Intestinal lymphangiectasia and reversible high liver stiffness
Department of Biomedical and Clinical Sciences Luigi Sacco, University of Milan, Milan, Italy
Address reprint requests to: Laura Milazzo, M.D., Infectious Diseases Section, L. Sacco Department of Biomedical and Clinical Sciences, University of Milan, Via G.B. Grassi 74, 20157, Milan, Italy. E-mail: firstname.lastname@example.org; fax: +390250319758.
Potential conflict of interest: Nothing to report.
Primary intestinal lymphangiectasia (PIL) is a protein-losing enteropathy characterized by tortuous and dilated lymph channels of the small bowel. The main symptoms are bilateral lower limb edema, serosal effusions, and vitamin D malabsorption resulting in osteoporosis. We report here a case of long-lasting misdiagnosed PIL with a peculiar liver picture, characterized by a very high stiffness value at transient elastography, which decreased with clinical improvement. The complex interplay between lymphatic and hepatic circulatory system is discussed. (Hepatology 2014;60:759–761)
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A 52-year-old woman presented with chronic bilateral lower limb edema, ascites, and small pleural effusion which had been previously misdiagnosed as liver cirrhosis. The patient's medical history was notable for hypothyroidism, iron deficiency anemia, and osteoporosis. Laboratory tests showed hypoproteinemia (33 g/L), severe hypoalbuminemia (12 g/L), and low serum immunoglobulins (IgG 1.05 g/L, IgA 0.41 g/L, IgM 0.75 g/L).
Abdominal ultrasound and computed tomography (CT) scan demonstrated hepatomegaly with irregular margins, mild portal vein dilation, and splenomegaly (Fig. 1A). A small amount of fluid in the Douglas space and bilateral pleural effusions were detected. In addition, transient elastography (FibroScan; Echosens, Paris, France) revealed highly elevated hepatic stiffness (34.8 kPa; interquartile range [IQR] 4.3 kPa; success rate 100%), consistent with the hypothesis of cirrhotic liver disease. Nevertheless, liver histology showed a normal liver pattern with no signs of fibrosis, steatosis, or inflammatory infiltrate (Fig. 1C,D). Viral, autoimmune, and toxic hepatitis were ruled out.
Upper endoscopy showed small white spots scattered on duodenal mucosa with histologic evidence of markedly dilated villous lymphatics and a moderate inflammatory infiltrate consistent with a diagnosis of PIL (Fig. 1B).
Following 1 month of a low-fat diet associated with medium-chain triglycerides supplementation, the cornerstone of PIL management, serous effusions resolved and lymphedema improved. Interestingly, during the follow-up, liver stiffness showed a progressive decrease (to 26.6 and 14.3 kPa after 1 and 6 months, respectively; Fig. 2).
PIL is a rare disease characterized by congenital malformation of intestinal lacteals, lymph leakage into the intestinal lumen, and protein-losing enteropathy, leading to lower limb edema and serosal effusions. No association with hepatic disorders has been reported. A low-fat diet prevents the obstruction of the intestinal lymphatics with chyle, their rupture, and the consequent protein loss. As medium-chain triglycerides are directly absorbed into the portal venous system, they provide nutrient fat, avoiding lacteals obstruction.
We report an uncommon liver picture associated with PIL and propose a potential pathogenetic mechanism, represented by the increased hydrostatic lymphatic pressure in the liver or by decreased oncotic pressure. Noteworthy, about 50% of lymph flowing through the thoracic duct is produced in the liver and mostly drained into portal lymphatic vessels, which are virtually impossible to identify in standard histologic sections. The elevated liver stiffness in the presence of normal histology might result from elevated hydrostatic lymphatic pressure in bowel vessels, then transmitted to the upstream hepatic circle, since they merge hepatic lymphatics before draining into the thoracic duct. This may give rise to lymph stasis with impaired tissue fluid flow, similar to what is described in the cardiac failure population as a result of volume changes. Alternatively, due to the high permeability of sinusoidal endothelial cells, an increased amount of fluid flows into the space of Disse, as a result of the very low oncotic pressure.
The improvement of liver stiffness after dietary modification suggests a partially reversible pathologic picture that is alike to what was reported in patients with acute decompensated heart failure, although elastography is not validated in chronic liver diseases other than viral hepatitis.
The interconnections between the lymphatic system and blood circulation in portal hypertension have been recently suggested to play a role in the pathogenesis of ascites and edema formation in cirrhosis.[5, 6] Ribera et al. demonstrated an impaired lymphatic drainage in cirrhotic rats; hence, it might be reasonable to suppose that the complex interplay between the lymphatic and circulatory system could also justify a reverse mechanism for the increased liver stiffness in a primary impairment of splanchnic lymphatic circulation.
We thank Mrs. Bianca Ghisi for graphical assistance.