Paralytic rabies following cat scratch and intra-dermal anti-rabies vaccination


Abstract

Only few reports of failure of intradermal postexposure prophylaxis for rabies following cat scratch exist in the published literature. We are reporting such a case in a 15-year-old girl. The child had category III cat scratch on her face. She presented with progressive paralysis, finally developing quadriplegia and respiratory paralysis. Typical hydrophobia and aerophobia were absent. She received intra-dermal anti-rabies cell culture vaccine. She did not receive anti-rabies immunoglobulin. The girl succumbed on the 10thday of weakness. Diagnosis of rabies was confirmed by isolation of rabies virus RNA in cerebrospinal fluid and skin biopsy sample by reverse transcription polymerase chain reaction.

Introduction

Rabies is a fatal neuropathogenic disease caused by the rabies virus. Rabies can manifest as furious or paralytic forms in humans and dogs. Limbic signs dominate the clinical picture in the former whereas a paralysis of lower motor neuron type dominates the latter. Most (96%) of the human rabies cases are following dog bite.[1] The diagnosis of rabies is not difficult if it presents with classical symptoms of excitations or phobias. However, it poses a diagnostic challenge when presented as acute flaccid paralysis (AFP). We report a case of paralytic rabies following intradermal anti-rabies vaccine, following cat scratch.

Case Report

A 15-year-old girl was brought with the complaints of fever of 5 days, headache and vomiting of 4 days, weakness of bilateral lower limbs, followed by upper limbs, change in voice and nasal regurgitation of feeds since 2 days. Child had tachycardia, shallow respiration with paradoxical movement of the chest wall. Glasgow coma scale was 15/15. Gag reflex was absent with pooling of secretions and absence of movements of soft palate and uvula. Power in bilateral upper and lower limbs was 1/5 (Medical Research Council Grade). Other systemic examination was normal. Child was mechanically ventilated at admission in view of respiratory failure. Initially, a diagnosis of brainstem encephalitis was made. A diagnosis of brain stem mass lesion was also considered. Mother gave history of unprovoked cat scratch over the face 2 months back. She was immunized with a complete course of intradermal cell culture anti-rabies vaccine first dose started on day 2 of cat scratch. Updated Thai Red Cross schedule (2-2-2-2-2) was used for intra dermal vaccination. Cat scratch was not cleaned. Cat was bitten by a rabid dog according to the mother. Rabies immunoglobulin (RIG) was not given. Provisional diagnosis of paralytic rabies was made on the basis of paralysis with history of cat scratch. Although rare with the modern cell culture vaccines, the possibility of vaccine-induced GBS was also considered.

Laboratory investigations revealed normal complete blood counts, serum electrolytes, liver and kidney function tests. Cerebrospinal fluid (CSF) analysis showed 412 cells with 10% neutrophils and 90% lymphocytes with sugar of 62 mg/dl. Computed tomography brain was normal. Rabies virus RNA was detected in CSF and skin biopsy samples by reverse transcription polymerase chain reaction. Neutralizing antibodies to rabies virus were detected in both serum and CSF by the rapid fluorescent focus inhibition test.

Conservative management was started, but rapid progression with respiratory paralysis occurred over the next 2 days. There was no improvement and the patient succumbed on the 10th day of onset of the disease.

Discussion

Rabies is an important public health problem in India. About 55,000 human deaths occur due to rabies annually worldwide; about 36% of these deaths occur in India. Most animal bites in India (96%) are by dogs.[1] The disease infects domestic and wild animals, and is spread to people through close contact with infected saliva via bites or scratches. Our case had history of cat scratch over the face.

There are two forms of human rabies: (1) The well-known encephalitic (furious) and (2) 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-Barre-like, is characterized by progressive paralysis without an initial furious phase. Even though, the paralytic rabies is unfamiliar to health care providers, 20-30% of rabies victims present in this manner.[2]

Paralytic rabies is more common after rabid vampire bat bites and in persons who have received post-exposure vaccination.[3] Studies conducted in the United States by the Center for Disease Control and Prevention 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.[4] Clinical trials with rabies vaccine adsorbed and purified chick embryo cell vaccine have also demonstrated immunogenicity equivalent to that of HDCV.[5] Occasional failure has been reported with cell culture vaccines due to incorrect administration. Many individuals did not receive immunoglobulin where indicated, and some of them received the vaccine in the gluteal region instead of in the deltoid.[6] Although our patient had grade III cat scratch for which RIG is strongly recommended, she only received the vaccine in the deltoid region without RIG. This was most probably the cause of vaccine failure.

Neurological reactions following newer vaccine administration have been extremely rare. After millions of vaccinations worldwide, three Guillain-Barre type paralytic reactions have been described, and all cases recovered completely.[7,8] Rare findings in our case are paralytic rabies following cat scratch and development rabies after administration of intradermal rabies vaccine. The limitation of our report was that we were not able to do magnetic resonance imaging of brain and nerve conduction studies. Paralytic rabies should be considered if any child presenting with AFP with brain stem symptoms and signs, even if they had already received anti-rabies vaccination and also following cat scratch. Most rapidly immunogenic vaccine regimen should be used in patients at high risk, especially if RIG has not been given.

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