Chronic kidney disease Flashcards
What is chronic kidney disease?
This is a broad term for the gradual loss of kidney function over a period of months or years.
What do your kidneys do?
Your kidneys regulate your blood contents by removing waste, steadying electrolyte levels, and regulating water.
How does CKD affect the body?
-Normally urea in the blood gets excreted in the urine, but with CKD there is a decrease in the glomerular filtration rate meaning there is less urea being excreted into the urine and more in the blood, causing azotaemia. This causes symptoms like nausea and loss of appetite. If this becomes too much it can damage the central nervous system causing tremors, comas, and death. This can also cause pericarditis, which is the inflammation of the heart lining, leading to heart failure and CHD.
-The kidney helps with potassium excretion, meaning if someone has CKD, they will secrete less potassium meaning there will be more in the blood. This can lead to hyperkalaemia which can cause cardiac arrhythmia.
-The kidneys also balance calcium levels, which activate vitamin D. Vitamin D increases your calcium absorption, meaning there will be less Vitamin D activated and therefore less calcium in the blood. This is called hypocalcaemia, as the calcium in the blood decreases. Due to this the bones lose calcium making them weak and brittle.
What causes CKD?
CKD is usually a result of other conditions that put a strain on the kidneys, damaging the capillaries and glomerulus.
This interferes with ultrafiltration and absorption.
This can be caused by:
• hypertension
• diabetes
• lupus
• rheumatoid arthritis
• kidney inflammation (glomerulonephritis)
• high cholesterol
• kidney infections
• autosomal dominant polycystic kidney disease
• regular use of medications like lithium for bipolar disorder and non-steroidal anti inflammatory drugs.
How does hypertension cause CKD?
When your blood pressure is high the walls of your arteries thicken to withstand the pressure.
This narrows the lumen meaning there will be less oxygen and blood delivered to the kidneys, causing ischemic injury to the nephron’s glomerulus.
Due to this, immune cells such as foam cells slip into the damaged glomerulus and secrete growth factors.
This causes mesangial cells to regress to mesangioblasts, their more immature stem cell stage.
These mesangioblasts then secrete extra cellular structural matrix, leading to glomerulus sclerosis (the hardening and scaring of the glomerulus), eliminating the nephrons ability to filter blood which will cause chronic kidney disease over time.
How does diabetes cause CKD?
The excess glucose in the blood starts sticking to proteins, through glycation which affects the efferent arteriole by making it stiff and narrow.
This makes it hard for blood to leave the glomerulus, upping the pressure in the glomerulus.
This causes hyperfiltration, where more fluid is pushed through the glomerulus.
Due to the high blood pressure mesangial; cells secrete more structural matrix, expanding the glomerulus causing glomerulus sclerosis which diminishes the nephrons’ ability to filtering ability which will lead to chronic kidney disease over time.
How do you diagnose CKD?
When diagnosing CKD a change in the glomerular filtrate rate will indicate a decrease in kidney function. CKD is then confirmed by a kidney biopsy to look for glomerulosclerosis.
How do you treat CKD?
CKD is irreversible, so treatments are used to stabilise and stop the condition from worsening.
Treatments include:
• managing the underlying cause
• go on kidney dialysis
• get a transplant
• stop smoking to stop the condition from worsening
• avoid regular use of anti-inflammatory pain killers
• eat a healthy and balanced diet
• restrict you salt intake (less than 6g a day)
• BP medication
• cholesterol control
• potassium management.
What are ACE inhibitors and why are they used to treat patients with CKD?
Angiotensin converting enzyme inhibitors are medications for high blood pressure.
Examples include ramipril, enalapril and lisinopril.
Blood pressure control helps to protect your kidneys from further damage.
The side effects include a dry cough, dizziness, tiredness, and headaches.
What are statins and why are they used to treat patients with CKD?
Atorvastatin and simvastatin are both statins.
CKD puts you at a higher risk of developing heart disease, causing strokes and heart attacks.
This is because some of their causes are similar, like high blood pressure and cholesterol.
Statins reduce the amount of cholesterol made by the liver helping the liver to remove cholesterol already in the blood, so your arteries do not clog.
Side effects include headaches, sickness, constipation, diarrhoea and muscle or joint pain.
Why should you not give a patient with CKD certain high blood pressure medications?
Certain medications used to treat high blood pressure, will also increase your potassium levels so they should be avoided.
This is as-well as potassium supplements.
What % of the population does CKD affect?
It affects around 10% of the population worldwide.
In 2017, this was over 843 million people and in 2015 it causes 1.2 million deaths.
How does high cholesterol cause CKD?
High cholesterol can cause a build up of fatty deposits in the blood vessels supplying the kidneys, making it harder for them to work properly.
What is autosomal dominant polycystic kidney disease?
An inherited condition where cysts develop in the kidneys.
What are the symptoms of CKD?
In early stages it can be asymptomatic. As kidney function worsens various symptoms may be experienced:
• swelling of ankles, feet and hands caused by increased water retention. in extreme cases this can cause pulmonary oedema, which is an accumulation of fluid in the lungs.
• tiredness
• shortness of breath
• blood in urine
