Liver involvement in hereditary hemorrhagic telangiectasia: can breath test unmask impaired hepatic first-pass effect?

Minimal portosystemic encephalopathy: A new nosological entity in patients with hereditary haemorrhagic telangiectasia

BACKGROUND

Portosystemic shunts in Hereditary Haemorrhagic Telangiectasia (HHT) are often overlooked by conventional imaging although they could reduce hepatic clearance of gut-derived toxins.

AIMS

To evaluate, the presence of subclinical neurological alterations (SNAs), that we named "minimal portosystemic encephalopathy" (mPSE) in HHT patients without advanced liver disease (ALD).

METHODS

In this cross sectional study, consecutive HHT outpatients were firstly screened by critical flicker frequency (CFF) test (abnormal ≤39Hz), and the simplified animal naming test (S-ANT₁) (abnormal <15) was used to confirm the diagnosis of mPSE. Furthermore, we evaluated the effect of lactulose administration on mPSE. Multi-slice CT, cerebral dynamic magnetic resonance, laboratory analyses and transient elastography were also used.

RESULTS

None of the 37 enrolled patients showed portosystemic shunts at imaging techniques. However, 33 patients had normal CFF values (CFF-) and 4 displayed CFF alterations (37.0±0.7Hz, CFF+). The S-ANT₁ confirmed an impaired neurological performance (10.2±2.8) in CFF+ patients thus confirming the presence of mPSE. Noteworthy, lactulose administration determined a CFF increase (39.1±0.4Hz) and S-ANT₁ normalization in these patients. Neither mPSE- nor mPSE+ patients had ALD and showed similar demographic, clinical and laboratory parameters. Finally, no mPSE+ patient showed radiologically-detectable brain vascular malformations or other brain abnormalities at imaging.

CONCLUSIONS

HHT patients represent a human model of mPSE secondary to portosystemic shunts escaping radiological detection. mPSE evaluation should be incorporated in HHT surveillance protocols since it can affect both health-related/social aspects and pharmacokinetics of orally administered drugs with a narrow therapeutic index and high hepatic first-pass uptake.

Lactulose to the Rescue: A Case of Toxic Hepatic Encephalopathy Caused by Portosystemic Shunting and Epistaxis in a Patient with Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an uncommon autosomal dominant disorder characterized by telangiectasias and arteriovenous malformations. Multiple organ systems are involved including the skin, lungs, gastrointestinal tract, and brain. Hepatic encephalopathy is an extremely rare complication of HHT and early diagnosis and treatment can be life-saving. We present a rare case of hepatic encephalopathy caused by HHT-induced portosystemic shunting treated with lactulose.

Hereditary Hemorrhagic Telangiectasia: A Primer for Critical Care Nurses

Hereditary hemorrhagic telangiectasia is a rare, autosomal dominant genetic disease that causes abnormal growth of blood vessels and, subsequently, life-threatening arteriovenous malformations in vital organs. Epistaxis may be one of the initial clues that a patient has more serious, generalized arteriovenous malformations. Recommended treatment involves careful evaluation to determine the severity and risk of spontaneous rupture of the malformations and the management of various signs and symptoms. The disease remains undiagnosed in many patients, and health care providers may miss the diagnosis until catastrophic events happen in multiple family members. Prompt recognition of hereditary hemorrhagic telangiectasia and early intervention can halt the dangerous course of the disease. Critical care nurses can assist with early diagnosis within families with this genetic disease, thus preventing early death and disability.

13C Methacetin Breath Test for Assessment of Microsomal Liver Function: Methodology and Clinical Application

Assessment of the liver function, and the need of constant monitoring of the organ's capacity, concerns not only patients with primary liver diseases, but also those at risk of hepatopathies secondary to other chronic diseases. Most commonly, the diagnostics is based on measurements of static biochemical parameters, which allow us to draw conclusions only indirectly about the function and the degree of damage of the organ. On the other hand, liver biopsy is an invasive procedure and therefore it is associated with a considerable risk of complications. Dynamic tests enable us to assess quantitatively the organ's functional reserve by analyzing the kinetics of the metabolization of the substrate by the liver. In practice applied are breath tests using substances such as aminopyrine, caffeine, methacetin, erythromycin (for assessment of the microsomal function); phenylalanine, galactose (for assessment of the cytosolic function); methionine, octanoate, ketoisocaproic acid (for assessment of the mitochondrial function). The test with ¹³C methacetin belongs to the best described and most widely applied methods in noninvasive liver function assessment. Due to the rising availability of this method, knowledge concerning its limitations and controversies regarding the methodology, as well as its usefulness in chosen groups of patients, seems to be vital.