After 2 weeks of diarrhea, a 22 year old college female reports to the emergency room feeling faint. She says she recently took a trip to Mexico for spring break and became sick on her last day there. She has now had diarrhea for 2 weeks, with 3 watery bowel movements per day. She denies vomiting. Her mucous membranes are dry, and her capillary refill is 4 seconds. Her respiratory rate is 30 per minute.
What explains her increase respiratory rate?
A. Anion-gap metabolic acidosis
B. Normal anion gap metabolic acidosis
C. Respiratory acidosis
D. Respiratory alkalosis
E. Metabolic alkalosis
It is Normal anion gap metabolic acidosis (non anion gap) due to loss of HCO3- in the diarhheal fluids, with a compensatory respiratory alkalosis.
ReplyDeleteThe most common cause of normal anion gap acidosis is diarrhea. Bicarbonate is lost in the stool causing a decrease in pH and volume. The kidneys compensate by increasing Na and Cl resorption. Increased serum chloride compensates for lost bicarbonate and normalizes the anion gap.
Anion gap is AG = Na – (Cl + HCO3).
A normal anion gap is 8-12 mEq/L .
Other causes of normal anion gap metabolic acidosis include renal tubular acidosis, hyperalimentation, and the use of acetozolamide.
A – Anion-gap metabolic acidosis is caused by several mechanisms. Remember the mnemonic MUDPILES (methanol, uremia, diabetic ketoacidosis, propylene glycol, isoniazid, lactic acidosis, ethylene glycol, salicylates).
C – Respiratory acidosis is caused by hypoventilation. Some causes include: COPD, Obesity hypoventilation syndrome, and neuromuscular disorders (i.e. – myasthenia gravis, Guillain-Barré syndrome, amyotrophic lateral sclerosis.
D – Respiratory alkalosis is caused by hyperventilation. The most common cause is anxiety. Other causes include stroke, fever, pregnancy, and asthma.
E – Metabolic alkalosis is caused several mechanisms, the most common being vomiting.
Conn’s syndrome, contraction alkalosis, hypokalemia, and increased intake of sodium bicarbonate are being the most of the metabolic acidosis.