medical decision support medical decision support
Sign In

Clinical and Laboratory Features of Sulfhemoglobinemia

Description

Sulfhemoglobinemia occurs when a sulfur atom is introduced into the porphyrin ring of heme. Sulfhemoglobin is unable to transport oxygen; however, a rightward shift in the oxygen dissociation curve means that remaining normal hemoglobin has less affinity for bound oxygen, with less tissue hypoxia and milder symptoms.


 

Clinical features:

(1) cyanosis

(2) history of exposure to a drug containing sulfur group (acetanilid, phenacetin, metoclopramide, sulfonamides, sumatriptan, glutathione) or to sulfur compounds

(3) history of ingesting an oxidative agent (with sulfur released from hydrogen sulfide generated in the intestines)

 

Laboratory features:

(1) dark, greenish blood

(2) desaturation (low oxygen saturation) on pulse oximetry

(3) normal PaO2 in mild cases

(4) presence of sulfhemoglobin on spectrophotometric analysis (absorption maximum 620 nm; cyanosis appears at 2-5 g/L)

 

Differential diagnosis:

(1) methemoglobinemia (which may be coexistent)

 


To read more or access our algorithms and calculators, please log in or register.

Specialty