A single worm-like structure in a urine collection bag: a case report

Abstract

Background

The presence of a foreign body resembling a worm in a urine collection bag should lead to etiological investigation, as it may not be a parasite. It is thus important to consider the context and origin of the patient, together with the size, length, appearance, and characteristics of the suspected worm.

Case presentation

The presence of an apparently mobile black filament resembling a worm was reported in the urine collection bag of a 77-year-old African male resident of our long-term care facility. We initially suspected a parasitic infection. The description of this foreign body suggested Dioctophyma renale (giant kidney worm); however, the analysis of the sample concluded that it was a blood clot. Its worm-like appearance was due to the tube-like nature of the urethra, causing the blood clot to be squeezed into a worm-like shape.

Conclusion

Such presentations can be misleading and may lead to unnecessary concern and investigations. A parasitological analysis can be essential for precise diagnosis.

Introduction

The presence of foreign bodies mimicking worms in urine collection bags should lead to etiological investigations. The context and origin of the patient, together with the size, length, appearance, and characteristics of the suspected worm should be considered, particularly as not all such foreign bodies are parasites. We describe here the case of a string-like blood clot mimicking a parasitic worm. The uncommon nature of such presentations can confuse clinicians, especially as few similar clinical cases are reported in medical literature. This rare case therefore highlights the importance of considering a broad differential diagnosis and performing parasitological analyses of such samples.

Case description

We describe the case of a 77-year-old African man, who is a resident at our long-term care facility since September 2019 owing to a loss of autonomy resulting from two severe medical antecedents. They consisted of a stroke with right hemiparesis in 2017 and hepatitis C complicated by cirrhosis and dilated blood vessels in the esophagus and stomach. The patient is no longer very mobile, remaining in bed or in an armchair, and requires assistance for all activities of daily living. He is occasionally visited by his son.

The patient was born in Congo but has been living in France since 2017 and is not known to have traveled to his country of origin in the recent past. A double J stent was implanted after left obstructive pyelonephritis due to kidney stones in 2019. In January 2022, given the persistence of a left lumbar ureteral calculus of 8.7 mm in diameter and atrophy of the left kidney with no abnormality of the right kidney, a left rigid ureteroscopy was performed without complication. Since this operation, the patient has presented several episodes of urinary tract infection, in a context of colonization with multidrug-resistant (MDR) bacteria following repeated treatments. The decision to insert a suprapubic catheter was finally taken after a new episode of acute urinary retention and failed attempts at urethral catheterization.

On 22 October 2024, the nurse reported the presence in the urine collection bag of a long black filament that appeared to be mobile and resembled a worm (Fig. 1). The patient presented neither fever nor an inflammatory syndrome. He had no abdominal pain or other complaints, and his transit was unchanged and regular. Blood tests showed no abnormality, with an absence of eosinophilia in particular. The “worm” was extracted and sent to the parasitology department for testing. The analysis concluded that the sample received contained a blood clot, but no macroscopic parasitic element. The patient has had no other similar episodes and no other blood clot has been detected in his urine collection bag. The blood clot had no impact on catheter management. A timeline for the case report is presented in Fig. 2.

Fig. 1

Urine sample with worm-like blood clots

Fig. 2

Timeline of the case report

Discussion

Given the patient’s country of birth and the nurse’s description of a mobile element in the urine collection bag, we initially suspected a parasitic infection. Few parasites have a tropism for the urinary system, but several have nevertheless been found in the urinary tract, causing local symptoms of variable severity. The two principal parasites affecting the human urinary system are urinary bilharzia due to infestation with Schistosoma [1] and echinococcosis [2]. In both cases, the symptoms tend to take the form of hematuria or pain, and it is the eggs, rather than the adult worms, that are found in the urinary tract. There are indeed few published descriptions of the presence of worms in the urine or urinary tract.

With the exception of two outdated references from the Western Journal of the Medical and Physical Sciences in 1833 [3] and the Southern Medical Record in 1884 [4] reporting descriptions of worms discovered in the urinary tract, this situation has been described very rarely, with only a few recent cases reported. Comparisons of the worm we discovered with the size, length, appearance, specific organs, or other characteristics in the worm body described in these papers could suggest a possible diagnosis.

Ginesin et al. [5], from Haifa (Israel), reported the case of an 84-year-old man who was treated by suprapubic catheterization for acute urinary retention in a context of benign prostatic hypertrophy. Upon admission, the patient complained of acute urinary retention and pain in the lower abdomen. Physical examination revealed a yellowish green discharge around the cystotomy, with many worms surrounding the catheter. This cause of catheter obstruction seems rare, as this is the only such case reported in literature. The suspected etiology was weakened defense mechanisms due to aging and poor personal hygiene. The worms identified in this clinical case were very different in appearance from our suspected worm.

Another obstruction, reported by Birare et al., was caused by a Guinea worm, or Dracunculus medinensis. Infestations with this helminth are well documented, but the urinary bladder remains a very unusual site of infestation, again with only one description of obstructive uropathy due to an adult noncalcified Guinea worm [6]. A 25-year-old woman from a village in India presented with a snake bite on the right foot. She subsequently developed oliguria and fragments of Guinea worm were removed after urethral catheterization. The authors were unable to explain how the Guinea worm entered the urinary bladder. They hypothesized that it might initially have been located around the urinary bladder and that an unknown stimulus, possibly snake venom in this case, increased the motility of the worm leading to its entry into the urinary bladder and the development of obstructive uropathy.

In neither of these reported cases did the clinical presentation or the living context of the patient resemble those of our patient.

Several other worms normally restricted to the gastrointestinal tract have occasionally been found in the urinary bladder. Enterobius vermicularis is a parasite well-adapted to humans and found throughout the gastrointestinal tract; however, ectopic migration involving the urinary tract is also possible. However, even when very small, white worms are found in the urine, the principal presentation is recurrent urinary tract infection [7]. In cases of fistulas connecting the rectum and bladder, Ascaris lumbricoides may be able to migrate into the bladder. Indeed, a few cases of infection have been reported in the urogenital system, including the kidney, urinary bladder, and uterus, with or without fistula formation [8]. The “worm” discovered in the urine of our patient did not match the features of Ascaris lumbricoides, and the patient had no symptoms suggestive of Ascaris lumbricoides infestation. Instead, the “worm” seemed to be more similar to Dioctophyma renale (giant kidney worm), even though cases in humans are rare and have never been described in France [9]. Dioctophyma renale normally infests principally fish-ingesting mammals, such as dogs [10].

Therefore, the hypothesis of a parasite appeared less likely, and it was necessary to investigate the possibility of a foreign body mimicking a parasitic worm. The presence of foreign bodies within the bladder is well-documented [11]. They are generally inserted by the person via the urethra for the purposes of erotic stimulation or due to psychiatric illness; alternatively, the source may be iatrogenic, due to the retention or migration of medical devices, for example [12]. Obviously, not all of these causes were possible in the patient described here, who is not very autonomous and has a urinary catheter preventing the insertion of any foreign body. However, worm-like blood clots can occur, and the parasitology department concluded that the sample received contained a blood clot. Worm-like blood clots in urine are mostly due to bleeding in the bladder or urethra, mostly without pain or discomfort [13]. Such clots remain relatively rare, and the most common causes include all kidney or urinary tract diseases that can cause bleeding (infection, cancer, kidney stones, and so on) and all types of medication affecting the blood, such as aspirin and blood thinners. The worm-like appearance of the clot results from the tube-like nature of the urethra, which squeezes blood clots into a worm-like shape as they exit the body. In 2020, Kim et al. [14] described a fibrin clot that was mistaken for a worm, this time in an intravenous line. The clot appeared as a long, white deposit closely resembling a worm, but pathology tests confirmed that it was actually a fibrin deposit.

Conclusion

Presentations of this type can be misleading, potentially leading to unnecessary investigations. Even with a precise description of the clinical presentation of the patient and a morphological examination of the “worm”, clinicians may find it difficult to differentiate between worm-like clots and parasites in routine practice. Often only parasitological analysis can provide a precise diagnosis, making it possible to propose an appropriate therapeutic strategy.