RE: Black ant stings caused by Pachycondyla sennaarensis: A significant health hazard

To the Editor: I read with keen interest the article published by Soldo-Juresa et al in the last issue of the journal.1 I would like to make some comments: First, Still disease should be kept in mind whenever macrophage activation syndrome is considered in a patient with the clinical picture shown. In fact the patient’s condition fulfills the criteria published by Yamagushi for Still disease.2 I would like to remark that the measurement of soluble IL-2R (also known as CD25s) could be helpful in distinguishing between Still disease and MAS.3 Furthermore, the development of MAS in Still disease is not infrequent and intravenous gamma globulins have shown promising results in treatment.4,5 Second, as the authors rule out a C1q-linked vasculitis, C4 and alternative complement pathway activity should be measured. It is well known that in esterase inhibitor type II levels of C1-inhibitor esterase are normal although C4 is decreased due to low functional C1-inhibitor levels.6 Hypocomplementemic vasculitis has been also described in patients with factor I deficiency.7 I have attended recently a patient with vasculitis secondary to factor I deficiency. This factor was not measured by the author in this patient. Third, the authors recognize that DNA of parvovirus B-19 can persist in bone marrow for years. This is why we should distinguish between MAS secondary to viral infection or underlying Still disease that needs long-term treatment and follow-up. Luis Gonzalez-Granado


RE: Reactive macrophage activation syndrome (MAS) in a patient with parvovirus B19 infection, lymphocytic lichenoid vasculitis, urticaria and angioedema
To the Editor: I read with keen interest the article published by Soldo-Juresa et al in the last issue of the journal. 1 I would like to make some comments: First, Still disease should be kept in mind whenever macrophage activation syndrome is considered in a patient with the clinical picture shown. In fact the patient's condition fulfills the criteria published by Yamagushi for Still disease. 2 I would like to remark that the measurement of soluble IL-2R (also known as CD25s) could be helpful in distinguishing between Still disease and MAS. 3 Furthermore, the development of MAS in Still disease is not infrequent and intravenous gamma globulins have shown promising results in treatment. 4,5 Second, as the authors rule out a C1q-linked vasculitis, C4 and alternative complement pathway activity should be measured. It is well known that in esterase inhibitor type II levels of C1-inhibitor esterase are normal although C4 is decreased due to low functional C1-inhibitor levels. 6 Hypocomplementemic vasculitis has been also described in patients with factor I deficiency. 7 I have attended recently a patient with vasculitis secondary to factor I deficiency. This factor was not measured by the author in this patient. Third, the authors recognize that DNA of parvovirus B-19 can persist in bone marrow for years. This is why we should distinguish between MAS secondary to viral infection or underlying Still disease that needs long-term treatment and follow-up.

RE: Black ant stings caused by Pachycondyla sennaarensis: a significant health hazard
To the Editor: We read with interest the article on black ant stings by Alanazi et al 1 and would like to make the following comments. We agree with the authors that black ant stings are a significant and growing problem in Saudi Arabia. Both cases 2 and 3 had significant symptoms after black ant stings. In both cases, among other management, epinephrine was used, but it was given subcutaneously. It should be pointed out that the current recommendation is to give epinephrine intramuscularly in the lateral aspect of the thigh (vastus lateralis) 2 because there is a significant difference in the absorption of epinephrine when it is given intramuscularly in the lateral aspect of the thigh vs intramuscularly in the deltoid, or subcutaneously in the upper arm. Mean Cmax was significantly higher (P<.01) after epinephrine IM injection into the thigh, either from an ampule or an EpiPen, than after epinephrine IM or SC injection into the upper arm, or after saline solution IM or SC injection into the upper arm. 3 We have a number of patients with black ant allergy and they have tested positive to an extract prepared in house. They carry two pack of Epipen and have been trained in how and when to use them. We are currently in the process of developing immunotherapy for desensitization to black ant venom. We will be very happy to accommodate any patients that need further work up/treatment for black ant allergy.

Reply
We agree that the intramuscular route is superior to the subcutaneous in terms of better absorption and we would like to thank Dr. Gazlan for his comment.

Fludarabine-induced bradycardia in a patient with refractory leukemia
To the Editor: A 22-year-old male diagnosed with acute myelogenous leukemia in November 2005 achieved complete remission after two courses of induction chemotherapy with idarubicin (12 mg/ m 2 intravenously for 3 days) and cytosine arabinoside (200 mg/m 2 in a 24-hour infusion for 7 days). He then received an additional two courses of cytosine arabinoside (3000 mg/m 2 ) in a 3-hour continuous intravenous infusion twice daily for 3 days in April 2006 for intensification. Six months later, the leukemia relapsed and was refractory to re-induction chemotherapy (idarubicin 12 mg/m2 on days 1-3 and cytosine arabinoside 200 mg/m 2 on days 1-7). With the exception of myelosuppression, no toxic events occurred during idarubicin and cytosine arabinoside treatment. Due to the refractoriness to re-induction chemotherapy, salvage chemotherapy with the FLAGI regimen (fludarabine 30 mg/m 2 on days 1-5, cytosine arabinoside 2000 mg/m 2 on days 1-5, and idarubicin 12 mg/ m 2 on days 7-8) was prescribed. Before chemotherapy, his vital signs were stable, with a blood pressure of 111/65 mm Hg, a respiratory rate of 19/min, a heart rate of 97/min, and a body temperature of 36.6ºC. An electrocardiogram (ECG) showed a normal sinus rhythm ( Figure  1a). Premedication included dexamethasone, granisetron, and metoclopramide, which were prescribed in previous chemotherapy. Thirty minutes after the fludarabine infusion had been started, he developed sudden-onset general weakness, which lessened 5 minutes later. At that time, persistent bradycardia (48 beats per minute) was noted; vital signs were otherwise normal (blood pressure, 120/70 mm Hg; respiratory rate, 20/min; and body temperature, 36.1ºC). ECG revealed sinus bradycardia but no   atrioventricular block, ST segment elevation or depression, or T wave inversion (Figure 1b). The patient did not have chest tightness or pain, dizziness, cold sweats, palpitations, dyspnea, or fever with chills. Investigations showed serum potassium 4.9 mmol/L (normal, 3.5-4.5 mmol/L), creatinine 1.0 gm/dL (normal, 0.5-1.3 g/dL), CPK 19 IU/L (normal, 38-174 IU/L), creatine kinase MB fraction 2.7 U/L (normal, 3-10 U/L), and troponin I < 0.04 ng/ml (normal, <0.8 ng/ mL). No specific therapy was administered; however, oxygen was given at 4 L/min via nasal cannula. The persistent bradycardia resolved gradually, 3 hours after cessation of the 5-day fludarabine infusion ( Figure 1c); he then received 2 days of idarubicin treatment without incident ( Figure 2).
Cytosine arabinoside is frequently used in the treatment of hematologic malignancies, especially acute myelogenous leukemia. Sporadic cases of pericarditis, pericardial effusion, cardiac tamponade, congestive heart failure, and sinus bradycardia have previously been reported as complications of cy-