Rabies: Treatment, symptoms, advice & help
Rabies is a viral disease that causes inflammation of the brain caused usually by a bite from an infected animal but occasionally by other forms of contact. Rabies is fatal if post-exposure prophylaxis is not administered prior to the onset of symptoms.
Rabies: Incidence, age and sex
Almost all human rabies cases are reported from Asia and Africa. There are an estimated 55,000 human deaths annually from rabies worldwide, with about 31,000 in Asia, and 24,000 in Africa. It is rare in Europe and North America
Signs and symptoms of rabies: Diagnosis
At the onset there may be fever and paraesthesia at the site of the bite. There is a prodromal period of 1-10 days, during which the patient is increasingly anxious followed by the characteristic ‘hydrophobia’. Although the patient is thirsty, attempts at drinking provoke violent contractions of the diaphragm and other inspiratory muscles. Delusions and hallucinations may develop, accompanied by spitting, biting and mania, with lucid intervals in which the patient is markedly anxious. Terminal hyperpyrexia is common. Death ensues, usually within a week of the onset of symptoms.
During life, the diagnosis is usually made on clinical grounds but rapid immunofluorescent techniques can detect antigen in corneal impression smears or skin biopsies.
Causes and prevention of rabies
Rabies is caused by a rhabdovirus which infects the nervous tissue and salivary glands of mammals, and is usually conveyed by saliva though bites or licks on abrasions or on the mucous membranes. Humans are most frequently infected from dogs.
Prevention: Pre-exposure prophylaxis is required by those who handle potentially infected animals professionally. Protection is afforded by two intramuscular injections of 1 ml, given 4 weeks apart, followed by yearly boosters.
Post-exposure prophylaxis: After an animal bite or scratch the wounds should be thoroughly cleaned, preferable with a quaternary ammonium detergent or soap; damaged tissues should be excised and the wound left unsutured. Human rabies immune globulin should be administered; the dose is 20 U/kg body weight. Half is infiltrated around the bite and half is given intramuscularly at a different site from the vaccine. Human diploid cell strain vaccine; 1.0 mL is given intramuscularly on days 0, 3, 7, 14, 30 and 90.
Rabies is almost invariably fatal.
Only a few patients with established rabies have survived. All received some post-exposure prophylaxis and needed intensive care facilities to control cardiac and respiratory failure. Otherwise, only palliative treatment is possible once symptoms have appeared. The patient should be heavily sedated with diazepam 10 mg 4-6 hourly, supplemented by chlorpromazine 50 – 100mg if necessary. Nutrition and fluids should be given intravenously or through a gastrostomy.