Tissue Cestodes - PDF

Tissue cestodes ILOs At the end of this session, the student will be able to: ▪ Understand epidemiological disease distribution both worldwide as well as in areas of high endemicity in Egypt. ▪ Recognize hydatid, cysticercosis, sparganosis a...

Tissue cestodes ILOs At the end of this session, the student will be able to: ▪ Understand epidemiological disease distribution both worldwide as well as in areas of high endemicity in Egypt. ▪ Recognize hydatid, cysticercosis, sparganosis and coenuriosos infections as zoonotic disease where man is an accidental intermediate host. ▪ Understand pathophysiological mechanisms of cyst development in the human body. ▪ Recognize hydatid disease as a cause of single or multiple cysts of the liver, spleen, and lungs. ▪ Differentiate hydatid disease from other causes of cystic diseases of the liver, spleen, or lungs. ▪ Utilize laboratory and radiological investigations to reach a final diagnosis. ▪ Design an appropriate management strategy according to the site and stage of disease. ▪ Understand the role of medical treatment in managing hydatid and other tissue cystodes diseases. ▪ Understand appropriate preventive measures for tissue cystodes based on an understanding of their life cycle. Cysticercosis Definition Infection of human tissues with larvae of the pork tapeworm Taenia Solium Human cysticercosis It is acquired through oral- fecal route When humans ingest tapeworm eggs, they develop cysticerci within their tissues in the same way pigs do. Cysticercosis is therefore contracted from ingesting material contaminated by human feces containing tapeworm eggs and not from eating infected pork containing cysticerci. Humans are incidental intermediate host and represent a dead end for the parasite. Humans harboring an intestinal tapeworm can infect themselves with cystcercosis (anus-hand-mouth) Or others directly through unhygienic food preparation. Page 1 of 5 Epidemiology Neurocysticercosis is estimated to be the most common parasitic infection of the brain and the most common cause of adult-onset epilepsy worldwide Clinical manifestations The clinical features of cyticercosis are variable, depending on the inflammatory response around cysticerci and their numbers, size and the location. Neurocysticercosis Epilepsy Focal seizures with secondary generalization are most common Single or multiple cyseticerci are usually present within the brain parenchyma and may be surrounded by focal encephalitis and edema Raised ICP Dementia or psychiatric illness Hydrocephalus Chronic meningitis Basal arachnoiditis Cranial nerve palsies Vasculitis and cerebral infarcts due to death of cysticerci Spinal cysticercosis Ophthalmic cysticercosis Most common in retina or sub retina May float in vitreous or aqueous humor Choridoretinitis Retinal detachment vasculitis Muscular and subcutaneous cysticercosis Palpable or pea-like nodules Asymptomatic, although transient local pain and tenderness may occur Page 2 of 5 Massive muscular pseudohypertrophy Diagnosis Biopsy for subcutaneous lesions Radiology : plain x ray of the thigh or other muscles, Plain x ray of skull-----intracranial calcifications CT MRI Serology Enzyme linked immunoelectrotransfere blot Differential Diagnosis TB Neoplasm Hydatid cyst toxoplasmosis Treatment Praziquantel (50-75mg/kg/day PO for 2 weeks) or Albendazole 15mg/ kg/PO for 8-15 days Recently short course of three doses of 75-100 mg/kg of praziquantel in the same day has been reported Between the 2nd and fifth day of therapy, patients have exacerbation of neurologic symptoms due to local death of larvae--------treated by corticosteroids to control edema Symptomatic neurocysticercosis Anticonvulsant drugs for seizures Oral corticosteroids for raised ICP and arachoniditis Insertion of ventriculo-persistent shunt for hydrocephalus Ophthalmic cysticercosis Local and systemic corticosteroids Page 3 of 5 Cestoidar drugs? Cryotherapy?? Photocoagulation? Excision of a living cysticerci before the onset of significant intraocular inflammation has a good prognosis Muscular and subcutaneous cysticercosis Asymptomatic lesions do not require treatment Excision or treatment with cestoidal drugs for lesions causing pressure Sparganosis It is caused by infection with spargana, which are second-stage larvae (plerocercoids) of diphyllobothrid tapeworms of the genus spirometra It is present in Southeast Asia The adult parasite does not develop in humans. Mode of infection: Ingesting the procercoid in the first intermediate host (cyclops) when drinking contaminated water Ingesting the plerocercoid in second intermediate hosts such as frogs From poultices prepared from frogs infected with plerocercoids that are applied directly to ulcers, sores, and inflamed eyes Clinical manifestations Skin: Encapsulated inflammatory nodules in subcutaneous tissues which may develop into abscesses Eye: conjunctivitis, periorbital edema CNS: brain abscesses, intradural spinal cord infection, seizures, headache, hemiparesis, paresthesia, memory loss and confusion Diagnosis Extraction of intact parasite ELISA assay Page 4 of 5 Treatment Surgical excision Praziquantel might be advisable Coenuriasis it is a zoonotic disease of humans caused by infection with the larval stage ( coenurus) of Taenia Multiceps. Adult tape worm are found in the small intestine of canids usually dogs. Gravid proglottids are passed in feces and disintigrate to free eggs. Eggs when ingested by humans , the eggs develop into coenuri Human coenuriasis is rare but it has been reported in USA, England, France and Brazil Clinical manifestations Neural coenuriasis: Space-occupying lesions in the cerebrum, ventricles, posterior horn, brain stem, spinal cord, and among the cranial nerves Subcutaneous coenuri: in intercostal regions and anterior abdominal wall. These cysts are confused with lipoma, ganglion, and neurofibroma Ocular coenuri: in the vitreous, anterior chamber, and conjunctiva. Diagnosis X- ray CT Subcutaneous cysts may be palpated Ocular lesion by ophthalmoscope Treatment Surgical excision is the usual treatment Praziquantel can cause serious toxic endophthalmitis and loss of vision The best treatment is removal through closed vitrectomy Page 5 of 5