Threadworms_Flashcards
What are threadworms also known as?
Enterobius vermicularis or pinworms.
How common is threadworm infestation among children in the UK?
Extremely common.
How does threadworm infestation occur?
After swallowing eggs that are present in the environment.
What percentage of threadworm infestations are asymptomatic?
Around 90% of cases.
What are possible features of threadworm infestation?
Perianal itching, particularly at night. Girls may have vulval symptoms.
How is the diagnosis of threadworm infestation typically made?
By applying Sellotape to the perianal area and sending it to the laboratory for microscopy to see the eggs. However, most patients are treated empirically.
What is the recommended management for threadworm infestation according to CKS?
A combination of anthelmintic with hygiene measures for all members of the household. Mebendazole is used first-line for children > 6 months old. A single dose is given unless infestation persists.
summarise threadworms
Threadworms
Infestation with threadworms (Enterobius vermicularis, sometimes called pinworms) is extremely common amongst children in the UK. Infestation occurs after swallowing eggs that are present in the environment.
Threadworm infestation is asymptomatic in around 90% of cases, possible features include:
perianal itching, particularly at night
girls may have vulval symptoms
Diagnosis may be made by the applying Sellotape to the perianal area and sending it to the laboratory for microscopy to see the eggs. However, most patients are treated empirically and this approach is supported in the CKS guidelines.
Management
CKS recommend a combination of anthelmintic with hygiene measures for all members of the household
mebendazole is used first-line for children > 6 months old. A single dose is given unless infestation persists
A mother brings in her 6-year-old boy who complains of ‘an itchy bottom’ at night. He is otherwise systemically well, developing normally and denies any change in his bowel habit. An external examination of the anus is unremarkable.
Which one of the following is the most likely cause?
Threadworms
Human roundworm
Psoriasis
Haemorrhoids
Tapeworm
Threadworms are a common cause of anal itching in children. Examination is often unremarkable. Threadworms are best seen at nighttime and appear like moving white threads in the anal area.
Human roundworm does not usually cause itching and are rare in the UK.
Tapeworms are parasites that can live in the intestine, they do not cause anal itching and are often asymptomatic
Psoriasis is usually found on the elbows, knees, scalp and lower back. It may also be found in the genital area and would present with scaly, red skin.
Haemorrhoids are swollen vessels located around the anus which can result in itching and rectal bleeding, usually on a background of constipation.
An 8-year-old girl is brought to her GP by her mother due to her complaint of perianal itching, particularly at night, persisting for about one week. Her brother has recently started exhibiting similar symptoms.
Upon examination, two slender white worms are noted in the perianal region of the child.
What is the most likely causative organism?
Ascaris lumbricoides
Echinococcus granulosus
Enterobius vermicularis
Taenia solium
Trichinella spiralis
Enterobius vermicularis
Perianal itching in children, possibly affecting other family members → Enterobius vermicularis (threadworms)
Important for meLess important
Enterobius vermicularis, commonly known as threadworms or pinworms, may be asymptomatic but can cause perianal pruritus, particularly at night. The act of scratching transfers the ova beneath the fingernails, facilitating their dissemination onto various surfaces, objects, and foods. These eggs are viable for approximately two weeks outside the host. In this scenario, it appears that the infection has been transmitted to the patient’s sibling. The therapeutic approach involves administering oral mebendazole and hygiene measures.
Ascaris lumbricoides, also referred to as giant roundworm, is transmitted via ingestion of infectious eggs similar to Enterobius vermicularis; however, it does not cause perianal itching. Clinical manifestations are variable and can include visceral larva migrans and ocular complications such as retinal granulomas. The treatment of choice for Ascaris lumbricoides is diethylcarbamazine.
Echinococcus granulosus transmission occurs through the ingestion of ova present in canine faeces. This zoonosis is more frequently encountered in individuals with close contact with dogs that have consumed hydatid cysts from infected sheep, such as farmers. Clinical presentation diverges from that described in our case study by typically involving hepatic cyst formation and potential anaphylactic reactions if these cysts rupture.
Taenia solium, or pork tapeworm, is acquired through the consumption of undercooked pork containing larval cysts and does not manifest with perianal pruritus. Instead, it leads to conditions such as cysticercosis and neurocysticercosis, which can result in symptoms including headaches and seizures.
Trichinella spiralis, contracted by ingesting raw or undercooked pork products, characteristically presents with a clinical picture distinct from our case study: fever, periorbital oedema, and myositis are common features. Management includes treatment with either mebendazole or albendazole.
