In a patient with blood pressure of 90/60 mm of Hg, blood drawn was chocolate colored, lips and peripheries were cyanosed. The condition is due to?
ANSWER: (A) MethaemoglobinemiaREF: Harrisons Internal Medicine 17th edition Chapter 99. Disorders of Hemoglobin Methemoglobinemia:Methemoglobin is generated by oxidation of the heme iron moieties to the ferric state, causing a characteristic bluish-brown muddy color resembling cyanosis. Methemoglobin has such high oxygen affinity that virtually no oxygen is delivered.Hypotension is seen in methemoglobinemia due to hemolysisMethemoglobin should be suspected in patients with hypoxic symptoms who appear cyanotic but have a Pa02 sufficiently high that hemoglobin should be fully saturated with oxygen.A history of nitrite or other oxidant ingestions may not always be available; some exposures may be unapparent to the patient, and others may result from suicide attempts.The characteristic muddy appearance of freshly drawn blood can be a critical clue.The best diagnostic test is methemoglobin assay, which is usually available on an emergency basis.Methemoglobinemia often causes symptoms of cerebral ischemia at levels >15%; levels >60% are usually lethal.Intravenous injection of 1 mg/kg of methylene blue is effective emergency therapy. Milder cases and follow-up of severe cases can be treated orally with methylene blue (60 mg three to four times each day) or ascorbic acid (300-600 mg/d).(Same features can be seen in hypovolemic shock, hemorrhagic and cardiogenic shock but what catches the answer is presence of central cyanosis and presence of chocolate color blood)
Methaemoglobinemia
Hypovolumic shock
Cardiogenic shock
Hemorrhagic shock
Shock