Excessive vomiting with gastric outlet obstruction secondary to pyloric stenosis leads to -

Ans. is 'a' i.e., Hypokalemic hypochloremic metabolic alkalosis Metabolic consequences of persistent vomiting in case of pyloric stenosis:* The metabolic consequences of benign pyloric stenosis are unique.* The vomiting of hydrochloric acid results in hypochloraemic alkalosis.* Initially, the sodium and potassium may be relatively normal. However, as dehydration progresses, more profound metabolic abnormalities arise, partly related to renal dysfunction.* Initially, the urine has a low chloride and high bicarbonate content, reflecting the primary metabolic abnormality. This bicarbonate is excreted along with sodium, and so with time the patient becomes progressively* Hyponatraemic and more profoundly dehydrated.* Because of the dehydration, a phase of sodium retention follows and potassium and hydrogen are excreted in preference.* This results in the urine becoming paradoxically acidic and hypokalaemia ensues. This finally culminates into hypokalemic hypochloremic metabolic alkalosis.* Alkalosis leads to a lowering in the circulating ionised calcium, and tetany can occur.