WBR1067

Author	[[PageAuthor::Mohamed Moubarak, M.D. [1]]]
Exam Type	ExamType::USMLE Step 3
Main Category	MainCategory::Emergency Room
Sub Category	SubCategory::Electrolytes
Prompt	[[Prompt::A 67 year-old male brought to Emergency department by his son after he became disoriented and confused. His son mentioned that he is living alone, ¬¬and he was okay at his last visit 2 days ago, and he showed some seizures while on the way. The patient has a past medical history of alcoholic liver cirrhosis. On examination, the patient is confused, disoriented to time and place. His blood pressure is 90/60 mmHg, pulse 120 beat per minute, respiration 23/m, and temperature 37 C. Cardiopulmonary exam was unremarkable. Abdominal exam shows tense ascites and a shrunken liver. Lower extremities had 3+ pitting edema. His laboratory tests are shown below. • Sodium 110 (N: 135-146 mmol/L) • Potassium 3.8 (N: 3.5-5.3 mmol/L) • Glucose 100 (N: 70-110 mg/dl) • Chloride 98 (N: 98-108 mmol/L) • Total CO2 25 (N: 23-27 mmol/L) Which of the following is the best next step in managing his hyponatremia?]]
Answer A	AnswerA::Hypotonic saline infusion
Answer A Explanation	[[AnswerAExp::Incorrect Hypotonic saline infusion will increase the hyponatremia degree and worsen the case.]]
Answer B	AnswerB::Isotonic saline infusion
Answer B Explanation	[[AnswerBExp::Incorrect Isotonic saline infusion is not used in acute cases who need rapid correction of the hyponatremia to prevent the occurance of cerebral edema. Instead 3% NaCl is used, then transition to 0.9% NaCl/vaptans at sodium levels > 125 mEq/L.]]
Answer C	AnswerC::Hypertonic saline infusion
Answer C Explanation	[[AnswerCExp::Correct Acute severe hyponatremia treated with 3% NaCl, then Transition to 0.9% NaCl/vaptans at sodium levels > 125 mEq/L.]]
Answer D	AnswerD::Water restriction
Answer D Explanation	[[AnswerDExp::Incorrect Water restriction is used wen the case is mild asymptomatic.]]
Answer E	AnswerE::Intravenous diuretics
Answer E Explanation	[[AnswerEExp::Incorrect Diuretics are not indicated in the treatment of hyponatremia.]]
Right Answer	RightAnswer::C
Explanation	[[Explanation::The decrease in effective circulating arterial volume due to this patient`s liver disease is responsible for ADH secretion in this patient. Hyponatremia is defined as plasma sodium concentration less than 135 mEq/L. Most patients with hyponatremia are asymptomatic. Symptoms do not usually appear until the plasma sodium level drops below 120 mEq per L. Hyponatremia can be developed in cases of excess water intake that exceed the excretory capacity of the kidneys. Other causes include impared renal functions and ability to excrete excess water, or inappropriate secretion of ADH. Acute severe hyponatremia (i.e., less than 125 mmol per L) usually is associated with neurologic symptoms and should be treated urgently because of the high risk of cerebral edema and hyponatremic encephalopathy. Treat with 3% NaCl to begin with (100 ml infused over 10 minutes and repeated once if needed). Transition to 0.9% NaCl/vaptans at sodium levels > 125 mEq/L. Educational Objective: Acute severe hyponatremia (i.e., less than 125 mmol per L) usually is associated with neurologic symptoms and should be treated with 3% NaCl to begin with (100 ml infused over 10 minutes and repeated once if needed). Transition to 0.9% NaCl/vaptans at sodium levels > 125 mEq/L. References: http://www.wikidoc.org/index.php/Hyponatremia_resident_survival_guide]]
Approved	Approved::No
Keyword	[[WBRKeyword::Hyponatremia]]
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