Exam 1: CMP Flashcards
What 3 things can cause hypoglycemia?
Drugs, starvation, and endocrine disorders (Addisons and Hypopituitarism)
What two endocrine disorders can cause hyperglycemia?
Cushing and acromegaly
What is BUN?
A byproduct of protein metabolism
-BUN test indirectly measures the metabolic function of liver and excretory function of the kidney.
Is BUN increased or decreased in primary liver disease?
Decreased secondary to decreased urea synthesis
Is BUN increased or decreased in primary renal disease?
Increased, secondary to reduced urea excretion
How does hydration status affect BUN?
Dehydration concentrates BUN, so the level increases.
Overhydration dilutes BUN so the level decreases
How do GI bleeds affect BUN?
Blood overloads the gut with protein so levels increase
How does protein intake affect BUN?
Low protein diet decreases BUN and high protein diet increases BUN
What is creatinine?
A catabolic product of creatine phosphate that is excreted entirely by the kidney, thus a measurement of renal function
Creatinine has an inverse relationship with what?
GFR
What differentials can cause increased creatinine?
AKI, chronic kidney disease, rhabdomyolysis, and dehydration
What differentials can cause decreased levels of creatinine?
Debilitation, muscular dystrophy, and myasthenia Travis
What is BUN/Creatinine ratio helpful in determining?
Cause of AKI
What is a normal BUN/Cr ratio?
10-20/1
What are the 3 causes of AKI?
Prerenal, intrinsic renal, and post renal
What conditions cause prerenal AKI?
Hypovolemia, CHF, and change in vascular resistance
What conditions cause intrinsic AKI?
Acute tubular necrosis from IV contrast
What conditions cause postrenal AKI?
Urethral stones, bladder outlet obstruction, BPH, and urethral stricture
Shifts in chloride levels usually accompany shifts in ** and **
Sodium and bicarbonate
CO2 is an indirect measurement of what?
Bicarbonate
You use fractionation of total protein to diagnose, monitor, and evaluate what conditions?
Liver disease, edematous states, protein losing conditions, nutrition status, immune disorders, and cancer
What does the measure of albumin reflect?
Synthetic function of the liver
What does albumin do?
-Maintains osmotic pressure by keeping fluid within the vascular space and transporting hormones, enzymes, and drugs
Where is globulin produced?
Mainly bone marrow and lymph tissue
What are the 3 groups of globulins?
Alpha, beta, and gamma
When is globulin normally elevated?
When albumin is low to maintain normal total protein levels?
What makes up total protein?
Albumin + globulin
What conditions can cause hypoalbuminemia?
Liver disease, protein losing enteropathies, protein losing nephropathies (Nephrotic syndrome), burns, malnutrition, and inflammatory disease
What condition can result in normal total protein with low albumin and normal/increased globulin?
Chronic liver disease and collage vascular disease
What condition can cause increased total protein with increased globulin fraction?
Multiple myeloma (M spike and bence jones proteins)
What labs will be elevated if the condition in hepatocellular in pattern?
There is injury to the hepatocytes = elevated ALT and AST
What labs will be elevated if the condition is cholestatic in pattern?
There is injury to the bile ducts and/or bile flow = elevated ALP and total bili
Where is AST found?
Liver, cardiac and skeletal muscle, kidney, and brain
Where is ALT found?
Predominantly in the liver, small quantities in kidneys and cardiac and skeletal muscle
Is AST or ALT more specific to the liver?
ALT
Where is ALP found?
Predominantly in the liver, biliary tract, and bone
If ALP is the only elevated enzyme, what is the likely source?
Bone
What conditions can increase ALP?
Conditions that obstruct the flow of bile because it is excreted in the bile
What makes up total bilirubin?
Unconjugated (indirect) and conjugated (direct)
If AST and ALP are more elevated than ALP, what does that indicate, including differentials.
A hepatocellular process such as liver drug toxicity, viral hepatitis, alcoholic liver disease, NAFLD, cirrhosis, liver tumor, and genetic liver disorders
If ALP is more elevated than AST and ALP, what does that indicate?
Cholestatic process, such as biliary obstruction, hepatitis, cirrhosis, liver CA, and drug toxicity.
What is the most frequent extrahepatic source of ALP and what conditions cause this?
Bone is the most frequent source of elevated ALP, caused by physiologic growth, healing fracture, bone metastasis, etc.
What conditions can cause unconjugated bilirubin to be elevated?
Hemolysis, impaired hepatic bilirubin uptake (heart failure), and impaired bilirubin conjugation (Gilbert syndrome)
What conditions can cause conjugated bilirubin to be elevated?
Hepatitis, drugs and toxins, liver infiltration, and biliary obstruction
What will the LFTs look like with hepatocellular disease?
Disproportionately elevated AST and ALP when compared to ALP
-Serum bili may be elevated
What will the LFTs look like with cholestatic disease?
Disproportionate elevation in ALP when compared to ALT and AST
-Serum bili may be elevated
Calcium has an inverse relationship with ***.
Phosphorus
Although 99% of the body’s calcium is in bone, where is the majority of the remaining 1%?
Free ionized calcium
When serum albumin is low, what else will be low?
Calcium
What accounts for 90% of the cases of hypercalcemia?
Primary hyperparathyroidism and malignancy
What is the clinical presentation for hypercalcemia?
- Decreased neuromuscular excitability
- Cardiovascular effects
- nephrolithiasis, polydipsia, and polyuria
- constipation, N/V, anorexia
What is likely to be seen on EKG in a patient with hypercalcemia?
Short QT interval
What is the management for hypercalcemia?
Management of underlying cause, volume expansion, and calcitonin/bisphosphates
What is the most common cause of hypocalcemia?
Hypoalbuminemia
What should you do if the diagnosis of hypocalcemia is in doubt?
Check a corrected calcium (serum ionized calcium)
What conditions can cause hypocalcemia?
Hypoalbuminemia, hypomagnesemia, hypoparathyroidism, parathyroidectomy, renal failure, and intestinal malabsorption
How can hypomagnesemia cause hypocalcemia?
Mg deficiency inhibits parathyroid hormone activity, which is associated with refractory hypocalcemia
What is the clinical presentation of hypocalcemia?
- Increased neuromuscular excitability
- paresthesias, hyperactive reflexes
- Chvosteks sign
- Trousseaus sign
- cardiovascular effects
What is Chvosteks sign?
Tapping of the facial nerve against the bone just anterior to the ear results in contraction of the facial muscles
What EKG changes are you likely to see in a patient with hypocalcemia?
Prolonged QT
What is trousseaus sign?
Occluding the brachial artery for 3 minutes with BP cuff results in carpal spasms
What is the management for mild hypocalcemia?
Oral calcium and possible vitamins D supplementation
What is the management for severe and symptomatic hypocalcemia?
Give IV calcium Gluconate
What is the most important regulatory of serum phosphate?
The kidney
What conditions can cause hyperphosphatemia?
Renal failure (most common), hypoparathyroidism, hypocalcemia, and exogenous phosphorus
What conditions can cause hypophosphatemia?
Malnutrition, hyperparathyroidism, chronic alcoholism, severe vomiting and diarrhea, and cellular shift
What are the two kinds of cellular shift that can cause hypophosphatemia?
Insulin: insulin drives electrolytes into the cell
Refeeding syndrome: refeeding a malnourished patient too quickly causes intracellular shift
What is the clinical presentation of hypophosphatemia?
Muscle weakness, rhadomyolysis, and seizures
What two electrolytes are tied to Mg?
Calcium and potassium
How can hypomagnesemia cause hypocalcemia and hypokalemia?
Low Mg inhibits PTH which leads to hypocalcemia. Low Mg also impairs the ability of the kidney to conserve potassium
What conditions can cause hypermagnesemia?
Renal insuffiency and large Mg load
What conditions can cause hypomagnesemia?
Malnutrition, severe diarrhea, alcoholism, cellular shift
What is the clinical presentation of hypermagnesemia?
Decreased DTRs, bradycardia, and hypotension
What is the clinical presentation of hypomagnesemia?
Neuromuscular excitability and cardiac arrhythmias (Torsades De pointes)
What is the management of hypermagnesemia?
Cessation of magnesium containing mediations, isotonic fluids and loop diuretics, dialysis, and IV calcium
