EM9 Severe metabolic alkalosis in the presence of severe dehydration and elevated lactate. (Emergency Medicine).

EM9 SEVERE METABOLIC ALKALOSIS IN THE PRESENCE OF SEVERE DEHYDRATION AND ELEVATED LACTATE. Antonio E. Muniz, MD. Department of Emergency Medicine and Pediatrics, Medical College of Virginia of VCU, Richmond.

Metabolic alkalosis has different causes. It can occur from either a gain in bicarbonate or a loss of acid. Conditions that produce chloride loss may include vomiting, diarrhea, diuretic therapy, and chloride-wasting diseases (CF and chloride wasting enteropathy). These conditions reduce both serum chloride concentration and extracellular volume. The reduction in volume stimulates mineralocorticoid activity, which enhances sodium reabsorption and potassium and hydrogen ion secretion in distal tubule, which enhance bicarbonate generation. A 59-year-old man presented. to the ED with a 2-day history of nausea, vomiting, upper abdominal pain, and constipation. He had been discharged 2 days earlier for dehydration. He denied fever, diarrhea, or cough. His medical history was remarkable for a hemicolectomy for adenocarcinoma of the colon. His medications included docusate and oxycodone. He had a temperature of 35.0[degrees]C, initial BP 43 mm Hg, heart rate 162/mm, and respiratory rate 22/min. After 500 mL of norma l saline, his blood pressure was 120/70 mm Hg, His physical examination was remarkable for dry mucous membranes and tachycardia. His abdominal examination showed diffuse tenderness and tympany. His initial pulse oximetry was 72%. His WBC was 11,300/mm' with 85% neutrophils. His hemoglobin was 16.6 g/dL and platelets 193,000/[mm.sup.3]. His electrolytes showed potassium 3.1 mEq/L, chloride 80 mEq/L, [CO.sub.2] 40 mEq/L, BUN 71 mg/dL, and creatinine 5.9 mg/dL. His lactate was 5.9 mg/dL. His pH was 7.76, P[CO.sub.2] 28 mm Hg, and P[O.sub.2] 153 mm Hg on 100% oxygen. His ECG showed sinus tachycardia and LVH. His abdominal and chest radiograph was normal. An abdominal US revealed no aneurysm of the aorta. He was admitted for intravenous hydration. He underwent a gastrostomy and did well. He was discharged in stable condition. Severe metabolic alkalosis in a patient with severe dehydration and vomiting results in a hypokalemic, hypochloremic alkalosis. Severe alkalosis may manifest with neurologic abnormalities, su ch as tetany, neuromuscular instability, and seizures. Reduction in hydrogen ion concentration results in reductions in ionized calcium, potassium, magnesium, and phosphorus levels. Constriction of arterioles may result in coronary and cerebral blood flow deficiency. This type of alkalosis will respond to normal saline (chloride-responsive alkalosis) hydration.