Prions

Question 1

What are prions?

Answer 1

Accumulation of host protein PrP which have misfolded with an increased beta structure

Causes microscopic vacuoles in grey matter

Question 2

What are the different types of TSEs, and examples?

Answer 2

Idiopathic: sporadic CJD

Familial: GSS, fatal familial insomnia

Acquired: kuru, iatrogenic CJD, vCJD

Question 3

What are high risk tissues for prion diseases?

Medium and low risk?

How should these be handled?

Answer 3

High risk: brain, spinal cord, dura mater, posterior eye, pituitary, cranial nerves, ganglia (CL 3)

Medium risk: spinal ganglia (risk assess for CL3)

Low risk: CSF, blood, urine, saliva (routine)

Question 4

What decontamination is used for prions?

Answer 4

Reduces but doesn’t eliminate infectivity

Do not allow instrument to dry for more than 15 min
Endoscopes cleaned immediately at bedside
Sodium hypochlorite >20000 ppm for 1 h
Incineration at 850C
Autoclave at 121C for 15 min

Question 5

Clinical features of prion disease?

Answer 5

Rapidly progressive dementia
Focal neurological signs
Ataxia
Myoclonus
Visual disturbances
Rigidity
Death within 4-6 m

Question 6

Sources of iatrogenic CJD

Answer 6

Corneal grafts
Human derived pituitary hormones
Human derived duar mater grafts
Contaminated neurosurgical instruments

Question 7

Which patients are at increased risk of CJD

Answer 7

Plasma products between 1990-2001
People who have had surgery using instruments previously used on someone with CJD
Organ recipient from someone who had CJD
Growth hormone before 1985
Gonadotrophin before 1973
Inheritance risk factors