The initial bite of the black widow spider may be unnoticeable to the victim. A mild local pain may be felt at most in adults while infants may present with persistent crying . The autonomic and the neuromuscular signs of spasms and muscle fasciculation sets in after a few hours to few days.
Some patients complain of muscle pain especially in the abdomen with increasing severity in time. These abdominal signs may be coupled by nausea and vomiting in some cases of Latrodectism. Systemic signs of fever, chills and hypertension are the direct effect of the excessive neurotransmitter released from the presynaptic cleft of the neuromuscular junctions which eventually make its way to the bloodstream.
The diagnosis of the Latrodectus bite may require a detailed history of the incident with detailed account on the part of the eyewitnesses. The accurate chronology of the clinical signs can aid in the actual diagnosis of the arachnid bite. When the spider specimen is available, experts may be called in to identify the species of the spider.
Black widow spiders have the characteristic shiny black body with large rounded abdomen, it has the red hourglass mark at the ventral abdomen, and a general body length measure of 11 to 13 cm.
Blood tests may show increased polymorphonuclear activity with eosinophilia but are relatively inconclusive. The serum Creatine Kinase (CK) markers are usually elevated .
The pre-hospital treatment of the black widow spider bite includes the washing and cleaning of the bite site with soap and water.
Suspicion of envenomation may benefit from a tourniquet at the upper portion of the bitten limb to impede circulation of the venom to distal organs. The affected extremity is elevated to slow down the spread of the venom. Oral analgesics like aspirin and acetaminophen may relieve signs of pain. The introduction of the antivenom in the field is grossly discouraged with the fear of serious allergic reactions .
It is important to bring the specimen of the spider to the hospital along with the patient for proper identification. Hospital phase of treatment is geared towards supportive care of the airways and cardiac support. Antivenoms should be considered when there is there is an eminent threat in pregnancy, loss of limb and patient has refractory tolerance to pain .
In general, bites from the black widow spider are self-limiting without intervention. The antivenom may shorten the bothersome clinical course which may debilitate the patient for a few days to weeks if left untreated.
It is well established that there are very rare instances where a black widow spider bite may cause complications and may even lead to death. Most of these cases involve the very young and the very old segments of the population with concomitant illnesses.
In allergic reactions in the bronchus, severe phlegm formation may clog the airways and cause difficulty in breathing. The autonomic dysfunction of the diaphragm puts the patient at risk for pulmonary edema which could be fatal if not brought to hospital attention.
To determine the definitive cause of the spider bite and dictate the course of treatment, one must be keen in identifying the offending spider.
The black widow spider has distinct marking in the ventral abdomen in a shape of an hourglass. This red-orange symbol is clearly visible in the shiny black body of the arachnid. The female widows are the only ones capable of envenominating humans measuring from half to one inch long. It is also noteworthy that not all venomous Latrodectus are black, the Latrodecus geometricus are brown which are also found in North America and the red back widow or Latrodectus hasselti which are endemic in Australia.
Widow spider bites number to approximately 2300 bites in the year 2012 according to the Annual Report of the American Association of Poison Control Centers’ (AAPCC) National Poison Data System (NPDS) . Almost all of the bites recorded in the US at that time were not serious and non-fatal since 1983.
The American Association of Poison Control Centers has given an estimated average of 2500 widow spider bites per year in the United States . The known average of widow spider death in the United States since was 4 deaths per year .
The venom of the Latrodectus spider is virtually a neurotoxin identified as the alpha-Latrotoxin which affect the neuromuscular junctions in the presynaptic end and opens cation channels to release myriads of neurotransmitters.
The excessive neurotransmitters in the blood stream causes the clinical manifestations like the spastic cramping of abdomen and stiffness of the extremities. Other autonomic implication of the neurotoxins are the persistent pain and hypertension associated with the black widow spider bite.
The Latrodectus spider only bites humans in defense and when its habitat is disturbed. The main objective of the black widow spider bite prevention is to lower down contact between spiders and human.
Useful tips include:
The Latrodectus mactans mactans or black widow spiders can inflict a noxious bite to humans that can cause a number of symptoms. A bite may manifest with a clinical syndrome of headache, nausea, vomiting, muscle cramping, joint stiffness, hypertension and diaphoresis otherwise known as Latrodectism .
Envenomation from dangerous spiders are relatively rare thus, the identification of the biting arachnid is paramount in the anti-venom vaccination of the patient. Black widow spiders lives in dirty places with minimal movement and lots of flies, more commonly in the attics, garage, outhouse, sheds and foliage where they usually come in contact with humans .
It is imperative that one should respect these spiders especially when found in their habitat. Removing them by hand will agitate them and bite in self-defense. When it is totally necessary to study them, one should use protective gloves and the proper instruments in handling them.
The female black widow spiders are the ones responsible for envenomation and are active during night time because they are nocturnal hunter .