What is Chronic Kidney Disease?

Chronic Kidney Disease (CKD) is an alteration in the normal function of the kidneys caused by a chronic process and it is usually not reversible. Functionally, the kidney tissue is less capable of performing its functions which include: the filtration of blood, the control of the acid base status, electrolyte concentration control, fluid and blood pressure management, generation of erythropoietin for red blood cell production and  activation of vitamin D.

The processes that most commonly result in CKD are persistent uncontrolled hyperglycemia from diabetes mellitus, persistently elevated blood pressures, acute or subacute inflammatory conditions of the kidneys and genetically mediated anatomic abnormalities such as polycystic kidney disease (PKD). These processes result in scarring and fibrosis of the kidney tissue, with loss of renal cells in the cortex and medullary portions of the kidneys. 

Chronic kidney disease is usually classified in stages, going from I to V. The function that has been chosen to  assign the stages is the filtration function, measured as a variable called glomerular filtration rate (GFR). Although the kidney has many different functions, they are related to each other. The relationship is not perfect, but is is safe to say that if there is a reduction on the filtration function function of the kidneys, the other functions will be affected, in variable degrees. It is also possible that certain functions of the kidney may be affected with little change in other functions, for example, there are conditions that involve abnormalities in the handling of potassium or acidity without a change in the filtration function or generation of erythropoietin, however, these conditions are not too common.

The final stage of CKD is called end-stage renal disease (ESRD). At this stage, renal replacement therapy (RRT) becomes necessary. RRT includes dialysis (in its different modalities) and renal transplantation.

Marco A. Ramos MD

5 Possible Consequences of Uncontrolled High Blood Pressure

Uncontrolled high blood pressure (hypertension) is associated with several health conditions. Hypertension is treatable, so this means that the following diseases can be prevented or delayed. 

1. Heart attacks. Elevated blood pressure is related to atherosclerosis, which, by narrowing the coronary arteries, can lead to heart attacks. Heart attacks can cause congestive heart failure and sudden death. 

2. Impaired vision. Hypertension can cause something called hypertensive retinopathy. This means that the retina (where the images are formed in the eye) can get damaged by chronic high blood pressure and can lead to impaired vision and blindness.

3. Amputation of limbs. High blood pressure can lead to the amputations of limbs, specially feet and legs. The problem starts with the atherosclerosis in the arteries of the limbs which eventually leads to obstruction and lack of blood supply to the feet and legs, especially. Hypertension is related to the atherosclerosis of the limb arteries, just as with the heart.

4. Stroke. The brain can also be the victim of atherosclerosis, which is related with hypertension (as we have just seen). In addition to this, if the blood pressure becomes too high, it can lead to bleeding inside the brain, by rupture of the arteries.

5. Kidney disease. The kidneys are very sensitive. Elevated blood pressure for a long time can cause scarring of the kidney tissue to the point that it cannot perform its functions anymore. The kidneys are important for sodium and potassium control, blood pressure control, generation of red blood cells, vitamin D and calcium metabolism and acid-base balance.

Marco A. Ramos MD

7 Interesting Facts About Vitamin D That You Were Probably Not Aware Of

1. Vitamin D is not a vitamin. It is a hormone. it is structurally related to steroids and has intracellular receptors. It does not function as a cofactor in biochemical reactions like vitamins¹.

2. There is a link between vitamin D deficiency and seasonal affective disorder (SAD), a form of depression which happens more often in winter months². 

3. Vitamin D is produced in the the skin (from the interaction with sunlight) and undergoes 2 modifications, one in the liver and another one in the kidney in order to achieve its full effects.

4. There are receptors for vitamin D, almost in every cellular type of the body. Intestines, bones, brain, kidneys are just examples of organs where vitamin D has an effect.

5. Darker skinned people are more vitamin D deficient than lighter skin people. Also, people living north (or south) of the 30th parallel are more deficient than those who do not.

6. There are significant associations between vitamin D deficiency and cancer, specially colorectal, breast and prostate cancers^3,4,5.

7. There is an association between all-cause mortality and low levels of vitamin D⁶.

References

1. Vitamin D: A Hormone for All Seasons - How much is enough? Understanding the New Pressures. Morris H. The Clinical Biochemist Review. 2005; 26(1): 21–32.

2. Association Between Low Serum 25-Hydroxyvitamin D and Depression in a Large Sample of Healthy Adults: The Cooper Center Longitudinal Study. Hoang, MinhTu T. et al. Mayo Clinic Proceedings. 2011;86(11): 1050-1055

3. Association between vitamin D and risk of colorectal cancer: a systematic review of prospective studies. Ma Y, Zhang P, Wang F, et al. Journal of Clinical Oncology. 2011;29(28): 3775-3782.

4. Vitamin D Deficiency Predicts Prostate Biopsy Outcomes. Murphy AB. Clinical Cancer Research. 2014;20(9): 2289–2299.

5. Vitamin D and Reduced Risk of Breast Cancer: A Population-Based Case-Control Study. Knight JA et al. Cancer Epidemiology Biomarkers Prevention. 2007;16(3):422–429

6. Meta-analysis of All-Cause Mortality According to Serum 25-Hydroxyvitamin D. Garland CF et al. American Journal of Public Health. 2014;104(8): e43-e50.

Marco A. Ramos MD

3 Common Ways Kidneys Get Damaged Acutely

The kidneys are very delicate organs. As it can be seen in a previous post, they are in charge of many different functions and need to have a good supply of blood at all times in order to perform appropriately. 

1. The most common reason the kidneys get damaged is when the blood supply decreases. This happens when an individual loses fluids through diarrhea, vomiting and does not replenish its fluids with salt-containing fluids. 

2. Certain pain medications, can affect the internal blood flow of the kidneys. If these medications are taken and the body is not adequately hydrated the blood flow to the kidney cells can severely decrease and cause kidney damage. The type of pain medications belong to a category called non-steroidal anti-inflammatory drugs. Common examples of them are ibuprofen, naproxen and ketorolac. Other medications, taken when the body is not well hydrated can also damage the kidneys these include diuretics and blood pressure medications called ACE-inhibitors (examples: captopril, lisinopril, enalapril) and angiotensin receptor blockers (examples losartan, valsartan, irbesartan).

3. Finally, the kidneys can get damaged by a substance that is necessary for certain diagnostic procedures. The use of radiocontrast for coronary angiograpahies or CT scans can damage the kidneys if they are already chronically damaged or if the patient is not adequately hydrated.

There are other causes for acute kidney damage. The post concentrates in the common ones.

All these causes are usually temporary and the faster they are corrected, the better the chances of avoiding longer damage. Whenever there is a change in the level of fluids a body, the balance has to be restored. Do not hesitate to talk to your doctor or go the the closest Emergency Department if you feel at risk.

Marco A. Ramos MD

How to Correctly Rehydrate a Person

How to Correctly Rehydrate a Person

Dehydration can occur due to many reasons. The most common reasons to become dehydrated are vomiting, diarrhea and lack of oral intake. Doctors prefer to use the term “intravascular volume depletion”, however, it sounds too long and complicated. For the sake of simplicity I will consider “dehydration” and “intravascular volume depletion” equivalent terms.

Many people believe that drinking water or beverages like juices or tea are good to rehydrate a dehydrated person. The problem is that when someone becomes dehydrated he or she loses salts together with water. The content of salts in the above mentioned solutions is minimal. As a consequence of that, the body loses salts and water and gets back water. The sodium (the main electrolyte in the extracellular fluid) becomes diluted. Too much sodium dilution can cause problems like headaches and lack of balance. Severe sodium dilution can cause seizures and death.

In addition to what I have just mentioned, when the body is dehydrated, there is a hormone called anti-diuretic hormone (ADH) which is secreted. This hormone does not allow water to leave the body. This can have the effect of diluting further the sodium in the body. This is why, we need the right amount of salts when rehydrating.

There are over the counter solutions available can can help with the rehydration process. A good salty broth can also do the trick. However, if the dehydration is severe and vomiting does not allow proper oral rehydration, you might need to go to the closest emergency department before there is kidney failure or before you collapse

Marco A. Ramos MD

The Importance of Organ Donation

Organ donation is extremely important. Many people are currently in waiting lists for kidney, liver, heart, lung, pancreas and intestine transplants. A significant percentage of these patients, pass away before receiving the transplant.

The situation for every organ is different. While people in need for a kidney transplant or a liver transplant can receive an organ (or part of it) from a living donor (provided that the donor is immunologically compatible with the recipient), the other organs need the donor to be a deceased person. Also, while people with kidney insufficiency can undergo dialysis treatments while waiting for a kidney transplant, the situation is different for the other organs because besides medical treatment, there is no effective way of replacing the organ functions. 

How to become an organ donor? There are a couple of ways. Any person, at the time of registering for an state ID or (renewing it) can register as an organ donor. In addition, there are state organ donation registries, accessible through the internet. It is important to carry a card that can provide consent for a donation of organs in the event of sudden death. Living donation is also possible in the event of a friend or relative needing an organ. There are also “paired donation programs” by which, in the event the donor is not compatible with the intended recipient, there could be a “cross donation” by which an organ will be given to a compatible recipient provided that this recipient has a donor compatible with the first recipient.

There are medical conditions that a living donor must not have in order to qualify to donate an organ . These are HIV disease, diabetes mellitus, malignancies or any chronic infectious problem. Also, the donor must not have any condition that may be worsened by organ donation like, for example, chronic kidney disease.

Finally, it is important to say that for the transplant recipient, the problems are not over after receiving the donated organ. They have to continue with lifelong immunosuppressive therapy which has risks of their own. However, overall, it is a second chance for enjoying life.

For further information visit: www.organdonor.gov

Marco A. Ramos MD

The Many Functions of the Kidney

The kidney has many vital functions. They can be altered by disease, trauma, medications or intoxications. Although the kidney is widely recognized as the organ which “makes urine” and in the process “cleaning the body from unnecessary substances”, it has many other functions.

The kidney regulates the level of fluid the body has. This function is closely tied with the regulation of the sodium and water contents of the body and with the blood pressure control. If this property fails, the could be high blood pressure, low blood pressure, high sodium or low sodium levels in the blood.

The body is alive because it can keep a tightly regulated pH (or acid-base status). If the blood pH drops below 6.8 or goes higher than 7.6 life is not sustainable. The kidney (together with the lung) is key in the control of the blood acid-base status.

The body needs a sensor to be able to create more red blood cells when they are needed. This sensor is the kidney. There is a hormone called erythropoietin which is secreted when there are less red blood cells or when the blood carries less oxygen.

The bone metabolism needs the kidney to produce activated vitamin D. This hormone is essential for the absorption of calcium from the intestine and to suppress another hormone called PTH, which if not suppressed it can lead to loss of bone mass and loss of phosphorus though the urine.

The body needs to keep a tight control of the potassium concentration in the extracellular fluid. The kidney is in charge to determine how much potassium should be allowed in the urine and how much should be retained.

The kidney has to be able to filtrate certain substances and to keep others. If the kidney were to let all substances be filtered, we would lose important proteins such as albumin and immunoglobulins (antibodies) though the urine.

By doing this quick summary, it is obvious that the kidney is a complex organ. The available forms of dialysis do a good job trying to mimic the function of the kidney, however, they are far away from perfect. The proof of this is how much better the results of kidney transplantation are compared to the results of dialysis.

Marco A. Ramos MD