Volume Balance in Chronic Kidney Disease: Evaluation Methodologies and Innovation Opportunities

BACKGROUND

Patients affected by chronic kidney disease are at a risk of cardiovascular morbidity and mortality. Body fluids unbalance is one of the main characteristics of this condition, as fluid overload is highly prevalent in patients affected by the cardiorenal syndrome.

SUMMARY

We describe the state of the art and new insights into body volume evaluation. The mechanisms behind fluid balance are often complex, mainly because of the interplay of multiple regulatory systems. Consequently, its management may be challenging in clinical practice and even more so out-of-hospital. Availability of novel technologies offer new opportunities to improve the quality of care and patients' outcome. Development and validation of new technologies could provide new tools to reduce costs for the healthcare system, promote personalized medicine, and boost home care. Due to the current COVID-19 pandemic, a proper monitoring of chronic patients suffering from fluid unbalances is extremely relevant. Key Message: We discuss the main mechanisms responsible for fluid overload in different clinical contexts, including hemodialysis, peritoneal dialysis, and heart failure, emphasizing the potential impact provided by the implementation of the new technologies.

Significance of serum Myostatin in hemodialysis patients

BACKGROUND

Malnutrition and muscle wasting are common in haemodialysis (HD) patients. Their pathogenesis is complex and involves many molecules including Myostatin (Mstn), which acts as a negative regulator of skeletal muscle. The characterisation of Mstn as a biomarker of malnutrition could be useful in the prevention and management of this condition. Previous studies have reported no conclusive results on the actual relationship between serum Mstn and wasting and malnutrition. So, in this study, we evaluated Mstn profile in a cohort of regular HD patients.

METHODS

We performed a cross-sectional study, enrolling 37 patients undergoing bicarbonate-HD (BHD) or haemodiafiltration (HDF) at least for six months. 20 sex-matched healthy subjects comprised the control group. Mstn serum levels were evaluated by ELISA before and after HD. We collected clinical and biochemical data, evaluated insulin resistance, body composition, malnutrition [by Malnutrition Inflammation Score (MIS)] and tested muscle function (by hand-grip strength, six-minute walking test and a questionnaire on fatigue).

RESULTS

Mstn levels were not significantly different between HD patients and controls (4.7 ± 2.8 vs 4.5 ± 1.3 ng/ml). In addition, while a decrease in Mstn was observed after HD treatment, there were no differences between BHD and HDF. In whole group of HD patients Mstn was positively correlated with muscle mass (r = 0.82, p < 0.001) and inversely correlated with age (r = - 0.63, p < 0.01) and MIS (r = - 0.39, p = 0.01). No correlations were found between Mstn and insulin resistance, such as between Mstn levels and parameters of muscle strength and fatigue. In multivariate analysis, Mstn resulted inversely correlated with fat body content (β = - 1.055, p = 0.002).

CONCLUSIONS

Circulating Mstn is related to muscle mass and nutritional status in HD patients, suggesting that it may have a role in the regulation of skeletal muscle and metabolic processes. However, also considering the lack of difference of serum Mstn between healthy controls and HD patients and the absence of correlations with muscle function tests, our findings do not support the use of circulating Mstn as a biomarker of muscle wasting and malnutrition in HD.

Severe cyclophosphamide-related hyponatremia in a patient with acute glomerulonephritis

Cyclophosphamide is frequently used to treat cancer, autoimmune and renal diseases, such as rapidly progressive glomerulonephritis. Its side effects are well-known, including bone marrow depression, infections, alopecia, sterility, bladder malignancy and hemorrhagic cystitis. Moreover, in some cases cyclophosphamide use has been related to the onset of hyponatremia, by development of a syndrome of inappropriate antidiuresis. Indeed, severe hyponatremia has been previously reported in patients treated with high-dose or moderate-dose of intravenous cyclophosphamide, while only few cases have been reported in patients treated with low dose. Here, we discuss a case of a syndrome of inappropriate antidiuresis followed to a single low-dose of intravenous cyclophosphamide in a patient with a histological diagnosis of acute glomerulonephritis, presenting as acute kidney injury. After cyclophosphamide administration (500 mg IV), while renal function gradually improved, the patient developed confusion and headache. Laboratory examinations showed serum sodium concentration dropped to 122 mmol per liter associated with an elevated urinary osmolality of 199 mOsm/kg, while common causes of acute hyponatremia were excluded. He was successfully treated with water restriction and hypertonic saline solution infusion with the resolution of the electrolyte disorder. This case, together with the previous ones already reported, highlights that electrolyte profile should be strictly monitored in patients undergoing cyclophosphamide therapy in order to early recognize the potentially life-threatening complications of acute water retention.

Global Performance Status Score: A New Tool to Assess Physical Performance in Kidney Transplant Patients

BACKGROUND

Information on physical performance in renal transplantation is limited because of the shortage of specifically designed evaluation instruments. Therefore, we elaborated and validated the Global Performance Status (GloPerSta) score to provide a new and comprehensive tool, exploring the different components of physical performance in kidney transplant patients.

METHODS

We elaborated the GloPerSta score on the basis of the data obtained from a cross-sectional study, in which we evaluated the physical performance of a cohort of kidney transplant patients. The results of these analyses were weighted to describe the different contribution of any single test, via the generation of a structural equation model, resulting in the definition of the GloPerSta. Then, to internally validate this score, we studied its correlation with clinical parameters and quality of life (evaluated as KDQOL-SF, Kidney Disease Quality of Life-Short Form) in the same patient population.

RESULTS

We enrolled 132 patients in whom the functional tests revealed a great heterogeneity. GloPerSta allowed the stratification of the patients in 3 different physical performance categories (low: score 0-11; medium: 12-22; high: 23-33). Internal validation showed that GloPerSta was directly and significantly correlated with the quality of life and allograft function, independent of the time from transplantation.

CONCLUSIONS

The GloPerSta is a reliable tool to assess physical performance in a kidney transplant population. Its application might be of help in identifying patients needing intensive and personalized rehabilitation programs.

[Report for the World Kidney Days in Italy 2015-2016]

World Kidney Day (WKD) is a global campaign, promoted by International Federation of Kidney Foundations (IFKF) and International Society of Nephrology (ISN) aimed at raising awareness among people on importance of our kidneys. This campaign includes many events across the globe. The main purpose of WKD is to create and spread awareness about preventive behaviours and risk factors for renal diseases. In Italy WKD is organized by the Italian Kidney Foundation (FIR) in collaboration with Italian Society of Nephrology (SIN) and the Red Cross of Italy. It takes place in hospitals, public spaces and in schools, where each participant is provided with informative material together with blood pressure and urine dipstick testing. Here, we present the data collected during the 2015 and 2016 WKD campaigns.

[Superior Cava Vein stenosis in a hemodialysis patient with long-term central venous catheter and vascular graft: a case report]

Recently, the use of central venous catheters (CVC) as a vascular access in patients undergoing hemodialysis is significantly increased, mainly because of the aging of this population and the presence of several comorbidities. However, the implantation and the long stay of CVC are associated with many complications. Among them, central venous stenosis represents one of the most common problems that, if not properly diagnosed, could lead to vascular thrombosis and consequent vascular access malfunction. Here, we report a case of a 38-year-old patient, who underwent hemodialysis firstly by a CVC long-term into right jugular vein and then by a prosthetic fistula in the ipsilateral limb. The patient presented many episodes of vascular access thrombosis that required endovascular interventions. The ultrasound screening and CT-angiography revealed an asymptomatic stenosis of the superior cava vein, which treatment with the implantation of vascular stent resulted in an initial improvement of vascular access performance. However, in the following months, a restenosis was observed that required new interventions to reestablish a satisfactory vascular access function. This case highlights that patients on hemodialysis should undergo proper clinical and instrumental follow-up in order to prevent or early recognize vascular access complications.

[Spontaneous rupture of a simple renal cyst: clinical management]

Spontaneous renal bleeding mainly occurs in patients with polycystic kidney diseases or cancer. Indeed, despite the high prevalence of simple cysts, their spontaneous atraumatic rupture is a rare event. Underlying mechanisms may involve the increase of intracystic pressure and/or the development of a haemorrhage into the cyst. Management of this condition includes surgery, interventional radiology or conservative strategies. Here, we report a case of spontaneous rupture of a simple renal cyst, successfully managed with conservative treatment.

["Deep" purple urine bag syndrome: physiopathology and clinical implications]

Urinalysis is a key part of the clinical evaluation of patients with kidney disease. It can provide several useful information for the diagnosis and management of diseases of kidneys and urinary tract. In particular, urine color can be affected by the presence of blood, infection and endogenous metabolites, such as bilirubin, or exogenous, for instance those derived from drugs. Therefore, the analysis of urine color may be helpful in identifying different clinical conditions. Here we report a case of a patient who presented purple-colored urine, the so-called " Purple urine bag syndrome", discussing the predisposing factors and the pathogenesis of this condition. We believe that this information can be useful to clinicians who might face this particular situation.

Gastric leiomyosarcoma. Comparative value of barium examinations, ultrasonography and CT scans

The authors discuss four cases of gastric leiomyosarcoma explored by various imaging techniques (barium examinations, ultrasound, CT scans). Barium examinations were normal in two cases, abnormal but insufficient for diagnosis in one, and sufficient to allow topographic diagnosis in one. Ultrasonography gave abnormal findings insufficient for diagnosis in two cases and allowed topographic diagnosis in the other two cases. CT scans were abnormal but insufficient for diagnosis in one case, allowed topographic diagnosis in 3 cases, and in two of the cases permitted initial diagnosis of a connective tissue malignancy. Due to the frequently subserosal nature of leiomyosarcoma of the stomach and of the digestive tract in general, analysis by CT in mandatory. Analysis of tumor relations with the spleen, the left kidney and the pancreas is facilitated by ultrasonography.

Value of ultrasound in localizing the internal mammary vessels

The authors discuss the value of ultrasound in determining the depth of the internal mammary vessels und their distance from the medial line. Real-time imaging with a high frequency transducer and a pulsed Doppler system gave highly accurate results. Depending on the intercostal space, the depth of internal mammary vessels varies from 17 to 22 mm. The distance of the internal mammary vessels from the medial line is a function of the intercostal space and the body side, and varies from 25 to 33 mm. Results were found to vary as a function of patient height and weight; likewise, mastectomy was seen responsible for a modification of 2 mm in measurements. Precise localization of the internal mammary vessels allows optimization of radiotherapy, and this rapid examination should be performed just prior to the start of irradiation.

Tongue and tonsil cancer: staging with US

A prospective study on the value of ultrasound (US) for the staging of 70 cases of cancer of the tongue and tonsil was performed. A real-time, high-frequency transducer was used, and the examination was often coupled with endobuccal palpation. US did not visualize the tumor in nine of 42 cases of tongue cancer (seven stage T1 and two anterior stage T2 tumors); US accurately defined tumor size in 33 cases. The degree of in-depth extension and the location with respect to the median line (only four false results) were evaluated correctly. With regard to 28 tonsil cancers, US depicted extension from the tonsillar fossa to the tongue in all cases but one (13 of 14 cases). US is valuable for the detection of cervical lymph nodes associated with both tongue and tonsil tumors and is a safe and helpful technique for the follow-up of medium-size lesions. The major limitations of US include the nonvisualization of superficial lesions, reduced accuracy for evaluation of the extension of large tumors, and analysis of posterior pharyngeal extension.

Axillary lymph node metastases in breast cancer: preoperative detection with US

The importance of axillary node status in the prognosis of breast cancer led the authors to conduct a prospective study comparing the value of clinical examination with ultrasound (US) performed by a transpectoral approach. All 60 patients examined underwent axillary dissection. Sensitivity was 45.4% for clinical examination versus 72.7% for US. US provides valuable information for breast cancers treated solely by irradiation, after insufficient dissection, and for large tumors not amenable to primary surgery. When the nodal region is treated by surgery and/or radiotherapy, local monitoring with US appears unnecessary owing to the low incidence of nodal recurrence.

Comparison of ultrasonographic and histological findings for multinodular lesions of the salivary glands

Fifteen cases of multinodular lesions of the salivary glands are presented. All nodules were hypoechoic, the largest measuring over 5 mm. The various etiologies represented included: 8 non-Hodgkin's lymphomas, 5 metastases of cancer of the tongue, 1 sarcoidosis limited to the submaxillary gland, and 1 case of oncocytosis involving all four salivary glands. After discussing the rarity and the general characteristics of these lesions, the authors propose a diagnostic strategy following examination by ultrasound.

[Contribution and current limitations of computed tomography in the diagnosis of cavernous hemangioma of the liver]

Based on findings for 30 patients, the authors assess the value of CT scans for the diagnosis of cavernous hemangiomas of the liver. Four images were retained, and were graded 0 (absence) or 1 (presence): hypodensity before injection of the contrast material, arteriolar halo after injection, progressive centripetal filling and late hyperdensity. A score of 3 or 4 after the CT scan allows diagnosis. Solitary lesions of at least 3 cm are correctly evaluated. When associated with other smaller lesions, or when smaller than 3 cm, CT scans are less helpful and arteriography is necessary. In all. CT scanning has four limiting parameters: lesion diameter, the number of images requiring exploration, the difficulty in obtaining exactly the same section in various sequences allowing effective scan analysis (thoraco-abdominal position of the liver) and problems specific to individual patients (poor circulation, iodine allergy or intolerance). These limiting factors explain the "wait-and-see" strategy suggested when confronted with solitary hyperechoic nodules smaller than 3 cm.

[High-definition real-time ultrasonic echography of tumors of the thyroid gland. Apropos of 379 surgically treated cases]

The authors present the results of a review of 379 cases of benign and malignant thyroid tumors examined by high frequency (7 MHz) ultrasound prior to surgery. Features of the 37 cases of cancer are described. Hyperechogenicity was almost always correlated with benign lesions (only 1 cancer out of 71 hyperechoic nodules). For 313 of the 342 cases of benign tumors a good correlation was found between sonograms and intraoperative examination of the two thyroid lobes. In the case of clinically evident polyadenomatous goiters, ultrasound is a highly accurate means of determining whether any zones of healthy tissue remain (sensitivity 104/110 cases, i. e. 93.7%). When a contralateral lobe is normal on sonograms, intraoperative examination only rarely reveals lesions (12/159 cases, including 2 false positives for surgical investigation). Due to the excellent concordance between ultrasound and intraoperative exploration, and the difficulties involved in anterior dissection, the results of sonograms can be used to decide on the surgical approach. Direct intraoperative surgical exploration of the lobe opposite a thyroid lesion appears unnecessary if the sonogram is normal (cases of non suspected occult thyroid cancer). Since intraoperative exploration can give false negatives, intraoperative ultrasound can be used in the rare cases where 1 or 2 deep micronodules have been detected by pre-surgery sonograms in the lobe contralateral to the main lesion.

[Interventional radiology in chemotherapy. Percutaneous arterial route and and embolization with microspheres]

The authors present their experience with interventional radiological techniques employed for chemotherapy: 205 intra-arterial chemotherapy (IAC) cycles were administered to 67 patients (lesion sites were: liver 20, pelvis 35, unknown 12). Catheters were left in place for 5 days in 89% of cases. The positions of the end of the catheter was checked by CT scan, with concomitant arterial opacification in the case of pelvic pathologies; this allowed evaluation of the tumor volume treated. Serious radiological complications of IAC included: 2 surgical thrombectomies and 2 surgical removals of broken catheters (2% complication rate for IAC). 15 embolizations with microcapsules of mitomycin were performed for 11 patients, using the technique of Kato. Venous blood samples revealed the persistence of mitomycinemia for up to four hours. three instances of pain were noted in the 24 hours following embolization. These two techniques have a low rate of serious complications; the therapeutic efficacy observed in certain cases warrants the use of these methods for cancers impossible to treat by radical procedures.

[Lymphoma of the kidney. Value of echography and x-ray computed tomography]

The most frequent site of involvement of the urinary tract by lymphomas is the kidney (68% of lesions, mainly secondary). Thirteen cases are described (2 Hodgkin's disease and 11 non-Hodgkin lymphomas, 2 of which were primary lesions). All 13 patients were investigated by ultrasound; 10 were also investigated by CT. Both solitary and multiple lesions were observed for these 13 patients: 8 cases of multinodular lesions (including 1 false negative sonogram), 4 cases of continuous spread from retroperitoneal nodes, 4 cases of a nodular lesion or solitary tumor, and 2 cases of an infiltrating lesion. Bilateral lesions were seen in 6 cases, and existed in the presence of concomitant hepatic (5 cases) or splenic lesions (4 cases). Comparison of the value of ultrasound and CT scanning over a period of time was performed for 6 patients: there was concordance of findings for 3 cases, better sensitivity with CT in 2 cases, and better sensitivity with ultrasound in 1 case. The general characteristics and the imaging of renal lymphomas along with the renal complications of lymphomas and complications resulting from treatment are discussed.

[Giant perirenal lipoma. Apropos of a case]

Giant perirenal lipomas are rare pathological entities. Ultrasonographic, CT scan and angiographic findings are described for a case involving a 60 year old male patient. Once the diagnosis was made, primarily thanks to CT scans, the patient was followed-up for two years, until he decided to undergo surgery. Giant perirenal lipomas are one of the focal lipomatoses that can be followed-up with CT scans since surgery is rarely required, except in cases of giant tumors as in our patient (6 kg).

Ear, nose, and throat cancer: ultrasound diagnosis of metastasis to cervical lymph nodes

We present the results of a study on the value of ultrasound in the detection of metastasis to the cervical lymph nodes in connection with cancer of the ear, nose, and throat. Comparison of clinical, ultrasound, and histological findings for 100 patients who underwent surgery revealed that clinical examination had a sensitivity of 78% versus 92.6% for ultrasound. All 18 cases of thrombosis of the internal jugular vein were detected by ultrasound. Clinical staging of the disease was modified in 28 of these patients based on ultrasound findings, including three false positive findings. Ultrasonographic follow-up at three months for a second group of 110 patients who did not undergo neck dissection provided prognostic information, since lesion stability or progression was correlated with death in less than one year in 41 of 43 patients. Ultrasound is of primary value in providing information of an anatomic nature, including the detection of subclinical lymph nodes, volumetric evaluation, and determination of vascular connections, particularly detection of internal jugular venous thrombosis. Furthermore, for patients whose necks have been thickened as a result of radiotherapy, ultrasound allows assessment of local status.

Metastases of the digestive tract. Report of 77 cases and review of the literature

In addition to personal observations of 77 patients with one or more metastatic sites in the gastrointestinal tract, the authors reviewed over 1000 similar cases in the literature. The general radiologic aspects of each location (oesophagus, stomach, intestine, colon/rectum) are discussed. The pathophysiology of this type of metastasis explains the radiologic images obtained during barium transit examinations. The lymphatic type of spread observed in the oesophageal region in connection with carcinoma of the breast is the origin of stenosis of the middle third. The haematogenous type of diffusion encountered during melanomas creates intramural or intraluminal radiologic images. Two means of spread can be observed in the stomach. Haematogenous spread can result in frequently multiple and ulcerated nodular submucosal lesions from melanomas and bronchogenic carcinomas; it can also cause a more or less stenotic invasive image, especially in connection with carcinoma of the breast. Dissemination by means of the mesenteric reflections, and in particular around the gastrocolic ligament, explains the spread of a carcinoma of the transverse colon towards the stomach. The most frequent secondary sites in the gastrointestinal tract occur in the small intestine, the majority of these metastases being caused by pelvic tumours. Whether occurring in the small intestine or the colon, the pathophysiology is similar: direct invasion by a non-contiguous primary carcinoma along the fascias and mesenteric attachments (more rarely by lymphatic permeation), dissemination by the peritoneal fluid or haematogenuous spread. In the first two types of dissemination cited, the image encountered is often hard to differentiate from radiation-induced lesions.

[Congenital cysts of the liver in echography]

The authors present 150 cases of congenital biliary cystic pathologies of the liver: solitary congenital cyst (98 cases), multiple congenital cysts (40 cases), hepatic polycystosis (8 cases), and Caroli's disease (4 cases). The general characteristics of these congenital liver affections are reviewed, including discussion of their frequency, classification and potential for evolution. The problems raised by this type of pathology and the benefits of ultrasonography are emphasized.

Echography in hepatic angiomas

All US patterns can be observed in hepatic angiomas; if the lesion is less than 3 cm, however, the echostructure is often hyperechoic and homogeneous.

[Echographic survey of hepatic metastases]

In a study covering 105 patients with hepatic metastases, all of whom underwent at least two echographies, the authors were able to make comparisons with the previous examination in 220 cases. Comparisons dealt with modifications in the echographic aspect (observed in 72 cases among the 220 comparisons), modification in volume and modifications in the number of metastases. In most cases, modification of the echostructure corresponded to a volumetric change. Three evolutionary parameters should be considered: the number of metastases, if there are no more than five; the diameter of the largest liver metastasis, unless it is over 7 cm, in which case it is also advisable to retain two other metastases of 5 cm or less: the size of the liver (left liver measured on the median line and right liver along the right mamillary line). This last parameter appears to be the only valid one when dealing with diffuse metastatic forms.

Echographic aspects of thyroid and parotid localizations in non-Hodgkin lymphomas

The authors present four observations of rare localizations of non-Hodgkin lymphomas (3 cases of lymphoma of the thyroid, 1 case of lymphoma of the parotid), all of which were studied by echography. In two of the thyroid localizations, the echographic pattern was identical to that observed for nodes in non-Hodgkin lymphomas, and thus differs from that of cysts and necrotized or cystic tumors. In the one case of secondary lymphoma of the thyroid, accompanied by diffuse enlargement of the gland but no histological proof, echography revealed only diffuse enlargement, without any anomaly in the echostructure. In the one case of lymphoma of the parotid, the echographic image was similar to that of a lymphomatous node, but it cannot be formally differentiated from the structure which can be observed for a mixed tumor or a cystic lymphangioma.

[The liver masses in ultrasonography. Report on 400 cases (author's transl)]

On the basis of 400 cases of liver masses, the authors have drawn conclusions that can be used to orient etiological investigations: --one or more well demarcated transsonic formations always correspond to a cystic etiology: --a hyperechoic metastatic liver points towards a primary cancer of the digestive tract whereas a hypoechoic metastatic liver is only rarely caused by such a cancer. The authors also propose a strategy for the exploration and surveillance of isolated hyperechoic or transsonic nodules of no more than 3 cm.

[Echography in tumor pathology of uterus (author's transl)]

Based on the study of 234 cases of uterine tumor pathology, the authors attempt to define the role and limits of echography. In the case of uterine cancers, the major role of echography concerns postoperative surveillance, except for cancers of the corpus uteri for which it allows exact measurement of the size of the uterus and thus the optimization of radiotherapy. Fibromas are easily detected by echography, but in the case of submucosal or subserosal forms this technique can give false negative (submucosal forms) or erroneous diagnosis of an ovarian tumor (subserosal fibroma). Only the tumoral forms of endometriosis uterina can be recognized using echography, generally showing up as small transsonic images; infiltrating forms cannot be visualized. Echographic diagnosis of uterine polyps is often difficult. Echography has become the foremost complementary procedure following clinical examination. However, a negative uterine echogram in the presence of warning signs and in particular menorrhagia systematically warrants obtention of a hysterography to detect a polyp, a submocusal fibroma, endometrial lesions or an infiltrating cancer of the corpus uteri.

Ultrasound evaluation of common bile duct size in normal adult patients and following cholecystectomy. A report of 750 cases

The authors present the findings of seven hundred and fifty adult patients without biliary tract disease for whom the internal diameter of the common bile duct was measured. Six hundred and seventy-three patients had no biliary tract disease whatever while seventy-seven had no clinical evidence of disease but had undergone cholecystectomy over one year ago. In our series, the mean diameter of the common bile duct in normal patients was 3.67 +/- 0.03 mm. Only 5.9% of normal patients were found to have a bile duct with a diameter greater than or equal to 5 mm. The frequency of this finding increased in patients over fifty years of age. The mean diameter of the common bile duct in the seventy-seven who had undergone cholecystectomy was 4.47 +/- 0.10 mm.