two cases of methemoglobinemia
TRANSCRIPT
Case of xenobiotic induced cyanosis
Dr.s.a.jayakumar IMCU chief -Prof. Dr.Chenthil
CASE 1Mr.Suresh 35/male
Admitted on 24.12.2010
Alleged h/o ingestion of some oil ?carburetor oil
He was found lying unconscious with a can of oil beside him; He had vomitted and he was covered with
vomitus ;
Past history : not a DM/HT/IHD/ BA/TB patient
Personal history : chronic alcoholic > 15 yrs -360 ml /day
Unconscious GCS E1 V1 M1Tachypneic Dyspnoeic Cyanosis + fingers toes , lips & tongue
Pulse : 110/mt BP : 80/60 mmhg RR: 30/mt
SpO2 :85 % ABG
p H 7.36 p O2- 107 p CO2 -32.6
Immediately patient was intubated & put on ventilator ;on ACMV mode;with FiO2 100%;
IVFDopamine infusion started at 10µg/kg/mt
Inj .methylene blue 1 mg/kg infusion given
Hb – 12.0 g/dl;TC- 9600; P80 ;L20;ESR - 5/12 mm;PCV-36%;Platelets -1.8 lakhs
RBS – 122 mg/dl;Urea- 26 mg/dl;Creatinine – 0.8 mg/dl
Na-138meq; k-4.8 meqCl -96meq;Hco3-22meq
Serum meth Hb -- ++
course after treatment;
initially patient improved consciuosness after 2 doses of methylene blue ;Cyanosis improved;Obeying commands ;
Within 2 days ,he developed fever ,progressive dyspnea ,extensive crepitations and despite antibiotics ,ventilatory support & other supportive measures died on the third day of admission ;
Case 2 Mrs.Devi , 28 yrs female
Admitted on 13.03.2011 ;
Alleged to have consumed some amount of a
product ‘ hytro-zyme ‘
Nitrobenzene
She was found unconscious in her house ,
with deep irregular breathing and secretions from mouth ;
Past history : not a DM/HT/IHD/BA/ patient
Personal history : regular menstrual cycles ; takes mixed diet
Unconscious E4 V1 M4DyspneicTachypneicCyanosis of lips,tongue ,fingers &
toes
Pulse 100/mt;BP- 90/60 mmhg ;RR- 34/mt
SpO2 -80%
ABG p H 7.4 p O2 128 p CO2 34
Immediately patient was intubated & connected to ventilator –ACMV mode with FiO2 -100 %;
IVF
Inj.methylene blue 1mg/kg ;
Hb-10.2g/dl;TC- 9800; P86 L14;ESR-10/22PCV-30%;Platelet :1.5 lakhs;
RBS- 131mg/dl;Urea -31Creatinine -1.1
Na 134; K 4.5Cl -98; Hco3-22
Serum meth hb +
Course after treatment
Patients SpO2 was constantly around 80 % despite ventilatory support ;Consciousness didn’t recover ;
She developed progressive hypotension and stayed unconscious ;
After 2 days despite all available measures she died
Case 1 ingestion of ? carburetor oil –
organic solvent cyanosis hypotension Meth
hemoglobinemia Initial improvement
with methylene blue
Case 2 Ingestion of nitro
benzene
cyanosis, Hypotension Meth
hemoglobinemia No improvement
despite treatment ;
cyanosis
high flow O 2 ( improves)
(no improvement )
met hb conc.
< 25% >25%
asymptom. Symptom methyleneblue
no respon.
respon
Basics Reversible binding of oxygen to
hemoglobin is ‘oxygenation’;Whereas oxidised hemoglobin is a
state where ferrous iron is converted to ferric
iron; such a hemoglobin (oxidised
hemoglobin)is called “meth hemoglobin “
Normally met Hb level is in the body < 1 % ;
Protective mechanisms
When there is a basic defect in the protective mechanisms
( HEREDITARY ) or When there is an external agent which
overwhelms the protective
mechanisms ( ACQUIRED )
clinically significant methhemoglobinemia results
HEREDITARY METHHEMOGLOBINEMIA
Deficiency of diaphorase I(NADH met Hb reductase):
type 1 - 85% ; autosomal recessive ; only mature red cells are affected;
type 2 - 10 -15 % of cases ; all cells are affected ;
developmental delay & early death ;
Hemoglobin M disease : autosomal dominant ; either alpha or beta
globin affected
other causes: pyruvate kinase deficiency G6PD deficiency
METH HAEMOGLOBINEMIA
Acetanilidp-Amino salicylic acidAniline dyes
Benzene derivativesClofazimine Chlorates
ChloroquineDapsoneBenzocaineLidocainePrilocaineMenadione
MetoclopramideMethylene blue*
Naphthoquinone
NaphthaleneNitritesAmyl nitriteFarryl nitriteSodium nitrite
NitroglycerinNitric oxideNitrobenzeneParaquatPhenacetinPhenazopyridine
PrimaquineResorcinol
Sulfonamides
Pathogenesis
Met Hb causes - decreased available O2 carrying
capacity ; -increased affinity of unaltered Hb FOR o2
,shifting the oxygen dissociating curve to left ;
Cyanosis develops when 1.5 g/dl met hb is present ;
Also depends on the rate of formation and elimination
of MetHb
1 - < 3 % Asymptomatic
3 – 15 % Slate grey color
Low SpO2
15 – 20 % Cyanosis Chocolate brown blood
20 – 50 % Dyspnea , dizziness,exercise intolerance ,syncope ,headache weakness
50 – 70 % Tachypnea ,arrhythmia ,metabolic acidosis ,seizures ,CNS depression ,Coma
> 70% Grave hypoxia ,death
Investigations PULSE OXIMETER :
-non invasive method; measures SpO2 ;
-2 light emitting diodes –measure absorbance at peak
wavelength for oxy & deoxy Hb – 940 & 660 nm respectively ;
-presence of meth Hb ,sulf Hb interfere with the accuracy of pulse oximeter;
presence of methylene blue too interferes
LP 15 defibrillator /pulse
oximeter ;
Advantage of monitoring meth hemoglobin
ABG
In cases of meth hemoglobinemia when there is cyanosis
and the SpO2 is abnormal with the help of ABG we can find out
that the PO 2 normal ; as the ABG is not affected by the abnormal hemoglobin
Co oximeters :
it is a spectrometer ;
uses 4 wavelengths of light;
measures oxyHb, deoxyHb, carboxyHb
& metHb
Met hb assay Quantitative test is by EVELYN MALLOY
method Take 2 aliquots of blood 1 & 2 ; 1) Absorbance measured at 630nm
(A1);add pot.cyanide; measure again absorbance(A2) ; if any met hb + the cyanide will abolish the absorbance peak
2)add pot.ferricyanide;all Hb converted to metHb;now measure absorbance before(A3) and after adding cyanide(A4) ;
% of met Hb = ( A1-A2)×100 / (A3-A4)
Treatment: 1.methylene blue; 1-2mg/kg infused over 5
mts ;not exceed 7mg/kg; clinical improvement seen within 1 hr ; contraindicated in G6PD deficiency 2. Hyperbaric oxygen ;3.Exchange transfusion ;NOTE: Blood transfusions and ascorbic acid are of
unproven value ;
CERTAIN INTERESTING ANECDOTES : 1. Ernst Felix Immanuel Hoppe-Seyler
german scientist first described meth hemoglobin ;
2. hyperlipidemia may spuriously cause elevated methb levels ;
3. foods having high nitrate content which might cause methb
cauliflower carrot spinach & broccoli;
4.Well water with high nitrate content can cause meth Hb ;
5.Dapsone induced meth hemoglobinemia ; -- use cimetidine as it prevents the
formation of toxic metabolite of dapsone