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Clinical Characteristics

The larval phase of ascariasis, especially in children, produces symptoms of bronchitis or pneumonitis at the time larvae are in the lungs. Thus, 5 to 6 days after ingesting infective eggs, patients may develop a fever of 37.5°-40°C (99°-105°F) with chills, dyspnea, paroxysmal coughing, and hemoptysis, which may worsen during the following week. In severe infections, there may rarely be tachycardia, a feeling of pain or pressure in the chest, and cyanosis. On physical examination, crackling rales and rhonchi and other signs of lobular consolidation may be noted bilaterally. These symptoms may persist for 7 to 10 days, after which the patient improves and becomes asymptomatic after 3 weeks.

Ascaris pneumonia, a leading cause of Löffler's syndrome (an acute eosinophilic pneumonia which can also be caused by the larvae of other worms such as Toxocara, Ancylostoma and Necator), is usually unsuspected clinically and rarely diagnosed. If examined, the sputum may show numerous eosinophils, Charcot-Leyden crystals, and Ascaris larvae, which may also be found in gastric washings. There may be a high blood eosinophilia during this larval stage of the disease. Symptoms in occasional patients may be quite severe, even leading to death in rare cases (Pigott, et al 1970). Symptomatology may be related to the numbers of migrating larvae within the lungs, to prior exposure to Ascaris and to puzzling racial patterns. For example, Indians react more severely to the presence of migrating larvae in the lungs than do other races. In one series, 96% of patients with asthma and bronchospasm were Indians in a region where there was an approximately equal incidence of ascariasis and hookworm disease in a mixed population of Fijians and Indians.

In adults, the mature worm in the gastrointestinal tract commonly produces few or no symptoms. Occasionally, nonspecific symptoms such as nausea, vomiting, anorexia, abdominal discomfort, or colicky pain, usually in the epigastric or periumbilical region, will be observed. Some patients will have abdominal distention, tenderness, and constipation. A few patients may exhibit hypersensitivity to the worms and present with urticaria, dyspnea, or even status asthmaticus; others will suffer idiopathic epilepsy or febrile convulsions, irritability, and other central nervous system manifestations which may be caused by the release of anaphylaxins, neurotoxins, and endocrinotoxins present in adult ascarids ("Ascaris encephalopathy"). Some authors doubt that Ascaris per se causes convulsions; they believe the passage of worms in such patients is more likely due to the migration of ascarids during a febrile episode. The eosinophil count may be normal or only slightly elevated during the phase of intestinal ascariasis.

The most frequent and severe complication of ascariasis is partial or complete intestinal obstruction caused by a heavy infection; this is seen much more commonly in children than adults. Worm burdens of several hundred ascarids per individual are not uncommon in highly endemic areas, and there are case reports of 1,063 and over 2,000 worms in individual children. When great numbers are present, there is a tendency for these roundworms to entwine themselves around one another into a large bolus, partially or completely blocking the intestinal lumen, especially during a febrile infection or after therapy with anthelmintics (Fig. 10.5). The most common site of obstruction is at or near the ileocecal region, although blockage by coiled ascarids can occur anywhere in the small or large bowel. With the onset of intestinal obstruction, the child (or, rarely, adult) may have severe colic at recurrent intervals of 10 to 15 minutes, usually in the periumbilical region or right lower quadrant. There may be abdominal distention and vomiting, increased peristalsis, slight fever, and eosinophilia. In half the patients, a mass may be palpated in the periumbilical area or right lower quadrant; its freely movable sausage shape may be confused with an intussusception. There may be recurring episodes of such symptoms for several weeks or months and often there will be a history of passage of adult ascarids through the mouth, nose or rectum.

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