Symptoms of legionellosis

Legionellosis symptoms are characterized by a wide spectrum. The infectious process can proceed subclinically, asymptomatically (according to some data, more than 20% of elderly people are seropositive). Legionellosis can manifest itself as acute respiratory infections, pneumonia, bronchitis, alveolitis, or can be characterized by a severe condition, multiple organ damage with the development of sepsis.

A distinction is made between acute respiratory legionellosis (Pontiac fever), pneumonia (Legionnaires' disease, acute alveolitis), and fever with exanthema (Fort Bragg fever).

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Acute respiratory legionellosis

In many ways it resembles acute respiratory disease. The incubation period lasts from 6 hours to 3 days. The disease begins with progressive malaise, diffuse muscle pain. From the first days of the disease, an increase in body temperature from 37.9 to 40 ° C is characteristic. This is accompanied by chills, headache, muscle pain. Neurological symptoms of legionellosis are often noted: dizziness, photophobia, insomnia, impaired consciousness of varying degrees and coordination.

Respiratory syndrome is characterized by a dry cough, chest pain when breathing is possible. Some patients complain of a sore throat and dryness in the oropharynx. Legionellosis symptoms, respiratory syndrome are often combined with abdominal pain, vomiting. As a rule, there are no signs of kidney and liver damage in these patients. Hemogram changes include moderate leukocytosis. Acute disease ends without treatment within 2-5 days. Asthenovegetative syndrome persists for a long time during the convalescence period.

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Pneumonia (Legionnaires' disease, acute alveolitis)

The incubation period lasts from 2 to 10 (usually up to 5) days. The disease begins subacutely with a prodromal period, which lasts 1-2 days. During this period, patients complain of increased fatigue, decreased appetite, and moderate headache. Quite often, diarrhea syndrome develops in the prodromal period. The peak period is characterized by an increase in temperature to 39-40 ° C. Fever (the most constant symptom of legionellosis) can last up to 2 weeks. It is remittent or irregular. It ends with lysis. The following symptoms of legionellosis are characteristic of the peak period: profuse sweating, severe asthenia, intense chest pain associated with breathing. Pleural pain is typical for most patients. In a third of patients, the localization and intensity of pain exactly corresponds to the developing parapneumonic fibrinous pleurisy, aggravated by respiratory failure. A dry cough appears on the 2nd or 3rd day of illness. Sputum is scanty, viscous, mucopurulent. One third of patients have hemoptysis. Pneumonia is determined both physically and radiologically. Shortening of percussion sound is determined over the affected area of the lung, and moist fine bubbling rales are detected during auscultation. Dry rales are heard in half of the patients, indicating the development of bronchial obstruction. Legionella pneumonia differs from other pneumonias by the variety of localization of the pathological process and a significant frequency of total and subtotal lung lesions (in every fifth patient). Radiologically, unilateral pleuropneumonia is more often determined, which is characterized by long-term preservation of infiltration, pleural changes and their slow involution. In patients with immunodeficiency of various origins, destruction of lung tissue is determined.

Patients with legionellosis quickly develop symptoms of pulmonary failure. Severe shortness of breath is typical, and many patients have to be transferred to artificial ventilation at an early stage.

Along with respiratory damage, signs of pathology in other organs and systems are often observed. Thus, most patients in the acute period of the disease have arterial hypotension, relative bradycardia, alternating with tachycardia. Heart sounds are muffled. More than a third of patients develop loose watery stools on the 4th-5th day of the disease. Diarrhea lasts an average of about 7 days and is accompanied by abdominal pain of various localizations and flatulence. In approximately 30% of patients, liver damage is manifested by an increase in the activity of aminotransferases, jaundice is possible. Liver function is restored during the first 2 weeks of the disease, and liver failure is not observed later. Kidney function is often impaired during the course of the disease, mainly due to focal nephritis. Renal failure may develop, which can persist for a long time after the acute phase of the disease (up to 9 months).

CNS lesions are characteristic of most patients to varying degrees. They are mainly manifested by headaches and encephalopathy. The most frequently affected structures are the cerebellum and brainstem. This is manifested by dysarthria, ataxia, nystagmus, and paralysis of the oculomotor muscles. Depression and emotional lability are characteristic. Meningoencephalitis is possible. During the recovery period, many patients complain of memory impairment, some of them cannot remember the events that happened to them in the acute phase of the disease.

In the peripheral blood, an increase in leukocytes to 10-15x10 ⁹ /l is noted. A shift in the leukocyte formula to the left is often observed; in severe cases, thrombocytopenia and lymphopenia are possible. ESR can increase to 80 mm/h.

With a favorable course of the disease, the condition of patients improves from the 2nd week. During the recovery period, weakness, dizziness, and irritability persist for a long time. X-ray changes in the lungs can persist for 10 weeks. In isolated cases, the disease is complicated by lung abscess and pleural empyema. A more frequent complication of the disease is the development of infectious toxic shock.

Acute alveolitis

Acute onset with a rise in body temperature to 39-40 °C is typical. Patients complain of headaches and muscle pain. A dry cough appears from the first days of the disease. Later, shortness of breath increases, a cough with the separation of scanty (mucous or mucopurulent) sputum appears. Auscultation of the lungs reveals widespread bilateral abundant long-term crepitation. With a protracted progressive course, fibrosing alveolitis develops.

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Acute febrile illness

The incubation period is from several hours to 10 days. The main symptoms of legionellosis are: fever up to 38 °C, chills, headache, polymorphic rash. The duration of the disease is 3-7 days. The course is favorable.

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Complications of Legionellosis

The most serious complications of legionellosis are acute respiratory failure, acute renal failure, and infectious toxic shock. Bleeding (nasal, gastrointestinal, and uterine) and thromboembolism may develop. Acute liver failure and suppurative processes in the lungs (lung abscess, pleural empyema) are rarely recorded.

Mortality

In the pneumonic form of legionellosis reaches 15-20%, more often observed in people with chronic lung diseases, immunodeficiency. Causes of death - the development of infectious-toxic shock, pulmonary-cardiac insufficiency or superinfection.