the diagnosis of rabies is not very difficult when associated with the classical features of excitations or phobias ( aerophobia , hydrophobia ) .
but it can be quite challenging when presented as acute flaccid paralysis ( afp ) .
we report here two cases of paralytic rabies who received four doses of postexposure ( grade iii dog bite ) vaccination without rabies immunoglobulin .
paralytic rabies occurring after postexposure antirabies vaccination creates a diagnostic dilemma as vaccine - induced gbs becomes a distinct possibility .
a ten year - old boy presented with sudden weakness of both lower limbs for two days .
he also had a history of fever , vomiting , and back pain for three days .
his past history elicited an incident of an unprovoked bite by a street dog in his right hand ( grade iii ) three weeks back .
four doses of purified chick embryo cell ( pcec ) antirabies vaccine were administered according to schedule in the deltoid , starting from the day of the bite .
the patient had complained of back pain , but there was no typical history of pain , tingling , numbness at the site of the bite , hydrophobia , or behavioral changes .
his temperature was 39.5c , pulse rate was 110/min , blood pressure 100/70 mm hg , respiratory rate 30/min , and spo2 96% . neurological examination detected grossly reduced muscle tone and power ( lower limb 2/5 , upper limb 3/5 ) with areflexia ( both superficial and deep tendon reflexes were absent ) in all four limbs and the trunk along with urinary incontinence .
the failure to administer rig after the grade iii bite favored a provisional diagnosis of paralytic rabies was made even though the classical symptoms of rabies were absent .
although rare with the modern cell culture vaccines , the possibility of vaccine - induced gbs was also considered .
laboratory investigations showed hemoglobin : 11.5 g / dl , white cell count : 70000/cu.mm ( neutrophil : 58% , lymphocyte : 40% , eosinophil : 2% ) , platelet count : 1,90000/cu.mm .
cerebrospinal fluid analysis showed cell count : 10/cu.mm ( all lymphocytes ) , protein : 50 mg / dl , and sugar : 80 mg / dl ( no albumino - cytological dissociation ) .
the electrophysiological test designed to identify features of demyelination ( slowing of nerve conduction velocity with marked prolongation of distal latencies and occasional conduction block ) , was inconclusive .
serum electrolytes were normal  na : 136 meq / l , k : 5 meq / l .
liver function , renal function tests , and repeat csf examination on the 7 day were unremarkable .
conservative management was started but rapid progression of paralysis occurred over the next two days .
intravenous immunoglobulin ( 2 g / kg / total dose ) was given over 12 hours for the sake of caution , but there was no improvement and the patient succumbed on the 10 day of onset of the disease .
due to inadequate stool collection by the afp surveillance worker , all the documents were sent to the national expert committee ( national polio surveillance project ) as a special case .
they classified the case as being nonpolio and as paralytic rabies . a six year - old girl presented with sudden onset of quadriparesis for one day , preceded by fever , myalgia , and vomiting for four days .
there was also a history of a dog bite in her right upper arm ( grade iii bite ) three weeks back .
the child was given the pcec vaccine as per schedule in the deltoid and received a total of four doses before the development of any symptoms .
the patient was treated conservatively , but the clinical features and the progression of disease was similar to the first case , except for the presence of myoedema , a striking feature of rabies . in spite of good supportive measures , she expired on the 12 day of disease onset .
results of laboratory investigations on the 11 day of the illness were also quite similar to the first case .
neutralizing antibodies to rabies virus were detected in both serum and csf by the rapid fluorescent focus inhibition test ( rffit ) .
a ten year - old boy presented with sudden weakness of both lower limbs for two days .
he also had a history of fever , vomiting , and back pain for three days .
his past history elicited an incident of an unprovoked bite by a street dog in his right hand ( grade iii ) three weeks back .
four doses of purified chick embryo cell ( pcec ) antirabies vaccine were administered according to schedule in the deltoid , starting from the day of the bite .
the patient had complained of back pain , but there was no typical history of pain , tingling , numbness at the site of the bite , hydrophobia , or behavioral changes .
his temperature was 39.5c , pulse rate was 110/min , blood pressure 100/70 mm hg , respiratory rate 30/min , and spo2 96% . neurological examination detected grossly reduced muscle tone and power ( lower limb 2/5 , upper limb 3/5 ) with areflexia ( both superficial and deep tendon reflexes were absent ) in all four limbs and the trunk along with urinary incontinence .
the failure to administer rig after the grade iii bite favored a provisional diagnosis of paralytic rabies was made even though the classical symptoms of rabies were absent .
although rare with the modern cell culture vaccines , the possibility of vaccine - induced gbs was also considered .
laboratory investigations showed hemoglobin : 11.5 g / dl , white cell count : 70000/cu.mm ( neutrophil : 58% , lymphocyte : 40% , eosinophil : 2% ) , platelet count : 1,90000/cu.mm .
cerebrospinal fluid analysis showed cell count : 10/cu.mm ( all lymphocytes ) , protein : 50 mg / dl , and sugar : 80 mg / dl ( no albumino - cytological dissociation ) .
the electrophysiological test designed to identify features of demyelination ( slowing of nerve conduction velocity with marked prolongation of distal latencies and occasional conduction block ) , was inconclusive .
serum electrolytes were normal  na : 136 meq / l , k : 5 meq / l .
liver function , renal function tests , and repeat csf examination on the 7 day were unremarkable .
conservative management was started but rapid progression of paralysis occurred over the next two days .
intravenous immunoglobulin ( 2 g / kg / total dose ) was given over 12 hours for the sake of caution , but there was no improvement and the patient succumbed on the 10 day of onset of the disease .
due to inadequate stool collection by the afp surveillance worker , all the documents were sent to the national expert committee ( national polio surveillance project ) as a special case .
a six year - old girl presented with sudden onset of quadriparesis for one day , preceded by fever , myalgia , and vomiting for four days .
there was also a history of a dog bite in her right upper arm ( grade iii bite ) three weeks back .
the child was given the pcec vaccine as per schedule in the deltoid and received a total of four doses before the development of any symptoms .
the patient was treated conservatively , but the clinical features and the progression of disease was similar to the first case , except for the presence of myoedema , a striking feature of rabies . in spite of good supportive measures , she expired on the 12 day of disease onset .
results of laboratory investigations on the 11 day of the illness were also quite similar to the first case .
neutralizing antibodies to rabies virus were detected in both serum and csf by the rapid fluorescent focus inhibition test ( rffit ) .
there are two forms of human rabies : i ) the well - known encephalitic ( furious ) and ii ) the paralytic ( dumb ) rabies .
the encephalitic form starts with fever , malaise , pharyngitis , and paraesthesia at the site of the bite followed by the classical neurological symptoms of hydrophobia , aerophobia , agitation , hypersalivation , and seizures .
this is followed by paralysis and coma ; death is usually due to respiratory failure .
the second clinical form of rabies , paralytic ( dumb ) or guillain - barr - like , is characterized by progressive paralysis without an initial furious phase . even though the paralytic rabies is unfamiliar to health care providers , 2030% of rabies victims present in this manner .
paralytic rabies is more common after rabid vampire bat bites and in persons who have received postexposure vaccination .
distinction of paralytic rabies from gbs may be difficult , although individuals with gbs usually do not have urinary incontinence , which is common in rabies . in our two cases ,
fever at the onset of disease , the absence of albumin - cytological dissociation , even repeat csf examination and persistent urinary incontinence was against the diagnosis of vaccine - induced gbs .
different sites of neural involvement and possibly different neuropathogenetic mechanisms may explain the clinical diversity in human rabies .
it is unclear whether weakness results from the involvement of anterior horn cells or of motor nerve fibers .
most likely , peripheral nerve dysfunction , due to demyelination , contributes to the weakness seen in paralytic rabies . on the other hand ,
progressive focal denervation starting at the bitten segment , was evident in furious rabies , even in the absence of demonstrable weakness .
intense inflammation of the spinal nerve roots was observed to a greater extent in paralytic rabies patients .
inflammation was mainly noted in the spinal cord segment corresponding to the bite in all cases .
however , central chromatolysis of the anterior horn cells could be demonstrated only in furious rabies patient . in both patients , ncv findings revealed features of demyelination which may occur in paralytic rabies as well as in gbs .
studies conducted in the us by the center for disease control and prevention ( cdc ) have documented that a regimen of one dose of rig and five doses of the human diploid cell culture vaccine ( hdcv ) over a period of 28 days was safe and induced an excellent antibody response in all recipients .
clinical trials with rabies vaccine adsorbed ( rva ) and purified chick embryo cell ( pcec ) vaccine have also demonstrated immunogenicity equivalent to that of hdcv .
many individuals did not receive immunoglobulin where indicated and some of them received the vaccine in the gluteal region instead of in the deltoid . although both of our patients had grade iii dog bite for which rig is strongly recommended , they only received the vaccine in the deltoid region without rig .
neurological reactions following newer vaccine administration have been extremely rare . after millions of vaccinations worldwide , three guillain - barr type paralytic reactions have been described , and all cases recovered completely . if our patients had vaccine - induced gbs , definitely they were improved by good supportive measures . during the early stages of paralytic rabies ,
notable signs include myoedema , particularly in the region of the chest , deltoid muscles , and thighs . however , this phenomenon , a brief , unpropagated , localized muscle contraction that appears in response to percussion with a tendon hammer , is not a confirmatory sign of paralytic rabies but was present in our 2 case .
if there is an inadequate stool sample with residual paralysis , death of the patient , or loss to follow - up at the time of afp surveillance , the case is referred to the national expert committee ( national polio surveillance project ) review for final classification as nonpolio afp or compatible with poliomyelitis . in our first case
, there was inadequate stool sampling , so it was reviewed by the expert committee and declared to be paralytic rabies .
 two clinical forms of rabies are recognize : i ) a furious form associated with classical signs of excitation or phobic symptoms , ii ) dumb rabies ( paralytic rabies ) characterized by progressive paralysis without an initial furious phase wherein distinction from guillain - barr syndrome may be difficult . 
 paralytic rabies is more common in persons who have received postexposure vaccination . 
 we report here the diagnostic dilemma of two cases of acute flaccid paralysis due to rabies . 