Cysticercosis

 Cysticercosis

Human cysticercosis is infection by the larval (cysticercus) stage of the

Tapeworm T. solium. Prevalence rates upto 10% are recognized in some endemic areas.

The natural history of the infection is incompletely known. Cysticerci complete their development within 2-4 months after larval entry and live for months to years.

Several factors give rise to symptoms. Initially, the live larva within a thin- walled cyst (vesicular cyst) is minimally antigenic.

When the host immune response or chemotherapy results in gradual death of the cyst, there may be cyst enlargement (colloidal cyst) with mechanical compression, inflammation with pericyst edema, and (sometimes) vasculitis that can result in small cerebral infarcts, increased intracranial pressure. Subsequently, as the cyst degenerates over 2-7 years, it may disappear or be replaced by a granuloma, calcification, or residual fibrosis.

Cysts at different life cycle stages-active (live), transitional, and inactive (dead)-may be present in the same organ. Although some patients develop an intense immune response to the parasite, others show a remarkable tolerance.

Locations of cysts in order of frequency are: 

  • central nervous system
  • subcutaneous tissues
  • striated muscle
  • globe of the eye
  • rarely, other tissues.

Cysts reach 5-10 mm in soft tissues but may be larger (up to 5 cm) in the central nervous system. Attached to the inner wall of the cyst is an invaginated protoscolex with four suckers and a crown of hooks.

Clinical findings

Neurocysticercosis

In many patients, cysts remain asymptomatic. When symptomatic, the incubation period is highly variable (usually from 1 to 5 years but sometimes shorter). Manifestations are due to mass effect, inflammatory response, or obstruction of the brain foramina and ventricular systems. Neurologic findings are varied and nonspecific, in large part determined by the number and location of the cysts.

Acute invasive stage: This rare event, occurring shortly after invasion, results from extensive acute spread of cysticerci to the brain parenchyma. Fever, headache, myalgia, marked eosinophilia, and coma may occur.

Parenchymal cysts: Cysticerci can present singly or multiple and may be scattered or in clumps. Findings include epilepsy (focal or generalized), focal neurologic deficits, intracranial hypertension (intense headache, vomiting, papilledema, visual loss), and altered mental status. Seizures usually do not occur until the cyst or cysts have begun to die.

Subarachnoid space cysts and meningeal cysts: Small to large cysts are generally located in the cortical sulei or basal cisterns. The arachnoid is the principal basal membrane affected. Adhesive arachnoiditis may result in obstructive hydrocephalus, intracranial hypertension, arterial thrombosis leading to transient ischemia or stroke, and cranial nerve dysfunction (most often of the optic nerve).

Ventricular cysts: may float freely (usually singly) within the ventricles or cerebral aqueduct or may be attached to the ventricular wall. They are usually asymptomatic but can cause increased intracranial pressure as a result of intermittent or total blockage.

Racemose cysts: are rare aberrant forms that are multiple-branched, nonencysted, and lack a scolex; they present as grape-like irregular clusters and may reach over 10 cm in diameter. They generally are found in the ventricular and basal subarachnoid spaces, where they cause marked adhesive arachnoiditis and often-obstructive hydrocephalus.

Spinal cord cysts: can be extraspinal or intraspinal and cause arachnoiditis (meningitis, radiculopathy) or pressure symptoms.

Ophthalmo-cysticercosis

Usually there is a single cyst, free-floating in the vitreous or under the retina. Presenting symptoms include periorbital pain, scotomas, and progressive deterioration ofvisual acuity. Findings may include disk hemorrhage and edema, retinal detachment, iridocyclitis, and chorioretinitis. MRI but not CT may assist in diagnosis; immunologic tests are negative.

Subcutaneous and striated muscle cysticercosis

Subcutaneous cysts present as nodules that tend to appear collapse and disappear, and then reappear in other sites after variable periods of time. They are usually asymptomatic.

Appearance  of subcutaneous nodules when associated with other symptoms, for example episodes of seizures, help in diagnosing the condition of cerebral cystecercosis.


INVESTIGATIONS

Laboratory tests:

Definitive diagnosis of Neurocysticercosis requires finding the parasite on histological section of specimens removed by excision biopsy of skin or subcutaneous. Patients should be thoroughly examined by palpation for pea-sized nodules.

Imaging

Plain radiographs of muscle may detect oval or linear calcified lesions (4-10 X 2-5 mm). The lesions are usually multiple, sometimes in the hundreds, and the long axis of the cysts are nearly always in the plane of the surrounding muscle fibers.

Plain skull films may demonstrate calcified cysticercosis. 

CT and MRI

Immunologic tests

Immunoelectrotransfer blot test appears to reach nearly 100% specificity and 95% sensitivity (sensitivity appears to decline if only one or two cysts are present).

Patients presenting with only calcified lesions or granulomas are generally serologically negative.

, whereas the ELISA showed. respectively, 63% and 65%. Hydatid disease and H nana infections cross- react in the ELISA. Sensitivity using cerebrospinal fluid was 86% by immunoblot and 62% by ELISA..

Other tests: The cerebrospinal fluid in neurocysticercosis should be evaluated for IgM (by ELISA) and IgG antibody.  The fluid typically shows increased protein, decreased glucose, and a cellular reaction of mainly lymphocytes and eosinophils.  Eosinophilia over 20% is diagnostically important. EEG may be abnormal.

Differential diagnosis

The differential diagnosis includes tuberculoma, tumor, hydatid disease, vasculitis, chronic fungal disorders, toxoplasmosis and other parasitic diseases, and neurosyphilis.

TREATMENT

 Medical treatment is with Albendazole (preferred) or Praziquantel. Albendazole is more effective, and when corticosteroids are given concurrently, the plasma level of albendazole increases but that of praziquantel decreases.

Treatment should be conducted in hospital. In less than a week after starting treatment, inflammatory reactions around dying parasites may be manifested by meningismus, headache, vomiting, hyperthermia, mental changes, and convulsions. It remains controversial whether to give steroids concomitantly to avoid or diminish this reaction. Anticonvulsants must be continued during drug treatment and probably for an indefinite time afterward.

Following treatment, 50% cure rates (disappearance of cysts and clearing of symptoms) have been reported both for albendazole and praziquantel. Of the remaining patients, many have amelioration of symptoms, including intracranial hypertension and seizures.

In ocular cysticercosis, treatment with albendazole plus corticosteroids kills the cysts, reducing subretinal cysts to a small scar and allowing for easy extraction of vitreous cysts.

Albendazole: A dosage of 15 mg/kg/d in divided doses with meals for 8 days is as effective as the former 30- day course. Albendazole should be taken with a fatty meal to increase absorption.

Praziguantel: Give 50 mg/kg/d for 15 days in three divided doses. Phenytoin, phenobarbital, and corticosteroids, when administered with praziquantel, reduce serum levels of the latter; high doses of praziquantel have been tried in these circumstances.

Surgery:  May be needed to remove orbital, cistemal, and ventricular cysts and, if accessible, cerebral, meningeal, or spinal cord cysts. When hydrocephalus is present, surgical shunt is required even when the parasites have been destroyed.

Prognosis

The fatality rate for untreated neurocysticercosis is about 50%; survival time from onset of symptoms ranges from days to many years. Drug treatment has reduced the mortality rate to about 5-15%. Surgical procedures to relieve intracranial hypertension along with use of steroids to reduce edema improve the prognosis for those not effectively treated with the drugs.



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About Manbir & Gurpreet

Gurpreet Kaur’s journey in this world .... Gurpreet Kaur was a Musician. She was a singer and a composer of music. Her interest was composing and singing Gurbani Shabads in Indian Classical style. She sang Shabads in All the Raags mentioned in Sri Guru Granth Sahib Ji. She also taught Gurmat Sangeet at Gurmat Gian Missionary College, Jawadi, Ludhiana. Elder child to Pushpinder Kaur and Dr. Brig. Harminder Singh, was born in Amritsar on 13th Jan 1962. She attended various convent schools as a child because her father would get frequent Army postings as a dental surgeon. She graduated with Music Honors from Govt. College for Women, Chandigarh. Music was her hobby and she composed and sang Raag based Gurbani Shabads. Doing Kirtan was part of growing up nurtured by her parents. She learned music from her father Dr. Brigadier Harminder Singh who was a dental surgeon in Indian Army and a very good singer himself. Gurpreet’s Bhua (father’s sister), Ajit Kaur retied as a Head of Department of Music from Govt. College for Women Ludhiana, and was a renounced Punjabi singer of her time. Gurpreet Kaur also learned nuances of Indian Classical Music from Pandita Sharma. She was a mother of three children, and a grandmother. Her daughter Keerat Kaur is a Computer Engineer. Her two sons Gurkeerat Singh and Jaskeerat Singh are doctors in USA. Her daughter Keerat Kaur too was part of her group ~ Gurmat Gian Group. Gurpreet Kaur left this world at the age of 54yrs on 12th Sept 2016 in Baltimore USA. She had recorded around 25 cds of Gurbani Keertan. 'Raag Ratan' Album (6 CDs) is a Compilation of Shabads in All the 31 Sudh Raags of Sri Guru Granth Sahib Ji. 'Gauri Sagar' Album (3 CDs) is a Compilation of All forms of Raag Gauri in Sri Guru Granth Sahib Ji. 'Nanak Ki Malhaar' ~ ((3 CDs) is an album of Raag Malhar Shabads in various forms of Malhar. 'Gur Parsaad Basant Bana' ~ (3 CDs) is an album of Shabads in Raag Basant sung in various forms of Raag Basant. Har Ki Vadeyai Sarni Aayea Sewa Priya Kee Preet Piyaree Mohan Ghar Aavho Karo Jodariya Mo Kao Taar Le Raama Taar Le Tere Kavan Kavan Gun Keh Keh Gawan Mera Baid Guru Govinda Saajanrraa Mera Saajanrraa

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