Page 21 - JSOM Summer 2019

ankle joint but did not extend proximal to the constricting developed during or after the removal, but there were also
band. Circulation distal to the band appeared intact, albeit no improvements in numbness, tingling, or pruritus. At 2326
diminished, as assessed by slightly delayed capillary refill hours (H ), involuntary tremors developed in the bitten limb
1.5
time (roughly 5 seconds) at the nailbed. The band was left that extended past the ankle but ended several inches below
in place to continue the assessment. The patient was moder- the knee. The patient had a heart rate of 82 bpm, blood pres-
ately diaphoretic and had a rate of 75 beats per minute (bpm), sure of 100/70 mmHg, respiratory rate of 15 breaths per min-
respiratory rate of 16 breaths per minute, blood pressure of ute, and Spo of 98%.
2
100/70mmHg, Spo of 99%, and body temperature of 36º C.
2
He was alert and oriented and denied use of alcohol or any At 0110 hours (H ), the local paresthesias, trembling, and pru-
3
other substances. There were no signs of weakness, dyspnea, ritus persisted but had not progressed beyond the permanent
or cranial nerve palsy affecting eye or facial expression indica- marker outlines from H . The patient remained moderately di-
0
tive of systemic neurotoxic envenomation. A single 1mm-long aphoretic but no more so than when he arrived. He continued
superficial laceration was located over the navicular bone on to display the abnormal gait with foot drop, difficulty bearing
the bitten foot, consistent with the history of a snake that was weight, and lack of sensation to the bitten foot; he was admit-
violently dislodged while chewing the skin. There was no local ted overnight for observation.
pain, edema, or tissue destruction and no sign of abnormal
bleeding from the bite site, the gingival sulci, or elsewhere The next morning at 1000 hours (H12), the local paresthesias,
as is often seen following viper envenomations in West Af- lack of sensation, and gait abnormalities persisted as before,
rica. He was able to ambulate with assistance and displayed but the tremors and pruritus had resolved overnight. The rest-
3–5
a markedly abnormal gait with foot drop, difficulty bearing lessness, anxiety, and diaphoresis he had exhibited in the first
weight on the bitten foot, and significant supination with in- hours after the bite were no longer present. At 2200 that eve-
ternal rotation. The left foot dragged along the ground be- ning (H ), the situation remained the same and the patient
24
tween steps. A basic sensory examination was performed, and continued to experience significant disability from the lack of
he was unable to identify light touch or pinprick stimulation sensation in his left foot. Serious snakebites are characterized
on the dorsal or plantar surface of the foot. by a progressive syndrome of local and/or systemic findings,
the absence of which led to a reconsideration of the possible
After assessing for immediate life threats and obtaining an ini- causes of the paresthesias. These are listed in Table 1.
tial set of vital signs, an 18-gauge IV catheter was placed in the
left arm and 2 mL of venous blood was drawn and placed into TABLE 1 Differential Diagnosis for Persistent Paresthesia After a
a clean glass 10mL test tube to perform a whole blood clotting Witnessed Snakebite
test (WBCT) for venom-induced consumptive coagulopathy Direct action of snake venom after a true envenomation
(VICC). 3,6–8 The tube was placed upright and uncovered at the Mild atypical envenomation from a young forest cobra (Naja sa-
bedside, and timers were set to interpret the test at precisely vannula) or other dangerous elapid. This was unlikely due to the
the 20th minute (WBCT20) and 30th minute (WBCT30) after absence of any other symptoms associated with the syndrome but
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collection, as described elsewhere. 3,6–9 A second 18-gauge IV line potentially treatable using Antivipmyn Africa.
was established in the right arm with a maintenance infusion of Half-banded garter snake (Elapsoidea semiannulata moebiusi) en-
100 mL/h of 0.9% sodium chloride. The left foot was cleaned, venomation. A little-known elapid with symptoms such as pain,
swelling and nasal congestion documented in the few existing case
and a permanent marker was used to circle the bite site and the reports. Not treatable with Antivipmyn Africa.
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proximal border of the paresthesias. The observation time was Envenomation from an unknown NFFC snake. Poorly understood
recorded on the patient next to each circle in order to chart snakes that possess venoms with largely unknown clinical effects.
the progression of signs and symptoms, and a detailed physical A plausible diagnosis but no antivenom or specific treatments
examination and history were performed. The WBCT20 and available to address it.
WBCT30 both revealed a solid, stable clot (normal coagulation) Mild atypical envenomation by one of several species of burrowing
and remained negative during serial reevaluations performed at asp (Atractaspis spp.), a genus of small, dark, burrowing snakes
that cause painful but rarely fatal envenomations with profound
3, 12, 24, and 36 hours after initial assessment (H , H , H , local swelling, pain, and blistering as the most common symptoms.
3
12
24
and H ).
36 Psychosomatic response to a dry bite with early paresthesia from
constricting band
With vascular access established and the primary assessment Initial paresthesia resulted from tourniquet use or venom but per-
completed, preparations were made to resuscitate the patient sisted after removal due to psychosomatic response to the stress of
in the event of a rapid deterioration after removal of the con- the bite, examinations, and hospitalization
stricting band due to a surge of venom into systemic circula- Acute onset or exacerbation of injury unrelated to the bite itself
tion. Critical supplies were placed within reach at the bedside Compression of the superficial peroneal nerve due to ischemic or
10
including 12 vials of polyvalent antivenom (Antivipmyn mechanical injury caused by prolonged application of the con-
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Africa; Bioclon, Mexico), additional IV fluids, 1:1000 epi- stricting band. This would cause weakness of ankle eversion (pero-
nephrine, and H antihistamines to manage early antivenom neus longus and brevis muscles) and sensory loss of the anterolat-
eral aspect of the lower leg and the foot dorsum.
1
reactions, and a bag-valve mask along with an assortment of
oral and nasal airway adjuncts, supraglottic airway devices, Acute exacerbation of other physical injury or illness unrelated to
the event such as sciatic nerve damage, infection, diabetic neurop-
and endotracheal tubes. Removal of the constricting band be- athy, or aggravation of a pre-existing injury, etc.
gan at 2235 hours and proceeded in a stepwise fashion (loosen
slightly, maintain briefly, tighten again, observe, repeat) during The leading differentials at this time were either (1) mild en-
a period of 15 minutes. No signs of systemic envenomation venomation by a young forest cobra (Naja savannula [Figure
(such as hypotension or other significant changes in vital 1]); (2) envenomation by a half-banded garter snake (Elap-
signs, bleeding, pain and swelling, neuromuscular weakness, soidea semiannulata moebiusi [Figure 2]); (3) envenomation
or “SLUDGEM” toxidrome indicative of cholinergic crisis) by one of the numerous small, dark, and NFFC species native
A Case of Fright or a Deadly Bite? | 19