Introduction
Chronic kidney disease is a disorder that develops in almost 10 percent of the world's population. The incidence can be higher in a few developing countries, leading to irreversible kidney damage. In a few patients, the disease may ultimately lead to kidney failure that requires dialysis or a transplant. The disease progression does not occur in all patients with chronic kidney disease. However, it is difficult to distinguish whether or not the patients develop kidney failure. Currently, clinical monitoring of proteinuria and glomerular filtration rate are used to help with chronic kidney disease diagnosis. But radiographic imaging can help with better disease understanding and diagnosis. This article provides information on magnetic resonance spectroscopy use in chronic kidney disease.
What Is Chronic Kidney Disease?
Chronic kidney disease leads to gradual loss of kidney function, causing a build-up of electrolytes, fluid, and waste products within the body. Chronic kidney disease is a challenging disease to diagnose and treat. The condition increasingly affects the elderly. Since the early stages are asymptomatic, a few percent of the population know their disease's presence. The presenting symptoms include nausea, vomiting, loss of appetite, sleep issues, high blood pressure, and chest pain. Characteristic features for diagnosing chronic kidney disease are kidney damage, such as proteinuria, and a reduced glomerular filtration rate lasting more than three months.
What Are the Stages of Chronic Kidney Disease?
Chronic kidney disease is classified based on the glomerular filtration rate measured by serum creatinine and urine albumin to creatinine ratio. Serum cystatin C is a more sensitive and less frequently available approach for the classification of chronic kidney disease. The disease is classified into five stages and are:
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Stage 1: The kidney is normal or functioning highly. They can provide earlier evidence for chronic kidney disease development.
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Stage 2: Mild reduction in kidney function.
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Stage 3: Mild to moderate reduction in kidney function. There is an increased incidence of cardiovascular disease.
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Stage 4: Severe reduction in kidney function.
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Stage 5: Kidney failure.
What Is the Cause of Chronic Kidney Disease?
The factors causing chronic kidney disease cannot be readily determined. However, the risk factors contributing to disease development and progression are the patient's age, presence of hypertension, diabetes mellitus, glomerulonephritis, and autosomal dominant polycystic kidney disease. Nephrotoxins can also be a risk factor, as medications such as NSAIDs (nonsteroidal anti-inflammatory drugs) and chemotherapeutic agents. Kidney disorders such as a history of acute kidney injury, systemic lupus erythematosus, pyelonephritis or interstitial nephritis, and kidney obstruction could contribute to chronic kidney disease development.
The kidney is increasingly prone to age-related degeneration, which increases the risk for chronic pathology compared to other vital organs. The mechanism through which chronic kidney disease develops depends on the underlying cause. The metabolic function of the kidney produces a large amount of energy throughout life to maintain its physiologic function. If the mitochondria function within the kidney is lost due to aging, it can adversely impact kidney functioning.
How Is Chronic Kidney Disease Diagnosed?
The diagnostic measures for chronic kidney disease are:
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Radiographic Methods: It is a powerful tool used in recent years to help with disease diagnosis. These methods help in the non-invasive diagnosis of disease.
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Magnetic Resonance Imaging (MRI): Various MRI modalities such as diffusion-weighted MRI, blood oxygenation level-dependent MRI, and arterial spin labeling MRI are used for measuring the degree of fibrosis.
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Magnetic Resonance Spectroscopy (MRS): The advantages of using this technique to analyze metabolite changes caused by kidney damage are the sample is indestructible, highly reproducible, and needs little or no sample preparation.
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Ultrasound: This imaging technique can analyze kidney shape and size.
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Computed Tomography: It analyzes any anatomical abnormalities in the kidney or urinary tract. CT scans are not the ideal method for diagnosis as the dyes used could damage kidneys.
What Is the Significance of MRS in Chronic Kidney Disease Diagnosis?
The amount of information regarding the usefulness of MRS in chronic kidney disease is limited in comparison to MRI scans. The application of MRS for kidney fibrosis diagnosis is limited to animal models. However, this method could help with disease diagnosis, its progression, and monitoring of treatment response. It is susceptible, accurate, and can detect various metabolites in plasma.
Magnetic resonance spectroscopy is a type of nuclear magnetic resonance different from MRI, which allows organic molecule measurement in specific regions. This diagnostic method can provide insights into the metabolic changes that can develop in the kidney of patients with chronic kidney disease. It also aids in the diagnosis of altered tissue chemistry in affected kidneys. The MRS analyzes urine, plasma, and other biofluids to detect metabolite alterations.
Changes to plasma metabolites in rat models were analyzed with magnetic resonance spectroscopy. It was done to analyze disturbances to the metabolic function of the kidney in the early stage of the disease. The study demonstrated that the rats showed increased levels of organic acids such as citrate, beta-hydroxybutyrate, acetate, lactate, acetoacetate, and fumarate. There were also increased levels of glutamine and alanine. However, further analysis of plasma metabolites in chronic kidney disease is required to understand the disease more deeply.
What Is the Treatment for Chronic Kidney Disease?
The underlying cause of chronic kidney disease must be treated to halt or slow the progression of the disease. Chronic kidney disease could have adverse effects on various organs within the body. There is an increased risk for cardiovascular events, bone disease, anemia, and uremia. Therefore, chronic kidney disease complications must be managed and monitored effectively to avoid unwanted complications.
With worsening kidney function, patients become increasingly susceptible to kidney failure. Such patients require dialysis or kidney transplantation for survival. Palliative care may be needed in patients that cannot undergo dialysis or transplantation. Delaying treatment for the condition could lead to significant morbidity and mortality.
Conclusion
Chronic kidney disease has increasingly been diagnosed in the population. Since the late diagnosis can cause untoward complications, newer modalities must be identified for earlier disease recognition. Magnetic resonance spectroscopy is a newer procedure for analyzing metabolite changes within body fluids for earlier disease diagnosis. However, their application has been limited to rat models and requires further research on their efficiency.
