lab

//Rules of Thumb: You always need to consider volume status when interpreting labs - volume overload ("hyperaquemia") will lead to dilution of electrolytes, making everything seem low. Similarly, volume depleted patients will seem to have elevated levels of everything. Different attendings have different levels of concern regarding electrolyte imbalances. The lists that follow are intended to give you a general idea of issues that are potentially pertinent, but they certainly aren't exhaustive - you need to think about whatever is happening with the specific patient in front of you.// Na+ (hyponatremia): nl=140. Low < 135 mEq/L. Worry < 125. Na+ (hypernatremia): nl=140. High > 144 mEq/L. Worry > 150. K+ (hypokalemia): nl=4-4.5. Low < 3.3 mEq/L. K+ (hyperkalemia): nl=4-4.5. High > 4.9 mEq/L. Cl- (hypochloremia): nl=100. Cl- (hyperchloremia): nl=100 Bicarbonate: nl=26 in METABOLIC ACIDOSIS. Also seen in respiratory alkalosis as compensatory mechanism. Seen in DKA, HONK, heat stroke. See mnemonic section for good list. in METABOLIC ALKALOSIS. Also seen in respiratory acidosis as compensatory mechanism. BUN (blood urea nitrogen): nl=8-18. in liver disease, malnutrition, pregnancy, celiac disease in GFR, renal insufficiency, drugs (antibiotics, diuretics, steroids), ATN, dehydration, GI bleeding, heat stroke, cirrhosis, pancreatitis. Increases ~ 20-40/day in acute post-renal or intrarenal disorders. Creatinine: nl=0.6-1.2 in muscle mass (old age, muscle wasting), pregnancy in GFR, renal insufficiency, ATN, UTI, DKA, heat stroke, rhabdomyolysis. Increases ~ 2-4/day in acute post-renal or intrarenal disorders. BUN/Creatinine Ratio: In prerenal disorders becomes >10:1. Glucose (hypoglycemia): nl <125. nl fasting <110, >70. Low <70. Glucose (hyperglycemia): nl <125. nl fasting <110, >70. High >125, >110 fasting. Ca+ (hypocalcemia): nl= Ca+ (hypercalcemia): nl= Magnesium (hypomagnesemia): nl 1.8-3.0. Low <1.8 mg/dl. Magnesium (hypermagnesemia): nl 1.8-3.0. High >2.3 mg/dl Phosphate (hypophosphatemia): <2.5 mg/dl Phosphate (hyperphosphatemia): >5 mg/dl
 * || Electrolytes ||
 * S/Sx:** confusion, muscle cramps, anorexia, nausea. Severe = seizures, coma
 * Think:** DILUTION. SIADH, renal failure, TB, diuretics, vomiting, diarrhea, hyperglycemia, third spacing, meds.
 * Tx:** fluid restrict. 3% NS in emergencies (usually <120) (watch for central pontine myelinolysis!! [[image:http://www.anisman.com/images/therefore.gif width="12" height="10"]] <12mEq / 24hrs).
 * S/Sx:** confusion, lethargy, seizures, coma.
 * Think:** vomiting, diarrhea, diabetes insipidus, adrenal insufficiency, Cushing's Syndrome, diuretics, excess salt intake.
 * Tx:** fluids (D5W). Treat underlying disorder.
 * S/Sx:** muscle weakness [[image:http://www.anisman.com/images/thickright.gif width="12" height="9"]] paralysis. Arrythmias [[image:http://www.anisman.com/images/thickright.gif width="12" height="9"]] death. EKG changes.
 * Think:** DILUTION. ALKALOSIS. Insulin, diuretics (lasix particularly), DKA, vomiting, diarrhea.
 * Tx:** Potassium (in the form of potassium chloride). Do not give > 40 mEq/hour!
 * S/Sx:** weakness, irritability, arrythmias, paralysis. EKG changes.
 * Think:** ACIDEMIA. Renal insufficiency, K+ sparing diuretics, insulin deficiency, magnesium deficiency.
 * Tx:** correct acidosis. Can give glucose and insulin. IV Ca+ in emergency. Dialysis.
 * S/Sx:** No specific symptoms - generally a finding suggesting other etiology.
 * Think:** DILUTION. CHF, SIADH, vomiting, diarrhea, DKA, Addison's disease, nephritis.
 * Tx:** treat underlying disorder
 * S/Sx:** No specific symptoms - generally a finding suggesting other etiology.
 * Think:** dehydration, cystic fibrosis, hyperparathyroid, metabolic acidosis, chronic diarrhea, drugs
 * Tx:** treat underlying disorder
 * S/Sx:** sweating, anxiety, tremors, tachycardia, seizures, fatigue, syncope, HA, visual changes, [[image:http://www.anisman.com/images/psych.gif width="9" height="10"]] changes.
 * Think:** INSULIN OVERDOSE. insulinoma, factitious (insulin or sulfonylurea use), liver or renal disease, alcohol abuse, hormone deficiency.
 * Tx:** glucose
 * DKA (typically seen in Type I):**
 * S/Sx:** nausea/vomiting, polyuria, polydipsia, abdominal pain, anorexia, drowsiness, stupor, coma, dyspnea, malaise, fruity breath odor, dehydration.
 * Think:** poorly controlled diabetes - insufficient insulin.
 * Tx:** fluids, insulin, replace K+ & phosphate
 * HONK [HyperOsmolar Non-Ketotic Coma] (typically seen in Type II):**
 * S/Sx:** [[image:http://www.anisman.com/images/psych.gif width="9" height="10"]] changes, dehydration, seizures, polyuria, N/V
 * Think:** poorly controlled diabetes - insufficient oral agents, insulin requiring, or insufficient insulin
 * Tx:** fluids, low dose insulin, replace K+ Ca+ Mag and phosphorous
 * S/Sx:** tetany, paresthesias, seizures, weakness, [[image:http://www.anisman.com/images/psych.gif width="9" height="10"]] changes, arrythmias, EKG changes.
 * Think:** Hypoalbuminemia, renal insufficiency, vitamin D deficiency, hypomag, pancreatitis. Chvostek's sign, Trousseau's sign.
 * Tx:** replace albumin, mag, or vit D.
 * S/Sx:** constipation, N/V, CNS changes, [[image:http://www.anisman.com/images/psych.gif width="9" height="10"]] changes, myopathy, weakness, hypertension, polyuria
 * Think:** MALIGNANCY. Hyperparathyroid, MEN syndromes, thiazides, vit D intoxication.
 * Tx:** hydration & lasix, calcitonin, glucocorticoids, phosphates. Treat underlying cause.
 * S/Sx:** weakness, hyperreflexia, tremors, convulsions, coma, arrythmias. hypokalemia & hypocalcemia.
 * Think:** malabsorption, alcoholic, diarrhea, fistula, diuretics, ATN, DKA, SIADH, hyperthyroid, hyperparathyroid, drugs (digoxin, cyclosporin, amphotericin, methotrexate, antibiotics)
 * Tx:** Magnesium, treat underlying disorder.
 * S/Sx:** paresthesias, hypotension, confusion, paralysis, coma, hypocalcemia. EKG changes.
 * Think:** [[image:http://www.anisman.com/images/thickdown.gif width="7" height="10"]] GFR, endocrinopathy, DKA, pheo, antacid/laxative abuse, rhabdomyolysis.
 * Tx:** treat underlying disorder. IV calcium gluconate for cardiac conduction abnormalities. Dialysis if severe.
 * S/Sx:** proximal muscle weakness, bone pain, paresthesias, seizures, coma, ataxia, anemia, platelet dysfunction, rhabdomyolysis
 * Think:** [[image:http://www.anisman.com/images/thickdown.gif width="7" height="10"]] intake, alcoholic, malabsorption, antacids, renal dysfunction, DKA, steroids, TPN, theophyllin, hyperthermia.
 * S/Sx:** Same as hypocalcemia (tetany, paresthesias, seizures, weakness, [[image:http://www.anisman.com/images/psych.gif width="9" height="10"]] changes, arrythmias, EKG changes). Also, various calcifications occur.
 * Think:** Renal dysfunction, sickle cell anemia, chemotherapy, acidosis, rhabdomyolysis, hypoparathyroid, excessive intake.