A Case of Hepatorenal Syndrome and Abdominal Compartment Syndrome with High Renal Congestion

Hepatorenal syndrome: Paving a pathway from a fatal condition to an opportunity to preserve kidney function

In the 19th century, von Frerichs F and Flint A identified a type of acute renal impairment associated with advanced liver disease, characterized by oliguria, absence of proteinuria, and normal renal histology, which was later termed hepatorenal syndrome (HRS). HRS primarily affects cirrhotic patients with ascites and often follows severe infections, digestive hemorrhages, or high-volume paracentesis. Pathophysiologically, HRS involves low glomerular filtration rate, hypotension, renin-angiotensin axis activation, water clearance, hyponatremia, and minimal urinary sodium excretion. These conditions mimic those seen in decreased effective circulatory volume (ECV) scenarios such as septic shock or heart failure. HRS represents a specific form of prerenal acute kidney injury (AKI) in patients with baseline renal ischemia, where the kidney attempts to correct decreased ECV by retaining sodium and water. Intense renal vasoconstriction, passive hyperemia from ascites, and acute tubular necrosis (ATN) with specific urinary sediment changes are observed. Persistent oliguria may transition HRS to ATN, although this shift is less straightforward than in other prerenal AKI contexts. Notably, liver grafts from HRS patients can recover function more rapidly than those from other ischemic conditions. Experimental studies, such as those by Duailibe et al, using omega-3 fatty acids in cirrhotic rat models, have shown promising results in reducing oxidative stress and improving kidney function. These findings suggest potential therapeutic strategies and underscore the need for further research to understand the mechanisms of HRS and explore possible treatments. Future research should address the impact of omega-3 on survival and secondary outcomes, as well as consider the balance of therapeutic risks and benefits in severe liver disease.

Update on Hepatorenal Syndrome: From Pathophysiology to Treatment

Hepatorenal syndrome-acute kidney injury (HRS-AKI) occurs in the setting of advanced chronic liver disease, portal hypertension, and ascites. HRS-AKI is found in ∼20% of patients presenting to the hospital with AKI, but it may coexist with other causes of AKI and/or with preexisting chronic kidney disease, thereby making the diagnosis challenging. Novel biomarkers such as urinary neutrophil gelatinase-associated lipocalin may be useful. While HRS-AKI is a functional form of AKI related to circulatory and neurohormonal dysfunction, there is increasing recognition of the importance of systemic inflammation and the renal microenvironment. Early diagnosis and initiation of HRS-AKI-specific treatment can improve outcomes. The mainstay of therapy is a vasoconstrictor (terlipressin or norepinephrine) combined with albumin, which achieves resolution of HRS in 40-50% of cases. Liver transplantation is the only option for patients failing to respond to medical therapies.

From past to present to future: Terlipressin and hepatorenal syndrome-acute kidney injury

Hepatorenal syndrome (HRS) is a rare and highly morbid form of kidney injury unique to patients with decompensated cirrhosis. HRS is a physiologic consequence of portal hypertension, leading to a functional kidney injury that can be reversed by restoring effective circulating volume and renal perfusion. While liver transplantation is the only definitive "cure" for HRS, medical management with vasoconstrictors and i.v. albumin is a cornerstone of supportive care. Terlipressin, a V1a receptor agonist that acts on the splanchnic circulation, has been used for many years outside the United States for the treatment of HRS. However, its recent Food and Drug Administration approval has generated new interest in this population, as a new base of prescribers now work to incorporate the drug into clinical practice. In this article, we review HRS pathophysiology and diagnostic criteria, the clinical use of terlipressin and alternative therapies, and identify areas of future research in the space of HRS and kidney injury in cirrhosis.

Pathophysiology of Hepatorenal Syndrome - Acute Kidney Injury

Hepatorenal syndrome is a complication of liver cirrhosis with ascites that results from the complex interplay of many pathogenetic mechanisms. Advanced cirrhosis is characterized by the development of hemodynamic changes of splanchnic and systemic arterial vasodilatation, with paradoxical renal vasoconstriction and renal hypoperfusion. Cirrhosis is also an inflammatory state. The inflammatory cascade is initiated by a portal hypertension-induced increased translocation of bacteria, bacterial products, and endotoxins from the gut to the splanchnic and then to the systemic circulation. The inflammation, whether sterile or related to infection, is responsible for renal microcirculatory dysfunction, microthrombi formation, renal tubular oxidative stress, and tubular damage. Of course, many of the bacterial products also have vasodilatory properties, potentially exaggerating the state of vasodilatation and worsening the hemodynamic instability in these patients. The presence of cardiac dysfunction, related to cirrhotic cardiomyopathy, with its associated systolic incompetence, can aggravate the mismatch between the circulatory capacitance and the circulation volume, worsening the extent of the effective arterial underfilling, with lower renal perfusion pressure, contributing to renal hypoperfusion and increasing the risk for development of acute kidney injury. The presence of tense ascites can exert an intra-abdominal compartmental syndrome effect on the renal circulation, causing renal congestion and hampering glomerular filtration. Other contributing factors to renal dysfunction include the tubular damaging effects of cholestasis and adrenal dysfunction. Future developments include the use of metabolomics to identify metabolic pathways that can lead to the development of renal dysfunction, with the potential of identifying biomarkers for early diagnosis of renal dysfunction and the development of treatment strategies.

Renal vein measurement using ultrasonography in patients with cirrhotic ascites and congestive heart failure

PURPOSE

Ascites can cause compression of the inferior vena cava (IVC), leading to increased renal venous pressure and renal congestion. Previously, the left renal vein diameter in liver cirrhosis patients with ascites was measured using computed tomography, showing that enlargement of the left renal vein diameter affects the prognosis. Herein, the diameter and flow velocity of the renal veins were measured using ultrasonography.

METHODS

Abdominal ultrasonography was performed on 186 patients. The patients were divided into four groups: normal liver (n = 102), liver cirrhosis (LC) without ascites (n = 37), LC with ascites (n = 30), and congestive liver (n = 17). Ultrasonographic measurements for diameter and flow velocity of the IVC, left renal vein main trunk, and segmental renal vein were performed.

RESULTS

The left renal vein diameter increased in the following order: normal liver, LC, LC with ascites, and congestive liver groups (P < 0.001). IVC flow velocity was lower and left renal vein diameter was larger in the congestive liver and LC with ascites groups. These results suggest that the two groups have different pathological conditions, but the mechanism of renal congestion is similar. In patients with LC, IVC compression due to ascites might cause blood stagnation and renal congestion.

CONCLUSION

The left renal vein and IVC can be measured using ultrasonography. It might help in furthering our understanding of the pathophysiology of renal congestion in these patients.

Renal venous congestion following hemorrhagic shock due to traumatic liver injury

A 78-year-old woman who sustained traumatic liver injury with hemorrhagic shock was hospitalized. She was admitted to the ICU after blood transfusion and emergent angiography. AKI was observed on the following day. Blood transfusion was continued because initial assessment was prerenal AKI due to hypovolemia. Despite transfusion of blood products and administration of diuretics, aggravated renal dysfunction, and low urine output continued, resulting in respiratory failure due to pulmonary edema. Renal venous congestion was suspected as the primary cause of AKI, since IVC compression from a hematoma with IVC injury was observed on CT imaging captured on admission, and renal Doppler ultrasonography demonstrated an intermittent biphasic pattern of renal venous flow. It was finally concluded that renal venous congestion resulted from IVC compression, since urine output increased remarkably after RRT without additional diuretics, and follow-up CT and renal Doppler ultrasonography revealed improvements in IVC compression and renal venous flow pattern, respectively. Renal venous congestion has been often reported to be associated with acute decompensated heart failure and, to our knowledge, this is the first report to describe trauma-induced renal venous congestion. Trauma patients are at risk for renal venous congestion due to massive blood transfusion after recovery from hemorrhagic shock; therefore, if they develop AKI that cannot be explained by other etiologies, physicians should consider the possibility of trauma-induced renal venous congestion and perform renal Doppler ultrasonography.

Evaluation of Renal Disease in Patients With Cirrhosis

Renal dysfunction in cirrhosis is common and is associated with increased mortality. Identifying and treating reversible causes of renal disease can significantly improve outcomes. The etiology, approach, and evaluation of renal disease in this group of patients is similar to the noncirrhosis patient, with a few specific caveats. Renal disease may be unrelated to the cause of cirrhosis (eg, prerenal acute kidney injury, acute tubular necrosis), occur as a manifestation of the same systemic disease responsible for the liver disease (eg, chronic viral hepatitis B and C infection) or as a consequence of cirrhosis (hepatorenal syndrome). Kidney impairment may be underrecognized in patients with cirrhosis due to over-reliance on creatinine-based glomerular filtration rate equations used in clinical practice. The first steps of evaluation for the renal disease include a thorough medical history to identify the underlying cause of cirrhosis and any potential trigger for renal dysfunction, physical examination, and review of prior laboratory records for baseline renal function. Renal imaging and urinalysis should be performed on all cirrhotic patients with renal dysfunction to establish the presence of urinary obstruction, chronicity and intrinsic renal disease.

Protective Effects of Methane-Rich Saline on Renal Ischemic-Reperfusion Injury in a Mouse Model

BACKGROUND Renal ischemic-reperfusion (RIR) injury remains a major cause of acute kidney injury, with increased in-hospital mortality and risks for chronic kidney disease. Previous studies have proposed that oxidative stress, inflammation, and renal apoptosis are the most common causes of injury, whereas recent research proved that methane, the simplest alkane generated by an enteric microorganism or accompanying the production of reactive oxygen species (ROS), can alleviate inflammation and oxidative stress and reduce apoptosis in different organs. MATERIAL AND METHODS In the present study, we analyzed the possible effects of methane-rich saline in RIR injury in a mouse model and analyzed its possible protective effects on inflammation, oxidative stress, and apoptosis. RESULTS The results showed that treatment with methane significantly improved blood creatinine and blood urea nitrogen (BUN) levels and improved renal histology in RIR injury. Further experimentation proved that this protective effect was primarily manifested in decreased oxidative stress, less apoptosis, and reduced inflammation in renal tissues, as well as improved general responses. CONCLUSIONS Our present study proved the protective effects of methane in RIR injury and, together with previous research, confirmed the multi-organ protective effects. This may help to translate methane application and develop its use in organ ischemic-reperfusion injury.