Enterovirus Infections - Symptoms

Enterovirus infection has an incubation period of 2 to 10 days, on average 3-4 days.

Symptoms of enterovirus infection allow us to classify enterovirus diseases (O.A. Chesnokova, V.V. Fomin):

• typical forms:
  • herpangina;
  • epidemic myalgia;
  • aseptic serous meningitis;
  • exanthema;
• atypical forms:
  • inapparent form;
  • minor illness ("summer flu");
  • catarrhal (respiratory) form;
  • encephalitic form;
  • neonatal encephalomyocarditis;
  • poliomyelitis-like (spinal) form;
  • epidemic hemorrhagic conjunctivitis;
  • uveitis;
  • nephritis;
  • pancreatitis.

Often there are combined symptoms of various clinical forms - mixed forms of enterovirus diseases.

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Herpangina

Caused by Coxsackie A viruses (serotypes 2, 3, 4, 6, 7 and 10) and Coxsackie B (serotype 3). The characteristic clinical picture of herpangina occurs in a third of patients, while in the rest the disease occurs in the form of a mild febrile condition. The onset is acute with a rapid increase in body temperature to 39.0-40.5 C, while the general condition of patients may remain relatively satisfactory. Fever lasts from 1 to 5 days (usually 2-3 days). Examination of the oropharynx reveals hyperemia of the mucous membrane of the soft palate, palatine arches, uvula, and posterior pharyngeal wall. Within 24-48 hours, 5-6 to 20-30 small grayish-white papules with a diameter of 1-2 mm appear on the anterior surface of the tonsils and palatine arches, which can occur in groups or separately. Soon they turn into bubbles filled with transparent contents. After 12-24 hours (less often on the 3rd-4th day of illness), after they open, erosions up to 2-3 mm in diameter are formed, covered with a grayish coating, which can merge. A rim of hyperemia is formed around the erosions. Sore throat is moderate or absent, but can increase with the formation of erosions. Erosions heal within 4-6 days without defects in the mucous membrane. The disease often recurs. Sometimes herpangina develops against the background of serous meningitis.

Epidemic myalgia

Pleurodynia (Bornholm disease) is caused by Coxsackie B (types 1-5), Coxsackie A (serotype 9) and ECHO (serotypes 1, 6, 9) viruses.

Prodromal phenomena are rare. Typically, an acute, sudden onset with chills and a rise in body temperature to 39-40 °C, general weakness, nausea, often vomiting, as well as severe headache, pain in the chest muscles, epigastric and umbilical regions, back, and limbs. The appearance of myalgia is associated with the development of myositis. The pain intensifies with movement, coughing, often becomes excruciating and is accompanied by profuse sweating. The duration of pain attacks ranges from 5-10 minutes to several hours (usually 15-20 minutes). In some cases, attacks are accompanied by vomiting and recur after 0.5-1 hour. The appearance of tension in the muscles of the abdominal wall and their sparing during breathing often suggest acute abdomen syndrome, in connection with which patients are often sent to the surgical department. In some cases, chest pain is mistakenly diagnosed as pleurisy, pneumonia, or an attack of angina. When pain occurs, motor restlessness is noted. Between attacks, patients are depressed, apathetic, lie quietly, and give the impression of sleeping. Fever lasts 2-3 days. During pain attacks, tachycardia often occurs, but relative bradycardia is also possible. The pharynx is hyperemic, granularity is often found on the mucous membrane of the palate, cervical lymphadenitis is characteristic. Some patients experience hepatosplenomegaly. Muscle pain becomes less intense or disappears by the third day of the disease, although it sometimes persists after the temperature has returned to normal. The average duration of the disease is 3-7 days. With a wave-like course of the disease (2-3 exacerbations with an interval of 2-4 days), the duration of the disease increases to 1.5-2 weeks.

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Serous enteroviral meningitis

One of the most common and severe forms of enterovirus infection. Caused by neurotropic genotypes of enteroviruses: Coxsackie A (serotypes 2, 4, 7, 9), Coxsackie B (serotypes 1-5), ECHO (serotypes 4, 6, 9, 11, 16, 30). It is registered both as epidemic outbreaks and sporadic cases. Rarely, a prodromal period lasting 1-2 days is observed, during which weakness, irritability, drowsiness occur. An acute onset of the disease with symptoms of general intoxication and an increase in body temperature to 38.0-39.0 ° C, less often to higher numbers. Symptoms of meningitis occur in the first days of the disease, sometimes on the 3rd-5th day, accompanied by a repeated increase in body temperature. General hyperesthesia (hyperacusis, photophobia, hyperesthesia of the skin), intense bursting headache, projectile vomiting without preceding nausea, which occurs in the first hours of the disease, are characteristic. In some cases, psychomotor agitation and convulsions are observed. Deep disturbance of consciousness is extremely rare. Patients have meningeal symptoms, in some cases, dissociation of meningeal symptoms or incomplete meningeal syndrome is characteristic (for example, the presence of rigidity of the occipital muscles with a negative Kernig's sign and vice versa). Fever and meningeal symptoms usually persist for 3-7 days. In the acute period, relative bradycardia is more often observed, less often tachycardia and absolute bradycardia. With the development of edema-swelling of the brain, an increase in blood pressure is noted. Patients have no appetite, the tongue is coated with a whitish coating and thickened. Flatulence often occurs, rumbling is detected on palpation of the abdomen. Catarrhal phenomena are possible. Moderate leukocytosis, neutrophilia with a shift to the left are noted in the peripheral blood, which is subsequently replaced by lymphocytosis. The cerebrospinal fluid is colorless, transparent. During puncture, it flows out with increased pressure (250-350 mm H2O). Lymphocytic pleocytosis is noted (several tens and hundreds in 1 mm ³ ). However, in the first 1-2 days of the disease, neutrophils may predominate in the cerebrospinal fluid (up to 90%). In some cases, a mixed nature of cytosis is noted. Protein content is within normal limits. Glucose level is within normal limits or increased. Recurrent meningitis is possible. In this case, the increase in meningeal symptoms is accompanied by a rise in body temperature.

According to M.A. Dadiomov (1986), 15-30% of patients have no pronounced meningeal symptoms, while inflammatory changes are detected in the cerebrospinal fluid. In some patients with clear meningeal symptoms, the composition of the cerebrospinal fluid does not change (meningism). The composition of the cerebrospinal fluid is completely normalized after 10-12 days (less often by the end of the third week from the onset of the disease).

Minor illness

(Coxsackie and ECHO fever: three-day, or indeterminate, fever; "summer flu") can be caused by all types of low-virulence strains of enteroviruses. Clinically, minor illness is characterized by short-term fever (no more than 3 days), weakness, fatigue, moderate headache, vomiting, myalgia, abdominal pain. Catarrhal symptoms from the upper respiratory tract occur in less than two-thirds of patients. A two-wave course of the disease is possible.

Enteroviral exanthema

(Epidemic, or Boston, exanthema, as well as measles-like and rubella-like exanthema) is caused by ECHO viruses (types 4, 5, 9, 12, 16, 18), less often by Coxsackie viruses (types A-9, A-16, B-3). It is a mild form of enterovirus infection. Enterovirus exanthema is most often recorded in the form of small outbreaks, but large epidemics have also been described. The disease develops acutely with a rise in body temperature to 38-39 ° C. General weakness, severe headache and muscle pain, sore throat, cervical lymphadenitis, exanthema on the face, trunk and limbs are characteristic. The rash is rubella-like, less often maculopapular, bullous, petechial, and lasts 2-4 days. A spotted enanthem is noted on the mucous membrane of the oropharynx. In the acute period, pharyngitis and conjunctivitis often occur. In some cases, the disease is accompanied by meningism or is combined with serous meningitis. Fever lasts 1-8 days

In some cases, enterovirus exanthema occurs only with damage to the hands, feet, and oral cavity (in German literature - HFMK, short for Hand-Fuss-Mundkrankheit). The disease is caused by Coxsackie A viruses (serotypes 5, 10, 16). In this form, against the background of moderate intoxication and a slight increase in body temperature, a vesicular rash with elements 2-3 mm in diameter, surrounded by an inflammatory rim, appears on the fingers and toes. At the same time, isolated small aphthae are found on the tongue and mucous membrane of the cheeks and palate.

Catarrhal (respiratory) form is a common enterovirus infection caused by many types of enteroviruses. This form predominates in infections caused by the Coxsackie A-21 virus. Both children and adults are affected. It develops acutely, in the form of a flu-like disease with an increase in body temperature and symptoms of intoxication. Rhinitis with serous-mucous discharge, dry cough, hyperemia and granularity of the mucous membrane of the pharynx are characteristic. Manifestations of the disease in the form of pharyngitis with regional lymphadenitis and short-term subfebrile fever are possible. Children sometimes develop false croup, and the course of the disease in some cases is complicated by pneumonia and myocarditis. In uncomplicated cases, the fever lasts about 3 days, catarrhal phenomena - about a week.

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Enterovirus diarrhea

(Viral gastroenteritis, "vomiting sickness") is most often caused by ECHO viruses. Mostly children under 2 years old are affected, less often - adults. A short prodromal period is possible, which is manifested by general malaise, weakness, headache, loss of appetite. The disease develops acutely with a rise in body temperature to 38-39 ° C, less often to subfebrile numbers. The febrile period lasts on average about a week. Simultaneously with an increase in body temperature, loose stools without pathological impurities are noted up to 2-10 times a day. Bloating is characteristic, pain on palpation is possible (more pronounced in the ileocecal region). There is no appetite. The tongue is coated. In the first days, multiple vomiting is often noted, but even with a duration of dyspeptic phenomena from 2 days to 1.5-2 weeks, significant dehydration does not occur. Hepatosplenomegaly is sometimes noted. Signs of catarrhal inflammation of the upper respiratory tract are often observed.

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Encephalomyocarditis of newborns

The most severe type of enterovirus infection caused by Coxsackie B viruses (types 2-5) and occurring in outbreaks in maternity hospitals. The source of the infectious agent may be women in labor (infection occurs through the placenta or during childbirth) or medical personnel. Against the background of a rise in temperature, loss of appetite, drowsiness, vomiting, and diarrhea are noted. Fever has a two-wave nature (sometimes absent). Characteristic are cyanosis or gray skin, tachycardia, shortness of breath, enlarged heart borders, muffled tones, abnormal heart rhythms, heart murmurs, enlarged liver and spleen, edema, and in rare cases jaundice and hemorrhagic rash. When the central nervous system is affected, convulsions occur, and coma may develop. When examining the cerebrospinal fluid, lymphocytic pleocytosis is detected.

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Paralytic form of enterovirus infection

(Spinal, poliomyelitis-like) form is caused by Coxsackie viruses A (types 4, 7, 10, 14) and B (types 1-6), as well as ECHO viruses (types 2, 4, 6, 1, 9, 11, 16). The disease is most often registered in the warm season as sporadic cases in children aged 1-5 years. It occurs mainly in the form of mild paralytic forms. Severe forms are rare. A third of patients experience a preparalytic period, which is characterized by symptoms typical of other forms of enterovirus infection (minor illness, respiratory, herpangina). Most often, paresis occurs acutely, against the background of complete health, while body temperature rises slightly or remains normal. Usually, the lower limbs are affected and the so-called morning lameness develops. Gait disturbance in the form of limping occurs, with the knee bending, the foot hanging down, the leg rotating outward and muscle tone decreasing. Superficial and deep reflexes are not impaired; hypo- or hyperreflexia is observed less frequently. In the presence of fever, a slight increase in protein content and moderate lymphocytic pleocytosis are detected in the cerebrospinal fluid. Paresis passes relatively quickly, usually with complete restoration of motor functions, but in rare cases hypotension and hypotrophy of the affected muscles persist for several months. In severe cases of bulbar, bulbospinal forms of infection, cases of fatal outcome have been described.

Rare forms of enterovirus infections include encephalitis, meningoencephalitis, myocarditis, pericarditis, epidemic hemorrhagic conjunctivitis, uveitis, nephritis, pancreatitis, and hepatitis.

Enteroviral encephalitis and meningoencephalitis

Caused by various types of enteroviruses Coxsackie and ECHO. Characterized by acute onset with severe headache, vomiting and fever, which can be two-wave. In severe cases, impaired consciousness is noted, seizures are possible, focal neurological symptoms (nystagmus, cranial nerve palsy, etc.).

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Enterovirus pericarditis and myocarditis

Caused by Coxsackie B viruses (types 2-5), less often by ECHO viruses (types 1, 6, 8, 9, 19). Most often, heart damage develops in older children and adults after a respiratory form of enterovirus infection (after 1.5-2 weeks), less often - in isolation. At the same time, against the background of moderate fever, general weakness increases, pain in the heart area appears. During examination, dilation of the heart borders, muffled tones, pericardial friction noise are revealed. The course of the disease is benign, the prognosis is favorable.

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Epidemic hemorrhagic conjunctivitis

It is most often caused by enterovirus type 70, less often by other enteroviruses. The disease begins acutely with damage to one eye. In some cases, the other eye is also affected after 1-2 days. Characteristic are a sensation of a foreign body, "sand" in the eyes, lacrimation and photophobia. Examination reveals swelling of the eyelids, hemorrhages in the hyperemic conjunctiva and scanty mucopurulent or serous discharge. The disease often proceeds benignly, recovery occurs in 1.5-2 weeks.

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Complications of enterovirus infection

In epidemic myalgia, aseptic serous meningitis, encephalitis and meningoencephalitis, cerebral edema and swelling develop in some cases. In bulbar disorders, severe aspiration pneumonia is possible. In some cases, the respiratory form is complicated by secondary bacterial pneumonia and croup. In 8-10% of cases, epidemic hemorrhagic keratoconjunctivitis and uveitis lead to the development of cataracts and bilateral blindness.

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