What are the other Names for this Condition? (Also known as/Synonyms)

• Dioctophymatosis Renalis
• Dioctophyme Renale Infection
• Giant Kidney Worm Infection

What is Dioctophymiasis? (Definition/Background Information)

• Dioctophymiasis is the result of an infection by Dioctophyme renale, a rare, large parasitic roundworm commonly found infecting the kidney tissue of carnivorous animals, such as minks and other wild mammals, and domesticated dogs
• The parasitic worm is commonly called the giant kidney worm, and hence, the condition is also known as Giant Kidney Worm Infection. There is a low incidence of human infection, but infestation of human kidneys has been reported, typically due to the consumption of infected mollusks
• Most cases of human infection present with symptoms including (but not limited to) severe pain in the abdomen, weight loss, and irritation of the ureter due to the movement and destruction of the kidneys by the parasite
• Dioctophymiasis can result in the eventual destruction of renal functional tissue, leaving only the remains of the kidney capsule filled with fluid and worms. A diagnosis can be made by a healthcare provider after inspection of the stool or by performing an exploratory surgery
• Treatment most commonly involves a surgical removal of the infected kidney tissue. The prognosis of Dioctophymiasis is generally good, following prescribed treatment and/or surgical removal of the infected tissue

Who gets Dioctophymiasis? (Age and Sex Distribution)

• While cases are rare in humans, individuals of all ages, races, ethnic groups, and both genders are susceptible to Dicrocoeliasis
• A worldwide distribution of parasitic infection by D. renale is noted; although, most cases present in mammals rather than in humans

What are the Risk Factors for Dioctophymiasis? (Predisposing Factors)

• The frequent ingestion of undercooked mollusk is the primary risk factor for Dioctophymiasis. Most cases of human infection have been related to infected mollusk consumption

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Dioctophymiasis? (Etiology)

• Dioctophymiasis is caused by the infection of Dioctophyme renale parasite, which is often passed on from one of two intermediate hosts; either of the hosts can directly infect humans
• The most common method of human transmission occurs following the consumption of undercooked and infected mollusks (classified as paratenic hosts)
• The earthworm is also a common carrier of an encysted (embedded and inactive) larval form of the parasite. It can infect an individual by excysting (activating) from the worm and penetrating the intestinal wall once inside the digestive tract
• Within six months of infection, the larvae will develop and migrate to the kidneys. In most cases, only one kidney is infected while the other retains normal function
• Humans can be the final hosts of the D. renale worm, if undercooked forms of the paratenic host (such as undercooked fish or amphibian) are ingested, or if some portion of food contains remnants of an infected earthworm

However, humans are often not the definitive host of D. renale. Presentation in the kidneys of humans is mostly rare, even though there have been several reported cases of human kidney infestation.

What are the Signs and Symptoms of Dioctophymiasis?

The signs and symptoms of Dioctophymiasis often vary in occurrence and severity, because in most cases, the uninfected kidney will attempt to compensate for the low functionality of the infected kidney and there may be no clinical signs.

However, increased longevity and severity of infestation by D. renale may result in the following symptoms to appear:

• Fever
• Severe abdominal pain
• Rapid weight loss
• Irritation in the ureter due to movement of D. renale to the kidneys (contributes to abdominal irritation)
• Hematuria (blood in the urine) and ischuria (inability to completely empty the bladder), both related to poor kidney function
• Hypertrophy (enlargement) of the unaffected kidney: It is a common occurrence when one kidney attempts to compensate for the low-functioning infected kidney

How is Dioctophymiasis Diagnosed?

The diagnosis of Dioctophymiasis is made by the following tests and exams:

• A complete physical examination and a thorough assessment of symptoms
• Evaluation of the affected individual’s medical history
• Examination of the urine for D. renale eggs
• Examination of the stool for D. renale worms: Worms are often passed in the stool of the infected individual, if they have not yet fully migrated to the kidneys

Kidney infestation by the parasite can also be diagnosed during surgical procedures, such as through:

• A laparotomy procedure, in which an incision is made in the abdomen to provide physiological information of the internal organs for diagnostic purposes. This procedure is performed while the individual is under anesthesia
• A hysterectomy procedure, which is a surgery performed on women to remove the uterus. It requires an opening in the abdominal cavity to be made and can provide information regarding other organs in the abdominal cavity as well. Hysterectomies are often performed if the uterus is suspected to be the cause of blood presenting in the urine (a symptom of Dioctophymiasis). Hence, it is possible that this procedure can reveal other complicating issues causing similar symptoms (such as Dioctophymiasis)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Dioctophymiasis?

The potential complications of Dioctophymiasis include:

• A wide variety of long-term complications due to poorly-functioning kidneys
• A rupture through the wall of the body cavity by the D. renale worm after having degraded a large amount of kidney tissue. This condition is extremely rare though
• Individuals with poorly-controlled diabetes may be at risk for severe symptoms of the disease and associated complications

How is Dioctophymiasis Treated?

Dioctophymiasis generally presents as an infestation of the kidneys too complicated to treat with medication.

• Surgery has been the only reported treatment that resolves the infestation in human cases. A procedure called a nephrectomy is considered the only viable treatment option. A nephrectomy is the surgical removal of the infected kidney tissue
• Symptomatic treatment often involves antibiotics, IV fluids, and gastrointestinal irritation aids, to help relieve secondary symptoms of a D. renale infection. Nevertheless, these symptomatic treatment measures do not provide a permanent resolution of Dioctophymiasis

How can Dioctophymiasis be Prevented?

Prevention of Dioctophymiasis may be possible by considering the following factors:

• Thoroughly cooking fish, mollusks, and frogs, to decrease the chances of infection. Most cases of human infection by the D. renale have been caused by the consumption of undercooked and infected mollusks
• Boiling water before consumption, especially in the endemic regions. Avoiding the consumption of water from any unreliable sources

What is the Prognosis of Dioctophymiasis? (Outcomes/Resolutions)

• In the very rare case of human contraction, the prognosis of Dioctophymiasis can be good, following immediate surgical removal of the infected kidney tissue by nephrectomy procedure
• The surgical removal of the infected tissue has often resulted in a full recovery and a gradual resolution of all associated symptoms

Additional and Relevant Useful Information for Dioctophymiasis:

• There have been 23 cases of human infection by the D. renale organism that have been officially documented
• Contraction of Dioctophymiasis is very unlikely, but will often present similar symptoms to many other conditions. This makes it difficult to diagnose the condition
• D. renale worms appear blood red in color and cylindrical in shape. They are also one of the largest roundworm parasites, with some measuring up to a meter in length