The incidental finding of old Dracunculus medinensis infection in a Sudanese patient who presented following trauma to the right knee.
A 30 year old immigrant from Sudan presented to the Accident and Emergency department complaining of right knee pain after sustaining an injury while working at a construction site. Examination of the right knee revealed a few abrasions and a small joint effusion.
AP and lateral views of the right knee joint were taken. These showed numerous calcified lesions in the soft tissues around the joint. Both oval, dystrophic calcifications as well as more convoluted "chain-mail" calcified lesions were detected (Fig. 1a, b). A PA view of the chest showed the presence of a calcified lesion, having a serpentine appearance, in the soft tissues overlying the lateral aspect of the right side of the chest (Fig. 2). No signs of trauma were detected.
The characteristic appearance, combined with the patient’s background, led to a diagnosis of old Dracunculus medinensis infection which was unrelated to the patient's presenting complaints.
Dracunculus medinesis (Guinea-worm) is a nematode that causes dracunculiasis.
Dracunculiasis is a parasitic infection endemic to the Nile Valley, central and western Africa, India, Iran, and other parts of the Arabian peninsula.
Transmission is through consumption of contaminated water. The guinea-worm larvae mature in the human body and migrate towards the skin surface for 1 year, during which the host remains asymptomatic. When it reaches the skin surface, the female worm dies and releases millions of juveniles in a milky white liquid. The host's immune system recognises these juveniles and causes an intense allergic reaction and extreme discomfort. This reaction provokes the formation of a painful blister, which bursts into an ulcer, causing the anterior end of the worm to be exposed. If the affected portion of the body (usually the foot or leg) is cooled by immersion in water, the milky white liquid that contains the larvae is expelled and contaminates the water starting the cycle over again.
The diagnosis of dracunculiasis is usually established by observing the head of the worm in a cutaneous blister and its body as a thread-like cord in the subcutaneous tissues. There is usually a moderate to occasionally marked eosinophilia.
When still alive, the worm is radiolucent. However, after its death, it may undergo calcification in several forms. In its typical location in the lower extremities, the female nematode often appears as long, string-like, serpiginous or curvilinear calcification which may extend up to 1 meter. Elsewhere in the body, such as in the thorax, pelvis and scrotum, the death worms often appear as convoluted, whorled and tangled "chain mail" calcifications in the soft tissues of these regions. In cases in which the reaction around the necrotic worm has been severe, with resultant fibrosis or myositis, there may be extensive dystrophic calcification producing a round or oval, amorphous, calcific density which is well defined, but in which the individual loops of the coiled worm are poorly recognised or unrecognisable. In the majority of patients, such amorphous calcification will be associated with other, more typical, linear, serpentine, convoluted, or "chain mail" calcifications elsewhere in the body.
When a guinea worm dies close to a joint, such as the knee or ankle, a severe inflammatory reaction around the dead worm may cause effusion into the joint and secondary bacterial infection, resulting in acute pyogenic arthritis. Radiographs taken years later may show fragments of calcified worms adjacent to the damaged or ankylosed joint.
The above mentioned patterns of calcification may cause problems in diagnosis. The amorphous, dystrophic pattern of calcification can be mistaken for a pulmonary granuloma when it overlies the chest wall or calcification within lymph nodes. At times, a calcified worm may be seen on films of the abdomen or pelvis in the vicinity of the bladder and may be mistaken for calcification within pelvic vessels, the vas deferens, or the bladder. However, its smooth outline and almost inevitable association with calcified guinea worms elsewhere in the body will permit its true identification.
Dracunculus medinesis infection.
1. Multiple elongated, band-like, or slightly spiral-shaped calcifications are seen in the soft tissues of the right knee joint and lower leg. Some areas appear patchy or cord-like, with a wide range of extension.
2. Most calcified lesions are located in the subcutaneous tissue or muscle compartments. They present with irregular shapes, showing linear or arc-shaped high-density shadows, and some may exhibit a “beaded” or “curved cord-like” appearance.
3. The overall bony structure of the knee joint and its joint space remain relatively intact, with no obvious signs of severe bone destruction or large-scale damage to the joint structure.
4. On the chest X-ray (frontal view), the pulmonary markings are natural, with no apparent lesions. The mediastinum and trachea are in the midline, and the cardiac silhouette is essentially normal. A few linear calcifications are projected onto the chest wall soft tissue, likely representing the same source of calcifications (possibly the same parasitic calcifications).
Based on the patient’s regional background (Sudan), clinical data (history of parasitic infection), and imaging findings (curved, linear soft tissue calcifications), the following diagnoses or differential diagnoses should be considered:
Considering the patient is a 30-year-old male with a history of living in Sudan, and multiple linear calcifications were incidentally found during evaluation of a right knee injury with no active clinical symptoms or evidence of parasitic activity, the most likely diagnosis is:
Residual calcification from an old Dracunculus medinensis infection.
1. Treatment Strategy:
For old Dracunculus medinensis infections that have calcified and are asymptomatic, no specific treatment is usually required. The focus should be on managing the current right knee trauma and potential associated conditions (e.g., joint effusion, soft tissue injury, secondary infection). Based on the severity of the knee injury, the following options can be considered:
2. Rehabilitation and Exercise Prescription:
For recovering from the right knee injury and preventing recurrence of soft tissue inflammation, a gradual and personalized rehabilitation program following the FITT-VP principle is recommended:
In all phases, monitoring the knee joint’s response is essential. If significant discomfort or worsening pain occurs, seek medical advice or modify the rehabilitation plan.
Disclaimer: This report is based on the current imaging and medical history information. It is for reference only and cannot replace an in-person consultation or professional medical advice. Patients are advised to consult orthopedics or parasitology specialists for a more thorough evaluation and guidance if they have further concerns.
Dracunculus medinesis infection.
