Visceral leishmaniasis treated with liposomal amphotericin B.

Abstract

Visceral leishmaniasis is an endemic disease in India, Asia, South America and along the Mediterranean coasts, with most cases occurring inchildren. In Italy the disease occurs mainly in the Southern regions, such as Sicily, but also in the regions of Latium, Tuscany, Liguria and the Adriatic coast.1, 2 The number of reported cases in Italy increased from 32 in 1988 to 104 in 1992. This might be explained, in part, by the withdrawal of DDT (dichlorodiphenyltrichloroethane) in high risk zones with a consequent increase in the vector (Phlebotomus) of leishmaniasis, the increase in stray dogs, opportunistic infections occurring in patients with HIV living in endemic areas, improvement in surveillance and more accurate reports from regional epidemiology observers. The etiologic agent in Italian leishmaniasis is Leishmania infantum, and the major reservoir is the dog, in which complete eradication of the infection with pharmacologic therapy is difficult. Humans are usually infected by a bite from a previously infected Phlebotomus female. The incubation period is variable, ranging from 1 to 2 or even 10 months. Pediatric infection is usually characterized by a variable onset, with malaise, fever and weight loss, followed by high, irregular fever, sometimes with two peaks during the day. The fever is often resistant to antipyretics and alternates with periods of low or absent fever. Typical findings from a physical viewpoint include paleness of skin and mucosae, hepatosplenomegaly and lymphadenopathy. The clinical course, without therapy, may be fatal, with renal, hepatic and cardiac failure as well as bacterial complications. Laboratory data usually show severe and progressive hypochromic anemia, leukopenia with a predominance of lymphocytes and macrocytes, thrombocytopenia, hypoalbuminemia with polyclonal hypergammaglobulinemia and, at times, even an increase in liver function test results. Diagnosis of visceral leishmaniasis is based on the historical, clinical and laboratory data as well as direct and indirect methods to assess the presence of the etiologic agent (bone marrow, liver and/or spleen biopsy with culture isolation on rabbit blood agar, where Leishmania grows in 5 to 20 days at 24°C as promastigotes); indirect methods are used to detect antibodies directed to the parasite. Prognosis depends on early diagnosis and treatment. After resolution patients should be followed up with clinical and laboratory investigations at least during the first year, to prevent and treat possible relapses.3 Drugs usually used in leishmaniasis are antimonial derivatives, such as N-methylglucamine antimoniate (Glucantim) and stilbogluconate sodium (Pentostam). Glucantim is the first line agent and is given in a dosage of 60 to 100 mg/kg, in two divided doses. Treatment protocol comprises two cycles of 15 to 20 days each, with a rest period of 15 days between each cycle. Several side effects have been reported during Glucantim treatment, including painful injection, diarrhea, emesis, abdominal discomfort and hepatic, renal and particularly cardiac toxicity. Cardiac impairment is related to the accumulation of the drug in myocardial cells and results in electrocardiographic abnormalities (reversible repolarization disorders, rhythm disturbances and bradycardia) and myocardial ischemia. In the presence of resistance or intolerance to antimonial derivatives, pentamidine isethionate is used in a dosage of 2 to 4 mg/kg daily for a total of 2 weeks of treatment.4 Amphotericin B has good antiprotozoan activity but has limitations because of its dose-dependent side effects including nephrotoxicity and thrombophlebitis.5, 6 Amphotericin B is given in doses of 3 mg/kg iv daily for 4 consecutive days or for 5 days plus another single dose 10 days after the beginning of treatment.7-9 Recently liposomal amphotericin B has been used in pediatric visceral leishmaniasis. This drug is produced by combining amphotericin B to the fatty double layer of liposomes, resulting in a strong tropism for the macrophages of the reticuloendothelial system (the major host reservoir of Leishmania) as well as offering an improved stability in plasma and lower renal and cardiac toxicity. Case 1. A 2-year-old white male child, coming from Tuscany, presented with a 1-week history of high continuous fever, fatigue and pallor. The hemoglobin (Hb) was 7.1 g/dl, white blood cells (WBC) 2617/μl, platelets 72 000/μl. A bone marrow biopsy demonstrated the presence of intracellular Leishmania. The history revealed that the child had been bitten on the left foot by an insect at the seaside. Physical examination on admission revealed an ill appearing child with pale skin and mucosae and hepatosplenomegaly. Laboratory tests showed: Hb 6.2 g/μl, WBC 1990 μl, platelets 59 000 μl, aspartate aminotransferase (AST) 140 units/l, alanine aminotransferase (ALT) 157 units/l, hypoalbuminemia with hypergammaglobulinemia. Anti-Leishmania antibodies were positive with a 1:80 titer. Electrocardiogram was normal. The administration of Glucantim (60 mg/kg/day in two daily doses) was commenced. The clinical course during the first 4 days was characterized by high fever, a decrease in Hb to 5 g/dl necessitating transfusion, thrombocytopenia (platelets 37 000/μl) and an increase in AST and ALT values to 410 and 461 units/l, respectively. Subsequently the general condition improved, with fever disappearing on Day 5. Liver size and hematochemical abnormalities had returned to normal. On Day 7 of treatment the child was monitored for cardiac toxicity from Glucantim, and the presence was noted of coronal sinus rhythm and bradycardia (from 95 to 75 beats/min). Treatment was therefore suspended and liposomal amphotericin B (vials containing 50 mg of amphotericin B.P., encapsulated in liposomes consisting of approximately 213 mg of cholesterol, phatydiglycerol together with 900 mg of sucrose B.P., 27 mg of disodium succinate hexahydrate and 0.64 mg of alpha-tocopherol, obtained from Vestar Ltd., UK) started in a dosage of 3 mg/kg/day iv for 5 days, the last dose being given 10 days after the beginning of treatment. The electrocardiogram returned to normal 2 days after withdrawal of Glucantim. The child, 28 months after treatment, was good condition, the infection being completely eradicated and no relapse being reported. Case 2. An 18-month-old white male child presented with a 20-day history of high, continuous fever, fatigue and loss of appetite. Physical examination showed pale skin and mucosae and slight liver and spleen enlargement; the possibility of visceral leishmaniasis was taken into consideration because of the history (the child came from Sicily, a region with high frequency of infection) and the clinical presentation (continuous fever, paleness, liver and spleen enlargement) of the patient. Laboratory studies revealed anti-Leishmania antibodies with a 1:80 titer. Tests for other bacterial or viral infections were negative. The child was then admitted to our unit. Further laboratory investigations showed Hb 8.2 g/μl, WBC 4980/μl, platelets 123 000/μl, AST 72 units/l, ALT 102 units/l, prothrombin time 6.2 s; bone marrow biopsy was negative for Leishmania. Despite the negative biopsy therapy was begun with N-methylglucosamine 50 mg/kg/day in two daily doses. On Day 3 another bone marrow biopsy was still negative for Leishmania, and treatment was withdrawn. At that time the electrocardiogram showed a small pericardial effusion. Five days later the child was afebrile with a normal blood cell count and no change in the Leishmania antibody titer. The child was discharged but was readmitted 28 days later because of a 10-day history of high fever, resistant to antipyretic drugs. Physical examination showed pale skin and mucosae and marked spleen enlargement (3 cm). Laboratory data showed Hb 9 g/μl, WBC 8230/μl, platelets 185 000/μl, AST 67 units/l, ALT 62 units/l, prothrombin time 6.5 s. Bone marrow biopsy demonstrated the presence of a few Leishmania organisms. Echocardiography showed persistent pericardial effusion; therefore therapy with liposomal amphotericin B (diluted with 12 ml of refrigerated sterile water for injection to yield a preparation containing 4.0 mg/ml amphotericin, then administered in a 5% dextrose injection diluted with 7 parts by volume, light-protected: obtained from Vestar Ltd.), 3 mg/kg/day iv, was started. The child's condition quickly improved and fever soon disappeared, with recovery of bone marrow function and reduction in spleen enlargement. No side effects (hepatic, cardiac, renal) were observed. At follow-up 5 months after the end of treatment, the two patients showed no signs of infection, and anti-Leishmania antibody titer was low. Discussion. Visceral leishmaniasis is a becoming a common pediatric infection in Italy. On account of the high incidence of reservoir infection in dogs, it is desirable to effect eradication of the vectors. Diagnosis may be difficult in children in that it can present with negative bone marrow biopsy and a low concentration of Leishmania antibodies. In the two cases presented here liposomal amphotericin B treatment was effective in the management of visceral leishmaniasis. General conditions quickly improved in both patients, with disappearance of fever, reduction in spleen and liver enlargement and return to normal of laboratory data within a few days. No local (skin rash, itching) or systemic (fever and rigors during administration, renal and cardiac toxicity) side effects were observed. Both children are now in good health, with no signs of infection after a follow-up of >1 year. The high cost of treatment with liposomal amphotericin B is partially balanced by the shorter hospitalization period compared with that with conventional antimonials or pentamidine administration. Liposomal amphotericin B should, in our opinion, be considered as a first line treatment in pediatric visceral leishmaniasis. Salvatore Catania, M.D. Camilla Aiassa, M.D. Sonia Tzahtzoglou, M.D. Natalia Catania, M.D. Laura Tucciarone, M.D. Alessandro Antimi, M.D. Giuseppina Ragni, M.D. Anna Clerico, M.D. Departments of Infectious Diseases (SC, CA, ST) and Pediatrics (NC, LT, AA, GR, AC) University of Rome "La Sapienza"; Rome, Italy