Case Report Patient without neurotoxic symptom after being bitten by an eastern green Mamba (Dendroaspis angusticeps) Masamitsu Shirokawa 1, Kaoruko Seki 1, Yasushi Nakajima 1 Shigeru Koyama 1, Makoto Mitsusada 2 ABSTRACT We describe rare envenomation by an eastern green mamba (Dendroaspis angusticeps). A 40-years-old man was bitten by an eastern green mamba that he had kept illegally and brought to the emer- gency room within 30 minutes of the bite. We confirmed severe pain, swelling and continuous bleeding from his left index finger. We did not administer antivenom considering the risk of anaphylaxis and the time required to obtain it. We simply washed the wound and observed the patient. Swelling spread to the trunk within 3 days and blood blisters formed on his left forearm. A coagulation disturbance that seemed to be caused by the snake venom spontaneously improved within 6 days. The blood blisters were all epitheli- alized within 13 days. The patient was discharged on hospital day 44. The focal puncture site was deeply ulcerated and required 136 days to epithelialize. Mamba venom reportedly contains neurotoxins that cause paralysis and death due to respiratory failure, but disordered blood coagulation is rare. Accumulated case reports will help to understand mamba envenomation. (JJAAM. 2011; 22: 777-81) Keywords: snakebite, envenomation, hemostasis, vesicle formation Received on March 29, 2011 (11-029) We describe a bite by an eastern green mamba that Introduction caused swelling of the entire bitten limb, vesicle formation and disrupted hemostasis instead of Snakebites have not been studied in detail and precise neurotoxic symptoms. statistics are not available. An estimated 2.5 million ven- omous snake bites occur globally per annum 1,2). Case report The mambas (genus Dendroaspis) comprise four known species of the African Elapidae family of snakes A 40-year-old previously healthy man was bitten by an and case reports of snakebites by green mambas are rare. eastern green mamba (Fig. 1) that he had kept illegally as The described symptoms of mamba bites are mostly a pet. He called the emergency medical system 20 min- neurotoxic. This has led to preparations for neurotoxic utes after the bite and was brought to emergency room syndrome such as respiratory failure being recommend- (ER) 10 minutes later. ed. Reports indicate that elapid venom does not contain significant protease activity and it does not characteristi- 1. Physical examination cally produce swelling or subsequent tissue destruction An emergency medical technician applied a tourniquet and necrosis 3-6). to his left upper arm. A puncture mark was found at the ventral side of the left index finger distal to the interpha- 1 Emergency Care Center, Tokyo Metropolitan Hiroo General Hos- langeal (DIP) and proximal interphalangeal (PIP) joints. pital The index finger was dark red and the wound would not 2 Department of Surgery, Yokosuka General Hospital Uwamachi stop bleeding. Swelling spread to the wrist and the index Crrespondence author: Masamitsu Shirokawa, MD; Emergency finger was extremely painful. Vital signs were all normal. Care Center, Tokyo Metropolitan Hiroo General Hospital, 34-10 Ebisu 2-chome, Shibuya, Tokyo 150-0013 Japan JJAAM. 2011; 22: 777-81 777 Masamitsu Shirokawa, et al tor-plasmin complex (PIC), < 0.2 µg/ml (normal value < 0.8); tissue plasminogen activator-plasminogen activator inhibitor 1 complex (t-PA･PAI-1), 14.1 ng/ml (normal value, < 50). The WBC count was increased to 12,100 / µl. The Japanese Association for Acute Medicine dissem- inated intravascular coagulation score (JAAM DIC score) was 1 point and DIC could not be diagnosed. Swelling spread to the upper left side of the trunk on hospital day 3. Edema appeared to be spreading through- out the subcutaneous tissue. Bleeding was confirmed in the blisters around the left forearm. A blood blister also formed in the oral cavity. Figure 3 shows the blood blis- Fig. 1. Eastern green mamba responsible for biting the patient. ters on the forearm on hospital day 6. Hypoesthesia of This snake is about 1.85 m length. (The picture was taken by the left arm persisted. Forearm skin tension was hard and Dr. Toriba of Japan Snake Institute.) intramuscular pressure was 50 mmHg. We did not apply a relaxation incision because neurological manifestations 2. Laboratory ndings on admission had not worsened, peripheral circulation was maintained, The complete blood count (CBC) findings were all and the coagulation disturbance was too severe. normal. The blood coagulation test was normal except Although bleeding persisted, the blood coagulation for a slightly decreased fibrinogen level. All other bio- findings improved. The PT-INR and APTT fell to 1.54 chemistry findings were normal (Table 1). and 53.1 sec, respectively, fibrinogen increased to 499 mg/dl and D-dimer was slightly elevated to 0.7 µg/ml. 3. Clinical course The platelet count was 18.5×104 /µl. The JAAM DIC We spread and washed the fang puncture site in the ER score remained at 1 point. The CK level decreased to 341 and applied cephazoline for 72 hours and tetanus toxoid. IU/l. Antivenom was not administered considering the risk of Swelling started to decrease from hospital day 4. anaphylaxis and the time required to obtain it. Pentazo- Blood coagulation parameters normalized on hospital cine was administered to control the pain. Since mambas day 6 and bleeding stopped. The puncture site was deeply deliver neurotoxins that block respiration and muscle ulcerated and required debridement. All blisters were epi- movement, we admitted the patient to the intensive care thelialized by the hospital day 13 but deep ulcers re- unit in anticipation of respiratory failure. mained. Three hours after the bite, inflammation spread to the Hypoesthesia of the left arm improved from hospital upper arm and a blood blister formed at the puncture site. day 5. However, dysesthesia developed around the punc- Respiration remained normal and hypoesthesia of the left ture site from hospital day 16 and paroxysmal shooting arm was the only neurotoxic symptom. pain developed on hospital day 23. Pentazocine was fre- Swelling spread to his left shoulder on hospital day 2 quently administered to control pain. We considered that and blisters formed around his forearm. The puncture site neuranagenesis of the peripheral nerve at the fang punc- was necrotic and continued to bleed (Fig. 2). Mild tachy- ture site was the cause of the neuropathic pain. Clomip- cardia with a heart rate around 90 beats per minute and ramine and carbamazepine were effective against the low grade fever of about 37˚C were the only abnormal dysesthesia and shooting pain, respectively. vital signs. Urine output was free of hematuria. The Since legal proceedings restricted the patient from free blood coagulation results were the worst at this time. The access to the outpatient department, he was obliged to PT-INR increased to 2.21 and the APTT increased to stay in the hospital until wound care had simplified. He 93.7 seconds, but the fibrinogen level and the platelet was discharged on hospital day 44 under continued am- count were increased to 277 mg/dl and 22.5×104 /µl, re- bulatory care. The deep ulcer at left index finger finally spectively. Other findings were as follows: D-dimer, 0.5 epithelialized at 136 days after the bite. PIP joint stiffness µg/ml (normal range 0.0 - 1.0); thrombin antithrombin III persisted. complex (TAT), 3.5 µg/l (normal range 1.0 - 4.1); plasmi- nogen, 64% (normal range, 69 - 111); a2-plasmin inhibi- 778 JJAAM. 2011; 22: 777-81 Green mamba bite without neurotoxity Table 1. Main laboratory data upon admission. pH 7.525 (7.350-7.450) WBC 5,800/µl (3,500-9,500) Alb 4.3 g/dl (3.3-5.1) CK 150 IU/l (18-150) 4 PaCO2 32.5 mmHg (35.0-45.0) RBC 530×10 /µl (450-650) BUN 14.2 mg/dl (7.0-22.0) LDH 178 IU/l (110-255) 4 PaO2 207.9 mmHg (75.0-100) PLT 18.9×10 /µl (14.0-38.0) Cre 0.7 mg/dl (0.5-1.1) CRP <0.3 g/dl (<0.3) HCO3 26.2 mmol/l (20.0-26.0) PT-INR 1.09 (0.8-1.2) T-bil 0.9 mg/dl (0.3-1.0) Base excess 4.1 (-3.0-3.0) APTT 34.7sec (27.0-38.0) AST 16 IU/l (8-37) Lactate 3.66 mmol/l (0.5-2.0) Fib 184 mg/dl (200-400) ALT 19 IU/l (5-35) Arterial blood gas was obtained under breathing 6 L/min of oxygen from a mask. Values in brackets are normal ranges or values. Alb: albumin, ALT: alanine aminotransferase, APTT: activated partial thromboplastin time, AST: aspartate aminotransferase, BUN: blood urea nitrogen, CK: creatine kinase, Cre: creatinine, CRP: C-reactive protein, Fib: fibrinogen, HCO3: hydrogen car- bonate, IU: international units, LDH: lactic dehydrogenase, PaCO2: pressure of arterial carbon monoxide, PaO2: pressure of arte- rial oxygen, PLT: platelets, PT-INR: prothrombin time international ratio, RBC: red blood cells, T-bil: total bilirubin, WBC: white blood cells. Fig. 2. Appearance of puncture site on hospital day 2. Fig. 3. Blood blisters on left forearm of patient on hospital Puncture mark is located on the ventral side of DIP and PIP day 6. joint of the left index finger. The necrotic wound continued to Blisters are 5 to 10 cm in diameter. Skin tension was hard with bleed without clotting. inflammation. bite and rapidly progresses to fatal respiratory paralysis 7). Discussion Mamba bites also cause numbness, sweating, gooseflesh, salivation, viscous respiratory tract secretions, diarrhea, The mambas comprise four known species of the Afri- fasciculation and other involuntary muscle spasms, as can Elapidae family of snakes (black mamba, D.