Microbial Diseases Tularemia and Infectious Mononucleosis


Microbial Diseases Tularemia and Infectious Mononucleosis

The haematologic and seismologic findings are usually distinctive. Cat scratch. The disease is characterized by peripheral ulceration and regional nephropathy; a history of contact with cats, the cutaneous reactions to specific antigens, and the absence of agglutinates for Infectious Mononucleosis f. Tularemia's are distinguishing features. Thyme and tuberculosis are similar in some respects to this form of tularemia, although lymphatics and systemic signs are less likely to develop. The lesions of trichinosis are multiple, occur along the course of lymphatics, attach themselves firmly to the skin, and are freely movable. Certain forms of tularemia may present with clinical features similar to those of psittacosis, q fever, and cytoplasm pneumonia.

Broad-spectrum antimicrobial drugs are effective in each of these conditions. Appropriate serologic tests or viral isolation may be required to define the precise cause. Influenza with associated pneumonia is similar but does not respond to specific drugs, and its clinical course is short. Fungal diseases, such as histoplasmosis and coccidioidomycosis, may be acute and may simulate pulmonary tularemia. Consideration of the history, the epidemiologic data, and the cutaneous manifestations, as well as the bacteriologic and serologic findings, usually will permit proper identification.

The presence of unexplained pleural effusion, similar to tuberculous fibrinous pleurisy, requires differentiation. The results of cultural and serological tests will aid in differentiation. Complications. Pericarditis and. Meningitis is a distinctive but unusual complication of tularemia. Pericardial involvement may develop by direct extension from the pulmonary lesions or lymph nodes, and is characterized by a fibrinous or fibrocaseous exudate. In untreated patients, constrictive pericarditis may. Ensure. Tularemic meningitis is characterized by a lymphocytic pleocytosis in the cerebrospinal fluid and was usually fatal prior to the availability of specific antimicrobial drugs. Rare instances of tularemic peritonitis, perisplenitis, osteomyelitis, and endocarditis have been reported.

Treatment. Specific therapy. Tularemia is very amenable to treatment with antimicrobial drugs. Streptomycin is preferable, but the broad-spectrum antimicrobials are equally beneficial in ameliorating the active manifestations. They are less effective; however, in eradicating the organism, primarily because of their bacteriostatic mode of action. With the latter drugs, relapses are liable to occur if treatment is initiated within the first week of illness. Streptomycin. Streptomycin, when given in. Doses of 1.0 gram daily to adults for about one week, results in prompt recovery. Most patients are improved within 24 hours and are afebrile within 48 hours. Relapses are uncommon with streptomycin except when the insufficient drug is given during the very early stages of illness. Strains resistant to streptomycin do appear, a fact

Infectious Mononucleosis is of no clinical significance when the infection is acquired naturally. Chloramphenicol and tetracycline treatment. Broad-spectrum antimicrobials are very effective in rendering the patient afebrile and free from toxicity within 48 to 72 hours. Relapses are uncommon when therapy is initiated 10 to 12 days after the onset of illness, but are frequent if it is given during the first week. F. tularensis does not develop resistance to chloramphenicol or tetracycline; hence, re-treatment leads to prompt response. Tetracycline is the preferable drug solely because reactions to it are less potentially serious.

The following dosage schedule is considered optimal: for chloramphenicol, an initial oral dose of 50 mg. Per kilogram of body weight, and for tetracycline, 25 mg. Per kilogram of body weight. Subsequent daily doses are calculated on the same basis as the initial loading dose, dividing the requirements equally and giving it at six- to eight-hour intervals. Antimicrobial therapy is continued until the patient is improved and has been afebrile for about five to ‘seven days. Any of the above three-drug regimens is wholly satisfactory, and no supplementary chemotherapy is necessary. General management. An adequate diet with appropriate protein intake is advisable. Oxy-gen treatment is indicated for all severely ill patients with pneumonia whether or ‘not cyanosis, is present. Other supportive measures useful for treating patients with pneumonia, such as frequent turning and the performing of a tracheostomy to provide a proper airway, are indicated.

Thoracentesis for removal of fluid will allay respiratory embarrassment. The presence of any superimposed infection is detected by an appropriate examination of the sputum, blood, or tissues. The local ulcer requires no special measures. During the early several weeks of illness, lymph nodes should not be manipulated unduly or incised. Later, fluctuant buboes, which are usually sterile, may require incision and drainage. Recovery en-sues rapidly. Prognosis and postinfection. Immunity. In untreated patients, the case fatality rate in ulcer-glandular tularemia was formerly approximately 5 percent. However, of those patients with typhoid tularemia or with pulmonary manifestations, about 30 percent succumbed.

Infectious Mononucleosis With the advent of streptomycin and later the broad-spectrum antimicrobials, death from tularemia has been virtually eliminated and the morbidity shortened drastically to several days after the institution of treatment, even among severely ill patients. Second attacks of tularemia with systemic complications are uncommon because recovery from the initial episode usually confers immunity. However, it is not unusual for patients to develop primary lesions when reinfected long after the initial systemic infection. Viable f. Tularensis may be isolated from such recurrent primary ulcers, which resemble a Koch reaction. Under these conditions, systemic manifestations are unusual. Under test conditions in volunteers, when strep-

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