KIDNEYS

Kidneys:


(renal function)

• The kidneys are complicated organs that have numerous biological roles.


• Their primary role is to maintain the homeostatic balance of bodily fluids by filtering and secreting metabolites (such as urea) and minerals from the blood and excreting them, along with water, as urine.


• Because the kidneys are poised to sense plasma concentrations of ions such as sodium, potassium, hydrogen, oxygen, and compounds such as amino acids, creatinine, bicarbonate, and glucose, they are important regulators of blood pressure, glucose metabolism, and erythropoiesis (the process by which red blood cells (erythrocytes) are produced).


• The medical field that studies the kidneys and diseases of the kidney is called nephrology.


• The prefix nephro- meaning kidney is from the Ancient Greek word nephros (?ef???); the adjective renal meaning related to the kidney is from Latin renes, meaning kidneys.

STROKE IN CHRONIC KIDNEY DISEASE

New insight into stroke in Chronic Kidney disease
By: Sami L. Khella
Department of Neurology,
University of Pennsylvania School of Medicine,
Philadelphia, PA.

• Patients with chronic kidney disease are predisposed to stroke, especially as the estimated glomerular filtration rate diseases.


• This update reviews the pathologic mechanisms particular to this stroke population.


• The treatment for primary and secondary prevention of stroke is reviewed with respect to antiplatelet agents, anticoagulants, surgery, and carotid stenting.


• The control of chronic hypertension is particularly important in reducing stroke risk in CDK. In patients with prior stroke from atherosclerosis, antiplatetet agents are most beneficial in reducing secondary stroke risk.


• Those with atrial fibrillation and CDK may benefit from warfarin anticoagulation.


• Statin in CDK for stroke reduction in diabetics receiving dialysis are not useful, and the data are pending for their use in stroke reduction in the general CDK population. In carefully selected cases, carotid endarterectomy can be a treament.


• The data on carotid stenting are conflicting.

RESEARCH IN NUTRITION

Outcomes Research in Nutrition and Chronic Disease

Perspectives, Issues in practice, Processes for improvement

by: Laura D. Byham-Gray
Department of Primary Care,
Graduate Programs in Clinical Nutrition,
University of Medicine and Dentistry of New Jersey,
School of Health Related Professions,
University Educational Center, Strtford, NJ

Despite greater access to health care and advances in medicine and technology, the morbidity and mortality among patients diagnosed with chronic kidney disease (CDK) remain unacceptably high discrepancies in patient care outcomes exist between the United States and other industrialized countries and and are partly explained by variances reported in clinical practice.

Outcomes research (OR) has been the primary methodology used to more fully explore the root causes for the practice variation and to uncover which indicaors have the greatest impact.

Research has established the relatioships between early diagnosis and treatment, cardiovascular disease, quality of life, and malnutrition with morbidity and mortality rates among patients with kidney disease.

Although nutrition parameters are predictive of mortality, they are complex to understand and even more difficult to improve, largely because of the effects of the imflammatory process and the lack of direct measure that defines nutritional status.

Future OR projectsmust focus on specific nutrition-related outcomes and the effectiveness of intervention, as these outcomes can establish clinical guidelines, lead to changes in practice, and create more controlled clinical trials that continue to search for answer to questions on the impact of nutrition and others.

NUTRITION INTERVENSION

Nutrition intervention to address
Cardiovascular outcomes in
Chronic kidney disease
By: Judith A. Beto & Vinod K. Bansal
Loyola University Medical Center, Division of Nephrology and Hypertension, Marywood, IL,USA.

• The high mortality in chronic kidney disease has been linked to cardiovascular risk and this patients are considered at high risk. Dietary intervention can directly address nutritional risk factors in lipid management, calcium-phosphorus balance, and body composition to reduce risk of cardiovascular disease. Nutrient intake can also indirectly address less over risks of dental health, nutritional supplements, and compliance issues.

BACKGROUND

Chronic kidney disease is a major public health problem. However, no study to date has estimated the prevalence of chronic kidney disease base on the clinical guidelines established by the National Kidney Foundation and few studies have explored the rate of diagnoses by primary care providers.

PROGNOSIS

The prognosis of patients with chronic kidney disease is guarded as epidemiological data has shown that all cause mortality (the overall death rate) increases as kidney function decreases.

The leading cause of death in patients with chronic kidney disease is cardiovascular disease, regardless of whether there is progression to stage 5.

While renal replacement therapies can maintain patients indefinitely and prolong life, the quality of life is severely affected.

Renal transplantation increases the survival of patients with stage 5 CKD significantly when compared to other therapeutic options; however, it is associated with an increased short-term mortality (due to complications of the surgery).

Transplantation aside, high intensity home hemodialysis appears to be associated with improved survival and a greater quality of life, when compared to the conventional three times a week hemodialysis and peritoneal dialysis

TREATMENT

The goal of therapy is to slow down or halt the otherwise relentless progression of CKD to stage 5. Control of blood pressure and treatment of the original disease, whenever feasible, are the broad principles of management.

Generally, angiotensin converting enzyme inhibitors (ACEIs) or angiotensin II receptor antagonists (ARBs) are used, as they have been found to slow the progression of CKD to stage 5.

Replacement of erythropoietin and vitamin D3, two hormones processed by the kidney, is usually necessary, as is calcium. Phosphate binders are used to control the serum phosphate levels, which are usually elevated in chronic kidney disease.

When one reaches stage 5 CKD, renal replacement therapy is required, in the form of either dialysis or a transplant.

COMMON CAUSES

The most common causes of CKD are diabetic nephropathy, hypertension, and glomerulonephritis. Together, these cause approximately 75% of all adult cases. Certain geographic areas have a high incidence of HIV nephropathy.
1.) Vascular, includes large vessel disease such as bilateral renal artery stenosis and small vessel disease such as ischemic nephropathy, hemolytic-uremic syndrome and vasculitis

2.) Glomerular, comprising a diverse group and subclassified into

• a.) Primary Glomerular disease such as focal segmental glomerulosclerosis and IgA nephritis


• b.) Secondary Glomerular disease such as diabetic nephropathy and lupus nephritis
  

3.) Tubulointerstitial including polycystic kidney disease, drug and toxin-induced chronic tubulointerstitial nephritis and reflux nephropathy

• a.) Polycystic kidney disease (PKD, also known as polycystic kidney syndrome) is a progressive, ciliopathic, genetic disorder of the kidneys. It occurs in humans and other organisms. PKD is characterized by the presence of multiple cysts (hence, "polycystic") in both kidneys. The disease can also damage the liver, pancreas, and rarely, the heart and brain. The two major forms of polycystic kidney disease are distinguished by their patterns of inheritance.


• b.) Reflux nephropathy, RN is a term applied when small and scarred kidneys (chronic pyelonephritis, CPN) are associated with vesico-ureteric reflux (VUR). CPN being the commonest cause, there are other causes including analgesic nephropathy and obstructive injury. Scarring is essential in developing RN and occurs almost during the first five years of life. The end results of RN are hypertension, proteinuria, CRF and eventually ESRD, end stage renal disease.

4.) Obstructive such as with bilateral kidney stones and diseases of the prostate

• a.) The prostate (from Greek p??st?t?? - prostates, literally "one who stands before", "protector", "guardian" is a compound tubuloalveolar exocrine gland of the male mammalian reproductive system. Women do not have a prostate gland, although women do have microscopic paraurethral Skene's glands connected to the distal third of the urethra in the prevaginal space that are homologous to the prostate.
  
  

The prostate differs considerably among species anatomically, chemically, and physiologically.

STAGES

• 1.) All individuals with a Glomerular filtration rate (GFR) <60>
  
• 2.) All individuals with kidney damage are classified as having chronic kidney disease, irrespective of the level of GFR. The rationale for including individuals with GFR 60 mL/min/1.73 m2 is that GFR may be sustained at normal or increased levels despite substantial kidney damage and that patients with kidney damage are at increased risk of the two major outcomes of chronic kidney disease: loss of kidney function and development of cardiovascular disease.

DIAGNOSIS

Diagnosis In many CKD patients, previous renal disease or other underlying diseases are already known. A small number presents with CKD of unknown cause. In these patients, a cause is occasionally identified retrospectively.

• It is important to differentiate CKD from acute renal failure (ARF) because ARF can be reversible. Abdominal ultrasound is commonly performed, in which the size of the kidneys are measured. Kidneys with CKD are usually smaller (<>
  
• Additional tests may include nuclear medicine MAG3 scan to confirm blood flows and establish the differential function between the two kidneys. DMSA scans are also used in renal imaging; with both MAG3 and DMSA being used chelated with the radioactive element Technetium-99.
  


• In chronic renal failure treated with standard dialysis, numerous uremic toxins accumulate. These toxins show various cytotoxic activities in the serum, have different molecular weights and some of them are bound to other proteins, primarily to albumin. Such toxic protein bound substances are receiving the attention of scientists who are interested in improving the standard chronic dialysis procedures used today.

SIGN & SYMPTOMPS

CREATININE
Initially it is without specific symptoms and can only be detected as an increase in serum creatinine or protein in the urine. As the kidney function decreases:

• 1.) blood pressure is increased due to fluid overload and production of vasoactive hormones, increasing one's risk of developing hypertension and/or suffering from congestive heart failure


• 2.) Urea accumulates, leading to azotemia and ultimately uremia (symptoms ranging from lethargy to pericarditis and encephalopathy). Urea is excreted by sweating and crystallizes on skin ("uremic frost").


• 3.) Potassium accumulates in the blood (known as hyperkalemia with a range of symptoms including malaise and potentially fatal cardiac arrhythmias)


• 4.) Erythropoietin synthesis is decreased (potentially leading to anemia, which causes fatigue)

ERYTHROPOIETIN SYNTHESIS

• 5.) Fluid volume overload - symptoms may range from mild edema to life-threatening pulmonary edema


• 6.) Hyperphosphatemia - due to reduced phosphate excretion, associated with hypocalcemia (due to vitamin D3 deficiency).


• 7.) Metabolic acidosis, due to accumulation of sulfates, phosphates, uric acid etc. This may cause altered enzyme activity by excess acid acting on enzymes and also increased excitability of cardiac and neuronal membranes by the promotion of hyperkalemia due to excess acid (acidemia)
  

BLOOD PLASMA

Blood serum:

Blood plasma is the liquid component of blood, in which the blood cells are suspended. It makes up about 55% of total blood volume. It is composed of mostly water (90% by volume), and contains dissolved proteins, glucose, clotting factors, mineral ions, hormones and carbon dioxide (plasma being the main medium for excretory product transportation).

Blood plasma is prepared simply by spinning a tube of fresh blood in a centrifuge until the blood cells fall to the bottom of the tube.

The blood plasma is then poured or drawn off. Blood serum is blood plasma without fibrinogen or the other clotting factors.

The first place where urine is formed in the kidney, filters fluid from the blood

GLOMERULUS

Glomerular:
A glomerulus is a capillary tuft surrounded by Bowman's capsule in nephrons of the vertebrate kidney. It receives its blood supply from an afferent arteriole of the renal circulation. Unlike most other capillary beds, the glomerulus drains into an efferent arteriole rather than a venule. The resistance of the arterioles results in high pressure in the glomerulus aiding the process of ultrafiltration where fluids and soluble materials in the blood are forced out of the capillaries and into Bowman's capsule.

A glomerulus and its surrounding Bowman's capsule constitute a renal corpuscle, the basic filtration unit of the kidney. The rate at which blood is filtered through all of the glomeruli, and thus the measure of the overall renal function, is the glomerular filtration rate (GFR).

CHRONIC KIDNEY DISEASE

Chronic kidney disease(CKD):

Also known as chronic renal disease, is a progressive loss of renal function over a period of months or years through five stages. Each stage is a progression through an abnormally low and deteriorating glomerular filtration rate, which is usually determined indirectly by the creatinine level in blood serum.

People with chronic kidney disease suffer from accelerated atherosclerosis and are more likely to develop cardiovascular disease than the general population. Patients afflicted with chronic kidney disease and cardiovascular disease tend to have significantly worse prognoses than those suffering only from the latter.

CONGESTIVE HEART FAILURE

Heart failure is a cardiac condition, that occurs when a problem with the structure or function of the heart impairs its ability to supply sufficient blood flow to meet the body's needs.

Heart failure should not be confused with cardiac arrest. It can cause a large variety of symptoms (chiefly shortness of breath and ankle swelling) but some patients can be completely symptom free. Heart failure is often undiagnosed due to a lack of a universally agreed definition and challenges in definitive diagnosis, particularly in early stage. With appropriate therapy, heart failure can be managed in the majority of patients, but it is a potentially life threatening condition, and progressive disease is associated with an annual mortality of 10%.

It is the leading cause of hospitalization in people older than 65