Latrodectism
Encyclopedia
Latrodectism is the clinical syndrome caused by the neurotoxic venom
(see latrotoxin
), that can be injected by the bite of any spider
that is a member of the spider genus Latrodectus, in the family Theridiidae.
The most well known of members of the Latrodectus genus are the Black Widow Spider (L. mactans), the Australian Redback spider (L. hasselti), the brown widow (L. geometricus), the European black widow (L. tredecimguttatus) and the katipo
spider (L. katipo).
s acetylcholine
, norepinephrine
, and GABA
. The release of these neurotransmitters leads to the clinical manifestations of envenoming.
If enough venom is injected into a person's body, initially a severe pain in local muscle groups occurs, and the pain then spreads to regional muscle groups. The spread relates to the toxin initially being carried by the lymphatic system until it reaches the blood stream. Once in the blood, the venom is moved by circulation, causing its toxins to be deposited in nerve ends where nerves insert into muscle.
The venom acts at nerve endings to prevent relaxation of muscles, causing tetany
— constant, strong, painful muscle contractions. Thus initial pain is often followed by severe muscle cramps. Contraction of musculature may extend throughout the body, though cramping in the abdomen is frequently the most severe. Back and leg muscles can often be affected too.
In some rare and extreme cases, severe complications can arise:
Symptoms that may be present at or near the wound:
, acute abdomen
, and myocardial infarction
. Laboratory workups are of limited value.
Standard treatments usually involve symptomatic therapy with pain medication, muscle relaxants, and antivenom. The venom does not typically cause problems at the bite site itself, unless a secondary skin infection occurs.
Antivenom is used widely in Australia for Latrodectus bites, however in the United States it is generally reserved for use only when absolutely necessary. Due to the low mortality rate, the risk of major injuries or death due to anaphylaxis
or serum sickness
are greater than the risk of death due to the venom itself. In past years, injections of calcium gluconate
were used to replace calcium rendered unusable by the neurotoxins, but hospitals have been switching to the use of prescription painkillers — especially opiates such as morphine
— to reduce symptoms, as the calcium injections do very little for the pain and do not significantly reduce the recovery time.
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
(see latrotoxin
Latrotoxin
A latrotoxin is a high-molecular mass neurotoxin found in the venom of spiders of the genus Latrodectus . Latrotoxin are the main active components of the venom and are responsible for the symptoms of latrodectism....
), that can be injected by the bite of any spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
that is a member of the spider genus Latrodectus, in the family Theridiidae.
The most well known of members of the Latrodectus genus are the Black Widow Spider (L. mactans), the Australian Redback spider (L. hasselti), the brown widow (L. geometricus), the European black widow (L. tredecimguttatus) and the katipo
Katipo
Latrodectus katipo, the katipo, is an endangered species of spider native to New Zealand. A member of the genus Latrodectus, it is related to the Australian redback spider, and the North American black widow spiders. The species is venomous to humans, capable of delivering a comparatively dangerous...
spider (L. katipo).
Venom method
The venom spreads rapidly throughout the body and acts by causing the release of the neurotransmitterNeurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...
s acetylcholine
Acetylcholine
The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...
, norepinephrine
Norepinephrine
Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...
, and GABA
Gabâ
Gabâ or gabaa, for the people in many parts of the Philippines), is the concept of a non-human and non-divine, imminent retribution. A sort of negative karma, it is generally seen as an evil effect on a person because of their wrongdoings or transgressions...
. The release of these neurotransmitters leads to the clinical manifestations of envenoming.
If enough venom is injected into a person's body, initially a severe pain in local muscle groups occurs, and the pain then spreads to regional muscle groups. The spread relates to the toxin initially being carried by the lymphatic system until it reaches the blood stream. Once in the blood, the venom is moved by circulation, causing its toxins to be deposited in nerve ends where nerves insert into muscle.
The venom acts at nerve endings to prevent relaxation of muscles, causing tetany
Tetany
Tetany has two meanings, though both are related to the muscular system.* Tetany * Tetany The terms "tetany" and "tetanus" are distinct....
— constant, strong, painful muscle contractions. Thus initial pain is often followed by severe muscle cramps. Contraction of musculature may extend throughout the body, though cramping in the abdomen is frequently the most severe. Back and leg muscles can often be affected too.
Symptoms
Symptoms occur in three main phases: exacerbation phase, dissipation phase and residual phase.Exacerbation phase
During the first 24 hours after a bite:- Severe pain in muscle groups local to the bite.
- Muscle cramping, primarily in the abdomenAbdomenIn vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
, back and thighs. - Headache, dizziness, tremors, salivation, diaphoresisDiaphoresisDiaphoresis is excessive sweating commonly associated with shock and other medical emergency conditions.Diaphoretic is the state of perspiring profusely, or something that has the power to cause increased perspiration....
(excessive sweating), nausea and vomiting. - AnxietyAnxietyAnxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
, fatigue, insomniaInsomniaInsomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
. - Lacrimation (tearing of the eyes).
- Migratory arthralgiaArthralgiaArthralgia literally means joint pain; it is a symptom of injury, infection, illnesses or an allergic reaction to medication....
(joint pain). - TachycardiaTachycardiaTachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
(rapid heart beat), bradycardiaBradycardiaBradycardia , in the context of adult medicine, is the resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min. It may cause cardiac arrest in some patients, because those with bradycardia may not be pumping enough oxygen to their heart...
(very slow heart beat), restlessness, hypertensionHypertensionHypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
(elevated blood pressure), TachypneaTachypneaTachypnea means rapid breathing. Any rate between 12-20 breaths per minute is normal. Tachypnea is a respiration rate greater than 20 breaths per minute. - Distinction from other breathing terms :...
(hyperventilation).
In some rare and extreme cases, severe complications can arise:
- Spontaneous abortion, preterm labor
- PriapismPriapismPriapism is a potentially harmful and painful medical condition in which the erect penis or clitoris does not return to its flaccid state, despite the absence of both physical and psychological stimulation, within four hours. There are two types of priapism: low-flow and high-flow. Low-flow...
- Acute renal failureRenal failureRenal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
(failing of kidney function). - MyocarditisMyocarditisMyocarditis is inflammation of heart muscle . It resembles a heart attack but coronary arteries are not blocked.Myocarditis is most often due to infection by common viruses, such as parvovirus B19, less commonly non-viral pathogens such as Borrelia burgdorferi or Trypanosoma cruzi, or as a...
, rhabdomyolysisRhabdomyolysisRhabdomyolysis is a condition in which damaged skeletal muscle tissue breaks down rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure...
, paralysisParalysisParalysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
. - Shock, comaComaIn medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
, and deathDeathDeath is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
.
Symptoms that may be present at or near the wound:
- Rash, slight erythemaErythemaErythema is redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection, or inflammation...
(redness of skin), Piloerection (goose bumps). - Mild edemaEdemaEdema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
(swelling due to excess fluid). - LesionLesionA lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
or mild infection (rare).
Residual phase
During the following weeks or months:- Muscle spasm, tingling, nervousness and weakness. There is a potential risk of paralysis.
Diagnosis
Diagnosis is obvious in victims reporting contact with any Latrodectus spider. However, the absence of such a report, either through inability to communicate or unawareness, greatly complicates diagnosis as symptoms overlap with a variety of other serious clinical syndromes such as tetanusTetanus
Tetanus is a medical condition characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, rod-shaped, obligate anaerobic bacterium Clostridium tetani...
, acute abdomen
Acute abdomen
The term acute abdomen refers to a sudden, severe abdominal pain of unclear etiology that is less than 24 hours in duration. It is in many cases a medical emergency, requiring urgent and specific diagnosis...
, and myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...
. Laboratory workups are of limited value.
Treatment
People who have been bitten by a venomous spider should always seek professional medical assistance immediately. Though complications are rare, and death is even rarer, negative developments can proceed at a quick pace. Changes in heartbeat, breathing or blood pressure should be considered especially ominous.Standard treatments usually involve symptomatic therapy with pain medication, muscle relaxants, and antivenom. The venom does not typically cause problems at the bite site itself, unless a secondary skin infection occurs.
Antivenom is used widely in Australia for Latrodectus bites, however in the United States it is generally reserved for use only when absolutely necessary. Due to the low mortality rate, the risk of major injuries or death due to anaphylaxis
Anaphylaxis
Anaphylaxis is defined as "a serious allergic reaction that is rapid in onset and may cause death". It typically results in a number of symptoms including throat swelling, an itchy rash, and low blood pressure...
or serum sickness
Serum sickness
Serum sickness in humans is a reaction to proteins in antiserum derived from an non-human animal source. It is a type of hypersensitivity, specifically immune complex hypersensitivity . The term serum sickness–like reaction is occasionally used to refer to similar illnesses that arise from the...
are greater than the risk of death due to the venom itself. In past years, injections of calcium gluconate
Calcium gluconate
Calcium gluconate is a mineral supplement.-Hypocalcemia:10% calcium gluconate solution is the form of calcium most widely used in the treatment of hypocalcemia. This form of calcium is superior to calcium lactate, but it only contains 0.93% calcium ion. Calcium gluconate is a salt of calcium and...
were used to replace calcium rendered unusable by the neurotoxins, but hospitals have been switching to the use of prescription painkillers — especially opiates such as morphine
Morphine
Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
— to reduce symptoms, as the calcium injections do very little for the pain and do not significantly reduce the recovery time.