Biochemistry Flashcards
What does PP mean?
Increased/excessive appetite
What does PU mean?
Polyuria
What does WL mean?
Weight loss
What does PD mean?
Polydipsia
What is Azotaemia?
Azotaemia is a medical condition characterized by abnormally high levels of nitrogen-containing compounds (such as urea, creatinine, various body waste compounds, and other nitrogen-rich compounds) in the blood. It is largely related to insufficient or dysfunctional filtering of blood by the kidneys. It can lead to uraemia and acute kidney injury (kidney failure) if not controlled
What is Uraemia?
Uraemia is the condition of having high levels of urea in the blood. Urea is one of the primary components of urine. It can be defined as an excess of amino acid and protein metabolism end products, such as urea and creatinine, in the blood that would be normally excreted in the urine.
What do the kidneys do?
Regulates blood pressure, blood sugar, blood volume, water composition in the blood, and pH levels.
What is urea?
Produced from the breakdown of proteins and is normally partially excreted in the kidneys
What is creatinine?
Produced as the result of normal muscle metabolism and filtered freely through the glomerulus and is not reabsorbed in the tubules
What are the pre-renal causes of azotaemia?
Reduced blood flow to the kidneys due to dehydration, haemorrhage, heart failure, toxins, illness, medications.
Usually nothing wrong with the kidney itself.
What are the renal causes of azotaemia?
The kidneys are not working = reduction of GFR to less than or equal to 25% of normal (chronic or acute renal failure).
What are the post-renal causes of azotaemia?
After leaving the kidneys successfully urinary waste products cannot exit the body E.g. Urethral obstruction, ruptured ureter or bladder (uroabdomen).
What are the diagnostic features of pre-renal azotaemia?
Presence of azotaemia with a urine specific gravity that is greater than or equal to 1.030 in dogs or greater than or equal to 1.035 in cats.
BUN, CRE, TP, PCV, USG = ^
What are the diagnostic features of renal azotaemia?
Presence of mild to marked azotaemia with a urine specific gravity that is less than 1.030 in dogs and less than 1.035 in cats (often in the isosthenuric range: 1.007-1.015)
BUN, CRE, = ^
TP, PCV, USG = v
What are the diagnostic features of post-renal azotaemia?
Presence of a mild to marked azotaemia, a variable urine specific gravity and clinical signs of obstruction (ie. Distended, turgid urinary bladder)or urine leakage (distended, fluid-filled abdomen or lack of bladder filling)
BUN, CRE, TP = ^
PCV = Normal
USG = No sample
What is the most sensitive liver enzyme to test?
ALT, it is found in liver cells.
What is released from RBC breakdown and seen in high amounts from IMHA?
Bilirubin
What is EPO?
It is a hormone secreted by the kidneys, this hormone signals the production of red blood cells.
What is acidosis?
Blood pH is too high, acidic blood.
Normal levels of blood glucose are…
6-8, slightly higher is likely from stress.
What does ALP stand for and what is it?
Alkaline Phosphatase. It is an enzyme found in the liver, intestinal mucosa, bone, kidney, placenta, leukocytes.
What does ALT stand for and what is it?
Alanine Aminotransferase. Enzymes that detect liver injury: These enzymes are found in the liver cells and leak out with injury to hepatocytes or biliary cells.
What does increased ALP indicate?
- Increased results from increased production by cells of the bile canaliculi rather than from leakage.
- High in large, growing young dogs and dogs with osteosarcoma
- Hyperadrenocorticism can cause HUGE increases
- In cats, increases in cholestatic disease (blocked bile flow in liver) such as cholangiohepatitis (inflamed liver and bile ducts), hepatic lipidosis, lymphoma
- Can rise in biliary disease and GGT will be high as well
What does increased ALT indicate?
- leaks into circulation from damaged hepatocytes. Marked increase = severe liver insult
- Mild increase = less severe insult or chronic disease
- Also found in muscle cells but AST and CK are typically elevated to a much higher degree with muscle damage
- Haemolysis will give a falsely high reading
What is renal failure?
It’s when excretory and renal endocrine function can’t maintain homeostasis.
What is BUN?
Determines the ability of the renal filtration system to remove this waste product of protein metabolism from the blood stream. Urea, which is the principle waste product of the body’s protein metabolism, is hard to determine in the laboratory. The blood concentration of urea nitrogen is proportional to the protein content of the diet and renal excretory capacity of the animal.
What does BUN stand for?
Blood Urea Nitrogen
What are the symptoms of azotaemia?
Symptoms often occur gradually over an extended period of time:
-Vomiting and lethargy
-Diarrhoea or Constipation
-Depression and Weight loss
-Increased thirst and lack of appetite (anorexia)
-Acute blindness, seizures and comas
-Blood in the urine (haematuria)
-An increase in the frequency and amount of urination
What things increase BUN?
Increased values can be seen with dehydration, urinary obstruction, uraemia, nephritis, surgical shock and intestinal obstruction. Intestinal bleeding may also increase the BUN.
What things decrease BUN?
Acute liver failure and intestinal disease. Because this value is related to protein metabolism, it is very dynamic and can change quickly based on changes in the diet as well as the condition of the kidneys.
What are the causes of increased urea?
High-protein diet
Tissue catabolism
GI haemorrhage
Drugs (Corticosteroids)
What is a promising marker for early kidney disease?
Symmetric dimethylarginine (SDMA) is a small molecule formed by methylation of arginine, and released into blood during protein degradation. SDMA is primarily eliminated by renal excretion and is a promising endogenous marker of glomerular filtration rate (GFR)
When GFR goes down through kidney Dz the SDMA goes up followed by CRE, followed by BUN. Somewhere during this process the USG goes down
Most useful when trying to decide if kidney Dz is present in the very early stages. Often used as a tie-breaker when values contradict
“This test, especially when run spontaneously by the lab as a promotional practice, is a classic example of how inappropriate screening can lead to overdiagnosis. When the prior probability of the disease is low, then the positive predictive value of the test is low. And when there is no intervention proven to alter the long-term outcome of a positive screening test, it is considered unethical to offer the test in human medicine because all we accomplish is to create anxiety. Effective screening which actually reduces morbidity and mortality requires adequate information and planning, which rarely seem available when such tests are introduced in vet med.” anonymous but not alone
What are the functions of the liver?
- Removes potentially toxic byproducts of some medications
- Prevents shortages of nutrients by storing vitamins. minerals and sugar
- Metabolizes/breaks down nutrients from food to produce energy when needed
- Produces most proteins needed by the body
- Helps your body fight infection by removing bacteria from the blood.
- Produces most of the substances that regulate blood clotting
- Produces bile a compound needed to digest fat and to absorb vitamins A, D, E and K.
What are the clinical signs of liver disease?
- Icterus (jaundice)
- Vomiting and diarrhoea (GI irritation)
- Hypersalivation (cats)
- Ascites (free abdominal fluid)
- Haemorrhage / petechiae (lack of production of coagulation factors)
- Anorexia/weight loss
What should be known about Bilirubin?
- Derived from RBC breakdown and excreted in bile
- Serum indicator of reduced hepatic function and cholestasis = accumulates in blood during cholestasis and spills into urine = bilirubinuria
- Seen with haemolytic anaemia
- In cats, mild INCREASE may accompany anorexia or severe inflammatory disease
What should be known about Albumin?
- Produced by the liver
- low Albumin = Hypoalbuminaemia decreased synthesis, inhibition of albumin release and increased volume of distribution with ascites
- high Albumin = Hyperalbuminaemia dehydration and hyperproteinaemia in acute liver disease
What should be known about Glucose?
- Decrease occurs with severe hepatic dysfunction
- Increase is only seen in end-stage liver disease or massive necrosis and puppies with portosystemic shunt.
What should be known about AST?
- Present in hepatocytes and skeletal muscle cells
- Often elevated following muscle injury
- When ALT levels are normal in the same blood sample, this indicates RBC destruction = haemolysed blood sample
What should be known about GGT?
- Marked increase = bile flow in liver is blocked (cholestasis), bile duct obstruction, liver tumours, pancreatic inflammation in cats
- Not on Gribbles form but shows up on IDEXX (REM Liver profile)
- Very sensitive for detecting liver damage (cholestasis) in cats (except for hepatic lipidosis = not that elevated)
What should be known about Cholesterol?
- Made in the liver
- Aids intestinal digestion and fat absorption
- May DECREASE in severe liver disease or portosystemic shunt
- May INCREASES in cholestasis
- DECREASES with malabsorption and protein-losing enteropathy
- INCREASES in hypothyroidism, diabetes mellitus, hyperadrenocorticism, nephrotic syndrome, acute pancreatitis
- Most common cause of HIGH cholesterol is collecting a post-prandial blood sample
What should be known about BUN?
- Ammonia comes from protein breakdown in the gut and is taken up by liver to be converted to urea
- Ammonia INCREASES with severe liver disease and porto-systemic shunt as it’s not removed by the liver = blood urea concentration is LOW in these animals (because liver not converting Ammonia to Urea)
- Ammonia is hard to analyse = volatile
When are liver function tests indicated?
For animals with suspected hepatic disease but normal serum hepatic enzyme concentrations, animals with increased serum enzyme concentrations but no clinical signs of hepatic disease, and evaluation of disease progression or response to treatment
