Abstract
A four-year-old boy presented to the hospital with a four-month history of recurrent bouts of fever and abdominal pain. Half a month before being admitted to hospital, multiple red cutaneous nodules had emerged at the left epigastric region and a dark red serpentine track appeared under the skin at the same site. The day after the patient was admitted to the hospital, a living worm broke through the skin and appeared at one end of the subcutaneous track. The flatworm was identified as Fasciola hepatica in its juvenile stage. Eosinophilia was distinct in our patient and provides an important clue to diagnosing parasitosis.
Introduction
Fascioliasis, a zoonosis caused by Fasciola hepatica, is endemic in South America, Europe and Africa, especially in the area of animal husbandry. However, it is rarer in China.
F.hepatica infect the liver and bile ducts, and ectopic infection cases have been recorded from around the world. However, none of them have reported an ectopic fascioliasis, caused by a living F.hepatica breaking through the skin.
We report on a four-year-old boy, from the inland and non-animal husbandry region of China, who presented with a four-month history of recurrent bouts of fever and abdominal pain. After investigation by histopathology, the boy was eventually diagnosed with subcutaneous fascioliasis, with a living fluke breaking through the skin and appearing at one end of the subcutaneous track.
Case report
A four-year-old boy from Yan-He County, Guizhou Province, China, presented with a four-month history of recurrent bouts of fever accompanied by abdominal pain. An abdominal computed tomography (CT) scan found dilation of the intrahepatic biliary tract, gallbladder stones and multiple low-density lesions. He was diagnosed with ‘liver abscess’ and was treated with antibiotics in the local hospital. Despite treatment, the symptoms continued. Half a month before, multiple red cutaneous nodules had emerged at the left epigastric region, and a dark red serpentine track also appeared under the skin at the same site. The nodules were the size of a vicia and painless. According to the child's parents, he was in the habit of drinking raw water and sometimes eating raw watercress. The next day, after the patient was admitted to the Children's Hospital of Chongqing Medical University, his parents noticed a small vesicle on the skin of the left epigastric region. At first the vesicle was the size of a soybean, but then it gradually became a serpentine and vesicular track that was painful and burning, and a light-brown living worm appeared at one end.
Physical examination of the patient revealed a poorly-built and nourished boy with normal facial features. His weight was 15 kg and height was 97 cm. His pulse rate was 75 bpm. Abdominal examination showed a hepatomegaly of 2 cm below the right costal margin in the midclavicular line, with a firm consistency and smooth surface. The spleen was 2 cm below the costal margin. On the skin in the left epigastric region, some small cysts measuring 75 × 100 mm and a dark red and serpentine tunnel-like track, 6 cm long, were found (Figure 1).
Cutaneous nodules and migratory track in the patient. Arrows point to the exit part where the fascioliasis burrows outside the surface of the skin
Laboratory investigations showed a white blood cell count of 12.36 ×109/L with 44% eosinophils. Liver function tests were normal. The urine test was negative. There were no parasitic eggs found on repeated stool examination. Ultrasonography showed multiple poor echo structure in the left lobe of the liver. A CT scan and magnetic resonance imaging (MRI) showed dilatation of intrahepatic bile ducts. The histopathological examination of the skin cysts revealed multiple abscesses and Charcot-Leyden crystals, surrounded by an inflammatory infiltrate with eosinophils (Figure 2). The flatworm was identified as F.hepatic in its juvenile stage.
Biopsy of skin cyst revealed multiple Charcot-Leyden crystals, surrounded by an inflammatory infiltrate with eosinophils, as shown by the arrow
Discussion
F.hepatic, also known as the common liver fluke, is a parasitic flatworm that infects the liver of various mammals, including humans. The disease caused by the fluke is called fascioliasis. Humans are infected by drinking fresh untreated water or ingestion of aquatic plants that contain the infected metacercariae. 1 First, excysted juvenile flukes penetrate the intestinal wall. The flukes then migrate within the abdominal cavity and penetrate the liver or other organs. Occasionally, ectopic locations of flukes such as the lungs, diaphragm, intestinal wall, kidneys and subcutaneous tissue are also found. Patients are classified as being in the acute, chronic and latent phases. If the duration of symptoms is <4 months and there are no motile echogenic images in the gallbladder on admission, it is classified as acute. If symptoms persist for >4 months or there are motile echogenic images in the gallbladder, it is classified as chronic. If fascioliasis is diagnosed during investigation for eosinophilia detected in routine screening, or during investigation of a patient's family members, it is classified as latent. 2 The major symptoms of this disease are fever, abdominal pain, loss of appetite, flatulence, nausea and diarrhoea. When adult flukes migrate into bile ducts, the resulting cholangitis and cholecystitis, combined with the large body of the flukes, are sufficient to cause mechanical obstruction of the biliary duct and lead to biliary colic. 3 As these clinical manifestations are indistinguishable from hepatic and biliary diseases such as acute hepatitis, neoplasm, visceral toxocariasis, biliary tract diseases, hepatic amebiasis and infection with other liver flukes like schistosomiasis, diagnosis and treatment are often problematic and delayed. Diagnosis of fascioliasis is usually achieved parasitologically by finding the fluke eggs in stool, and immunologically by enzyme-linked immunosorbent assay (ELISA) and Western blot. In addition, biochemical and haematological examinations of human sera support the exact diagnosis (eosinophilia, elevation of liver enzymes). Ultrasonography, CT scan and MRI can also be used. 4 Eosinophilia in fascioliasis cases is almost always present. Unfortunately, even though eosinophilia was so distinct in our patient, it could not be noted. The presence of eosinophilia might be a clue, and would result in a carefully diagnostic work-up being carried out to rule out the parasitosis. 5
Ectopic infection with fascioliasis can occur in other sites, apart from the liver. Extrahepatic fascioliasis has been reported in foci like the subcutaneous tissue, brain, lungs, epididymis, inguinal lymph nodes, stomach and the cecum. In Vietnam, there was a report of F. hepatica infection, in which a case presented with both subcutaneous locations and a migratory vesicular track. This is the first case report of cutaneous fascioliasis in a form similar to creeping eruption. 6 Our case seems to be the first report of fascioliasis with a living fluke breaking through the skin and appearing at one end of the subcutaneous track.
Although the clinical spectrum of fascioliasis is diverse, the presence of eosinophilia might be a clue, and would result in further examination to diagnose parasitosis.