Neuroimaging in Cerebral Ascariasis Because the host response to A. lumbricoides in humans is mild, neuroimaging might be expected to provide a number of clues to suggest this organism as the cause of an intracranial lesion. In Case 1, the lesion was not visible in a high-quality noncontrast CT scan, even in retrospect. The amount of tissue reaction was small, as was the region of central enhancement. In addition, cerebral ascariasis may deliver enteric bacteria to the central nervous system, causing the more extensive findings typical of an abscess, as demonstrated in Case 2. No specific serologic or other tests are available to diagnose ascaris larva migrans.
Histologic diagnosis is the only definitive test.
In such instances, presumptive therapy would need to be instituted based on the finding of fertile Ascaris eggs or of adult worms in the patient's stool. Alternatively, a therapeutic trial of an antihelminthic drug might be appropriate in a patient with a history of environmental exposure to A. lumbricoides and neuroimaging suggestive of possible cerebral ascariasis. Early surgery in such a case would offer the opportunity of obtaining a definitive diagnosis and of curing this potentially lethal infection. Case 2 illustrates the difficulty of treating an abscess associated with a foreign body by aspiration. We, therefore, recommend that excision of the abscess be considered when possible, to ensure removal of a potentially causative larva in cases of a cerebral abscess with multiple respiratory or enteric bacteria and concomitant A. lumbricoides infection.