Irukandji syndrome is a term used to describe symptoms that can be caused by stinging venom from a small group of box jellyfish. Typical symptoms include severe chest, back, and head pain, as well as muscle cramps, abdominal pain, nausea, vomiting, high blood pressure, and sweating. In some severe cases of normally nonfatal Irukandji syndrome, pulmonary edema and cerebral hemorrhage also occur.
What is Irukandji syndrome?
Irukandji syndrome represents a summary of symptoms that can result from contact with the stinging venom of a small group of cube jellyfish (Cubozoa). The name Irukandji syndrome is derived from the Irukandji cube jellyfish (Carukia barnesi) because it was erroneously believed that the poisonings were caused exclusively by this cube jellyfish. The Irukandji jellyfish takes its name from an Aboriginal tribe native to the Northern Territories of Australia. The Irukandji jellyfish, with its two-centimeter umbrella diameter and up to one-centimeter-long tentacles covered with cnidocysts, is hard to spot in the water. Contact with one of the cnidarian tentacles is hardly felt immediately and is roughly comparable in tactile sensation to a mosquito bite. The typical symptoms of Irukandji syndrome occur in about two-thirds of all people whose skin comes into contact with the nettle venom. The symptoms occur with a 30 to 60 minute delay from the time the venom enters the skin. Normally, the severe symptoms soon subside, and only in exceptional cases can serious complications develop, such as pulmonary edema from hemorrhage or cerebral hemorrhage.
Causes
The symptoms of Irukandji syndrome are caused by the venom that the stinging cells of the tentacles “shoot” into the skin when touched. The stinging cells of the Irukandji cube jellyfish contain a barbed stinging tube and a supply of their specific neurotoxin. A sensory flagellum (cilium) protruding from the cell activates the “firing mechanism” when touched, the cell bursts open and the cnidocyst bores into the skin, injecting the toxin. The sensory flagellum is similar in structure and working principle to mechanoreceptors. The injected venom is a complex neurotoxin, the composition and mode of action of which is not (yet) adequately understood. The jellyfish have cnidocytes on their umbrella and on their tentacles. The cnidocytes of the umbrella and the tentacles contain different toxins. Although the structure of both venoms is not fully known, it is assumed as certain that the jellyfish venom contains a component that attacks the smooth muscle of the heart muscle, i.e., has a cardiomyopathic effect.
Symptoms, complaints, and signs
A few minutes after skin contact with the stinging jellyfish’s stinging venom – but usually only after 30 to 60 minutes – approximately two-thirds of affected people show typical symptoms such as severe chest, back and head pain. Muscle cramps and abdominal pain occur, accompanied by violent vomiting. Acute and crisis episodes of hypertension occur, coupled with sweating. Symptoms may also occur in repetitive cyclic patterns. In most cases, a transient fear of death sets in. In isolated cases, complications such as pulmonary or cerebral hemorrhage may be caused by the acute hypertensive phases. Because the punctures of the hives into the skin are often not noticed, there are usually no early warning signs of the crisis-like, extremely painful, symptoms to come.
Diagnosis and course of the disease
Irukandji cube jellyfish do not usually occur in isolation, so their presence is known to occur in certain sections of Australia’s coastline at certain times of the year, and warning signs are posted on beaches to indicate this. The shock-like appearance of the symptoms combined with the possibility of isolated occurrences of Irukandji cube jellyfish on the beach in question initially obviates the need for further diagnostic procedures. If no further complications such as pulmonary edema or cerebral hemorrhage develop due to the acute hypertensive phases, the symptoms will subside after some time. A direct antidote that could reverse the effect of the injected neurotoxins does not (yet) exist. On the coasts of Australia, the main distribution area of the jellyfish, about 60 people a year are affected by Irukandji syndrome.
Complications
Various symptoms and complications result from Irukandji syndrome. In the worst case, without treatment, it can lead to the death of the patient if there is bleeding and paralysis in the brain or lungs. For this reason, contact with jellyfish should always be treated by a doctor. Most of those affected suffer from severe pain in the back and head. It is not uncommon for this pain to spread to other regions of the body and cause discomfort there. It is not uncommon for patients to also suffer from vomiting and nausea. Furthermore, there are sweating episodes and not infrequently a fear of death. The quality of life of the affected person is considerably limited and reduced by the Irukandji syndrome. The affected areas often hurt very much and swell up. Complications can then arise during the treatment itself, when blisters burst open on the skin, resulting in poisoning. Usually, medication and painkillers can resolve the symptoms. Life expectancy is not reduced if treatment is initiated early. Further poisoning can also be prevented with the help of medication.
When should you see a doctor?
A visit to the doctor is necessary as soon as noticeable skin changes appear. If painful punctures occur on the body, action is required. The punctures are often located on the back, abdomen, chest area and extremities. If the affected regions swell or discoloration appears on the skin, a doctor is needed. In case of inner restlessness, strong irritability, a feeling of illness or, if the belief that one’s own death is imminent is dominant, a doctor should be consulted. If severe anxiety sets in, panic attacks or aggressive behavior occur, a visit to the doctor is necessary. In case of sweating, vomiting, nausea and dizziness, closer examinations should take place to clarify the cause. If existing complaints increase rapidly in intensity within a short period of time, a visit to the doctor should be made. If high blood pressure, muscle cramps and a sudden feeling of nausea occur, a doctor should be consulted. Irukandji syndrome is characterized by a rapid and sudden onset of symptoms. Often the punctures are not noticed, but severe discomfort is felt within 30 to 60 minutes. Since in severe cases bleeding of the brain or lungs may occur, a physician should be consulted as soon as possible. In the event of impaired consciousness, breathing difficulties or bloody sputum, an ambulance must be alerted. First aid measures are required to ensure the survival of the victim.
Treatment and therapy
At the first signs indicating Irukandji syndrome, the most important action is to prevent hives that have adhered to the skin and have not yet “fired,” i.e., are still intact, from bursting open to prevent further poisoning. Washing the affected areas of skin with vinegar has proven most effective. The low pH prevents activation of the still intact cnidocytes because the cilia, the sensory hairs of the cnidocytes, are inactivated in the highly acidic environment. Washing off with drinking or salt water is counterproductive because the cilia of the cnidocytes then trigger and further poisoning occurs. Similarly, visible tentacles must not be removed mechanically because this causes further cnidocysts to burst with the consequence that further venom is introduced into the skin. To make the severe pain more bearable, treatment with opioid analgesics may be considered. Treatment with magnesium sulfate may also be helpful because magnesium sulfate has an antispasmodic effect. While the external application of vinegar is only to prevent additional poisoning, all other measures are for symptom control because no agent exists (yet) that could neutralize the neurotoxin of Irukandji jellyfish.
Outlook and prognosis
The prognosis of Irukandji syndrome depends on the steps chosen after contact with the stinging jellyfish. If medical care is sought as soon as possible, the outlook for recovery is favorable. If the affected person begins to clean the affected area with drinking or salt water, the prognosis worsens.There is an increase in discomfort with this action, as this action leads to a spread of the poisoning suffered. In the case of severe poisoning, without medical treatment, the affected person is at risk of death. Bleeding of the lungs or brain may occur. Paralysis and tissue damage are the result. The bleeding causes irreparable damage to the organism and can lead to the death of the patient if left untreated. If a patient survives despite internal bleeding, he or she must expect a severe reduction in quality of life. The best prognosis is given to patients who wash the affected area with vinegar water immediately after contact with the jellyfish and then consult a physician immediately. This approach has been shown to contain the poisoning and stop it as it progresses. Subsequent treatment measures focus on healing the skin lesions until freedom from symptoms is achieved. Scarring of the skin or other residue may still occur.
Prevention
Direct preventive measures that could prevent the occurrence of Irukandji syndrome after contact with the neurotoxin of the small Irukandji cube jellyfish are not known. The most important protection is to avoid waters where the jellyfish are known to occur or to wear appropriate protective suits when bathing, swimming, and diving, which are available in affected coastal areas, mainly in Australia.
Aftercare
In most cases, patients with Irukandji syndrome have no direct or specific options for follow-up care, so the disease itself must be detected and treated early in the first instance. Early diagnosis has a positive effect on the further course of the disease and can prevent further complications or further worsening of symptoms. The patient should seek medical attention and initiate treatment at the first symptoms and signs of the disease, as Irukandji syndrome cannot heal on its own. The person affected by Irukandji syndrome should in no case cause the cells to burst and protect them particularly well. Creams or ointments must also be used to alleviate the symptoms, taking care to use the correct dosage and application. The patient should not wipe the affected areas with water or with salt water, as this only intensifies the discomfort. Furthermore, contact with the jellyfish should of course be avoided to prevent further occurrence of the symptoms. In most cases, the life expectancy of the affected person is not reduced by the Irukandji syndrome.
Here’s what you can do yourself
Some of the symptoms of Irukandji syndrome can be avoided by the affected person following some points. As a rule, strenuous and especially stressful situations should be avoided, as they can lead to high blood pressure and further to sweating or to severe headaches. In case of anxiety or fear of death, the affected person must be calmed down in any case. In serious cases, an emergency doctor may be called. The patient must pay attention to regular and deep breathing in order not to lose consciousness. If there is a loss of consciousness, a visit to the hospital is necessary to rule out bleeding in the brain or lungs. Until the emergency physician arrives, ensure safe breathing and a stable lateral position. The blisters on the skin caused by the hives must not burst under any circumstances in Irukandji syndrome, as this can lead to infection or poisoning. Possible cramps can be treated with magnesium sulfate, and the medication should always be at hand. However, if the blisters do burst, they can be washed out with vinegar to prevent infections.
