Neurotrichinosis in a Pediatric Patient

Abstract

To the Editors: Neurotrichinosis is an infrequent but severe form of trichinosis. Pediatric neurotrichinosis reports in the medical literature are scarce and mostly outdated. We report a case of neurotrichinosis in a 14-year-old girl from a rural area in Argentina (province of La Pampa). The patient presented with a history of intermittent fever, fatigue and myalgia for 1 month before admission to the hospital, associated with progressive loss of function of the lower limbs. She had no significant previous medical history and had normal neurologic development. All the other members in her household were asymptomatic. The initial physical examination revealed an afebrile, sick-looking child, with weakness of the soft palate, left facial hemiparesis and bilateral brachiocrural hemiparesis, exhaustible clonus and loss of abdominal reflexes. Blood tests showed leukocytosis with severe eosinophilia (4500/mm3), elevated creatine phosphokinase (164 IU/mL) and lactate dehydrogenase (460 IU/mL), without other significant findings. Cerebrospinal fluid analysis was normal, and blood and cerebrospinal fluid cultures were negative for bacteria and fungi. Eye and cardiologic examinations and abdominal and muscle ultrasound examinations were normal. Trichinella spiralis-specific serology (enzyme-linked immunosorbent assay) was positive. On further questioning, the patient remembered intake of undercooked homemade pork products (charcuterie) 2 weeks before onset of symptoms. No other members of her family had ingested the products, explaining the lack of symptoms in the rest of the household. Brain computed tomography (CT) revealed hypodense, multifocal, small lesions in the cortex and white substance consistent with ischemia; magnetic resonance imaging (MRI) showed multifocal lesions hypointense in T1-weighted images and hyperintense in T2-weighted images. (Fig. 1)FIGURE 1: Brain MRI showed hypodense focal lesions in the white substance and in the periependymal region that enhance with contrast, without mass effect.The patient was treated with oral albendazole, 800 mg/day in 2 daily doses for 5 days, and oral methylprednisone, 1 mg/kg/day in 2 daily doses for 10 days. Within 4 days of treatment, muscle strength, hemiparesis, motility of the soft palate improved and muscle enzymes decreased in blood. After a week of treatment, myalgia receded and she was able to walk again. One month post-treatment, the patient was back to her normal activities, without sequelae; the follow-up CT showed full recovery. Trichinosis is caused by infection with the larvae of T. spiralis due to the ingestion of undercooked, contaminated meat (mainly pork, horsemeat and game). An estimated 10,000 cases of trichinellosis occur every year worldwide, with a death rate of 0.2%, according to reports from 55 countries where trichinellosis occurs autochthonously.1 The diagnosis of trichinosis is based on epidemiology, clinical manifestations, laboratory, serological tests and imaging (CT or MRI).1–3 Eosinophilia frequently appears 10 days after infection, peaking at the third or fourth week, followed by a gradual decline over months. Myositis, marked by myalgia and increased muscle enzymes in blood, is a common finding.1,4 Neurotriquinosis is a rare complication, characterized by altered level of consciousness and, frequently, somnolence and apathy. Anisocoria, facial nerve paresis and Babinsky’s reflexes have also been observed in severe cases.1,5 Our patient had central nervous system involvement evidenced by weakness and lesions consistent with ischemia in CT and MRI. Central nervous system localization is a rare but serious presentation and limited cases were reported,5,6 with few pediatric reports. Signs of central nervous system infection are evident in the phase of larval migration or tissue invasion, which begins at the end of the second week of illness and persists for 4 weeks. Several mechanisms have been proposed as responsible for the development of brain lesions, including cerebral blood vessels obstruction by larvae, cysts or granulomas, inflammation of brain parenchyma and reactive vasculitis with secondary thrombosis and infarction.2,7–9 As observed in our patient, treatment with corticosteroids rapidly improves myositis and vasculitis-related symptoms and prevents complications. Steroids should always be administered in combination with antihelmintics such as albendazole.2,4 In our patient, we observed clinical improvement after 4 days of treatment. Guillermo Moscatelli, MD Samanta Moroni, MD Facundo García Bournissen, MD Jaime Altcheh, MD Department of Parasitology Sordelli Nora, MD , De Mena Arturo, MD, Manonelles Gabriela, MD, Unit 10 Ricardo Gutierrez Childrens Hospital Buenos Aires, Argentina