Visceral Larva Migrans (Toxocariasis)

Key Features

• Visceral involvement, including hepatomegaly, marked eosinophilia, and anemia

• Posterior or peripheral ocular inflammatory mass

• Elevated antibody titers in serum or aqueous fluid; demonstration of Toxocara larvae in biopsy specimen

Clinical Findings

• Visceral larva migrans

  • Usually asymptomatic

  • Anorexia, fever, fatigue, pallor, abdominal pain and distention, nausea, vomiting, and cough may be present in children aged 1–5 years

  • Hepatomegaly is common, splenomegaly is unusual, and adenopathy is absent

  • Lung involvement, usually asymptomatic, can be demonstrated readily by radiologic examination

  • Seizures are common, but more severe neurologic abnormalities are infrequent

• Ocular larva migrans

  • Occurs in older children and adults who have a unilateral posterior or peripheral inflammatory eye mass

  • History of visceral larva migrans and eosinophilia are typically absent

  • Anti-Toxocara antibody titers are low in the serum and high in vitreous and aqueous fluids

Diagnosis

• Eosinophilia with leukocytosis, anemia, and elevated liver function tests are typical

• Hypergammaglobulinemia may be present and elevated isohemagglutinins sometimes result from cross-reactivity between Toxocara antigens and human group A and B blood antigens

• Diagnosis is confirmed by finding larvae in granulomatous lesions

• High ELISA serology and the exclusion of other causes of hypereosinophilia provide a presumptive diagnosis in typical cases

Treatment

• Albendazole (400 mg twice a day for 5 days) or mebendazole (100–200 mg twice a day for 5 days) is indicated for severe complications involving the brain, lung, or heart

• Treating any cause of pica, such as iron deficiency, is important

• Corticosteroids are used to treat marked inflammation of lungs, eyes, or other organs