Methemoglobinemia

1
Methemoglobinemia 
2
Methemoglobinemia 

• When excessive hemoglobin in the blood is
  converted to another chemical that cannot deliver
  oxygen to tissues, called methemoglobin.

3
What is Methhemoglobin?

• The molecule hemoglobin in the blood is
  responsible for binding oxygen to give to the
  body. When hemoglobin is oxidized to
  methemoglobin its structure changes and it is no
  longer able to bind oxygen

4
How much is normal

• . Hemoglobin is constantly under oxidizing
  stresses however, normally less than 1 of a
  person's hemoglobin is in the methemoglobin
  state.

5
Why?

• due to the body's systems that reduce
  methemoglobin back to hemoglobin.
• Infants have a higher risk of acquiring
  methemoglobinemia because infant hemoglobin is
  more prone to be oxidized to methemoglobin

6
How do I get it

• Methemoglobinemia can either be congenital or
  acquired

7
Congenital

• There are two causes of the congenital form. One
  cause is a defect in the body's systems to reduce
  methemoglobin to hemoglobin. The other cause is a
  mutant form of hemoglobin called hemoglobin M
  that cannot bind to oxygen. Both of these forms
  are typically benign.

8
Acquired

• Acquired methemoglobinemia is caused by an
  external source, usually a drug or medication.
  Some of these medications include benzocaine,
  lidocaine and prilocaine. These medications can
  inhibit the body's systems of reducing
  methemoglobin to hemoglobin resulting in
  methemoglobinemia

9
Signs 3 to 15

• With a methemoglobin level of 3-15 skin can turn
  to a pale gray or blue (cyanosis).

10
Symptoms above 25

• With levels above 25 the following symptoms may
  be present
• Cyanosis unaffected by oxygen administration
• Blood that is dark or chocolate in color that
  will not change to red in the presence of oxygen
• Headache
• Weakness
• Confusion
• Chest pain

11

• When methemoglobin levels are above 70 death may
  result if not treated immediately

12

• Diagnosis is based on the symptoms and history.
  If these are indicative of methemoglobinemia
  blood tests are performed to confirm the presence
  and level of methemoglobin.

13
Field monitoring of methhemoglobin

• The new LP15 will do non-invasive monitoring for
  methhemoglobin.
• The monitoring is done by finger probe using
  rainbow technology.

14
Treatment

• For acquired methemoglobinemia the typical
  treatment is with methylene blue. This is
  administered with an IV over a five-minute period
  and results are typically seen within 20 minutes.
  Methylene blue reduces methemoglobin back to
  hemoglobin.

15
Treatment

• Though congenital methemoglobinemia is usually
  benign, the form due to a defective reducing
  system can be treated with ascorbic acid (vitamin
  C) taken daily. The other congenital form due to
  hemoglobin M has no treatment as of late.

16
Prognosis

• If found early, acquired methemoglobinemia can be
  easily treated with no side effects. After
  treatment with methylene blue the patient can
  expect a full recovery.
• Congenital methemoglobinemia is typically benign
  and should be observed