CNS Infections- Mass Lesions & Neurocysticercosis

Question 1

Mass lesions AKA contrast/ring-enhancing lesions caused by Infectious abscesses and common parasitic diseases of the CNS via:

Answer 1

Neurocysticercosis (NCC) and Toxoplasma gondii/Toxoplasmosis

Question 2

Mass lesions manifest as

Answer 2

Fever, Severe headaches, Seizures

Question 3

Mass lesions due to abscesses are usually caused by procaryotic organisms, the most common pathogen being:

Answer 3

S. aureus

• Mixed anaerobic infections account for 1/2 of all cases
• Mostly Gram-negative rods and Gram-positive cocci

Question 4

Other causes of mass lesions due to abscess are

Answer 4

• L. monocytogenes or M. tuberculosis are also causes

- Fungi agents include Coccidioides immitis, Candida albicans

Question 5

Neurocysticercosis (NCC) is caused by

Answer 5

Taenia solium metacestodes

Most common parasitic CNS disease

Question 6

Neurocysticercosis (NCC) is the most common cause of _________ in the world

Answer 6

epilepsy

Question 7

Parenchymal cysts are mature, living cysticerci are viable for 2→10y, during which time they _________ and the host is usually ________.

Answer 7

suppress the host immune response

asymptomatic (with a few cysts); 6→10 or more can be symptomatic

Question 8

As cysticercus begins to die, they ________ causing an intense inflammatory response (with perilesional edema) & fibroblast form capsule around cyst. This causes the host to show signs and symptoms. Cyst degeneration takes 6→18 months. Rarely, parenchymal cysts growth causing _________.

Answer 8

leak antigens

mass effect on brain parenchyma

Question 9

Extraparenchymal Cysts: A few (@10%) oncospheres lodge in __________ and develop into atypical cysts (greatly enlarged) → obstruction of CSF pathway → may cause ___________.

Answer 9

• ventricles, subarachnoid space or meninges

- focal neurological signs or increased cranial pressure (hydrocephalus), and headaches

Question 10

Symptoms usually only occur if ________ are seen on an MRI

Answer 10

calcified lesions

Question 11

Differential for mass lesion

Answer 11

1. Neurocysticercosis (Taenia solium)
2. Cystic Echinococcosis-hydatid cyst (Echinococcus granulosus or multilocularis)
3. Raccoon Round Worm Encephalitis/Baylisascariasis (Baylisascaris procyonis)
4. Toxocaria (Toxocaria cannis or cati)
5. Toxoplasmosis (Toxoplasma gondii).
6. Abscess:
   - Bacteria: S. aureus, anaerobes, L. monocytogenes, M. tuberculosis.
   - Chronic fungi: C. immitis or Candida albicans

Question 12

T confirm diagnosis with Neurocysticercosis you must have 1 of the following 3:

Answer 12

1. Histological demonstration of parasite from biopsy of brain or spinal chord.
2. Cystic lesion showing the scolex on CT scan or MRI.
3. Direct visualization of retinal parasites by fundoscopic exam.

• Live cysts are none contrast-enchancing but dying-dead cysts are contrast-enchancing
• If pt doesn’t have at least 1, can use imaging to confirm diagnosis

Question 13

Imaging/other tests used to confirm diagnosis with NCC

Answer 13

1. **Positive serum enzyme-linked immunoelectrotransfer blot (EITB) for detection of anticysticercal antibodies has a sensitivity and specificity of more than 98% and is the serologic assay of choice for the detection of cysticercosis.
2. **CSF WBC with differential reveals an eosinophilia as high as 15%.
3. **Patient signs and symptoms.
4. EEG changes (focal discharge, sharp spike, slow wave) indicate active seizure focus.
5. History of travel, employment, living in an endemic area.
6. Documented familial infestation.
7. Resolution of cysts after treatment.
8. documented extra-CNS cysticercosis

Question 14

IN CSF WILL SEE

Answer 14

eosinophilia

Question 15

Treatment

Answer 15

Niclosamide, Praziquantel, Albendazole
all destroys VIABLE cyst in CNS

-anticonvulsants, corticosteroids, surgery