I-Methemoglobinemia

I-Methemoglobinemia (MetHb) yisifo segazi lapho kukhiqizwa inani elingajwayelekile le-methemoglobin. IHemoglobin yiprotheni esemaseli abomvu egazi (ama-RBCs) athwala futhi ahambise umoya-mpilo emzimbeni. I-Methemoglobin uhlobo lwe-hemoglobin.

Nge-methemoglobinemia, i-hemoglobin ingathwala umoya-mpilo, kepha ayikwazi ukuyikhipha ngempumelelo kwizicubu zomzimba.

Isimo seMetHb kungaba:

• Kudlule emindenini (ezuzwe njengefa noma kokuzalwa)
• Kubangelwe ukuvezwa yimithi ethile, amakhemikhali, noma ukudla (okutholakele)

Kunezinhlobo ezimbili zeMetHb ezuzwe njengefa. Ifomu lokuqala lidluliselwa ngabazali bobabili. Ngokuvamile abazali abanaso lesi simo ngokwabo. Baphethe ufuzo oludala isimo. Kwenzeka lapho kunenkinga nge-enzyme ebizwa nge-cytochrome b5 reductase.

Kunezinhlobo ezimbili zeMetHb ezuzwe njengefa:

• Uhlobo 1 (olubizwa nangokuthi ukushoda kwe-erythrocyte reductase) lwenzeka lapho ama-RBC engenayo i-enzyme.
• Uhlobo lwe-2 (olubizwa nangokuthi ukungenzi kahle kwe-redisedase) lwenzeka lapho i-enzyme ingasebenzi emzimbeni.

Indlela yesibili yeMetHb ezuzwe njengefa ibizwa ngokuthi yi-hemoglobin M disease. Kubangelwa ukukhubazeka kwiprotheni ye-hemoglobin uqobo. Munye kuphela umzali odinga ukudlulisa isakhi sofuzo esingajwayelekile ukuze ingane izuze lesi sifo njengefa.

I-MetHb etholakalayo ivame kakhulu kunezinhlobo ezizuzwe njengefa. Kwenzeka kwabanye abantu ngemuva kokuvezwa amakhemikhali nemithi ethile, kubandakanya:

• Ama-anesthetics afana ne-benzocaine
• I-Nitrobenzene
• Amanye ama-antibiotic (kufaka phakathi i-dapsone ne-chloroquine)
• Ama-nitrites (asetshenziswa njengezithasiselo ukuvimbela inyama ukuthi ingonakali)

Izimpawu zohlobo 1 MetHb zifaka:

• Umbala we-Bluish wesikhumba

Izimpawu zohlobo 2 MetHb zifaka:

• Ukubambezeleka kwentuthuko
• Ukwehluleka ukuchuma
• Ukukhubazeka kwengqondo
• Ukuquleka

Izimpawu zesifo se-hemoglobin M zibandakanya:

• Umbala we-Bluish wesikhumba

Izimpawu zeMetHb etholakele zifaka:

• Umbala we-Bluish wesikhumba
• Ubuhlungu bekhanda
• Ubuntwana
• Isimo sengqondo esishintshile
• Ukukhathala
• Ukuphelelwa umoya
• Ukungabi namandla

Ingane enalesi simo iyoba nombala wesikhumba ohlaza okwesibhakabhaka (cyanosis) lapho izalwa noma ngemuva nje kwalokho. Umhlinzeki wezokunakekelwa kwempilo uzokwenza ukuhlolwa kwegazi ukuthola isimo. Ukuhlolwa kungafaka:

• Ukuhlola izinga le-oxygen egazini (pulse oximetry)
• Ukuhlolwa kwegazi ukuhlola amazinga amagesi egazini (ukuhlaziywa kwegesi yegazi)

Abantu abanesifo se-hemoglobin M abanazo izimpawu. Ngakho-ke, kungenzeka bangadingi ukwelashwa.

Umuthi obizwa nge-methylene blue usetshenziselwa ukwelapha iMetHb enamandla. I-Methylene blue ingahle ingaphephi kubantu abanesifo segazi esibizwa ngokuthi yi-G6PD noma abanobungozi. Akufanele bathathe lo muthi. Uma wena noma ingane yakho unenkinga ye-G6PD, hlala utshela umhlinzeki wakho ngaphambi kokuthola ukwelashwa.

I-Ascorbic acid nayo ingasetshenziselwa ukunciphisa izinga le-methemoglobin.

Ezinye izindlela zokwelashwa zifaka i-hyperbaric oxygen therapy, ukufakwa kwegazi elibomvu nokufakwa kokushintshaniswa.

Ezimweni eziningi ze-MetHb etholwe ngobumnene, akukho ukwelashwa okudingekayo. Kepha kufanele ugweme umuthi noma ikhemikhali edale inkinga. Izimo ezinzima zingadinga ukumpontshelwa igazi.

Abantu abane-type 1 MetHb nesifo se-hemoglobin M bavame ukwenza kahle. Uhlobo lwe-2 MetHb lubucayi kakhulu. Imvamisa kubangela ukufa eminyakeni embalwa yokuqala yokuphila.

Abantu abane-MetHb etholakele bavame ukwenza kahle kakhulu uma umuthi, ukudla, noma ikhemikhali elidale inkinga lakhonjwa futhi lagwenywa.

Izinkinga ze-MetHb zifaka:

• Ukushaqeka
• Ukuquleka
• Ukufa

Shayela umhlinzeki wakho uma:

• Yiba nomlando womndeni we-MetHb
• Thuthukisa izimpawu zalesi sifo

Shayela umhlinzeki wakho noma abezimo eziphuthumayo (911) ngaso leso sikhathi uma uphefumula kanzima.

Ukwelulekwa ngofuzo kuphakanyiswa imibhangqwana enomlando womndeni weMetHb futhi icabanga ukuba nezingane.

Izingane ezinyangeni eziyisithupha noma ngaphansi zinamathuba amaningi okuthuthukisa i-methemoglobinemia. Ngakho-ke, ama-purees okuzenzela ukudla okwenziwe ngemifino equkethe amazinga aphezulu ama-nitrate emvelo, njengezaqathe, ama-beetroots, noma isipinashi kufanele kugwenywe.

Isifo se-Hemoglobin M; Ukushoda kwe-erythrocyte reductase; Ukuntuleka kwe-reductase okujwayelekile; I-MetHb

• Amaseli egazi

I-Benz EJ, i-Ebert BL. Ukwahluka kwe-hemoglobin okuhambisana ne-hemolytic anemia, ukushintsha kwe-oxygen, kanye ne-methemoglobinemias. Ku: Hoffman R, Benz EJ, Silberstein LE, eds. I-Hematology: Izimiso Eziyisisekelo Nokuzijwayeza. Umhla wesi-7. IPhiladelphia, PA: Elsevier; 2018: isahluko 43.

I-Letterio J, Pateva I, Petrosiute A, Ahuja S. Hematologic kanye nezinkinga ze-oncologic ku-fetus neonate. Ku: Martin RJ, Fanaroff AA, Walsh MC, ama-eds. UFanaroff kanye neMithi kaMartin's Neonatal-Perinatal Medicine. Umhla ka-11. IPhiladelphia, PA: Elsevier; 2020: isahluko 79.

Kusho i-RT. Sondela kuma-anemias. Ku: IGoldman L, iSchafer AI, ama-eds. Imithi yeGoldman-Cecil. Umhla ka-26. IPhiladelphia, PA: Elsevier; 2020: isahluko 149.