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Iranian Journal of Pathology (2012)7 (2), 135 - 138 Case Report
Asma Saadia, Mohammad Haroon Yusaf, Sajid Azeem Qureshi, Asim Mumtaz
Dept. of Pathology, Shalamar Institute of Health Sciences, Lahore, Pakistan Congenital methemoglobinemia is a rare cause of cyanosis. We report a case of a girl, 17 years old with peripheral cyanosis and normal cardio-pulmonary system. She was diagnosed as a case of methemoglobinemia based on findings of polycythemia and HbM band on hemoglobin electrophoresis. We emphasize the importance of this rare entity in the differential diagnosis of cyanosis. Keywords: Methemoglobinemia, Congenital, Hb M, Cyanosis
due to methemoglobin reductase enzyme deficiency and the other due to an abnormal ethemoglobinemia is a rare cause oxygen affinity hemoglobin termed hemoglo- of cyanosis. Most of the cases re- ported in literature are of the ac- Cyanosis caused by abnormal forms of hemo- quired type from the effects of drugs or chem- globin can be life-threatening, and early rec- icals(1) including aniline, aminophenones, ognition is necessary to prevent delay in man- chlorates, Dapsone, Prilocaine, Nitrates, Ni- agement (4). Diagnosis of the variety with trobenzene, phenazopyridine, Primaquine abnormal hemoglobin structure and function and related anti-malarials and sulfonamides. is based on clinical suspicion when cyanosis Congenital or hereditary methemoglobin- is present with normal oxygen saturation and emia is even a rarer variety (2). The clinical in the absence of any cardiopulmonary abnor- features and long-term outcome are poorly mality and response to ascorbic acid therapy documented and there are no systematic re- (5). Electrophoresis is a useful tool in the de- views (3). Congenital methemoglobinemia is termination of abnormal hemoglobin such as further categorized into two main types–one hemoglobin M (4). The condition is generally Received: 12 July 2011 Accepted: 13 November 2011 Address communications to: Dr Asim Mumtaz, Department of Pathology, Shalamar Institute of Health Sciences, Lahore, Pakistan Vol.7 No.2, Spring 2012 IRANIAN JOURNAL OF PATHOLOGY
asymptomatic even when the methemoglobin and O2 saturation (SO2) of 96.6% (normal level is as high as 40 % of total hemoglobin range 96 – 100 %).
(6). In the patient described herein, pulmono- Liver function tests and thyroid function tests logic and cardiologic investigations failed to done were essentially normal while anti- yield a diagnosis which was later based upon nuclear antibody and C-reactive protein were physical findings, arterial blood gas analysis and hemoglobin electrophoresis. ECG and echocardiography were within normal limits. Based on the above clinical Case report
history and investigations, hemoglobin We report a case of a girl, 17 years old, electrophoresis was requested, to rule out resident of Lahore, Pakistan who presented methemoglobinemia, which revealed band of with bluish dusky coloration of lips, hands Hb M in addition to normal HbA2 and HbF and feet for the last 8-9 years. Her problem and lead to the diagnosis of congenital ( Hb of occasional shortness of breath on exertion M) methemoglobinemia .
for about two years prompted consultation. Hemoglobin electrophoresis revealed bands Growth and development was apparently of HbA and HbM. Quantitation showed 50 % normal. She reported that a first cousin of HbA and 50 % HbM (Fig. 1). The presence of her had similar symptoms. The discoloration HbM band confirmed the diagnosis of Con- of lips was persistent and not related to the genital methemoglobinemia (HbM disease).
intake of any drug, any particular food, any previous illness, or any season of the year.
On examination, she had peripheral cyanosis, especially on the lips and tips of hands and feet. Other systems in particular cardiovascular and respiratory systems were essentially unremarkable. No splenomegaly or hepatomegaly was noted.
Fig. 1 - Hemoglobin Electrophoresis Pattern
Laboratory investigations revealed: Hb:17.3 gm/dl (normal for her age is 11.0- RBC:5.5 x 10 6/ul (normal for age 4.0 – 6.0)PCV:52.3% (normal for age 36 – 48) Causes of cyanosis include those with MCV, MCH and MCHC were within normal decreased PaO2 and SO2 including cardiac right-to-left shunts and respiratory disorders Platelets, leukocyte count and differential and those with normal PaO2 and SO2 including count were also within normal limits. Methemoglobinemia (7-10). Our patient had cyanosis with normal PO2 and SO2 with Reticulocytes 1% (0.2-2.0%) no findings on ECG and Echocardiography Red cell distribution width 53 (39-46) ruling out cardiopulmonary causes and RBC morphology was normocytic-normo- indicating the possibility of any rare etiology of cyanosis.
Arterial blood gases revealed a normal pH Moreover, our case had polycythemia, indi- with PO2 at 83 % (normal range 80-100%) cating some hematological abnormality. Hy- IRANIAN JOURNAL OF PATHOLOGY
Vol.7 No.2, Spring 2012 Asma Saadia, et al. poxic causes of polycythemia include high neonatal period or early childhood while our altitude, hypoxic lung disease, cyanotic heart case became symptomatic in adolescence.
disease, smoking, and abnormal hemoglobin Nevertheless, congenital methemoglobin- with altered oxygen affinity including methe- emia is a very rare but treatable cause of cya- moglobin and sulfhemoglobin (11).
nosis and it is important to consider it as a Methemoglobinemia is a rare disorder of he- differential diagnosis in cyanosis with poly- moglobin molecule with high oxygen affin- ity causing tissue hypoxia. Methemoglobin is present in small amounts in normal indi- viduals (< 1.9 gm/dl) and up to 2.8 gm/dl in 1. Conway R, Browne P, O'Connell P. An full-term neonates. The patient is cyanosed unusual cause of methemoglobinemia. Ir Med J when the level is more than 10% and may not become symptomatic (breathlessness, head- 2. Miller DR. Hemoglobinopathies in children. ache)even when the level is more than 40 % Massachusetts: PSG Publishing;1980.
(6-10), while a level more than 75 % is in- 3. Ewenczyk C, Leroux A, Roubergue A, Laugel compatible with life (9). V, Afenjar A, Saudubray JM, et al. Recessive Hemoglobin M is an abnormal hemoglobin hereditary methaemoglobinaemia, type II: autosomal dominant condition usually due to delineation of the clinical spectrum. Brain spontaneous mutation (1). Majority of HbM cases have histidine replaced by tyrosine in 4. Da-Silva SS, Sajan IS, Underwood JP, III. the alpha or beta globin chain and tyrosine Congenital methemoglobinemia: a rare cause of stabilizes iron in its ferric form (1) which cyanosis in the newborn--a case report. Pediatrics alters oxygen affinity of the hemoglobin molecule. Alpha chain variants present at 5. Jamal A. Hereditary methemoglobinemia. J birth while beta chain variants present later in Coll Physicians Surg Pak 2006;16(2):157-9.
6. Hamirani YS, Franklin W, Grifka RG, Stainback life (2) as is the possibility in our case which RF. Methemoglobinemia in a young man. Tex started to experience the bluish discoloration Heart Inst J 2008;35(1):76-7.
of lips and extremities at about 8 years of age.
7. Mandel S. Methemoglobinemia following Ascorbic acid (which reduces methemoglobin) neonatal circumcision. JAMA 1989;261(5):702.
and methylene blue (that activates enzyme) 8. Pierce JM, Nielsen MS. Acute acquired are used to treat methemoglobinemia (7- methemoglobinemia after amyl nitrite poisoning. 10). In our case methylene blue could not be of use, so only ascorbic acid therapy was 9. Rieder HU, Frei FJ, Zbinden AM, Thomson DA. advised with fortnightly follow-up. Pulse oximetry in methemoglobinemia. Failure Although congenital methemoglobinemia has to detect low oxygen saturation. Anesthesia been rarely observed in Pakistan (5, 12, 13), all previous cases had cyanosis as the basic 10. Watcha MF, Connor MT, Hing AV. Pulse abnormality as also was seen in our case. Other oximetry in methemoglobinemia. Am J Dis Child presenting symptoms were not well elaborated and comparable in the previous reports as the 11. Howard MR, Hamilton PJ. Hematology. 1st ed. Edinburgh: Churchill Livingstone; 1997. type of methemoglobinemia in hemoglobin 12. AbdulRehmankhan FM, Shah SKA. Methe- M runs a benign course and the patients are moglobinemia. J Postgraduate Med Inst 1990; "more blue than sick". Furthermore, most of the previous reports were of children in 13. Nusrat M, Moiz B, Nasir A, Rasool HM. An Vol.7 No.2, Spring 2012 IRANIAN JOURNAL OF PATHOLOGY
insight into the suspected HbA2' cases detected Pakistan. BMC Res Notes 2011;4:103.
by high performance liquid chromatography in IRANIAN JOURNAL OF PATHOLOGY
Vol.7 No.2, Spring 2012

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