Thursday, March 29

Methemoglobinemia Treatment - Methemoglobinemia diagnosis & test

In mild cases of acquired methemoglobinemia, treatment may not be necessary. In fact mild methemoglobinemia may go unnoticed and undiagnosed.
Avoiding and withdrawing the causative food, chemical or drug itself will solve the problem.
Persons having inherited methemoglobinemia type 1 or hemoglobin M disease may be able to carry on their normal lives.
However individuals with hereditary type IIb5 cytochrome reductase deficiency have shortened life expectancy due to severe multiple physiological complications.

In persons with fair skin complexion, the diagnosis is easier requiring fewer tests as the bluish skin discoloration is apparent.
However in individuals with dark skin complexion and hyperpigmentation blemishes symptoms have to be studied and elaborate tests may be necessary for diagnosis and treatment.
Cyanosis and low O2 saturation reading around 90% may indicate methemoglobinemia.
The diagnosis of methemoglobinemia can be confirmed by test with multiple wavelength co-oximeter or multi-wave length pulse oximeter to directly measure methemoglobin.

Methylene blue in methemoglobinemia treatment

Methylene blue (methylthioninium chloride or C16H18N3SCl) is used in the treatment in severe cases of Methemoglobinemia.
Methylene blue 1% solution (10 mg/ml) 1 to 2 mg/kg is usually administered by the intravenous route.
This has to be done slowly for about five minutes followed by intravenous flush with saline. The IV administration of methylene blue may be repeated if necessary.
Oxygen supplementation is also done simultaneously.
Methylene blue functions as electron acceptor and makes the methemoglobin reductase enzyme to perform at five times the normal levels.
However in patients with the G6PD (Glucose-6-phosphate dehydrogenase) deficiency, an X-linked recessive hereditary disease, methylene blue is contraindicated.
In  G6PD patients it is very dangerous to use methylene blue as it can lead to severe hemolysis.
Methylene blue, being a potent oxidant, can actually cause methemoglobinemia when administered at levels greater than 7mg/kg.

Ascorbic acid in methemoglobinemia treatment

Vitamin C, being a potent antioxidant, reduces the level of methemoglobin in the blood.
Oral administration vitamin C at 500mg/d may be done on an ongoing basis when methemoglobin levels rise to more than 30%.
Oral methylene blue at about 200-300mg/d or riboflavin at 20mg/d also can be used instead of vitamin C.

Exchange transfusions and hyperbaric oxygen treatment

In severe life-threatening situations exchange transfusions are resorted to save the life of the patient.
In G6PD patients and in individuals in whom there is lack of sufficient progress with methylene blue treatment, exchange transfusion becomes necessary to save the life.
In exchange transfusion, basically, abnormal hemoglobin in RBC is replaced with normal hemoglobin.
In hyperbaric oxygen treatment, by use of plasma dissolved oxygen, tissue oxygenation is achieved.

In infant metabolic acidosis, methemoglobinemia resolution lies in reversal of acidosis with intravenous hydration and bicarbonates.

Methemoglobinemia treatment must done by a qualified professional preferably in a clinic or hospital.
Related topics:
What is methemoglobinemia?
Causes and symptoms

Current topic: Methemoglobinemia treatment

Thursday, March 15

Methemoglobinemia causes - Methemoglobinemia symptoms

The occurrence of methemoglobinemia may be congenital (hereditary) and occurring in families or may be acquired due to exposure to certain chemicals, medicines or foods.

Causes of methemoglobinemia inheritance

In this inherited ailment there are two forms. In the first form both the parents may be carrying single culprit autosomal gene (recessive) and yet may not show any symptoms and are carriers. If the child receives the affected gene from both the parents then the ailment shows up.
There are again two types in this recessive inherited form of congenital cytochrome b5 reductase deficiency.
The type one (Type Ib5R deficiency) is also called erythrocyte cytochrome reductase deficiency.
It occurs when the erythrocytes (red blood cells) lack the methemoglobin reductase enzyme which is responsible for reducing ferric form of heme group into ferrous form.
Symptoms of type 1 methemoglobinemia are:
Bluish discoloration of skin

Type two (Type IIb5R deficiency) is also called generalised cytochrome reductase deficiency.
It occurs when the methemoglobin reductase enzyme deficient/absent in the body.
Symptoms of type 2 methemoglobinemia are:
Bluish discoloration of skin
Developmental delay
Mental retardation
Seizures
Failure in survival
Hemoglobin M disease is the second form of inherited methemoglobinemia.
Any one parent can pass on the ailment to the child and all the family members will have the ailment.
The defective autosomal dominant gene causes defects in the hemoglobin molecule itself.
Symptoms of hemoglobin M disease are:
Bluish discoloration of skin

Causes of acquired methemoglobinemia

This form is more common in occurrence in children and adults exposed to causative agents.
Though these agents may not affect each and every individual, newborn, infants, children, elders, persons with debilitating diseases and persons with sensitivity to these agents have greater chances for getting acquired methemoglobinemia.
Infants have underdeveloped NADH methemoglobin reductase mechanisms and any severe infection, especially of the gastrointestinal tract causes systemic buildup of oxidants and causes this affliction.
Persons with reduced

Chemicals and environmental agents as causes:
Aniline dyes
Aromatic amines
Fertilizers containing nitrates
Arsine
Butyl nitrite
Copper sulfate
Chlorates
Chlorobenzene
Organic nitrite and nitrates
Chromates
Exhaust fumes
Amyl nitrite
Dimethyltoluidine
Isobutyl nitrite
Naphthalene
Nitroaniline
Sodium nitrite
Nitrobenzene
Nitrofurans
Nitroglycerin
Nitrophenol
Nitrosobenzene
Nitroprusside
Resorcinol
Nitric oxide
Silver nitrate
Nitrogen dioxide
Trinitrotoluene

Drugs and pharmaceutical agents as causes of methemoglobinemia:
Acetaminophen
Acetanilid
Benzocaine
Chloroquine
Cyclophosphamide
Celecoxib
Flutamide
Lidocaine
Ifosfamide
Prilocaine
Primaquine
Phenazopyridine
Phenacetin
Rasburicase

Antibiotics as causes:
Dapsone
Nitrofurans
Sulfonamides

Foods as causes:
Food rich in nitrites
Food rich in nitrates
Well water with high concentrations of nitrite and/or nitrate
Symptoms of acquired methemoglobinemia are:
Bluish discoloration of skin
Fatigue and lack of energy
Headache and giddiness symptoms
Shortness of breath as symptoms
High levels of methemoglobinemia can be debilitating and life threatening.
Knowledge of causes and symptoms of methemoglobinemia is required for proper medical care and emergency therapy.
Related topics:
What is methemoglobinemia?
Methemoglobinemia treatments
Current topic: Methemoglobinemia causes and symptoms

Sunday, March 11

Methemoglobinemia overview - What is Methemoglobinemia?


Methemoglobinemia is a form of blood hemoglobin disorder and is also known as hemoglobin M disease and Erythrocyte reductase deficiency.
In methemoglobinemia the oxygen carrying capacity of Red blood cells (RBC) is reduced and  oxygen supply to body tissues is affected.
Hemoglobin found in RBC is a characteristic multi-subunit globular protein and is also a metalloprotein containing iron.
The protein chain in each subunit is bound to a non-protein heme group.
The iron ion in the heme group is normally in ferrous (Fe2+) state (hemoglobin) which binds readily to oxygen in lungs during respiration.
However certain deficiencies in the enzyme mechanisms, certain harmful chemicals, drugs and/or certain hereditary factors can cause iron ion to remain in ferric (Fe3+) state (methemoglobin) and in this state the heme group is incapable of binding to oxygen.
This ferric state of heme group leads to oxygen starvation of body tissues causing discoloration and cyanosis (methemoglobinemia).
Though some methemoglobin is present in normal persons (1-2%), any further increase can result in methemoglobinemia conditions.

Methemoglobinemia may be caused due to exposure to certain drugs, food products and chemicals; this is the acquired form.
Antibiotics like dapsone and chloroquine, anesthetics like xylocaine and benzocaine, aniline dyes, preservative nitrite food additives and excess consumption of nitrate containing foods, especially by children, can cause acquired methemoglobinemia.
Methemoglobinemia may also result due to deficiency in the inherited enzyme mechanisms.
There are two types of inherited forms and in type 1 there is erythrocyte reductase deficiency. This type is caused by recessive gene and both the parents have to contribute the faulty gene for inheritance.
In the type 2 methemoglobinemia there is generalized reductase deficiency (hemoglobin M disease) and in this form a child inherits the disease even if only one parent has the culprit gene.

The initial symptom of acquired methemoglobinemia is slow setting of bluish discoloration of skin showing cyanosis.
The condition may not set right even on administration of oxygen.
Further the patient may lack energy and have fatigue, palpitations, confusion and headache.
The patient may show cellular hypoxia and at methemoglobin levels of 70% or more death may occur.
In the hereditary forms cyanosis can be seen at birth or soon after.
There may be developmental delay, mental impairment, seizures and death.
In fair skin complexion the blemishes and discoloration is apparent whereas in dark skin conditions it may become tougher.
Hence, the actual cause of methemoglobinemia must be investigated and depending on the causative factors various remedial measures can be taken.
Related topics:
Methemoglobinemia causes
Methemoglobinemia treatments