Snapshot A 56-year-old man is brought to the emergency department by his son due to mild confusion and shortness of breath. Prior to symptom develop he needed to sleep on a recliner due to feeling short of breath while supine. Medical history is significant for chronic obstructive pulmonary disease and a prior myocardial infarction requiring coronary artery bypass grafting. On physical exam, the patient is altered but able to follow commands. There is jugular venous distension, an S3 heart sound, and 2+ lower extremity pitting edema. Laboratory testing is significant for a brain natriuretic peptide 950 pg/mL and serum sodium of 130 mmol/L. (Hyponatremia secondary to congestive heart failure) Potassium Electrolyte Disturbances Hyponatremia Hypernatremia Definition serum sodium of < 135 mmol/L Etiology pseudohyponatremia hyperglycemia hyperlipidemia hypervolemic hyponatremia congestive heart failure nephrotic syndrome cirrhosis renal insufficiency hypovolemic hyponatremia vomiting and diarrhea burns sweating cystic fibrosis diuretic use (e.g., thiazides) angiotensin converting enzyme (ACE) inhibitor adrenal insufficiency euvolemic hyponatremia psychogenic polydipsia hypothyroidism syndrome of inappropriate anti-diuretic hormone (SIADH) diuretic use ACE inhibitors Presentation stupor coma seizures nausea malaise Studies assess volume status serum electrolyte and urine studies Treatment address underlying cause asymptomatic free water restriction moderate hyponatremia IV normal saline loop diuretics may be added severe hyponatremia hypertonic (3%) saline Complications rapid correction of hyponatremia can lead to osmotic demyelination syndrome Definition serum sodium of > 145 mmol/L Etiology insensible losses (e.g., sweating) osmotic diarrhea osmotic diuresis e.g., diabetic ketoacidosis poor fluid intake diuretic use osmotic diuresis vomiting and diarrhea central and nephrogenic diabetes insipidus hypertonic sodium gain Presentation stupor coma seizure Studies assess volume status serum electrolyte and urine studies Treatment address underlying cause intravenous (IV) 5% dextrose in water (D5W) isotonic fluids when hypovolemic Complications rapid corrrection of hypernatremia can lead to cerebral edema and herniation Hypokalemia Hyperkalemia Defintion serum potassium of < 3.5 mEq/L Etiology ↑ insulin hyperglycemia this stimulates endogenous insulin secretion from the pancreas in normal conditions β2-adrenergic agonists alkalosis hyposmolality diarrhea dehydration secondary to activation of the RAA system causing K and H wasting Presentation muscle and cardiac dysfunction muscular symptoms abdominal cramping muscle weakness and cramping cardiac symptoms palpitations parasthesias nausea and vomiting Studies electrocardiogram (ECG) findings U waves T wave flattening Treatment address underlying cause potassium repletion remember to not use dextrose-containing fluids as this will stimulate insulin release and shift potassium within the cell this worsens the hypokalemia replace magnesium in magnesium deficiency Definition serum potassium of > 5-5.5 mEq/L Etiology insulin deficiency β2-adrenergic antagonists acidosis cells attempt to buffer excess hydrogen ions to shift these ions into the cells in exchange for this intracellular uptake of hydrogen, potassium is transferred out the cell this attempts to achieve electroneutrality digitalis secondary to dose-dependent Na+/K+ -ATPase pump inhibition cell lysis (e.g., rhabdomyolysis) exercise hyperosmolarity succinylcholine TMP-SMX ACE inhibitors Presentation muscle and cardiac dysfunction muscular symptoms myalgias muscle paralysis chest pain cardiac symptoms arrhythmias and palpitations nausea and vomiting parasthesias Studies ECG findings peaked T waves and wide QRS Treatment address underlying cause IV calcium gluconate has no effect on potassium levels but stabilizes the myocardium shifting potassium within cells insulin plus glucose β2-adrenergic agonists lowering body potassium sodium polystyrene sulfonate this is a cation exchange resin dialysis used in patients unresponsive to medical therapy Hypocalcemia Hypercalemia Definition serum total calcium < 8.4 mg/dL decreased albumin can cause a decreased total calcium but a normal free calcium (thus the patient is asymptomatic) ionized fraction of calcium < 4.4 mg/dL Etiology renal failure hypoparathyroidism vitamin D deficiency hypomagnesemia inhibits PTH release pancreatitis alkalemia Presentation seizures tetany Chvostek sign ipsilateral facial muscle contraction caused by tapping the facial nerve Trousseau sign carpopedal spasms by inflating the sphygmomanometer above systolic blood pressure Studies QTc prolongation Treatment address underlying cause asymptomatic or patients with chronic hypocalcemia oral calcium replacement therapy such as calcium citrate calcium carbonate vitamin D supplementation thiazides for patients with hypoparathyroidism symptomatic patients IV calcium gluconate first-line chronic renal failure phosphate binders oral calcium replacement calcitriol Definition serum total calcium > 10.5 mg/dL ionized fraction of calcium > 5.6 mg/dL Etiology hyperparathyroidism humoral hypercalcemia of malignancy secondary to parathyroid hormone-related peptide (PTHrP) associated with squamous cell cancer and solid tumors involving the lung esophageus skin cervix breast kidney vitamin D overdose granulomatous diseases like sarcoidosis thiazide diuretics lithium calcium-containing antacids familial hypocalciuric hypercalcemia immobilization Presentation nephrolithiasis polyuria muscle weakness bone pain abdominal pain secondary to bowel hypomotility and constipation confusion stupor coma mnemonic: stones (renal), bones (pain), groans (abdominal pain), thrones (↑ urinary frequency), and psychiatric overtones (altered mental status) Studies ECG shortened QTc interval Treatment address underlying cause IV isotonic normal saline increases urinary calcium excretion calcitonin impairs bone resorption increases urinary calcium excretion bisphosphonates (e.g., zoledronic acid and pamidronate) has a delayed onset of action impairs bone resorption long term calcium control loops diuretics increases urinary calcium excretion Hypomagnesemia Hypermagnesemia Definition typically serum magnesium < 1.8 mg/dL Etiology magnesium redistribution refeeding syndrome malnutrition alcohol use disorder anorexia nervosa proton pump inhibitors loop diuretics digoxin Presentation tetany torsades de pointes hypokalemia hypocalcemia when significant (< 1.2 mg/dL) Studies ECG U waves T wave flattening QT prolongation widened QRS complexes Treatment magnesium repletion asymptomatic oral magnesium supplementation severe or symptomatic hypomagnesemia IV magnesium sulfate Definition typically serum magnesium > 2.6 mg/dL Etiology increased magnesium ingestion magnesium cathartics antacids laxatives dietary supplements renal insufficiency Presentation ↓ deep tendon reflexes bradycardia cardiac arrest hypocalcemia Studies ECG PR, QRS, and QT prolongation heart block Treatment address underlying cause IV isotonic saline loop diuretics can be considered Hypophosphatemia Hyperphosphatemia Definition serum phosphate < 2.5 mg/dL Etiology refeeding syndrome hungry bone syndrome inadquate phosphate intake hyperparathyroidism phosphate binders Presentation weakness muscle and bone pain osteomalacia rickets Treatment address underlying cause mild hypophosphatemia increase dietary phosphate intake moderate hypophosphatemia oral phosphate replacement therapy IV phosphate replacement in patients who are on a ventilator severe hypophosphatemia IV phosphate replacement Definition serum phosphate > 4.5 mg/dL Etiology acute phosphate ingestion hypoparathyroidism vitamin D toxicity renal failure rhabdomyolysis tumor lysis syndrome Presentation typically asymptomatic Treatment address underlying cause dietary modifications phosphate binders calcium carbonate or acetate
QUESTIONS 1 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Previous Next Lab Values Blood Hematologic Cerebrospinal Sweat, Urine, and BMI Blood, Plasma, Serum Reference Range ALT 8-20 U/L Amylase, serum 25-125 U/L AST 8-20 U/L Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL Calcium, serum (Ca2+) 8.4-10.2 mg/dL Cholesterol, serum Rec: < 200 mg/dL Cortisol, serum 0800 h: 5-23 μg/dL //1600 h: 3-15 μg/dL 2000 h: ≤ 50% of 0800 h Creatine kinase, serum Male: 25-90 U/LFemale: 10-70 U/L Creatinine, serum 0.6-1.2 mg/dL Electrolytes, serum Sodium (Na+) 136-145 mEq/L Chloride (Cl-) 95-105 mEq/L Potassium (K+) 3.5-5.0 mEq/L Bicarbonate (HCO3-) 22-28 mEq/L Magnesium (Mg2+) 1.5-2.0 mEq/L Estriol, total, serum (in pregnancy) 24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL 28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL Ferritin, serum Male: 15-200 ng/mLFemale: 12-150 ng/mL Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL Female: premenopause: 4-30 mIU/mL midcycle peak: 10-90 mIU/mL postmenopause: 40-250 pH 7.35-7.45 PCO2 33-45 mmHg PO2 75-105 mmHg Glucose, serum Fasting: 70-110 mg/dL2-h postprandial:<120 mg/dL Growth hormone - arginine stimulation Fasting: <5 ng/mLProvocative stimuli: > 7ng/mL Immunoglobulins, serum IgA 76-390 mg/dL IgE 0-380 IU/mL IgG 650-1500 mg/dL IgM 40-345 mg/dL Iron 50-170 μg/dL Lactate dehydrogenase, serum 45-90 U/L Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL Female: follicular phase: 5-30 mIU/mL midcycle: 75-150 mIU/mL postmenopause 30-200 mIU/mL Osmolality, serum 275-295 mOsmol/kd H2O Parathyroid hormone, serume, N-terminal 230-630 pg/mL Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L Phosphorus (inorganic), serum 3.0-4.5 mg/dL Prolactin, serum (hPRL) < 20 ng/mL Proteins, serum Total (recumbent) 6.0-7.8 g/dL Albumin 3.5-5.5 g/dL Globulin 2.3-3.5 g/dL Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h Thyroxine (T4), serum 5-12 μg/dL Triglycerides, serum 35-160 mg/dL Triiodothyronine (T3), serum (RIA) 115-190 ng/dL Triiodothyronine (T3) resin uptake 25%-35% Urea nitrogen, serum 7-18 mg/dL Uric acid, serum 3.0-8.2 mg/dL Hematologic Reference Range Bleeding time 2-7 minutes Erythrocyte count Male: 4.3-5.9 million/mm3Female: 3.5-5.5 million mm3 Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/hFemale: 0-20 mm/h Hematocrit Male: 41%-53%Female: 36%-46% Hemoglobin A1c ≤ 6 % Hemoglobin, blood Male: 13.5-17.5 g/dLFemale: 12.0-16.0 g/dL Hemoglobin, plasma 1-4 mg/dL Leukocyte count and differential Leukocyte count 4,500-11,000/mm3 Segmented neutrophils 54%-62% Bands 3%-5% Eosinophils 1%-3% Basophils 0%-0.75% Lymphocytes 25%-33% Monocytes 3%-7% Mean corpuscular hemoglobin 25.4-34.6 pg/cell Mean corpuscular hemoglobin concentration 31%-36% Hb/cell Mean corpuscular volume 80-100 μm3 Partial thromboplastin time (activated) 25-40 seconds Platelet count 150,000-400,000/mm3 Prothrombin time 11-15 seconds Reticulocyte count 0.5%-1.5% of red cells Thrombin time < 2 seconds deviation from control Volume Plasma Male: 25-43 mL/kgFemale: 28-45 mL/kg Red cell Male: 20-36 mL/kgFemale: 19-31 mL/kg Cerebrospinal Fluid Reference Range Cell count 0-5/mm3 Chloride 118-132 mEq/L Gamma globulin 3%-12% total proteins Glucose 40-70 mg/dL Pressure 70-180 mm H2O Proteins, total < 40 mg/dL Sweat Reference Range Chloride 0-35 mmol/L Urine Calcium 100-300 mg/24 h Chloride Varies with intake Creatinine clearance Male: 97-137 mL/minFemale: 88-128 mL/min Estriol, total (in pregnancy) 30 wks 6-18 mg/24 h 35 wks 9-28 mg/24 h 40 wks 13-42 mg/24 h 17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 hFemale: 2.0-8.0 mg/24 h 17-Ketosteroids, total Male: 8-20 mg/24 hFemale: 6-15 mg/24 h Osmolality 50-1400 mOsmol/kg H2O Oxalate 8-40 μg/mL Potassium Varies with diet Proteins, total < 150 mg/24 h Sodium Varies with diet Uric acid Varies with diet Body Mass Index (BMI) Adult: 19-25 kg/m2 Calculator ( ) xy AC 7 8 9 ÷ 4 5 6 × 1 2 3 - 0 . = + Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M2.RL.1) A 32-year-old man with a history of chronic alcoholism presents to the emergency department with vomiting and diarrhea for 1 week. He states he feels weak and has had poor oral intake during this time. The patient is a current smoker and has presented many times to the emergency department for alcohol intoxication. His temperature is 97.5°F (36.4°C), blood pressure is 102/62 mmHg, pulse is 135/min, respirations are 25/min, and oxygen saturation is 99% on room air. On physical exam, he is found to have orthostatic hypotension and dry mucus membranes. Laboratory studies are ordered as seen below.Serum:Na+: 139 mEq/LCl-: 101 mEq/LK+: 3.9 mEq/LHCO3-: 25 mEq/LBUN: 20 mg/dLGlucose: 99 mg/dLCreatinine: 1.1 mg/dLCa2+: 9.8 mg/dLThe patient is given normal saline, oral potassium, dextrose, thiamine, and folic acid. The following day, the patient seems confused and complains of diffuse weakness and muscle/bone pain. An ECG and head CT are performed and are unremarkable. Which of the following is the most likely explanation for this patient's new symptoms? Review Topic QID: 102617 1 Hypocalcemia 31% (12/39) 2 Hypoglycemia 3% (1/39) 3 Hypomagnesemia 5% (2/39) 4 Hyponatremia 44% (17/39) 5 Hypophosphatemia 15% (6/39) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 5 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M2.RL.4830) A 75-year-old man with coronary artery disease and mitral valve stenosis status-post coronary artery bypass graft and mitral bioprosthetic valve replacement is evaluated in the intensive care unit. His postsurgical course was complicated by ventilator-associated pneumonia and bilateral postoperative pleural effusions requiring chest tubes. He has been weaned from the ventilator and has had his chest tubes removed but has required frequent suctioning to minimize aspirations. He has been dependent on a percutaneous gastrostomy tube for enteral nutrition for the past four weeks. He is currently on aspirin, carvedilol, atorvastatin, ceftazidime, and pantoprazole. He has a history of prostate cancer status post radical prostatectomy. His temperature is 96°F (35.6°C), blood pressure is 95/55 mmHg, pulse is 50/min, and respirations are 20/min. On physical exam, he is not alert and oriented but responds with moans when stimulated. His laboratory data are listed below:Serum:Na+: 145 mEq/LCl-: 110 mEq/LK+: 3.4 mEq/LHCO3-: 26 mEq/LBUN: 10 mg/dLGlucose: 112 mg/dLCreatinine: 1.4 mg/dLThyroid-stimulating hormone: 10 µU/mLCa2+: 11.1 mg/dLPO4-: 1.0 mg/dLAST: 6 U/LALT: 10 U/LAlbumin: 2.5 mg/dLLactate dehydrogenase: 200 U/L (140-280 U/L)Haptoglobin: 150 mg/dL (30-200 mg/dL)1,25-(OH)2 D3: 10 pg/mL (15-75 pg/mL)Parathyroid hormone: 9 pg/mL (10-60 pg/mL)Leukocyte count: 10,000 cells/mm^3 with normal differentialHemoglobin: 9 g/dLHematocrit: 30 %Platelet count: 165,000 /mm^3His electrocardiogram and chest radiograph are shown in Figures A and B. What is the most likely cause of his hypercalcemia? Review Topic QID: 109466 FIGURES: A B 1 Hemolytic anemia 0% (0/49) 2 Euthyroid sick syndrome 10% (5/49) 3 Immobilization 71% (35/49) 4 Malignancy 12% (6/49) 5 Primary hyperparathyroidism 6% (3/49) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 3 (M2.RL.4799) A 62-year-old male with a history of chronic lymphocytic leukemia is admitted to the hospital for chemotherapy with fludarabine after transformation into prolymphocytic leukemia. Three days later, the nurse calls you because the patient is vomiting. The patient reports he is nauseous and he feels weak. On physical exam, he is ill-appearing, and you appreciate diffuse, bilateral lymphadenopathy, symmetrical muscle weakness, and bilateral areflexia. Labs are drawn and an electrocardiogram (EKG) is obtained, which is shown in Figure A. In addition to cardiac stabilization, which of the following is the best next step in management? Review Topic QID: 109340 FIGURES: A 1 Albuterol 44% (15/34) 2 Allopurinol 6% (2/34) 3 Furosemide 3% (1/34) 4 Rasburicase 26% (9/34) 5 Sodium polystyrene sulfonate 21% (7/34) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 1 (M2.RL.20) A 58-year-old man complains of ascending weakness, palpitations, and abdominal pain. He has a history of hypertension, type II diabetes mellitus, diabetic retinopathy, and end-stage renal disease requiring dialysis. He denies any recent infection. Physical examination is notable for decreased motor strength in both his upper and lower extremities, intact cranial nerves, as well as decreased bowel sounds. On further questioning, the patient shares that he has been depressed, as he feels he may not be able to see his grandchildren grow due to his complicated medical course. This caused him to miss two of his dialysis appointments. Which of the following will mostly likely be found on electrocardiography? Review Topic QID: 105386 1 Progressive PR prolongation, followed by a 'drop' in QRS 0% (0/0) 2 S wave in lead I, Q wave in lead III, and inverted T wave in lead III 0% (0/0) 3 ST-segment elevation in leads II, III, and aVF 0% (0/0) 4 Peaked T-waves and shortened QT interval 0% (0/0) 5 Diffuse PR segment depression and ST-segment deviations 0% (0/0) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 4 (M2.RL.2) A 54-year-old man presents with 3 days of non-bloody and non-bilious emesis every time he eats or drinks. He has become progressively weaker and the emesis has not improved. He denies diarrhea, fever, or chills and thinks his symptoms may be related to a recent event that involved sampling many different foods. His temperature is 97.5°F (36.4°C), blood pressure is 133/82 mmHg, pulse is 105/min, respirations are 15/min, and oxygen saturation is 98% on room air. Physical exam is notable for a weak appearing man with dry mucous membranes. His abdomen is nontender. Which of the following laboratory changes would most likely be seen in this patient? Review Topic QID: 104276 1 Anion gap metabolic acidosis and hypokalemia 0% (0/39) 2 Metabolic alkalosis and hyperkalemia 5% (2/39) 3 Metabolic alkalosis and hypokalemia 0% (0/39) 4 Non-anion gap metabolic acidosis and hypokalemia 13% (5/39) 5 Respiratory acidosis and hyperkalemia 79% (31/39) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 3 (M2.RL.30) A 19-year-old male with cystic fibrosis is evaluated in the clinic for regular health maintenance. He is compliant with his respiratory therapy, but states that he often "forgets" to take the medications before he eats. A panel of labs is drawn which reveals a moderate vitamin D deficiency. Which of the following electrolyte abnormalities might be seen as a consequence of vitamin D deficiency? Review Topic QID: 104304 1 Increased calcium and increased phosphate 0% (0/77) 2 Increased calcium and decreased phosphate 4% (3/77) 3 Decreased calcium and increased phosphate 35% (27/77) 4 Decreased calcium and decreased phosphate 56% (43/77) 5 Normal calcium and decreased phosphate 4% (3/77) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 4 (M2.RL.3) A 64-year-old man presents for a routine physical. He states that he has felt abnormally weak during this time and has had trouble focusing in the setting of losing 5 pounds. The patient states he has a decreased appetite and also has not had a bowel movement in the past 5 days and feels uncomfortable. On review of system, he endorses abdominal pain. His temperature is 97.5°F (36.4°C), blood pressure is 132/83 mmHg, pulse is 115/min, respirations are 15/min, and oxygen saturation is 98% on room air. Physical exam is notable only for the patient being able to recall 1 of 3 objects. His cranial nerve exam is unremarkable and his gait is stable. Urinalysis is initially notable for a clear and voluminous sample with a low specific gravity. Which of the following tests is most likely abnormal in this patient? Review Topic QID: 104277 1 Calcium level 0% (0/32) 2 Lead level 3% (1/32) 3 Phosphate level 6% (2/32) 4 Potassium level 78% (25/32) 5 TSH level 9% (3/32) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 1