A recent review of the health benefits of vitamin D has been published in the clinical journal of the american society of nephrology. It was based on the growing body of evidence that has pointed to the role of vitamin d in improving health and quality of life in patients with diverse health problems.

The review noted that numerous publications have described deficiencies of vitamin D in the general population in association with latitude, age and season based on the availability of different levels of sun exposure and quality of sunlight arriving at the skin which is a necessary step in the formation of vitamin D.

Deficiencies of vitamin D has been associated with higher levels of PTH. PTH is a hormone well known in the end stage renal disease community as it is important both in cardiovascular disease and bone disease as well many other systems in a manner that is not yet entirely clear.

The studies cited in this review focused on the general population where low vitamin D levels have been associated with calcification of blood vessels in the heart, and increased levels of risk for cardiovascular disease.

Infection of the kidney usually occurs as a consequence of an ascending urinary tract infection or UTI. The bacteria gain access to the bladder and multiply overcoming the defenses of the host and migrating up to the kidney where they produce the syndrome of pyelonephritis or kidney infection.

When a simple urinary tract infection ascends to become a kidney infection there is usually worsening of the fever and generalized weakness and lethargy associated with back pain and vomiting. There may also be tenderness of the back over the kidneys which are approximately mid way up the back on either side of the spine. The pain produced by tapping over this area is usually excruciating in nature. A severe kidney infection may also spread to the lungs and produces symptoms of pneumonia in some cases. Once the infection enters the blood stream the kidney infection is said to have caused sepsis. Sepsis is both the presence of the infecting bacteria within the blood as well as the reaction of the body to the bacteria which is usually associated with increased respiratory rate, increased pulse rate and decreased blood pressure.

Women are at increased risk of kidney infections as they have a higher overall prevalance of urinary tract infection. Because men are not predisposed to urinary tract infection the presence of a kidney infection should prompt a detailed search for the cause of the infection as it is not unusual to find an anatomical abnormality that has caused the kidney infection in a male or the presence of kidney stones.

Recurrent kidney infection in either sex should result in a detailed investigation of the urinary tract. The goal being to correct any abnormality predisposing to kidney infection. Thus preventing permanent kidney damage from the repeated healing of the inflammation produced by bacteria.

Shortness of breath or breathlessness is a common kidney symptom in advanced renal failure. The presence of breathlessness may be multifactorial. Retention of fluid may result in fluid accumulating within the lungs and reducing the available area for exchange of gases such as oxygen giving rise to the sensation of being unable to catch your breath. This is called pulmonary oedema and may occur as a direct consequence of fluid retention or as a result of another cardiovascular disease such as fluid around the heart due to renal failure, myocardial infarction or heart attack. Angina or an arrythmia which is an unusual and bizarre beating of the heart both may result in diminished ability of the heart to pump. This can be further worsened by anemia which is common in advanced kidney disease.

Chest pain is usually associated with ischemic heart disease such as a heart attack or angina. However chest pain may occur as a symptom of kidney disease. Chest pain occurring due to renal failure implies an inflammation of the tissues around the heart known as pericarditis. Pericarditis under these circumstances is quite dangerous as the inflammation of the lining of the heart that occurs results in fluid building up around the heart and compressing it preventing normal function. This can be a fatal complication, drainage of the fluid usually results in recollection of the fluid quickly. The best treatment if this is suspected is urgent dialysis. Frequently the patient will need three sessions of dialysis in rapid sequence to gain control of the situation and resolve the chest pain.

Swelling of the feet is also known as pedal oedema this occurs primarily in kidney disease because of retention of fluid. The kidney is responsible for several functions. When the ability of the kidney to remove fluid from the body is decreased fluid is retained. The increased fluids within the blood vessels eventually leak through the walls of the smallest capillaries and enter the soft and sponge like tissues beneath the skin known as the subcutaneous tissue giving rise to the symptom of swelling. Due to the fact that fluid always settles in a dependent position the swelling is usually observed to be in the lower limbs if the patient is standing or around the waste and back if sitting or lying down. Very severe cases of swelling may be seen with swelling of the entire body a situation known as anasarca. This symptom usually occurs in very severe kidney disease or in cases where there is retention of fluid due to losses of protein in the urine.

It is difficult to conceptualize at first that loss of protein in the urine may lead to retention of fluid within the body. However one of the roles of protein is to provide one of the main constituents of blood. This constituent is known as albumin the same albumin that is found in egg white. This protein attracts fluid to itself therefore the more albumin you have in your blood stream the more fluid will want to be attracted to and remain within the blood vessel. If the albumin levels within the blood are low then the fluid will be less attracted to remain within the blood vessels and instead will leak wherever there is a pressure difference such as in the loose tissues beneath the skin where there is relatively low pressure and a willingness to expand to accommodate fluid.

Nephrotic syndrome is a type of kidney disease where there are large quantities of protein leaking into the urine. The first symptom of kidney disease noted in these patients is usually swelling of the feet.

A study of 100 dialysis patients reported in the clinical journal of the american society of nephrology found that up to 51% of patients experienced chronic pain on hemodialysis. Pain derived from muscle and bone was the most prominent reported cause of pain. Headache was also very common and usually restricted to the dialysis sessions. However some patients did develop chronic headache as well. While patients with diabetic nerve damage of any kind were more likely to have pain on haemodialysis.

Patients with diabetes and chronic pain were most likely to have low vitamin d levels as well as low levels of parathyroid hormone (PTH). This correlation may imply that PTH and Vitamin D may play some role in the pathology of pain in these patients. This was further corroborated by the fact that calcium, which is closely regulated by both vitamin D and PTH, was an independent risk factor for chronic pain. Higher calcium levels were very significant for greater degrees of pain along with higher levels of PTH even if within the range considered normal for haemodialysis patients.

The correlation between pain and mineral metabolism of calcium is very interesting as PTH vitamin D and calcium are very closely related in the maintenance of good bone health on dialysis. It is already well known that disturbances of this important axis of hormones may lead to severe bone disease. However a new role in chronic pain for these markers may need to be explored by further studies.

Acetylsalicylic acid otherwise known as aspirin was a major advance in the treatment of inflammation when it was first discovered in 1853. The chemical compound had been used for centuires before that however in the form of bark and herbs which were found by early man to be helpful for the relief of pain.

NEGATIVE EFFECTS ON THE KIDNEY.

Aspirin reduces renal blood flow this is not usually a problem in a healthy person however in a patient who already has decreased blood volume such as patients with dehydration or blood loss this could precipitate acute renal failure. Several types of kidney disease unified by the loss of protein in the urine, may produce a relative low volume state. Despite the obvious retention of fluid in the skin of the feet and around the eyes, the blood vessels are depleted and hence the kidney is also starved for fluid. In such a setting aspirin will further cause reduction of renal blood flow and tip the patient over into acute renal failure.

Aspirin is an anti inflammatory agent yet it was on the causes of inflammation of the tissues of the kidney a state called an allergic interstitial nephritis. Patients with this disorder may have a skin reaction after administration of aspirin followed by high blood pressure abnormal kidney function and decreased urination, thank fully it is usually self limited.

Aspirin has the effect of reducing the flow of blood through the kidney in the areas responsible for filtration. While this may not sound to be a good thing this effect is similar to the effect of angiotensin converting inhibitors or ACEI which are prescribed for delaying progression of renal disease. This effect of aspirin is particularly useful in patients with high degrees of protein loss in the urine. Reduction of pressure within the kidney will lead to decreased filtration of protein by the kidney. Hence at one time aspirin was one of the major drugs used in the treatment of membranous nephropathy and other causes of nephrotic syndrome. The drug has fallen out of use for this indication however because of the negative effects on kidney function produced by aspirin. Inflammatory conditions of the kidney were also thought to be treatable by aspirin, conditions such as membranoproliferative glomerulonephritis which is a very rare form of inflammation of the kidney. However all recent trials have discounted any protective effect of aspirin in this and similar conditions.

Although an anti inflammatory agent aspirin has no role in the treatment of inflammatory disorders of the kidney. At this time superior antiinflammatory agents with less negative effects on the kidney are available.

In a recent study published in the annals of internal medicine, researchers from Italy followed 215 patients who were overweight and found that a low carbohydrate diet (called the mediterranean diet which obtained less than 50% of calories from carbohydrates) was superior for the control of glucose levels in type 2 diabetics.

Unfortunately this study did not have an index of the degree of atherosclerosis present in both groups. This would have been helpful as low carbohydrate diets have recently been found to increases the risk of atherosclerosis despite improvements in cholesterol levels. This risk has been postulated to be based on inability to repair damage caused during the process of atherosclerosis. It seems that carbohydrates may be needed to jump start the repair process in normal people.