving Away from Liver Biopsies

A recent review (EB Tapper, AS-F Lok. NEJM 2017; 377: 756-68) provides a good review of liver biopsy and liver imaging. My take of this review is that it highlights the emergence of noninvasive tools (imaging & fibrosis markers) which may supplant liver biopsy.  This article does not delve into how more widespread genetic testing may obviate a liver biopsy in many cases as well. The article notes that about 8% of persons in the U.S. have elevated liver enzymes.

Liver biopsy:

  • “A typical liver biopsy samples one fifty-thousandth of the liver.”
  • Limitations of liver biopsy: sampling error is common, biopsy interpretation is subjective, and biopsies can cause complications.  Pain is noted in 30-50% of patients, serious bleeding in 0.6%, injury to other organs (0.08%), and in rare cases, death (up  to 0.1%).
  • Cost: “the average direct cost of a percutaneous liver biopsy is $1448 (in 2016 U.S. dollars).” Transjugular biopsies are much more expensive.  In addition, there are unmeasured indirect costs, due to missing work.

Some prior blogs on liver biopsy

Blood tests:

  • The article details the formulas for biomarker measurements that predict the risk of fibrosis, inlcuding FIB-4, Lok Index, and NAFLD Fibrosis Score.
  • In most liver diseases, aspartate aminotransferase levels “exceed alanine aminotransferase levels when cirrhosis develops.”
  • Thrombocytopenia “is the earliest indicator of cirrhosis among routine blood tests…[due to] diminished liver function (throbopoietin underproduction) and portal hypertension (splenic sequestration).”
  • Proprietary algorithms to assess fibrosis have variable sensitivity, specificity –include FibroTest (aka FibroSure [LabCorp]), FibroMeter, HepaScore (Quest), FIBROSpect, and the Enhanced Liver Fibrosis Score.

Imaging:

  • Elastography with vibration-controlled transient elastography (VCTE) OR magnetic resonance elastography
  • “Elastography offers excellent negative likelihood ratios for advanced fibrosis but much poorer positive likelihood ratios.”
  • Patients with severe obesity are less likely to obtain adequate study with VCTE and could need magnetic resonance elastography to assess fibrosis.

My take: Noninvasive tests have already sharply reduced the need for liver biopsy.

Related posts:

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Updated Biliary Atresia Epidemiology

A recent retrospective study (PC Hopkins, N Yazigi, CM Nylund. J Pediatr 2017; 187: 253-7) provides an update on the recent incidence of biliary atresia in the US from 1997-2012. This study relied on coding for biliary atresia or Kasai hepatoportoenterostomy to identify cases using HCUP-KID database.  This database provides a nationally representative sample of pediatric hospitalizations and captures ~96% of pediatric hospitalizations in the US.

Key findings:

  • Incidence of biliary atresia (BA) was 4.47 per 100,000 (1 in 22,371 infants)
  • BA was more common in females (RR 1.43), Asian/Pacific Islanders (RR 1.89), and blacks (RR 1.30)
  • Median age at the time of the Kasai procedure was 63 days with no improvement over the course of the study period.  More than 50% of all children underwent the Kasai procedure after the optimal window of 60 days of life

My take: In my view, at this time, obtaining a blood test for direct bilirubin in the first two weeks of life will need to be adopted broadly if we are going to diagnose biliary atresia at an earlier age.

Related blog posts:

Dry Falls, Highlands NC

Dry Falls, Highlands NC

 

Recurrent Acute Liver Failure due to NBAS Deficiency

A recent case report (V Cardenas et al. J Pediatr 2017; 186: 179-82) describes recurrent acute liver failure (ALF) in the setting of neuroblastoma amplified sequence deficiency (NBAS).

The case report describes a 2 yo who developed very elevated aminotransferases (ALT >14,000), hypoglycemia, severe coagulopathy (INR 4.5)), lactic acidosis (6.5 mmol/L) and hyperammonemia (282 μmol/L) following a febrile illness.

Genetic testing uncovered 2 variants in the NBAS gene consistent with NBAS deficiency.

Key points:

  • Mutations in NBAS “have been identified as a molecular cause of ALF in children, leading to recurrent episodes of ALF after a febrile illness.”
  • NBAS deficiency should be part of the differential diagnosis of ALF in children
  • In a report of 14 patients with this disorder (J Inherit Metab Dis 2016; 39: 3-16), liver function normalized in between episodes.  Typically, episodes were most severe at younger ages.  ALF “may be prevented through early and effective antipyretic therapy and intravenous application of glucose and lipids.”

My take: NBAS deficiency, along with hemophagocytic lymphohistiocytosis (HLH), infections, and Kawasaki’s disease, needs to be considered in children with severe liver dysfunction associated with fevers.

“Big Improvements for Smallest Recipients” with Bad Liver Disease

A recent study (M Kasahara et al. Liver Transplantation 2017; 23: 1051-7, editorial 977-8) indicates improvement in survival among the smallest liver transplant patients. In this study of 12 patients less than 3 months of age, the cumulative 10-year patient and graft survival for both was 90.9%.

These patients received living donor liver transplantation. Living donors likely contributed to the excellent outcomes both in terms of enhancing the timing of transplantation and also with regard to size.  Whole organs are not likely to fit well in these small abdomens. The size of the patients ranged from 2.8 kg (at 29 days) to 5.5 kg).  11 of 12 had fulminant hepatic failure with 6 of these cases being considered unknown etiology.

Limitation: This was a very small sample size.

Programming for Fatty Liver Disease May Occur Prior to Birth

A recent study (KP Newton et al. J Pediatr 2017; 187: 141-6; associated editorial pg 13-15)) in a multicenter retrospective cross-sectional study of children (n=538) with biopsy-proven nonalcoholic fatty liver disease (NAFLD) showed that birth weight influenced the development of NAFLD.  The participants were enrolled in the Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN).

Key findings:

  • There was increased NAFLD among both low birth weight (LBW) and high birth weight (HBW).
  • LBW occurred more commonly in the NAFLD cohort 9.3% compared with the general population prevalence 6.1%.
  • HBW occurred more commonly in the NAFLD cohort 14.9% compared with the general population prevalence 10.5%

The authors speculate that the explanation/mechanisms for increase in both LBW and HBW are likely to differ. It has been recognized that LBW is associated with higher cardiovascular disease and type 2 diabetes.  HBW start bigger and often stay bigger; that is, there are increased risks of more severe obesity.

There are numerous limitations to this study -there is a lot of data that is not available, including gestational age, maternal weight, breastfeeding exposure, and antibiotic administration.

My take: These findings add to the literature that risks for NAFLD along with other metabolic problems may be present at birth.  Is there a way to modify this risk?

Related study: ET Jensen et al. J Pediatr 2017; 187: 50-7, editorial pg 10-12.  In this study of 535 ten-year-old children, enrolled in a prospective multicenter extremely low gestational age newborn cohort study, the authors found that maternal overnutrition and undernutrition affected the brain health of these children. The authors used neurocognitive assessment tools.

  • Children born to women with a pregravid BMI >30 scored “lower on measures of general cognitive ability, executive functioning, fine motor function, and academic achievement.”
  • Children born to women with inadequate maternal weight gain during pregnancy had “lower language and academic achievement.”

Hidden Falls, Highlands NC

 

6-Thioguanine Levels in Autoimmune Hepatitis

A recent retrospective study (MA Sheiko et al JPGN 2017; 65: 80-5) examines the issue of azathioprine (AZA) metabolites and outcomes in pediatric autoimmune hepatitis (AIH).

Study characteristics:

  • 66 children
  • Mean age of diagnosis 9.6 years
  • Mean follow-up 2.9 years
  • Study period 2002-2013

Key findings:

  • 79% achieved biochemical remission (defined as ALT ≤50 U/L); mean time was 6.2 months
  • 6% required liver transplantation
  • 18% were weaned off immunosuppression and remained in remission
  • 6-thioguanine (6-TGN) levels ranging from 50 to 250 (pmol/8 x 10 to 8th red blood cell count) were associated with biochemical remission

Our study suggests that AZA dosing of approximately 1.2 to 1.6 mg/kg/day will achieve 6-TGN levels of 50 to 250 pmol, which is sufficient to maintain biochemical remission in the majority of patients.

This is significantly lower than dosing recommended for inflammatory bowel disease (recommended levels 250-450). The associated editorial (pg 2-3, N Kerkar) cautions that while “lower levels are sufficient for maintaining biochemical remission…higher levels, similar to that used in IBD, are required for inducing remission.”

My take: Lower doses of azathioprine are likely to maintain biochemical remission and cause fewer side effects.  Metabolite levels can be helpful to assure reasonable levels of 6-TGN and to assure medication adherence.

Related blog entries:

Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

Shem Creek, SC

Neonatal Cholestasis for Neonatologists

I recently had the opportunity to review the topic of neonatal cholestasis with my neonatal colleagues.  I reviewed two related conditions: parenteral nutrition associated liver disease (PNALD) and neonatal acute liver failure (NALF).  Some of the material incorporates recommendations from NASPGHAN cholestasis guidelines and from NASPGHAN cholestasis slidesets. Much of the slideset information is publicly available on a YouTube lecture by Dr. Linda Book (link at bottom).

Full lecture: Neonatal Cholestasis for Neonatologists

Some screenshots:

Related blog posts:

Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.