The case of a Missouri man who died from rabies 2 weeks after he first visited an ED with symptoms shows that crucial early diagnosis of the virus may be hampered by delayed recognition, researchers wrote in MMWR.
The man, aged 52 years, lived in a rural, deeply wooded area and was likely infected by the bite of a tricolored bat in 2014. He was admitted to a hospital only after his third visit to an ED and amid rapidly worsening symptoms.
The researchers said public education campaigns to raise rabies awareness should address the threat of bats, which can infect humans with small, undetectable bites, leading to a delay in the response to a possible exposure.
“Bat exposures are high-risk exposures for rabies virus infection, particularly because the wounds inflicted by bats are often minor and easily overlooked,” they wrote.
The education campaigns also should emphasize completing postexposure prophylaxis (PEP) for confirmed cases of human rabies infection, the researchers said.
“In addition to the importance of public education,” they wrote, “health care workers should consider rabies in the differential diagnosis of any patient with acute, unexplained encephalitis, and use appropriate infection control practices when examining and treating patients with a suspected infectious disease.”
Man diagnosed after symptoms worsen
The man died on Sept. 26, 2014 — 2 days after he was diagnosed with rabies, and 2 weeks since his first visit to an ED, when he received a cervical spine radiograph after presenting with acute severe neck pain that radiated down his arm to his hand.
The researchers presented a timeline of the man’s illness:
- During his first ED visit, he was diagnosed with a cervical muscle strain and radiculopathy and received muscle relaxant and NSAID injections. He was instructed to take ibuprofen and a muscle relaxant.
- A day later, on Sept. 13, the man returned to the same ED after waking up with numbness and tingling in his arm, severe bilateral upper body tremors, sweating and continued neck pain. He was diagnosed with a herniated disk and sent home. After his symptoms worsened, he was taken back to the same ED that night by his family and began hallucinating. He was diagnosed with suspected serotonin syndrome secondary to the muscle relaxant and was admitted to the hospital.
- The man was transferred to a tertiary care referral hospital after his condition progressively worsened over the next day to include rigidity and action tremors in his upper extremities. He developed a 104.9° temperature, tachycardia, tachypnea and hypertension with bilateral upper extremity tremors and whole body myoclonic jerks.
- On Sept. 15, he was intubated — after orally communicating an aversion to water — and placed on a mechanical ventilator to protect his airway. Over the next 11 days, he tested negative for Rocky Mountain spotted fever, arbovirus, ehrlichiosis, syphilis and herpes simplex.
Laboratory testing for rabies began on Sept. 18 and samples were submitted 4 days later to the CDC, which confirmed rabies on Sept. 24. Genomic sequencing identified the tricolored bat — one of the smallest bats in North America — as the likely source. The man died on Sept. 26 after being taken off life support by his family.
Human rabies cases rare
It was just the second case of human rabies in Missouri since 1959, according to the researchers. The last one, in 2008, involved a man who died after being bitten on the ear by a bat.
Human rabies infection remains rare in the United States, with between one and three cases reported annually, according to the researchers. It can be deadly, however, if not treated promptly.
“This case illustrates the importance of educating the public about potential rabies reservoirs and exposure sources in the United States and of promptly seeking medical attention after any potential rabies exposure,” the researchers wrote. “Rabies is preventable after an exposure through timely PEP, which includes wound washing and administration of rabies immune globulin and rabies vaccine.”
Too late for Milwaukee protocol
According to the researchers, the man’s advanced illness and worsening prognosis during the final days of his life meant it was too late to initiate the experimental Milwaukee protocol, which was first used in 2004 to treat a girl diagnosed with rabies who survived with few complications.
The aim of the Milwaukee protocol is to keep a patient alive long enough to allow the immune system time to clear the rabies virus. It has been implemented with varying outcomes, according to the researchers. – by Gerard Gallagher
Medical College of Wisconsin. Milwaukee protocol, version 4.0. 2012: http://www.mcw.edu/FileLibrary/Groups/PedsInfectiousDiseases/Rabies/Milwaukee_protocol_v4_20913.pdf. Accessed March 17, 2016.
Disclosures: The researchers report no relevant financial disclosures.