Differential Diagnosis Between Venomous (Bothrops jararaca, Serpentes, Viperidae) and "Nonvenomous" (Philodryas olfersii, Serpentes, Dipsadidae) Snakebites: Is It Always Possible?

Bites of "nonvenomous" snakes can sometimes be mistaken for the bites of venomous snakes. As an example of this confusion, this report describes confirmed bites by Philodryas olfersii and Bothrops jararaca. In the first case, a 55-y-old man with a history of controlled hypertension was bitten on his right forearm by P olfersii. Physical examination revealed extensive edema, erythema, and widespread ecchymoses throughout his right upper limb. Laboratory tests indicated leukocytosis and high D-dimer levels, but normal coagulation, suggestive of a resolved recent coagulopathy. He received only supportive treatment. In the second case, a healthy 35-y-old man was bitten by B jararaca. Although the anatomic region of the bite and the results of physical examination were similar to those in the first case, laboratory tests showed mild coagulopathy, leukocytosis, and high D-dimer levels. The patient was treated with antivenom. In both cases, the 20-min whole blood clotting test results were normal. Patients bitten by P olfersii may present with local symptoms resembling B jararaca envenomation. Without snake identification and the detection of venom-induced consumption coagulopathy, especially in places where the 20-min whole blood clotting test is the only clotting test available, it is almost impossible to establish an accurate and safe differential diagnosis. In this context, the best alternative is to take the risk of prescribing antivenom for a possible P olfersii bite rather than failing to do so for a real Bothrops bite. Late treatment for Bothrops bite can result in severe complications and sequelae.

Clinical picture and laboratorial evaluation in human loxoscelism.

Loxosceles spiders are found globally, especially in South and North America. In Brazil, approximately 10,000 cases of Loxosceles spp. spider bites are reported annually. Herein we analyzed 81 patients diagnosed as either cutaneous or cutaneous-hemolytic loxoscelism, in a geographical area where most accidents are caused by Loxosceles gaucho, and we report their clinical and laboratory data obtained during week 1 and 2 after the bite. Massive hemolysis was noticed in only 2 cases, but high serum bilirubin and LDH levels, suggestive of hemolysis, were noticed in 25 cases on admission. Anemia was not frequent (14.7%), and reticulocytosis was particularly noticed during week 2 (in 56% of patients). High D-dimer levels were suggestive of endothelial cell activation and intravascular thrombin generation, but thrombocytopenia was noticed in only 17.6% of patients in week 1. Acute kidney injury (AKI) only occurred in patients with massive hemolysis. The definitive diagnosis of overt disseminated intravascular coagulation (DIC) could not be established on admission. Fever was associated with the presence of hemolysis (p = 0.03). Altogether, these findings provide evidence that mild hemolysis is frequent in loxoscelism and suggest that AKI is uncommon, exclusively occurring in patients with massive hemolysis.

Bites by the colubrid snake Philodryas patagoniensis: a clinical and epidemiological study of 297 cases.

We retrospectively analyzed 297 proven cases of Philodryas patagoniensis bites admitted to Hospital Vital Brazil (HVB), Butantan Institute, São Paulo, Brazil, between 1959 and 2008. Only cases in which the causative animal was brought and identified were included. Part of the snakes brought by the patients was still preserved in the collection maintained by the Laboratory of Herpetology. Of the 297 cases, in 199 it was possible to describe the gender of the snake, and seventy three (61.3%) of them were female. The length of snakes (snout-vent length) ranged from 160 to 1080 mm. In 117 snakes their state of preservation enabled the dissection and examination of their stomach contents. The stomach was empty in 106 snakes (89.1%). Most bites occurred in the seasons of spring and summer (n = 196, 66.0%) and during warmer periods of the day. The mean age of the victims was 24.1 +/- 15.1 years old and 206 (69.4%) patients were men. Around 92% of the patients sought medical care within 6 h after the bite. Both lower (n = 188, 63.3%) and upper limbs (n = 102, 34.3%) were most frequently bitten, especially the feet and hands (n = 205, 69.0%). The local clinical manifestations were pain (n = 151, 50.8%), transitory bleeding (n = 106, 35.7%), erythema (n = 47, 15.8%) and edema (n = 39, 13.1%). Ecchymosis was not observed. Only 7 (2.4%) patients reported systemic symptoms characterized by mild dizziness and 88 patients (29.6%) showed no evidence of envenoming. The whole blood clotting time was performed in 76 (25.6%) patients on admission and all of them had coagulable blood. Supportive treatment was offered to only 13.4% of patients, namely administration of antihistamines (n = 19, 6.4%) and analgesics (n = 12, 4.1%). Eight patients (2.7%) were mistreated with Bothrops antivenom before their admission to HVB. No sequels or relevant complications were observed in patients, and the prognostic was benign. Therefore, although P. patagoniensis accidents can cause mild local symptomatology, it is very important that health professionals know how to make the correct diagnosis to avoid unnecessary use of antivenom.

Predictors of Bothrops jararaca venom allergy in snake handlers and snake venom handlers.

Since allergic sensitization to snake venom has been reported, anaphylactic reactions to snake venom might be an underestimated factor contributing to fatal snakebites, independently from the toxicity of the venom itself. However, little information is available on the determinants of such reaction. Hence, we studied a group of workers exposed to Bothrops jararaca venom (BJV), in order to clarify the factors related with snake venom allergy. The aim of this work was to investigate the prevalence and predictors of venom allergy among workers exposed to BJV and to confirm the involvement of IgE-mediated mechanisms in this condition. Workers exposed to BJV were assessed for venom allergy using questionnaires and immunological tests. The presence of BJV sensitization was determined through quantification of specific IgE. Allergens were studied using the Western blots and inhibition assays. Of the 67 workers evaluated, 7 (10.4%) presented specific IgE antibodies to BJV. Of those, 6 presented typical symptoms of an IgE-mediated allergic reaction when exposed to BJV. Venom sensitization was associated with length of employment (P=0.042), high levels of total IgE (P=0.034), atopy (P=0.051), and specific tasks, primarily the handling of dried venom (P=0.014). Our observations suggest that exposure to BJV can result in allergic sensitization in snake handlers through IgE-mediated mechanisms. The prevalence rate of this condition appears to be high among these workers, and the handling of dried venom, total IgE level above 100 kU/L, length of employment, and probably history of atopy were predictors of its occurrence.

HLA-matched related donor hematopoietic cell transplantation in 43 patients with Fanconi anemia conditioned with 60 mg/kg of cyclophosphamide.

Cells from Fanconi anemia (FA) patients are hypersensitive to alkylating agents and radiation traditionally used as conditioning regimens for marrow cell transplantation, and patients experience serious toxicities. To reduce toxicities, we used progressively lower doses of cyclophosphamide (CY) for conditioning. Here, we report the results in 43 FA patients who received marrow transplantation from HLA-matched related donors (37 siblings and 6 other relatives). Conditioning consisted of 15 mg CY/kg/day for 4 days along with Mesna. Methotrexate and cyclosporine were given for graft-versus-host disease (GVHD) prophylaxis. Forty patients (93%) are alive with a median follow-up of 3.7 (range 0.6 to 7.9) years. One patient with primary graft failure was successfully retransplanted. Three of 4 patients with late graft failures were retransplanted, and 2 of those are alive; 1 died before a second marrow graft. Twelve patients including 3 with rejection had cytogenetic abnormalities in their marrow cells before transplantation. Acute grade II-III and chronic GVHD (aGVHD, cGVHD) were seen in 17% and 28.5% of patients, respectively. These results confirm and extend our previous observations that conditioning with 60 mg CY/kg allows for sustained engraftment of HLA-matched related marrow grafts in most FA patients and is associated with low toxicity, low incidences of aGVHD and cGVHD, and excellent long-term survival.

Autoimmune hemolytic anemia as a complication of primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is characterized by a continuous T-lymphocyte mediated attack on small intralobular bile ducts, with their gradual destruction. Patients with PBC often exhibit concomitant autoimmune conditions, and autoimmune hemolytic anemia (AIHA), that is idiopathic in 50% of cases, has rarely been associated to PBC. Ursodeoxycholic acid (UDCA) has been considered the main treatment to PBC patients through a decrease in the detergent effect of endogenous bile acids, concomitantly reducing the hemolytic process. We report the case of a female patient with AIHA complicating PBC, treated with short course prednisone and UDCA, with good response.