Human rabies includes generalized cranial artery spasm that responds to

tetrahydrobiopterin, L-arginine or nitroprusside

R.E. Willoughby, A. Roy-Burman, K.W. Martin, J.C. Christensen, D.F.

Westenkirschner, J.D. Fleck, C. Glaser, C.E. Rupprecht and K. Hyland

7 attempts at treating rabies with Milwaukee protocol

(excluding index survivor)

• 2 “good attempts” that fulfill assumptions and use ketamine, a benzodiazepine, amantadine and ribavirin

• Concrete mechanisms and physiology identified

0.00

0.25

0.50

0.75

1.00

0 20 40 60 80analysis time

Milw = 0 Milw = 1

Kaplan-Meier survival estimates, by Milw

p= .0037

Marburg, GermanyTransplant (+ rabies) recipient

Marburg z-score by age

z-sc

ore

BH

4,

HV

A,

5-H

IAA

-10

-5

0

5

10

15

20

Feb Mar

Apr May

Jun

NO

2+

NO

3 (

uM

)

0

20

40

60hospitalized EEG flat

MRA low flowbrain liquefaction

5-HIAAHVABH4

NOx

BH4 as Achilles’ heel for CNS

M

M

nM

Nitric oxide synthases

Kone BC (2003) Am J Physiol Renal Physiol 285: F178

ARGBH4

O2●-

NO+ citrulline

qBH2

ONOO-

Nitric Oxide Synthase(eNOS, nNOS) in cranial

arteries• NO is smooth muscle relaxant

• Not well known: neuronal NOS in vessel adventitia

– accounts for 10% of systemic vasodilator tone

– accounts for 50% of cranial vasodilator tone

• Rabies is neurotropic

– nNOS >> eNOSToda N (2000) Neuroscience 96: 393Pluta RM (2005) Pharmacol Ther 105: 23

Transcranial doppler ultrasound

VA

Flow = VA = kPr4

Bad Good

VmaxVminVmax

RI = (Vmax-Vmin) = 1.0 VmeanTAMMv

Indianapolis(bat strain)

• Recommended daily TCD– HD 6 normal– Vasopressors begun

• HD 10: Seizure by EEGFlat EEG

• HD 12 TCD: vasospasm– Nitroprusside 0.2ug/kg/min

• HD 13: cerebral edema– External ventricular drain– BH4 at CNS doses

• HD 14: – EEG responds– MCA velocities remain high

• HD 20: increased edema– Venous sinus thrombosis

TAMvMCA

0 7 14 21 28

Vel

ocity

(cm

/s)

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100

200

300

400

Hospital Day

0 7 14 21 28

Pul

satil

ity I

ndex

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1.0

1.2

1.4

Intr

acra

nial

Pre

ssur

e

0

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40

60

80

100

120

140

160

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200

Vmax MCA

TA

Mv

PI MCA

ICP

Hospi

taliz

atio

n

Trans

fer

EVD

Lim

it ca

re

Seizu

re

Flat E

EG

Nitroprusside

Vasopressor

MMWR (2007) 56: 361

Oakland(dog strain)

• HD 1: 2 arrests– On vasopressors

– BH4 2 mg/kg/24h

– Daily TCD

• HD 6: Vasospasm– Reversed by BH4

2mg/kg/8h

X Data

0 7 14 21 28

Blo

od v

eloc

ity (

m/s

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Hospi

taliz

ed

Arrest

x 2

type

1typ

e 2

Heart

bloc

k

isopr

oter

enol

Seizu

re

Flat E

EG

Cereb

ral e

dem

a

Hospital Day

0 7 14 21 28

Res

istiv

e In

dex

0.0

0.2

0.4

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1.0

BH

4 m

g/kg

/24h

Arg

g/k

g/do

se

0

5

10

15

20

25

MMWR (2007) 56: 361

Cranial artery spasm in rabies

• Seen early, hospital day 6-10 (mean HD8)

• Global, including internal carotid + MCA

• Transcranial doppler: high velocity, normal resistance

• Responsive to 6 mg/kg/24h BH4

- OR -

“low dose” 0.1-0.2 ug/kg/min nitroprusside

Oakland

• HD 11 TCD:– Decreased velocity– Increased RI

• No cerebral edema• Low opening

pressure– Reversed by

“CNS dosing” of BH4 20mg/kg/24h

+L-arginine IV 0.5g/kg/12h

– Increase in CSF protein

X Data

0 7 14 21 28

Blo

od v

eloc

ity (

m/s

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Hospi

taliz

ed

Arrest

x 2

type

1typ

e 2

Heart

bloc

k

isopr

oter

enol

Seizu

re

Flat E

EG

Cereb

ral e

dem

a

Hospital Day

0 7 14 21 28

Res

istiv

e In

dex

0.0

0.2

0.4

0.6

0.8

1.0

BH

4 m

g/kg

/24h

Arg

g/k

g/do

se

0

5

10

15

20

25

TAMvMCA

0 7 14 21 28

Vel

ocity

(cm

/s)

0

100

200

300

400

Hospital Day

0 7 14 21 28

Pul

satil

ity I

ndex

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Intr

acra

nial

Pre

ssur

e

0

20

40

60

80

100

120

140

160

180

200

Vmax MCA

PI MCA

ICP

Hospi

taliz

atio

n

Trans

fer

EVD

Lim

it ca

re

Seizu

re

Flat E

EG

Nitroprusside

Vasopressor

Vm

ax

Vmax ICA

Indianapolis

• HD 17 TCD: – Sudden drop in MCA

velocity

– No comparables for PI

– Sudden drop in ICP

– Increase in CSF protein

Cranial artery spasm in rabies• Small numbers, n=3/3 when looked for• Sporadic correlations with MRA, brain scan• Associated with declines in EEG

• Type 1 (high velocity, normal RI) day 6-10– Responsive to BH4 6 mg/kg/day

• Type 2 (low velocity, high RI) day 13-17– 7 days after type 1– Responsive (in part) to BH4 20 mg/kg/day

+ L-arginine 1.0 mg/kg/day given slowly– Associated with increased CSF protein

Why does rabies virus kill?• BH4 and

neurotransmitter deficiency– Subset of symptoms– Wasting

• Cranial artery spasm– BH4 + L-arginine– Ca++ channel blockers– “Triple H” therapy– Hypercarbia

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0.25

0.50

0.75

1.00

0 20 40 60 80analysis time

Milw = 0 Milw = 1

Kaplan-Meier survival estimates, by Milw

rewillou@mcw.eduwww.mcw.edu/rabies