Imaging Diagnosis Of Parasitic Helminthes 3Pulmonary and soft tissue diseases

By Sh.Ghaffary January 2008

Lung Diseases

Paragonimiasis Pulmonary Strongyloidiasis Pulmonary Capillariasis

Paragonimiasis:

Pulmonary Paragonimiasis:

The radiologic findings vary with the stage of the disease. Early findings include pneumothorax or hydropneumothorax, focal air-space consolidation, and linear opacities. Later findings include thin-walled cysts, dense masslike consolidation, nodules, or bronchiectasis.

Paragonimiasis:Chest radiograph of a 39-year-old man with sudden onset of chest pain 3 weeks after eating pickled freshwater crabs. Crampy abdominal pain and diarrhea developed 2 days after eating. Note bilateral hydropneumothoraces (arrows) without a pulmonary lesion.Defects on the surface of the visceral pleura caused by migration of juvenile worms result in pneumothorax.

Paragonimiasis:After penetration of the visceral pleura, thejuvenile worms migrate within the lung, causingfocal hemorrhagic pneumonia that appearsas patchy air-space consolidation onchest radiographs. The air-space consotidationfrequently shows a change in position onfollow-up radiographs

Paragonimiasis:

Initial chest radiograph shows patchy

pneumoniain the left upper lung

(arrow).

Follow-up radiograph obtained 1 month later

shows no consolidation in the left upper lung but a new linear opacity in the

left parahilar area, suggesting a worm

migration track

Radiograph obtained 2 days later shows ill-

defined consolidation at the end of the linear

opacity (arrow).

Paragonimiasis:Chest radiograph of a 46-year-old woman with pulmonaryparagonimiasis shows variousfindings including nodules (white arrow), a ring shadow (black solid arrow), and patchy airspace consolidation (open arrow).

Pulmonary Strongyloidiasis •The chest radiograph will be normal in the majority of patients infected with Strongyloides, but those with clinical signs and symptoms of pulmonary strongyloidiasis will usually show abnormal findings on chest radiography or CT scanning.•During the stage of larval migration from the capillary bed into the alveoli, especially in cases of autoinfection, a foreign body reaction, pneumonitis, and hemorrhage can occur within the lungs. Fine miliary nodulation or diffuse interstitial reticulation will be seen on chest x-rays or CT scans at this stage.

Pulmonary Strongyloidiasis •As the infection intensifies, there may be bronchopneumonia with scattered, ill-defined, soft alveolar, segmental or even lobar opacities similar to those seen in Löffler's syndrome or eosinophilic pneumonitis .•These pulmonary opacities can be chronic and serial radiographs may show their migration through different portions of the lungs, often in a peripheral location and associated with peripheral blood eosinophilia. •Pleural effusions can develop as a result of larval migration from the pulmonary parenchyma into the pleural cavity, and are seen more commonly in patients with severe strongyloidiasis associated with preexisting lung disease or the hyperinfection syndrome.

Pulmonary Strongyloidiasis

Larval phase of strongyloidiasis involving the lungs. Diffuse miliary nodularity and ill-defined patchy consolidation scattered throughout both lungs

Pulmonary Strongyloidiasis

Overwhelming Strongyloides hyperinfection of the lungs in an immunosuppressed patient. The radiographic pattern is that of intense bilateral pulmonary edema.

Pulmonary CapillariasisCapillaria aerophila is a rare cause of acute bronchitis and bronchiolitis in humans. The parasite attaches to and develops in the epithelial lining of the respiratory tract, invading the mucosa of bronchioles and laying eggs which can cause acute bronchitis and bronchiolitis with episodes of asthma and a mild (9-12%) eosinophilia.On chest radiographs, the lungs may show hyperventilation from an acute obstructive airway process (bronchiolitis) as well as diffuse perihilar infiltrates and a reticulonodular pattern. Bilateral hilar lymph node enlargement may be present and at times is striking . These radiological features can resemble those found in patients with tropical pulmonary eosinophilia.

Capillaria aerophila infection showing changes over a 12-day period. There is bilateral hilar and paratracheal lymphadenopathy with extensive perihilar

infiltrates and diffuse reticulonodular densities within the lungs .

Soft Tissue Diseases

Filariasis Onchocerciasis loiasis Guinea Worm Infection

FilariasisWuchereria and Brugia spp

•When there is elephantiasis, the gross soft tissue deformity of the upper and lower limbs is easily appreciated on plain films (and clinically!). The long bones may show cortical thickening with a wavy contour due to periosteal new bone formation.•Chronic lymphatic obstruction and venous thrombosis may lead to tissue ischemia and calcification. Focal disuse osteoporosis may occur in feet, because people with elephantiasis perforce may be quite sedentary.

FilariasisWuchereria and Brugia spp

•Adult and larval stages of W. bancrofti and Brugia spp. are not visible in the soft tissues on plain films unless calcified; microscopic calcification is common but is not seen on imaging. Macroscopic calcification is less common and is infrequently seen by radiologists: when visible, there are no features which allow positive differentiation of any specific worm. The calcification may be thread-like or punctate.

FilariasisWuchereria and Brugia spp

•Ultrasonography has made it possible to visualize adult filarial worms within human lymphatic vessels: prior to this, all knowledge of worm location was based on biopsy or autopsy material.• living nematodes in the dilated lymphatic channels of the spermatic cord can be seen. Careful inspection of these lymphatics may reveal a peculiar and seemingly random motion referred to as the "filarial dance sign ".

Filariasis

Wuchereria and Brugia spp

• The "filarial dance" and dilated lymphatics are more often observed in asymptomatic patients with a high microfilaremia than in those with a low microfilaremia.

A Real-Time Ultrasound Demonstration Of Dancing Microfilaria: see the movie

Onchocerciasis•Nodules may be recognized in skin on various plain films of the skull, extremities, chest, and abdomen. Unless calcification has occurred, parasitic disease may not be suspected.•Nonspecific filamentous calcification within nodules may be seen radiographically, particularly on soft tissue extremity films or on mammograms.•Both CT and magnetic resonance imaging (MRI) will demonstrate onchocercal nodules, but there have been no studies to investigate their value in diagnostic or other aspects of disease.

OnchocerciasisUltrasonography

•Ultrasonography is becoming more widely available in the developing world and studies have demonstrated its value in onchocerciasis.• onchocercomata have been further characterized and differentiated from other nodules and lymph nodes. •A typical pattern comprises: (1) a lateral acoustic (refractive) shadow, (2) a hypoechoic rim or layer, and (3) a central zone of intermediate echogenicity in which numerous tiny, highly echogenic foci are seen (this is referred to as a worm center)

The characteristic sonographic appearance of a solitary onchocercal nodule. Note the worm center (small arrows) with small dot and rod-like echogenic

foci. The lateral acoustic shadows (larger arrows) and echo-poor capsule (arrowhead) are also visible.

OnchocerciasisUltrasonography

Ultrasonography can be used in epidemiological surveys and will more accurately define the prevalence of infection; compared with physical examination, ultrasonography will identify more nodules in patients than can be palpated. This is particularly useful in those with Sowda, where no nodules are palpable.Ultrasonography is also useful in clinical research to assess the effectiveness of antimicrofilarial drugs.

Loiasis•Since wandering adult worms eventually die and calcify, plain radiographs (particularly of the extremities) may show thread-like calcification that may appear as a coiled, broken line . •Hands and feet are especially common regions to find this whorled calcification. It has also been seen on mammograms .•Parasitic, granulomatous, and almost any dystrophic calcification may look similar. However, there may be some distinguishing features.

Loiasis•Small ovoid rim calcifications are seen in cysticercosis (Taenia solium)• If calcifications are larger, hydatid cysts should be considered.• Linear calcification suggests nematode infection. This includes filarial parasites and other nematode infections such as Dracunculus medinensis, subcutaneous dirofilariasis, Onchocerca volvulus, and larva migrans (Toxocara spp.).• The wandering larvae of geohelminths in the aberrant human host are too small to be seen on plain films, except perhaps by mammography, where they would appear as punctate calcifications.• Trichinella spiralis commonly calcifies when the encysted muscle larva is dead, but, again, it is too small to be seen on extremity radiography.

Loiasis

A spiral-shaped (arrow) and B rod-shaped calcification (small arrow). calcification morphology is better visualized due to the higher resolution of

mammography

Loiasis

Guinea worm •The live guinea worm will not be identified radiologically

•In its typical location in the limbs, especially the lower extremities, the female Dracunculus medinensis appears as a long, string-like, serpiginous or curvilinear calcification which may extend at times for as much as 1 meter.•Frequently, the calcification is segmented and beaded because muscle movement breaks up the necrotic worm .•Guinea worms found elsewhere in the body appear as convoluted, whorled and tangled "chain mail" calcifications in the soft tissues

There are several

calcified worms in the

calf and thigh. (B). These worms are elongated,

nodular, beaded and fragmented

due to muscular

action breaking particularly in

the calf .

Guinea worm

Convoluted, serpiginous calcification in a necrotic adult guinea worm in

the soft tissues of the footCalcified guinea worms in the pelvis,

scrotum, calf and thighs