American Journal of Emergency Medicine (2010) 28, 645.e5–645.e8
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Case Report Intestinal ascariasis presenting with chronic gastrointestinal complaints Abstract Ascaris lumbricoides infection affects one quarter of the world's population. Although considered rare in the United States, the organism is found in that country, particularly in the southeast. Epidemiologic studies suggest up to 4 million Americans may be infected, many with no symptoms. Ascaris is the most common helminthic infection in humans, and as travel, immigration, and international adoption become more common, it is likely to become more commonly seen in the United States. Ascaris infection can present early, with pulmonary symptoms related to worm migration, or late, with mechanical symptoms depending on worm number and location. We describe the case of a young woman presenting with intractable vomiting and diarrhea 8 months after returning to the United States from a trip to Peru. After 3 different medical visits, she was found to have ascariasis with a large worm burden. The clinician must maintain a high index of suspicion for this pathogen in patients with gastrointestinal tract symptoms and risk factors because it is not a rare entity in the developed world. A 23-year-old woman presented to her physician with epigastric pain, diarrhea, and vomiting of several days duration. She had no systemic symptoms. Her examination at that time revealed epigastric and right upper quadrant tenderness, and the patient was referred for right upper quadrant ultrasound, which showed possible cholelithiasis. The patient re-presented to the emergency department (ED) 3 weeks later with crampy abdominal pain, nausea, vomiting, and diarrhea. She described the pain as being similar to her previously diagnosed “gallbladder pain.” She reported no recent travel. She underwent laboratory evaluation, which was unremarkable, and was treated symptomatically and discharged. One week later, the patient presented to the ED, again with crampy abdominal pain, nausea, vomiting, and diarrhea. She was not able to keep anything down and stated that her abdomen was getting distended. The patient localized the abdominal pain to the epigastrium. She stated that the 0735-6757/$ – see front matter © 2010 Elsevier Inc. All rights reserved.
symptoms had been present intermittently for months, but had worsened about a day before presentation, and were described as severe but bearable. She also complained of fevers for the last day or 2. On further questioning, the patient reported no recent travel but had traveled to Peru 8 months before her ED visit and had a gastrointestinal tract illness then. Aside from intermittent abdominal cramping, nausea, and diarrhea for many months, she had been feeling otherwise well since. She had not had any weight loss or night sweats. On laboratory evaluation, the patient had a normal complete blood count with a normal white blood cell differential. Her chemistries were remarkable only for a total bilirubin of 2.2 mg/dL. Because of her intractable vomiting and distention, there was concern that the patient might have a bowel obstruction, so a contrasted CT scan of her abdomen and pelvis was ordered. These revealed innumerable elongated tubular filling defects throughout her small bowel, consistent with helminthic infestation (Figs. 1 and 2). The patient was treated with 500 mg of albendazole and was admitted to the hospital for inability to take anything per os. She did pass a worm, which was identified by pathology as Ascaris lumbricoides. She recovered completely within a few days. A lumbricoides is the largest nematode affecting the human gastrointestinal tract. It infects one fourth of the world's population, which translates into approximately 1.4
Fig. 1 Computed tomography image demonstrating tubular filling defects in small bowel, consistent with Ascariasis.
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Fig. 2 Coronal reconstruction of computed tomography showing large worm burden in jejunum.
billion people [1-3]. The highest infection rates are in Asia, followed by Africa and South America [1,2]. All age groups are affected; however, children ages 2 to 10 have the highest prevalence [1,2]. In the United States, ascariasis is the third most common helminthic infection, affecting 4 million people, or 2% of the population [1,4]. Some evidence suggests that the incidence may be much higher in young children, particularly in the southern United States [1]. It is estimated that 20% to 60% of US infections are in immigrants from developing nations, with the remainder of individuals contracting the helminth in the United States or while traveling abroad [1,5-7]. Ascaris infects more than 50% of US pigs in some series [8], and most cases of sporadic infection in the United States are thought to be secondary to cross-infection [9]. Other reasons cited for infection are improper sanitation [10]. A lumbricoides is transmitted via ingestion of soil containing embryonated eggs. Eggs in the soil may remain viable and infective for up to 10 years [1,2]. The eggs are resistant to chemical water purification but are susceptible to boiling [1,2]. Once ingested, gastric secretions dissolve the egg and allow the larvae to emerge, which then migrate through the gastrointestinal mucosa and enter the portal system. Subsequently, they enter the systemic circulation and are deposited in the lungs [1,2]. Some of the larvae enter the
Case Report lymphatic system as well, where they are discarded into the pulmonary system via the thoracic duct [1]. While in the pulmonary system, they ascend through the tracheobronchial tree and enter the hypopharynx, where they are swallowed [1]. Adult female worms in the jejunum produce on average 240 000 eggs a day, which are released in the fecal stream, continuing the cycle of infection. Adult worms live on average for 6 to 18 months [1,2]. Dead larvae in the liver and lungs cause a granulomatous reaction; and invasion of brain, kidney, and heart has been documented [1]. Although ascariasis infects 25% of the world's population, most infections are without clinical disease [1,2]. These cases are diagnosed with routine screening or when the patient passes a worm and presents for care. Clinical disease is usually the result of heavy worm loads, as in our case, or secondary to symptomatic worm migration [1,2], and can be divided into intestinal ascariasis, pulmonary ascariasis, and hepatobiliary ascariasis. Intestinal ascariasis usually presents with vague abdominal pain, distention, nausea, and occasionally diarrhea. Our patient had all these symptoms. Small bowel obstruction secondary to a mass of worms at the terminal ileum is a common complication in children with heavy worm burdens. In addition to the previous symptoms, these children may vomit worms or become obstipated. On physical examination, patients with ascariasis will often have abdominal distention, diffuse tenderness, and increased bowel sounds [11]. Those with obstruction may have a palpable mass. Plain radiographs may reveal multiple air fluid levels in the obstructed patient or may be completely normal [11], and eosinophilia is often absent, as in our case. Treatment is usually conservative, with fluid and electrolyte replacement, NG tube decompression, antihelminthic therapy, and antibiotics for the very ill patient [1]. Piperazine is the preferred drug in Ascaris intestinal obstruction because it causes neuromuscular paralysis of the worm. The dose is usually 150 mg/kg given via NG tube, and an additional 6 doses of 65 mg/kg may be given every 12 hours [11]. Some authors suggest a single high dose of piperazine may cause a volvulus. It is thought the bolus of worms act as a fixed point that allows the volvulus to occur [12]. Surgical decompression is indicated when there is shock or persistence of mass for greater than 24 hours with accompanying abdominal pain or an acute abdomen [11]. A lumbricoides may also enter the tip of the appendix, which results in appendiceal colic followed by a gangrenous tip [11]. Examination of the appendix after removal demonstrates no inflammation of the mucosa of the appendix [1,11]. Pulmonary ascariasis is due to larvae migration and typically presents 4 to 16 days after ingestion of embryonated eggs. The pneumonia is usually self-limited, lasting 2 to 3 weeks. It is common in children and may present with sudden onset of fever, cough, wheezing, dyspnea, and in some instances, hemoptysis [1]. Significant eosinophilia is seen in only about 10% of cases and typically occurs during migration but then decreases once the worms enter the intestines.
Case Report Chest radiography usually shows prominence of peribronchial regions and diffuse mottling [1]. Diagnosis of ascariasis pneumonia is made in the presence of an eosinophilia more than 20%, diffuse mottled pulmonary infiltrates, and respiratory symptoms in a patient from an endemic area [1]. Larvae maybe found in sputum or gastric washings between the 8th and 16th day of exposure but are not necessary to make the diagnosis [1]. Hepatobiliary/pancreatic ascariasis (HPA) is one of the most common symptomatic manifestations of Ascaris infestation. A lumbricoides in the duodenum may enter the ampulla of Vater causing an obstruction. They can travel further and invade the biliary and hepatic ducts, with some worms reaching the gallbladder. Others may enter the pancreatic duct. For reasons that are unclear, HPA is more common in women than in men, with adults being affected more often than children. Most patients with HPA have had previous surgery on the biliary tree, and endoscopic retrograde cholangiopancreatography (ERCP) may predispose to HPA in endemic areas and in patients with heavy worm burdens. Diagnoses can be made by ultrasonography or by ERCP. In the gallbladder, the worms appear as multiple, long, linear, or parallel echogenic strips without acoustic shadowing. They may also appear as a “bull's eye” pattern when visualized in cross section [12,13]. The live worm shows slow, pendular, nondirectional movements, known as the zigzag sign [13]. Hepatobiliary/pancreatic ascariasis can present as biliary colic, acalculous cholecystitis, acute cholangitis, acute pancreatitis, or hepatic abscess [1]. Treatment is usually ERCP or surgical decompression with antihelmithic therapy. In general, although the diagnosis of Ascaris infestation may be suggested by history, lab, radiographic, or ultrasonographic findings, the definitive diagnosis is made by stool microscopy [14]. Eggs will appear in feces 60 to 75 days after exposure but may be absent if the worms are mostly male or if the female worms are too old or too young to produce eggs [1,11]. Anti-helminthics work in different ways. Pyrantel causes spastic paralysis of the worm, and a single dose of 11 mg/kg is usually 90% effective but is worm load dependent [14,15]. It may take up to 3 days for the worms to clear. Mebendazole inhibits microtubules and irreversibly blocks glucose uptake by the worm. Mebendazole may cause abdominal pain, diarrhea, or even neutropenia and abnormal liver function tests. A dose of 100 mg twice daily for 3 days is recommended and has been shown to be 95% effective [1,14,15]. Albendazole also inhibits microtubule formation as well as glucose uptake and is dosed as a single 400-mg tablet [1,15]. It may cause abdominal pain and diarrhea or migration of the worm through the nose and mouth [1,14]. Prolonged use of albendazole has been associated with neutropenia as well as thrombocytopenia [1]. It is usually 100% effective, but reinfection commonly occurs [14]. It is important to remember that the antihelminthic treatment regimens are effective only against the adult
645.e7 worms and do not eradicate larvae [14]. Therefore, reevaluation should be done 2 to 3 months after treatment to ensure all adult worms were eliminated and that no remaining eggs or larvae have caused reinfestation [14]. Prevention of infestation is generally aimed at simple hand washing and drinking boiled water, as well as education regarding appropriate handling of animal and human excrement. Ascaris is ubiquitous in the world, and the United States is no exception, with estimated 2% of people infected. In spite of this, many practitioners believe that this is a disease of the developing world only. In addition to the infections that are present in new immigrants, refugees, and adopted children, an increasing number of people are traveling to exotic locations, where they may be exposed to Ascaris. Furthermore, studies of US soil samples indicate that the helminth is present in local soil and infests domesticated farm animals. A high index of suspicion must be maintained in patients who have traveled to endemic areas over the previous 2 years, and questioning should include clear timelines for travel. Simply asking about “recent travel” is inadequate, as many people will not consider 6 months prior as recent. Ascariasis should also be considered in small children with bowel obstruction without other risk factors and in those with subacute to chronic gastrointestinal complaints who live in areas with dug wells or poor sanitation. If there is any question regarding the possibility of this diagnosis, stool sampling should be undertaken, as this is a sensitive way to make the diagnosis. James Walker DO Rebecca Jeanmonod MD Department of Emergency Medicine St. Luke's Hospital Bethlehem, PA 18015, USA E-mail address:
[email protected] doi:10.1016/j.ajem.2009.09.016
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645.e8 [8] Morris RG, Jordan HE, Luce WG, et al. Prevalence of gastrointestinal parasitism in Oklahoma swine. Am J Vet Res 1984;45(11):2421-3. [9] Anderson TJ. Ascaris infections in humans from North America: molecular evidence for cross-infection. Parasitology 1995;110(Pt 2):215-9. [10] Embil JA, Pereira LH, White FM, et al. Prevalence of Ascaris lumbricoides infection in a small Nova Scotian community. Am J Trop Med Hyg 1984;33(4):595-8. [11] Akgun Y. Intestinal obstruction caused by Ascaris lumbricoides. Dis Colon Rectum 1996;39:1159-63.
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