Poliomyelitis (Infantile paralysis) presents with fever, headache, and sometimes mild GI symptoms followed in 3-10 days by fever, severe myalgia, stiff neck, and asymmetric flaccid paralysis. In about 1/200 cases, children have irreversible paralysis. 5% to 10% of paralyzed children die.
CASES/YEAR
0 (US); 223 (Global)
OTHER NAMES
Polioviral fever; Infantile paralysis; Polio; Polio encephalitis; Epidemic acute poliomyelitis;
INCUBATION
9-12 days with a range of 5-35 days; [PPID, p. 2221]
INITIAL SYMPTOMS
Fever, headache, and sometimes mild GI symptoms followed in 3-10 days by fever, severe myalgia, stiff neck, and asymmetric flaccid paralysis; [ID, p. 2044] 1/200 cases: irreversible paralysis; 5% to 10% of paralyzed children die; [WHO website]
PRECAUTIONS
"Occurrence of a single case of poliomyelitis due to wild poliovirus or a cVDPV [circulating vaccine-derived polioviruses] in a country that has interrupted transmission is a public health emergency prompting immediate investigation and planning for a large-scale response." [CCDM, p. 483]
COMMENTS
FINDINGS:
Flaccid paralysis of the lower extremities develops quickly. It is usually asymmetrical and is associated with fever, stiff neck, myalgias, and headache. Patients have diminished deep tendon reflexes, but no loss of sensation. [ID, p. 2044] Early signs of bulbar palsies include "dysphagia, nasal regurgitation, and nasal voice." [Merck Manual, p. 1541] About 90% of infections are inapparent or nonspecific. About 10% of patients have flu-like symptoms including fever, headache, and nausea. Flaccid paralysis develops in less than 1% of cases. [CCDM, p. 477-84] The three main varieties of disease are spinal paralytic poliomyelitis (0.1% of all polio infections), bulbar paralytic poliomyelitis (5% to 35% of paralytic cases), and polioencephalitis (uncommon). Severe myalgias and sometimes paresthesias and fasciculations herald the onset of the major illness. The paralysis is usually asymmetrical. Reflexes are hyperactive initially, then absent. Bulbar disease may include dysphagia, pharyngeal paralysis, and dyspnea. Polioencephalitis is uncommon, occurs mainly in infants, and is associated with seizures. Guillain-Barre syndrome should be suspected if sensory loss (very rare in polio). [PPID, p. 2221-2] Because polio is an infection of the anterior horns of the spinal cord, sensation is normal. [Cecil, 24th Ed, p. 2380]
DIFFERENTIAL DIAGNOSIS:
In the differential diagnoses are other enteroviral infections, West Nile virus infection, and Guillain-Barre syndrome, the last of which differs in having symmetrical weakness, sensory loss in 70% of cases, increased CSF protein but normal cell count, and no fever. [Merck Manual, p. 1541] Other causes of acute flaccid paralysis are other viral infections, Guillain-Barre syndrome, acute motor axonal neuropathy, transverse myelitis, traumatic neuritis, infectious and toxic neuropathies, tick paralysis, myasthenia gravis, porphyria, botulism, insecticide poisoning, polymyositis, trichinosis, and periodic paralysis. [CCDM]
PREVENTION:
The Global Polio Eradication Initiative (GPEI) eliminated polio in the Americas with the last wild poliovirus case reported in 1991. GPEI has reduced the number of reported cases in the world by more than 99% since the mid-1980s. Unvaccinated adults travelling to areas where polio has not yet been eradicated should receive three doses of IPV. [CDC Travel, p. 310-14]
EPIDEMIOLOGY:
Spread by food or milk may occur, but it is rare. The disease is transmitted mainly by the fecal-oral route. [CCDM] "Enterovirus 71 and West Nile virus can cause an identical clinical illness." [Cecil, 24th Ed, p. 2379]
DIAGNOSTIC
Viral culture of specimens from throat (as early as 36 hours after exposure), stool (as early as 72 hours after exposure), or CSF; Paired sera are less helpful because interpretation of antibody levels is difficult; [CCDM, p. 478]
SCOPE
As of April 2016, polio has never been interrupted in only 2 countries: Afghanistan and Pakistan; In 2018, polio virus circulated in Afghanistan, Pakistan, and Nigeria. [CDC Travel]
SIGNS & SYMPTOMS
-
>fever
-
>fever, biphasic or relapsing
-
>myalgia
-
E dysphagia
-
E pharyngitis
-
G abdominal pain
-
G nausea, vomiting
-
N confusion, delirium
-
N headache
-
N muscle weakness
-
N paresthesia
-
N seizure
-
N stiff neck
-
R dyspnea
-
*cranial neuropathy
-
*encephalitis
-
*meningitis
-
*myelitis
-
*myocarditis
-
*paralysis
-
*stupor, coma
SOURCE
Person-to-Person, Human Fecal-Oral, Eating Contaminated Food, Eating Unpasteurized Milk or Cheese, Waterborne (Ingesting, Inhaling, or Swimming)
RISK FACTORS
- Care for patients (fecal-oral pathogens)
- Fail to complete immunizations
- Ingest infectious agents in food/water
- Travel to endemic area
- Work in a medical or research lab
TREATMENT
No specific treatment; [CCDM, p. 483]
REFERENCES FOR CASES/YEAR
1.
2. (Global) Cases reduced by 99% since 1988; 350,000 cases in 1988; 223 cases in 2012; [Fact sheets from WHO 2013]