Haemorrhagic fever with renal syndrome: an emerging disease

Asian leadership in chronic kidney disease

Asian Pacific countries include those with the highest incidence of renal failure in the world, the richest and poorest economies and unparalleled diversity of economy, culture and geography. From this come many challenges, but also a strong basis for the introduction of strategies to combat renal diseases. With a rapidly developing scientific community, Asia needs to accept the challenge of becoming a global leader in nephrology in the near future.

Intestinal protein loss in patients with haemorrhagic fever with renal syndrome

BACKGROUND

In haemorrhagic fever with renal syndrome (HFRS) vascular dysfunction has been observed in various organs, but the involvement of the intestine has not yet been reported. This study was performed to evaluate the association of intestinal protein loss in this disease with other clinical parameters reflecting vascular permeability or disease severity.

METHODS

Twenty patients with HFRS were included in this study. Intestinal protein loss was measured by (99m)Tc-human serum albumin ((99m)Tc-HSA) scintigraphy in the acute stage, and quantitative analysis of protein loss was measured by the faecal clearance of alpha 1-antitrypsin (C(AT)) in the acute and the recovery stages. C(AT) was then compared with clinical parameters reflecting disease activity and vascular permeability.

RESULTS

(99m)Tc-HSA scintigraphy was positive in 13 (65%) patients, and C(AT) in the acute stage was significantly increased as compared with C(AT) in the recovery stage (40.5+/-24.1 vs 9.2+/-4.2 ml/day, P<0.001). C(AT) was associated with serum albumin levels, frequency of hypotensive episodes, severity of acute renal failure, and degree of thrombocytopenia.

CONCLUSIONS

Our data suggest that the increased vascular permeability of HFRS is associated with the increased intestinal loss of plasma proteins, which might represent one of the parameters of disease severity in HFRS.

Pathogenesis of puumala and other hantavirus infections

Hantaviruses are rodent/insectivore-borne negative-stranded RNA viruses which belong to the Bunyaviridae family. They do not cause any symptomatic disease in their adult carrier rodents, but in humans they are aetiologic agents of haemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS), both associated with a significant mortality. In cell culture hantaviruses do not cause cytopathic effects and the mechanisms of disease in man are not well understood. Increased capillary permeability is a central phenomenon in the pathogenesis of hantavirus infections. Although the viruses have in vivo a predilection for endothelial cells, it is presumed that inflammatory mediators of the host immune response play a significant role in the capillary leak that may produce abrupt hypotension and shock in severely ill patients. Mediators released by activated macrophages including NO and TNF-alpha are considered important. The pathogenesis of renal failure in HFRS also awaits to be resolved. This review summarises what is known about these phenomena and discusses also the molecular basis of the putative virulence factors of hantaviruses. Finally, the genetic predisposition and HLA association with severe Puumala virus infection will be discussed. Copyright 1998 John Wiley & Sons, Ltd.