Roundworms (Ascaris Lumbricoides)

In general, it is the nematode that infects people most frequently. There are two ways in which the parasite can injure people.  Larva form: They essentially cause symptoms related to the lungs. Adult forms: Typically result in digestive issues. Both are detrimental to people.

Eggs

When they get a conducive atmosphere for the maturation of eggs, which means a hot and humid environment is basically present in the tropical region; Eggs are very stable, meaning they can survive in a hostile environment for years without being destroyed; these are the reasons that Ascaris lumbricoides entered humans through eggs. It's the perfect setting for eggs to develop into embryos.

Ascaris lumbricoides eggs enter the human body through the feco-oral pathway; contaminated food and water are the source of this invasion. Ascaris lumbricoides develops from its eggs into larvae. It is the larva that poses a threat to people.
The larva first enters the portal circulation, travels to the liver, and then exits the liver to enter the systemic circulation, which passes via the lungs before arriving at the lungs.

When this larva enters the alveoli in the lungs, that's when the pulmonary symptoms start.

These larvae become tied up over time due to the pulmonary symptoms, and some of them are ingested by the gut.  As a result, they pass into the stomach and eventually the intestine.

They essentially develop into adult worms in the intestine. The symptoms related to the intestines are caused by these mature worms.

 As a result, they may block the intestines, interfere with the common bile duct and produce jaundice, or interfere with the pancreatic duct and induce pancreatitis. As a result, it may result in intestinal symptoms such as a blockage of the intestines as well as hepatobiliary symptoms.

All of these transformations take eight weeks to mature.

They are ready to infect the other individual, or they may lie dormant in the soil for years until they receive a favorable environment in the form of a hot and humid climate. The mature adult female worm, which is present in the small intestine, lays multiple eggs that are coming out in the stool.

Also Read: Surgical Ethics And Laws

Clinical Features

Larva Form

These patients' typical features include dyspnea, fever, chest pain, and dry cough. The chief symptoms observed in these individuals are all referred to as Loeffler's syndrome. The larvae produce pulmonary symptoms.

Adult Worms

The patients won't be able to thrive because adult worms may grow up to 45 cm in length and compete with people for food.
  Because of the surface area that these worms occupy, patients will not be able to digest their food properly, leading to malnutrition.  These adult worms have the ability to spread throughout the pancreatic and common bile ducts, as well as the small intestine and hepatobiliary system.These adult worms will cause pain in the abdomen and eventually clog the intestine if they are present.

Patients may get pancreatitis if the adult worms penetrate the pancreatic duct; if they enter the common bile duct, they may experience jaundice and cholangitis. Intestinal blockages may result from a worm bolus in the terminal ileum, particularly in children. The patient will require immediate surgery.Rarely, these boluses of worms in the gut can occasionally result in pressure necrosis of the intestine wall, which could lead to a perforation in the patient. The patient will require urgent surgery.

Investigations 

The eosinophil count will rise as a result of the blood testing done during the examination. Through the inspection of their stools, these patients' ova were discovered, and very infrequently, a few worms may emerge. In the event that lung symptoms manifest, the bronchoscopy can be carried out.

During bronchoscopy, a procedure known as broncho-alveolar lavage (BAL) may be carried out. Crystals of Charcot-Leyden are discovered in this. Furthermore, there will be larvae present as well.

Also Read: Percutaneous Endoscopic Gastrostomy And Tracheostomy 

Radiological Investigations

Loeffler's syndrome is characterized by fluffy exudates, which may be visible on the x-ray.  The cause of Loeffler's syndrome is the larva. It can exist without larvae, though.

Barium Meal

Ascaris lumbricoides was identified as being present inside the intestine when the roundworm absorbed the barium contrast during the barium meal procedure.Jaundice may result from the presence of worms in the common duct.

Our first suspicion in the case of jaundice in patients is typically the presence of a CBD stone. We would discover a roundworm in place of the stone if an MRCP or an ERCP had been done.

There's a chance the worm inside the common bile duct will show up on the ultrasound. 

Treatment

Treatment can be done in the pulmonary phase or in the intestinal phase.

In the Pulmonary Phase

 Patients in this pulmonary phase typically have self-limiting illness, but symptomatic therapy is still necessary.

In the Intestinal Phase

 These patients are prescribed antihelminthic medications. If the patient is receiving antihelminthic medication and there are a lot of worms in the terminal ileum, the worms may die and create a bolus of dead worms, which causes the small intestine obstruction.The patient did not previously have a tiny intestinal blockage; instead, the terminal ileum was overly infested with worms. They restrict the patient's small intestine by administering anthelmintics.In these situations, an intermittent or subacute blockage may be diagnosed based on the clinical presentation. 

In the event of intermittent or subacute obstruction: IV fluids, nasogastric tubes, and aspiration are required in order to prevent extremely high intestinal pressure in these individuals.

Increases intestinal motility and causes the worms to detangle when used in hypertonic saline enema.  Giving these patients a hypertonic saline enema will aid in removing the worms from their large intestine if they are located beyond the ileocecal junction.

In case of patients with intestinal obstruction, surgery was performed:                                

While having surgery these patients are then given a hypertonic saline enema, which may aid in moving the worms to the opposite side of the ileocecal valve by milking them over the ileocecal junction.

If it is not possible due to intestinal stricture, gut wall necrosis, or intestinal perforation, then there is no other course of action. This will aid in the expulsion of the worms from the intestine. Resection and anastomosis ought to be carried out in these circumstances.  If the gut wall is healthy yet it is not possible to milk these worms across the ileocecal valve, an enterotomy and worm evacuation should be done.

An enterotomy was done and all of these worms were removed. If the worms are present in the pancreatic or common bile ducts, it was not able to sort of milk them across the ileocecal valve because they are visible across the intestinal wall. An ERCP was carried out in this instance. Worms are extracted from the pancreatic or common bile ducts during ERCP procedures. However, a laparoscopic or open procedure is used if this doesn't work.

Hope you found this blog helpful for your NEET SS General Surgery preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.