Moffitt Pearls 6.30.17 – Behcet Disease and Methemoglobinemia

Thanks so much to TJ for presenting her first morning report case! She presented the case of a young man with history of Behcet disease on high dose steroids presenting with 5d of worsening skin lesions on his hands, legs, and abdomen, fever, new murmur and mild methemoglobinemia. Patient was also found to have MRSA growing from his wounds and given a TEE with a thickened mitral valve leaflet + MR he was treated for MRSA endocarditis w/ a 6 week course of IV antibiotics.

Key Pearls:

  1. Behcet’s is a clinical diagnosis with no “slam dunk” serology or pathology to guide the diagnosis. Generally, it is one of exclusion and a number of other diseases should be considered in the differential (see below).
  2. Dapsone is a common culprit of methemoglobinemia – diagnose this with an arterial co-oximetry.
  3. Duke’s Criteria should be used to help support or reject the hypothesis for endocarditis. One then needs to apply this information to the specific patient in front of them to weigh the risks and benefits. (

When should I think about Behcet disease?

Behçet’s syndrome is rare and remarkable for its ability to involve blood vessels of all sizes (small, medium, and large) on both the arterial and venous sides of the circulation. Because Behcet disease is a systemic vasculitis, multiple organ systems are generally affected. While painful mucocutaneous ulcers (including genital and oral) are the most classic symptom, these are relatively common and nonspecific for Behcet. Systemic manifestations that should raise concern for Behcet include the following:

  • Ocular disease: up to 2/3 of patients; hypopyon, uveitis (posterior or anterior), or retinal vasculitis; associated with greatest morbidity and mortality
  • Neurologic disease: < 10% of patients and is divided in parenchymal and non-parenchymal disease
  • Vascular disease: pulmonary artery aneurysms, Budd-Chiari syndrome, and cerebral venous thrombosis
  • Arthritis – ~ 50% patients affected with nonerosive, asymmetric, usually nondeforming
  • GI Involvement – difficult to distinguish from IBD
  • Pathergy – when minor trauma results in cutaneous pustules

Differential diagnosis of recurrent oral ulcerations – adapted from UpToDate


Rheumatologic diseases SLE
Reactive arthritis
GI diseases IBD – primarily Crohn’s disease
Autoinflammatory conditions Periodic fever, apthous stomatitis, pharyngitis and adenitis (PFAPA) syndrome
Hyperimmunoglobulinemia D syndrome
Infections HSV
Immunocomp: CMV, coxsackie, histoplasmosis
Dermatologic diseases Stevens-Johnson syndrome
Lichen planus
Hematologic conditions Cyclic neutropenia
Other Drugs including methotrexate, chemotherapy, nicorandil
Nutritional deficiencies: Vit B12, iron, folic acid
Recurrent apthous stomatitits

International Clinical Criteria for Behcet Disease

(one of many different existing sets of criteria)

  • Recurrent oral ulcerations (apthous or herpetiform) at least 3 times in one year


  1. Recurrent genital ulcerations
  2. Eye lesions (uveitis or retinal vasculitis) observed by ophthalmologist
  3. Skin lesions (erythema nodosum, pseudofolliculitis, papulopustular lesions, acneiform nodules) found in adult patients not being treated with coritcosteroids
  4. Positive pathergy test read by physician within 24-48 hours


  • Altered state of hemoglobin in which ferrous iron (Fe++) becomes oxidized to the ferric state (Fe+++)
  • Ferric heme of methemoglobin is unable to reversibly bind oxygen + the affinity of remaining ferrous hemes is increased
  • Results in “left-shift” of the oxygen dissociation curve and absolute oxygen delivery is impaired to the tissues

The percentage of methemoglobin will dictate the degree of symptoms:

Methemoglobin % Symptoms
<15% asymptomatic
20-30% cyanosis, confusion, syncope, dizziness
30-50% shortness of breath, headache
50-70% dysrhythmias, seizure, stupor, coma
>70% death


  • Discontinue inciting drug – in this case dapsone
    • Other causes include: chloroquine, primaquine sulfonamides, local anesthetics (benzocaine), nitrates/nitrites
  • Supplemental oxygen
  • Ascorbic acid (Vitamin c)
  • Consideration of methylene blue (don’t not use this in G6PD deficiency given hemolytic anemia risk)




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