Laboratory Module Flashcards
Hypernatremia
Cause: Impaired thirst mechanism
Uncontrollable water loss
Symptoms: Hyperreflexia, muscle twitching,
thirst, irritability, coma, death
Useful in determining the fluid balance and maintaining the appropriate transmembrane electrical potential in neuromuscular function
Hyponatremia
Severe dehydration
Water intake > output
DRUGS
Depressed reflexes, disorientation, muscle cramps, nausea
Also related to Neuromuscular function
K (potassium ions)
Responsible for the control of intracellular volume ; also related to protein synthesis, enzymatic reactions and carbohydrates metabolism
Hyperkalemia
Increased intake (Drugs, hemolysis, muscle damage, burns) Decreased output (Renal Failure, drugs) Extracellular shift (metabolic acidosis)
Arrythmias, hypotension, weakness, bradycardia, cardiac arrest
Hypokalemia
- *Decreased intake** (alcoholism, diets low in K, eating disorders)
- *Increased output** (drugs, laxatives, vomiting and diarrhea, Cushing syndrome)
- *Intracellular shift**: insulin administration ; alkalosis
Arrythmias, hypotension, weakness, muscle cramps
Hyperchloremia
Dehydration, acidemia
Limited to underlying disorder
Related to acid-base balance
Hypochloremia
Vomiting, alkalemia
Limited to underlying disorder
Hypermagnesemia
Over-repletion
Renal dysfunction
Bradycardia, sweating, hypocalcemia, drowsiness
Hypomagnesemia
Renal wasting
Alcohol abuse
Malnutrition
Diarrhea
Weakness, tremors, tetany,
Increased reflexes
Hypercalcemia
Malignancy
Hyperparathyroidism
Gastrointestinal complaints, neuromuscular symptoms
Hypocalcemia
DRUGS
Vitamin D deficiency
Hypoparathyroidism
Fatigue, memory loss, hallucinations, seizures, tetany
Hyperphosphatemia
Decreased excretion
Increased intake
Extracellular shift
Signs and symptoms of hypocalcemia and hyperparathyroidism
Hypophosphatemia
Increased excretion
Intracellular shift
Alcoholism
Malnutrition
Irritability CNS effects (drowsiness, difficulty thinking or cognition)
Hyperglycemia
Diabetes
Diet
DRUGS
Thirst (Polydipsia)
Urination (Polyuria)
Hypoglycemia
DRUGS
Sweating, trembling, palpitations, headache, confusion
SCr
is an endogenous marker of renal function
i. Inverse relationship with renal function
ii. Affected by: muscle mass, sex, age, race, drugs, assays, low-protein diets
iii. Reference range vs baseline
BUN
is used to assess or monitor hydration, renal function, and protein tolerance
BUN
High
Causes and Symptoms
High protein diet
Upper GI bleeds
DRUGS
Greater than 100mg/dL: high risk of uremic syndrome
Limited to underlying disorders
BUN
LOW
Causes and Symptoms
Malnourishment
Liver damage
Fluid overload
Limited to underlying disorders
BUN:Scr ratio
BUN:Scr ratio > 20:1 and elevated
Pre-renal causes: dehydration, blood loss, shock, severe heart failure
10:1 to 20:1 Intrinsic causes
Acute: drugs, severe hypertension, tubular necrosis Chronic: diabetes, pyelonephritis, renal tubular disease
RBC count
Normal range is decrease in adult females (blood loss during menstruation, but men have higher androgen levels that stimulate erythropoiesis)
Decreased in anemia (recommendations depend on types of anemia: iron deficiency, B12 deficiency, folic acid deficiency, hemolytic anemia, anemia of chronic disease, blood loss anemia)
Life span of 120 days
RBC Indices
tests that further describe RBCs
MCV – mean corpuscular volume – average volume; how large the blood cells are (macrocytic or microcytic anemia)
MCH – mean corpuscular hemoglobin- (amount of hemoglobin in the RBC- average)
MCHC – mean corpuscular hemoglobin concentration (amount of hemoglobin in the RBC as function of hematocrit- %volume)
RDW
and
Reticulocyte
RDW - RBC distribution width – indicates variation in size of RBC
Reticulocyte (immature RBC) count – indirect assessment of new RBC- precede mature RBC by 1-2days before they mature):
II. elevation occurs in acute blood loss b/c bone marrow trying to replenish RBC lost in the periphery)
ESR
Causes and Symptoms
Low and High
RBC usually settles slowly in plasma but will settle faster when there are changes in the electrostatic forces
ESR – erythrocyte sedimentation rate- rate RBC settles
- High
Causes: Pregnancy, Rheumatoid arthritis, Infection
Symptoms: Limited to associated disorder
- Low
Causes: Heart failure, High dose steroids, Liver disease
Symptoms: Limited to associated disorder
Hgb
–major content of RBC; carries O2 from lungs to the rest of body where it is then burned to create energy
II. - direct indication of oxygen-transport capacity of the blood
III. low in anemia (fatigue)
Hct
- percentage of blood composed of erythrocytes;
- Usually 3x the value of Hgb
- Decreased in anemia
WBC
- leukocytes (lymphocytes and granulocytes (which come from hematopoiesis)
High:
Causes: High Infection
Symptoms: Fever, chills
Low
Causes: Immune suppression
Symptoms: Limited to underlying disorder
Differential (CBC with Dif)
Left Shift – absolute increase in number of bands
Indicates an acute infection
Absolute Neutrophil Count (ANC)
ANC = [(WBC)(%PMN + %Bands)]/100%
ANC < 1500 indicates neutropenia (indicates risk of infection)
Caused by drugs (chemo) and by some diseases (HIV)
Diagnosing or predicting risk of thrombosis
d-dimer
- Primarily used to diagnose disseminated intravascular coagulation (DIC)
- Needs further study for other disorders
Monitoring anticoagulants
Normal INR in a non-anticoagulated patient: 1.0
Target INR/range for MOST indications: 2.5 (2-3)
Target INR for mitral valve replacement (MVR): 3 (2.5-3.5)
aPTT
Target aPTT: 1.5 to 2.5 times the control
Synthetic liver function
Albumin
Pre-albumin
- Shorter half-life (2 days)
- Smaller volume of distribution
- More sensitive to protein nutrition
- Less sensitive of liver disease and hydration
- Best test for assessing nutritional status (i.e. patients receiving TPN)
PT/INR
Total bilirubin = insoluble + soluble
= unconjugated + conjugated
= indirect + direct
Hepatocellular liver injury
False-positives: uremia, hemolysis, vigorous exercise
Medications: Rx, OTC, herbal STATINS
Unexplained: will usually return to normal
Inflammation of liver
- Specific histologic pattern in hepatocyte
- Multiple cause:
o Viral: Hep A, B, C, D, E, G
o Medication: majority are minor, transient, asymptomatic
o Fatty liver
Putting it all together (NEED TO KNOW)
AST/ALT >1000 International units/mL: acute viral hepatitis, severe drug/toxin reactions,
AST/ALT = 2 & GGT elevated: alcoholic hepatitis
Isolated increase in AST: cardiac or muscle damage
Elevated AST/ALT & elevated creatine kinase: muscle damage
Pancreatic function
>3-5 x ULN
Urinalysis
Macroscopic
Urinalysis
Microscopic
Cells
Casts – gives information about where the damage occurred
Urinalysis
Microscopic
Crystals
- Composed of uric acid, calcium phosphate, calcium oxalate, cystine
- Drug-induced: indinavir, sulfamethaxazole, ciprofloxacin
