Chronic kidney disease

Signs and symptoms

• Blood pressure is increased due to fluid overload and the production of vasoactive hormones created by the kidney via the renin-angiotensin system, increasing the risk of developing hypertension and heart failure. People with CKD are more likely than the general population to develop atherosclerosis with consequent cardiovascular disease, an effect that may be at least partly mediated by uremic toxins.
• Urea accumulates, leading to azotemia and ultimately uremia. Due to its high systemic concentration, urea is excreted in eccrine sweat at high concentrations and crystallizes on the skin as the sweat evaporates.
• Potassium accumulates in the blood. Hyperkalemia usually does not develop until the glomerular filtration rate falls to less than 20–25 mL/min/1.73 m², when the kidneys have decreased ability to excrete potassium. Hyperkalemia in CKD can be exacerbated by acidemia and from a lack of insulin.
• Fluid overload symptoms may range from mild edema to life-threatening pulmonary edema.
• Hyperphosphatemia results from poor phosphate elimination in the kidney, and contributes to increased cardiovascular risk by causing vascular calcification. Circulating concentrations of fibroblast growth factor-23 increase progressively as the kidney capacity for phosphate excretion declines, which may contribute to left ventricular hypertrophy and increased mortality in people with CKD.
• Hypocalcemia results from 1,25 dihydroxyvitamin D₃ deficiency and the skeletal resistance to the calcemic action of parathyroid hormone. Osteocytes are responsible for the increased production of FGF-23, which is a potent inhibitor of the enzyme 1-alpha-hydroxylase. Later, this progresses to secondary hyperparathyroidism, kidney osteodystrophy, and vascular calcification that further impairs cardiac function. An extreme consequence is the occurrence of the rare condition named calciphylaxis.
• Changes in mineral and bone metabolism that may cause 1) abnormalities of calcium, phosphorus abnormalities in bone turnover, mineralization, volume, linear growth, or strength vascular or other soft-tissue calcification. CKD–mineral and bone disorders have been associated with poor outcomes.
• Metabolic acidosis may result from decreased capacity to generate enough ammonia from the cells of the proximal tubule. Acidemia affects the function of enzymes and increases the excitability of cardiac and neuronal membranes by the promotion of hyperkalemia.
• Anemia is common and is especially prevalent in those requiring hemodialysis. It is multifactorial in cause but includes increased inflammation, reduction in erythropoietin, and hyperuricemia leading to bone marrow suppression. Hypoproliferative anemia occurs due to inadequate production of erythropoietin by the kidneys.
• In later stages, cachexia may develop, leading to unintentional weight loss, muscle wasting, weakness, and anorexia.
• Cognitive decline in patients experiencing CKD is an emerging symptom revealed in research literature. Research suggests that patients with CKD face a 35–40% higher likelihood of cognitive decline and or dementia. This relation is dependent on the severity of CKD in each patient; although emerging literature indicates that patients at all stages of CKD will have a higher risk of developing these cognitive issues.
• Sexual dysfunction is very common in both men and women with CKD. A majority of men have a reduced sex drive, difficulty obtaining an erection, and difficulty reaching orgasm, and the problems get worse with age. Most women have trouble with sexual arousal, and painful menstruation and problems with performing and enjoying sex are common.

  Causes

By anatomical location

• Vascular disease includes large-vessel disease such as bilateral kidney artery stenosis and small-vessel disease such as ischemic nephropathy, hemolytic–uremic syndrome, and vasculitis.
• Glomerular disease comprises a diverse group and is classified into:
• * Primary glomerular disease such as focal segmental glomerulosclerosis and IgA nephropathy
• * Secondary glomerular disease such as diabetic nephropathy and lupus nephritis
• Tubulointerstitial disease includes drug- and toxin-induced chronic tubulointerstitial nephritis, and reflux nephropathy
• Obstructive nephropathy, as exemplified by bilateral kidney stones and benign prostatic hyperplasia of the prostate gland; rarely, pinworms infecting the kidney can cause obstructive nephropathy.

  Other

• Genetic congenital disease such as polycystic kidney disease or 17q12 microdeletion syndrome.
• Mesoamerican nephropathy, is "a new form of kidney disease that could be called agricultural nephropathy". A high and so-far unexplained number of new cases of CKD, referred to as the Mesoamerican nephropathy, has been noted among male workers in Central America, mainly in sugarcane fields in the lowlands of El Salvador and Nicaragua. Heat stress from long hours of piece-rate work at high average temperatures of about 36 °C is suspected, as are agricultural chemicals.
• Chronic lead exposure
• Long term lithium treatment is known to cause chronic kidney disease after 10-20 years of treatment in 1-5% of people. End-stage renal disease due to lithium occurs in 0.53% of people versus 0.2% in the general population. Dosing lithium more than once per day is associated with more kidney damage. Kidney harm can be mitigated by dosing lithium once per day at night and keeping the dose as low as possible. Dosing lithium once per day allows for long periods where the kidney is exposed to low levels of lithium, which minimizes kidney harm.

  Diagnosis

Screening