II. PATHOPHYSIOLOGY OF NEUROCYSTICERCOSIS
Definition : It is a parasitic infection in the central nervous system that is caused by a tapeworm called Taenia solium (T. solium). Schematic Diagram: Predisposing Factors: >Race: Hispanics ethnicity >Age: Children older than 7 years old >Geographical >Geographical area: Latin America, Asia, Africa, Spain, and Eastern Europe. California and Texas and in the city of Chicago >Immigrant status from Mexico, Central and South America >Family history of taeniasis
Precipitating Precipitating Factors: >Exposure to areas of endemicity >Poor sanitation >Poor hygiene >Use of sewage for f ertilizer >Lack of controlled pens for pigs >Ingestion of undercook pork meats >Sharing of food from the same plate
Ingestion of Tapeworm larvae with undercooked pork
Worm attaches to the intestinal wall by means of suckers and hooks and it develops in the small intestine by forming segments (hermaphrodite proglottids containing more than 50,000 eggs) that arise from the caudal end of the scolex. The tapeworm matures over -
Diagnostic: Fecalysis: Parasites: Opaque, off-white in color, 1-2 cm long, 1 cm wide -
The eggs are intermittently pushed out from the proglottid into the intestine and proglottids may be shed in the
Ingestion of food containing eggs that are transferred from anus to mouth by unclean hands of an infected person
When these eggs are ingested and exposed to gastric acid in the human stomach, they lose their protective capsule and release a cyst form called oncosphere (the larva of the tapeworm armed with 4 hooks) and becomes active in the intestinal wall.
The larval cysts penetrate and erodes the intestinal mucosa and migrate throughout the body via the vascular system to the brain, muscle, eyes and other structures and lives in tissues as fluid-filled
Human Cysticercosis
The larval cysts lodge to the different parts of the brain with varying macroscopic
Brain parenchyma: Viable cysticerci measure approximately 10 mm tends to lodge in the cerebral cortex or the basal ganglia because of the high vascular
Ventricular area: Viable cysts are usually single lesions, that lodge to the choroid plexus or float freely within the ventricular cavities
Subarachnoid space: Viable cysticerci tends to lodge within cortical sulci or in the CSF (Cerebrospinal (Cerebrospinal Fluid) cisterns at the base of the brain and grow to reach 50mm or more because their growth is not limited by the
Neurocysticerco
MRI scan, CT scan
After entering the CNS, cysticerci are viable and induce slight inflammatory changes in the surrounding tissues. Minimum inflammatory reaction around the cyst because the parasite carry out prostaglandins and low molecular wieght molecules which decrease perilesional inflammation and secrete proteases that can degrade interleukin 2 and
Sudden Headache
Management: Corticosteroids The parasite remains alive and undergo different stages such as vesicular stage, colloidal colloidal stage, granular nodular stage, stage, and nodular calcified calcified
Vesicular stage: parasites have a transparent membrane, clear vesicular fluid, and larva or scolex and may remain for decades (asymptomatic). (asymptomatic).
As the result of a complex immunological attack from the host by releasing lymphocyte proliferation and macrophages, cytokines, T cells
Colloidal stage: parasite dies within 4-5 years untreated, or earlier with treatment and the cyst fluid becomes turbid. As the membrane becomes leaky edema surrounds the cyst.
Granular stage: the wall of the cyst thickens and scolex is transformed into coarse mineralized granules.
Mrdical management: >Antihelminthics: Albendazole, praziquantel >surgical removal of the cyst via endoscopy
Calcified stage: the parasite remnants appear as a mineralized nodule . Diagnostic tests: >CSF analysis: mild pleocytosis and elevated protein contents >ELISA and complement fixation test: positive of anticysticercal antibodies
Intense inflammation by the cysticerci in the subarachnoid space or in the ventricular areas in the brain with formation of a dense exudate composed of collagen fibers, lymphocytes, plasma cells, eosinophils, multinucleated giant cells, and hyalinized parasitic membranes leading to leptomeningeal thickening. It is called cysticercotic arachnoiditis. Occlusion by the thickened leptomeninges in the subarachnoid area or in ventricular area especially in the choroid plexus and ventricular wall.
Secretion of the CSF (cerebrospinal (cerebrospinal fluid) continues even if the flow of fluid through the ventricular system is blocked
Headaches, vomiting, nausea, papilledema, sleepiness, coma, seizures(tonic-clonic
Excessive accumulation of CSF within the ventricular spaces of
Surdical procedure: Ventricular
Signs & Symptoms: Sudden or severe Headache, fever Management: Corticosteroids
ocular palsies, altered level of consciousness, consciousness, back pain and papilledema. papilledema.
Compression and atrophy of the brain tissues around the dilated ventricles.
MRI scan, CT scan, EEG
Small penetrating arteries arising from the circle of Willis are also affected by this inflammatory reaction
Increased intracranial pressure Occlusion of the lumen of the vessels and decreased in cerebral tissue erfusion Weakness, loss of sensation on the opposite side of the body, abnormal pupil dilation, light reaction and lack of eye of eye movement on opposite side, speech will be slurred
Cerebrovascular Cerebrovascular accident Neurological Neurological impairement Death
Cerebral infarction
MRI scan, angiograp hy, CT scan
