Chronic Kidney Disease (CKD) - Risk Factors and Symptoms
This post takes an in-depth look into what amounts to chronic kidney disease, the risk factors to chronic kidney disease and the symptoms of the disease.
Introduction
Chronic kidney disease
(CKD) includes conditions that affect the kidney with the potential to cause
either progressive loss of kidney function or complications resulting from
decreased kidney function (Levey et al., 1999). Harris et al. (1998) also
defined CKD as the presence of kidney damage or decreased level of kidney
function for three months or more, irrespective of diagnosis which generally
results in death of patients. Thematic flowchart of CKD is shown in Figure 3
below as proposed by Thomas et al. (2008).
The decline in kidney
functions results in progressive deterioration in mineral homeostasis
(referring to the balance of elements like Calcium, Potassium etc in the body),
with a disruption of normal serum and tissue concentrations of phosphorus and
calcium and changes in circulating levels of hormones (Harmoinen et al., 2003).
Such hormones include parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D),
1,25-dihydroxyvitamin D (1,25(OH)2D), and other vitamin D metabolites,
fibroblast growth factor-23 (FGF-23), and growth hormone. Beginning in CKD
stage 3, the ability of the kidneys to appropriately excrete a phosphate load
is diminished, leading to hyperphosphatemia, elevated PTH, and decreased
1,25(OH)2D with associated elevations in the levels of FGF-23 (Hojs et al.,
2004).
The disease is a long term
condition caused by damage to both kidneys. According to Mussap et al. (2002),
CKD has multiple causes and the damage is usually irreversible and can lead to
ill health. In some cases dialysis or transplantation may become necessary. It
is only relatively recently that the epidemiology of CKD has been studied in
detail with the finding that it is more common than previously thought
(Chantrel et al., 2000; Perlemoine et al., 2003). Chronic kidney disease is
seen more frequently in older people and therefore has the potential of increasing
in a population (Burkhardt et al., 2004).
Figure
2.2: Interplay of processes secondary to chronic kidney disease leading to
cardiovascular disease and death. Red arrows: Pathogenetic pathways; black
arrow: Feedback loop; kidney disease worsened by heart failure (Source: Thomas
et al., 2008).
Risk Factors to Chronic Kidney Diseases
Risk factors make it more likely that a disease
would develop later. Some risk factors such as age or family history cannot be
controlled (Keith et al., 2004). However, other risk factors can be controlled
and perhaps, slow down or even prevent diseases. For instance, controlling
blood pressure and blood sugar level may aid in kidney functioning. Some of the
risk factors are as follow:
(i) High
Blood Pressure (Hypertension)
High blood
pressure puts more stress on blood vessels throughout the body, including the
kidney filters (nephrons) and thus, regarded as the number two cause of kidney
failure (National Collaborating Centre for Chronic Conditions, 2008). Weight
control, exercise, and medications which control blood pressure has the high
chance of preventing or reducing the progression from kidney disease to kidney
failure (Eknoyan, 2007).
(ii) Diabetes
According to
Crowe et al. (2008), almost 40% of dialysis patients have diabetes which makes
it the fastest growing risk factor for kidney disease. However, the type 2
diabetes is the prime cause of kidney failure in comparison to the type 1
diabetes.
(iii) Blockages
Scarring from
infections or malformed lower urinary tract system (birth defect) force urine
to back up into the kidney and damage it (Taylor et al., 2005). Blood clots or
plaques of cholesterol that block the kidneys’ blood vessels reduce blood flow
to the kidney and cause damage. Repeated kidney stones block the flow of urine
from the kidney thereby causing damage to them (Weiner et al., 2004).
(iv) Overuse
of painkillers and allergic reactions to antibiotics
Heavy usages
of painkillers containing ibuprofen (Advil, Motrin), naproxen (Aleve), or
acetaminophen (Tylenol) have been linked to interstitial nephritis, a kidney
inflammation lead to kidney failure (Eknoyan, 2007). Allergic reactions to, or
side effects of antibiotics like penicillin and vancomycin also cause nephritis
and kidney damage (National Kidney Foundation, 2002).
(v) Drug
Abuse
Use of certain
non-prescription drugs such as heroin or cocaine highly damage the kidneys and
may lead to kidney failure and dialysis (Burkhardt et al., 2004).
(vi) Family
History of Kidney Disease
Patients
belonging to a family having more of its members who suffer from CKD, are on
dialysis, or have a kidney transplant, stand a high chance of contracting CKD
(National Kidney Foundation, 2002). Inherited disease such as polycystic kidney
disease causes large, fluid-filled cysts that eventually crowd out normal
kidney tissue and subsequently results in CKD and kidney failure. There is,
therefore, the need that members from such families seek for regular screening
and medication.
(vii) Age
Since kidney
function is reduced in older people, the older one is, the greater the risk.
Although, the elevated relative risk of death with lower GFR has been shown in
a large population study to fall with increasing age (Foley et al., 1998) a reduced
GFR remains a strong predictor of all-cause and cardiovascular mortality, even
in elderly populations (Keith et al., 2004). In a large observational cohort
study of Department of Veterans Affairs patients who were aged 18 to 100 years
and had at least one outpatient serum creatinine measurement between 1 October
2001 and 30 September 2002, 20% of patients had an eGFR<60 ml/min per 1.73 m2,
ranging from 3% among 18- to 44-year-olds to as high as 49% among 85- to
100-year-olds (Eknoyan et al., 2007). However, the association of eGFR with
mortality was weaker in the elderly than in younger age groups.
Symptoms
of Chronic Kidney Diseases
There
are several symptoms of CKD exhibited by infected patients of which the most
prominent ones are as follow:
a. Changes in urination
Patients
suffering from CKD generally experience change in urination (Nilsson et al.,
2004). Thus, there is frequent urination, foamy or bubbly urine pass-out,
urinate in greater volume than usual with pale urine, passage of dark colored
urine which sometimes contain blood and feeling pressure or have difficulty in
urinating.
b. Swelling in the legs, ankles, feet, face, and/or hands
Failing
kidneys do not remove extra fluid, which builds up in the body causing swelling
of legs, ankles, feet, face and/or hands.
c. Fatigue
Healthy
kidneys make a hormone called erythropoietin that instructs the body to make
oxygen-carrying red blood cells (Le Bricon et al., 1999). Hence, as the kidneys
fail they make less erythropoietin with fewer red blood cells to carry oxygen
causing stress on both the muscles and brain.
d. Metallic taste in mouth/ammonia breath
A
build-up of wastes in the blood (called uremia) can make food taste different
and cause bad breath. There is also an incidence of loss of appetite for meat
and lose of body weight.
Some References
Harris MI, Flegal
KM, Cowie CC, Eberhardt MS, Goldstein DE, Little RR, Wiedmeyet H-M, Byrd-Holt
DD (1998). Prevalence of diabetes, impaired fasting glucose, and impaired
glucose tolerance in U.S. adults: The Third National Health and Nutrition Examination
Survey, 1988–1994. Diabetes Care 21:518–524.
Harmoinen, A.,
Lehtimaki T, Korpela M, Turjanmaa V, Saha H. (2003). Diagnostic accuracies of
plasma creatinine, cystatin C, and glomerular filtration rate calculated by the
Cockcroft-Gault and Levey (MDRD) formulas. Clin Chem 2003; 49(7):1223-5.
Levey AS, Bosch JP,
Lewis JB, Greene T, Rogers N, Roth D (1999). A more accurate method to estimate
glomerular filtration rate from serum creatinine: A new prediction equation.
Modification of Diet in Renal Disease Study Group. Ann Intern Med 130:461–470.
Thomas, R., Kanso, A. and Sedor, J.
R. (2008). Chronic Kidney Disease and Its Complications. Prim Care.
35(2): 329.
Hojs, R, Bevc S,
Antolinc B, Gorenjak M, Puklavec L. (2004). Serum cystatin C as an endogenous
marker of renal function in the elderly. Int J Clin Pharmacol Res 2004; 24(2-3):49-54.
Credit: C. N.
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