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KembaraXtra- Medicine- Ascariasis
Ascariasis is a parasitic infection caused by the nematode Ascaris lumbricoides. Although most infected individuals remain asymptomatic, clinical disease can occur due to pulmonary hypersensitivity reactions, intestinal obstruction, nutrient depletion, or other secondary complications. Ascariasis remains the most common helminthic infection worldwide. The ICD-10-CM codes include B77.0 (with intestinal complications), B77.81 (ascariasis pneumonia), B77.89 (with other complications), and B77.9 (unspecified).
Globally, A. lumbricoides infects more than one billion people, with approximately 71% of those at risk living in Asia and the Western Pacific. In the United States, the exact incidence is unknown, but prevalence is estimated at about 4 million cases, primarily in rural areas of the southeastern states where sanitation is poor. Infection rates are reported to be approximately three times higher in Black populations than in White populations. Both sexes are affected equally, with a possible slight female predominance. Ascariasis is most common in children aged 2 to 10 years and tends to decrease after age 15. Infections often cluster within families. Neonatal infection is considered possible, although it has not been well studied.
Most individuals infected with Ascaris are asymptomatic. When symptoms occur, they often appear 9 to 12 days after ingestion of eggs, corresponding to larval migration through the lungs. Pulmonary manifestations include nonproductive cough, substernal chest discomfort, and fever, consistent with a hypersensitivity reaction. In patients with heavy worm burdens, particularly children, intestinal complications may occur, including obstruction, perforation, volvulus, and intussusception. Migration of adult worms into the biliary tree can produce symptoms resembling biliary colic, pancreatitis, or acute appendicitis. Rare complications include interstitial nephritis and acute renal failure. In endemic regions of Asia and Africa, chronic intestinal carriage may lead to malabsorption of dietary proteins and vitamins, contributing to malnutrition.
Transmission typically occurs via the fecal–oral route, most commonly through contaminated hands or ingestion of vegetables grown in soil containing infective eggs. After ingestion, eggs hatch in the small intestine, and larvae penetrate the intestinal mucosa, migrating via the bloodstream to the lungs. The larvae pass through the alveoli, ascend the bronchial tree, are swallowed, and return to the intestines, where they mature into adult worms. Female worms begin producing eggs approximately 2 to 3 months after infection. Eggs are excreted in feces and can survive for years in warm, moist, shaded soil. Adult worms live for approximately 1 to 2 years within the human host.
The differential diagnosis includes drug hypersensitivity reactions and Löffler syndrome when pulmonary infiltrates and eosinophilia are present. Other intestinal nematode infections should also be considered. Diagnosis is primarily established by laboratory evaluation, most commonly by identifying Ascaris ova in stool specimens. The World Health Organization recommends the Kato-Katz thick smear technique for detecting soil-transmitted helminths. Adult worms may also be passed in stool or expectorated. Eosinophilia is common early in infection, often ranging from 5% to 12%, but may reach as high as 50%, and typically decreases once adult worms are established in the intestines. Serologic testing detects IgG antibodies but lacks specificity due to cross-reactivity with other helminths and is mainly useful for epidemiologic purposes. Polymerase chain reaction testing of stool samples can identify A. lumbricoides and differentiate it from other parasites.
Imaging studies may support the diagnosis in complicated cases. Chest radiographs can demonstrate transient bilateral pulmonary infiltrates consistent with Löffler syndrome. Abdominal plain films or contrast studies may reveal worm masses within bowel loops. Ultrasonography and endoscopic retrograde cholangiopancreatography are useful for detecting worms in the pancreaticobiliary tract, while CT scanning with oral contrast can aid in identifying gastrointestinal obstruction caused by parasites.
All infected individuals, including those who are asymptomatic, should be treated. First-line therapy is albendazole 400 mg orally as a single dose. Mebendazole is an alternative, given as 100 mg orally twice daily for three days or as a single 500 mg dose where available. Cure rates with these agents are high, ranging from 95% to 100%, though both are classified as FDA pregnancy risk category C. The World Health Organization permits albendazole use during the second and third trimesters. Common side effects include gastrointestinal discomfort and headache, with rare cases of leukopenia. Pyrantel pamoate is a safe alternative during pregnancy and is administered at 11 mg/kg orally, with a maximum dose of 1 g. Other alternatives include ivermectin, nitazoxanide, piperazine citrate, and levamisole, though some are less effective or not available in the United States. Complete intestinal obstruction requires surgical management.
The overall prognosis of ascariasis is good, though reinfection is common. Patients should be reevaluated within 2 to 3 months after treatment. Referral to a gastroenterologist is indicated for pancreaticobiliary or appendiceal involvement, and surgical consultation is required for complete obstruction or complications such as perforation or volvulus.
Preventive measures are essential to reduce disease burden and include routine hand washing with soap, proper disposal of human waste, thorough washing or cooking of food, boiling drinking water, and preventing young children from direct contact with contaminated soil.
Ascariasis is a parasitic infection caused by the nematode Ascaris lumbricoides. Although most infected individuals remain asymptomatic, clinical disease can occur due to pulmonary hypersensitivity reactions, intestinal obstruction, nutrient depletion, or other secondary complications. Ascariasis remains the most common helminthic infection worldwide. The ICD-10-CM codes include B77.0 (with intestinal complications), B77.81 (ascariasis pneumonia), B77.89 (with other complications), and B77.9 (unspecified).
Globally, A. lumbricoides infects more than one billion people, with approximately 71% of those at risk living in Asia and the Western Pacific. In the United States, the exact incidence is unknown, but prevalence is estimated at about 4 million cases, primarily in rural areas of the southeastern states where sanitation is poor. Infection rates are reported to be approximately three times higher in Black populations than in White populations. Both sexes are affected equally, with a possible slight female predominance. Ascariasis is most common in children aged 2 to 10 years and tends to decrease after age 15. Infections often cluster within families. Neonatal infection is considered possible, although it has not been well studied.
Most individuals infected with Ascaris are asymptomatic. When symptoms occur, they often appear 9 to 12 days after ingestion of eggs, corresponding to larval migration through the lungs. Pulmonary manifestations include nonproductive cough, substernal chest discomfort, and fever, consistent with a hypersensitivity reaction. In patients with heavy worm burdens, particularly children, intestinal complications may occur, including obstruction, perforation, volvulus, and intussusception. Migration of adult worms into the biliary tree can produce symptoms resembling biliary colic, pancreatitis, or acute appendicitis. Rare complications include interstitial nephritis and acute renal failure. In endemic regions of Asia and Africa, chronic intestinal carriage may lead to malabsorption of dietary proteins and vitamins, contributing to malnutrition.
Transmission typically occurs via the fecal–oral route, most commonly through contaminated hands or ingestion of vegetables grown in soil containing infective eggs. After ingestion, eggs hatch in the small intestine, and larvae penetrate the intestinal mucosa, migrating via the bloodstream to the lungs. The larvae pass through the alveoli, ascend the bronchial tree, are swallowed, and return to the intestines, where they mature into adult worms. Female worms begin producing eggs approximately 2 to 3 months after infection. Eggs are excreted in feces and can survive for years in warm, moist, shaded soil. Adult worms live for approximately 1 to 2 years within the human host.
The differential diagnosis includes drug hypersensitivity reactions and Löffler syndrome when pulmonary infiltrates and eosinophilia are present. Other intestinal nematode infections should also be considered. Diagnosis is primarily established by laboratory evaluation, most commonly by identifying Ascaris ova in stool specimens. The World Health Organization recommends the Kato-Katz thick smear technique for detecting soil-transmitted helminths. Adult worms may also be passed in stool or expectorated. Eosinophilia is common early in infection, often ranging from 5% to 12%, but may reach as high as 50%, and typically decreases once adult worms are established in the intestines. Serologic testing detects IgG antibodies but lacks specificity due to cross-reactivity with other helminths and is mainly useful for epidemiologic purposes. Polymerase chain reaction testing of stool samples can identify A. lumbricoides and differentiate it from other parasites.
Imaging studies may support the diagnosis in complicated cases. Chest radiographs can demonstrate transient bilateral pulmonary infiltrates consistent with Löffler syndrome. Abdominal plain films or contrast studies may reveal worm masses within bowel loops. Ultrasonography and endoscopic retrograde cholangiopancreatography are useful for detecting worms in the pancreaticobiliary tract, while CT scanning with oral contrast can aid in identifying gastrointestinal obstruction caused by parasites.
All infected individuals, including those who are asymptomatic, should be treated. First-line therapy is albendazole 400 mg orally as a single dose. Mebendazole is an alternative, given as 100 mg orally twice daily for three days or as a single 500 mg dose where available. Cure rates with these agents are high, ranging from 95% to 100%, though both are classified as FDA pregnancy risk category C. The World Health Organization permits albendazole use during the second and third trimesters. Common side effects include gastrointestinal discomfort and headache, with rare cases of leukopenia. Pyrantel pamoate is a safe alternative during pregnancy and is administered at 11 mg/kg orally, with a maximum dose of 1 g. Other alternatives include ivermectin, nitazoxanide, piperazine citrate, and levamisole, though some are less effective or not available in the United States. Complete intestinal obstruction requires surgical management.
The overall prognosis of ascariasis is good, though reinfection is common. Patients should be reevaluated within 2 to 3 months after treatment. Referral to a gastroenterologist is indicated for pancreaticobiliary or appendiceal involvement, and surgical consultation is required for complete obstruction or complications such as perforation or volvulus.
Preventive measures are essential to reduce disease burden and include routine hand washing with soap, proper disposal of human waste, thorough washing or cooking of food, boiling drinking water, and preventing young children from direct contact with contaminated soil.
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