Miliary Tuberculosis in Adults

Of 40 adults with miliary tuberculosis 24 had “overt” disease; in them miliary mottling was usually present on the chest radiograph, and tubercle bacilli were readily isolated from sputum, urine, or cerebrospinal fluid. In the remaining 16 patients the disease was termed “cryptic” because its usual clinical and radiographic features were absent. This cryptic type is as common as the overt type in patients over 60 years. In this series the peak age incidence was in the eighth decade, and possibly this increase in the incidence age is due to the breakdown of old tuberculous foci in patients with diminished immunological mechanisms.Cryptic miliary tuberculosis is a difficult diagnostic problem and should be suspected in any elderly patient, particularly a woman, who has an unexplained pyrexia, pancytopenia, or leukaemoid reaction. In 10 cases it was diagnosed by a therapeutic trial with para-aminosalicylic acid and isoniazid, a fall of temperature to normal (usually within a week), weight gain, a rise in haemoglobin, and increased well-being being the criteria of improvement The use of such a trial is strongly advocated as a specific method of diagnosing cryptic miliary tuberculosis.     

Isoniazid Chemoprophylaxis of Tuberculosis

A major step toward the eradication of tuberculosis in the United States has been the use of isoniazid for chemoprophylaxis in certain persons who have positive tuberculin skin tests but no other evidence of active infection. Chemical trials have demonstrated the effectiveness of chemoprophylaxis in groups where there is a relatively high risk of active tuberculosis. However, only the practicing physician can identify and offer chemoprophylaxis to many other susceptible persons. Even if the patient is a candidate for isoniazid, the risk of developing tuberculosis must be weighed against the cost and possible adverse effects of the drug. If isoniazid is given, the physician must be alert to the signs of possible drug toxicity. If isoniazid is not given, he must anticipate the development of active tuberculosis in susceptible persons.