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Cysticercosis
Aka: Cysticercosis, Neurocysticercosis, Pork Tapeworm, Taenia solium- Pathophysiology: Tapeworm lifecycle and pathogenesis
- Pork Tapeworm infection (Taenia solium)
- Infection originates in pigs as Tapeworm larvae (cysts)
- Key points related to Cysticercosis pathogenesis
- Tapeworms cycle between human hosts and pigs
- Ingestion of cysts does not cause Cysticercosis
- Cysticercosis is a result of fecal-oral ingestion
- Cysticercosis is not due to eating undercooked pork
- Cysticercosis occurs from infected human feces
- Can infect vegetarians from unwashed fruit
- Humans ingest Tapeworm larvae with undercooked pork
- Pigs ingest food contaminated with infected human stool
- Humans ingest food contaminated with infected stool
- Source: Ingested Tapeworm eggs
- Infected food handlers who do not wash hands
- Fruit or vegetables with infected fertilizer
- Source: Autoinoculation
- Cysticercosis occurs in similar fashion as with pigs
- Ingested eggs develop into Tapeworm larvae
- Larvae travel via blood to tissue where they embed
- Larvae form cysts in brain, eyes, spine, and muscle
- Source: Ingested Tapeworm eggs
- Signs
- General
- Distribution
- Brain Parenchymal Neurocysticercosis (90% of cases)
- Seizures (most common)
- Headaches
- Parkinsonism
- Encephalopathy (if numerous brain cysts)
- Obstructive Hydrocephalus (if ventricles involved)
- Meningitis (mass effect with large cysts)
- Cranial Nerve palsy (mass effect with large cysts)
- Radiculopathy (if spinal cord involved - uncommon)
- Skeletal muscle lesions
- Subcutaneous lesions
- Eye lesions (1-3% of cases)
- Ocular lesions (e.g. vitreous lesions)
- Extraocular muscle lesions
- Brain Parenchymal Neurocysticercosis (90% of cases)
- Imaging: CT Brain
- Diagnostic findings suggestive of Neurocysticercosis
- Single <2 cm lesion
- No midline shift
- Larval sucking parts (scolex) may be visible
- Differntiating cyst stage
- Viable non-degenerating cyst: Not contrast enhanced
- Degenerating cyst (symptomatic): Contrast-enhancing
- Old cysts: Calcified
- Differential diagnosis
- Tuberculosis
- Parasitic Brain Lesions (e.g. Toxoplasmosis)
- Brain Tumor
- Brain abscess
- Other imaging modalities
- Consider MRI brain if CT non-diagnostic
- Ultrasound or CT are approriate to image eye
- Diagnostic findings suggestive of Neurocysticercosis
- Labs
- Cysticercal Ab: Serum Enzyme-linked immunoblot assay
- Test Sensitivity: >65%
- Test Specificity: >67%
- Serum more accurate than CSF titers
- Biopsy of infected tissue
- Cysticercal Ab: Serum Enzyme-linked immunoblot assay
- Diagnostics
- Dilated eye exam if ocular involvement suspected
- Management
- Precautions: Do not start treatment without consult
- Treatment is individualized by multiple factors
- Antiparasitic agents are not uniformly indicated
- Overwhelming host response could be devastating
- Use may risk morbidity or mortality in some cases
- Consult infectious disease in nearly all cases
- Consult neurology and neurosurgery in CNS cases
- Skeletal muscle lesions
- No treatment unless painful
- Consider surgical excision
- Eye: Intraocular lesions
- Consult ophthalmology
- Surgical excision for intraocular lesions
- Eye: Extraocular muscle lesions
- Consult ophthalmology
- Surgical excision for intraocular lesions or
- Consider Albendazole with Corticosteroid
- Brain: Subarachnoid and intraventricular lesions
- Ventricular shunt placed if Hydrocephalus
- Surgical excision for most lesions or
- Consider Albendazole with Corticosteroid
- Brain: Parenchymal Neurocysticercosis
- Albendazole with Dexamethasone (preferred)
- Do not use in massive infection
- Not needed in calcified lesions
- Anticonvulsants if concurrent Seizures
- Albendazole with Dexamethasone (preferred)
- Precautions: Do not start treatment without consult
- References