Preventive Therapy for Persons with Positive Tuberculin Skin Test (PPD) Reactions

 

High risk groups:

(1) persons with HIV infection

(2) persons with unknown HIV status but with risk factors for HIV and suspected of having HIV infection

(3) close contacts of persons with newly diagnosed infectious tuberculosis

(4) children and adolescents who are tuberculin negative (reaction to 5TU PPD < 5 mm) and who have been close contacts of infectious persons within the past 3 months until a repeat tuberculin skin test is done 12 weeks after contact with the infectious source

(5) recent converters

(6) persons with abnormal chest radiographs that show fibrotic lesions likely to represent old healed tuberculosis

(7) intravenous drug users known to be HIV seronegative

(8) persons with medical risk factors increasing the risk of tuberculosis

 

Recent conversion:

(1) if age < 35 years: increase in tuberculin skin reaction >= 10 mm within a two year period

(2) if age >= 35 years: increase in tuberculin skin reaction >= 15 mm within a two year period

 

Medical risk factors increasing risk of tuberculosis:

(1) silicosis

(2) gastrectomy

(3) jejunoileal bypass

(4) weight of 10% of more below ideal body weight

(5) chronic renal failure

(6) diabetes mellitus

(7) conditions requiring prolonged high dose corticosteroid therapy or other immunosuppressive therapy

(8) malignant hematologic disorders such as leukemia or malignant lymphoma

(9) other malignancies

 

High incidence groups:

(1) foreign born persons from high prevalence countries

(2) medically underserved or low income populations, including high risk racial or ethnic minority populations, especially Blacks, Hispanics and Native Americans

(3) residents of facilities for long-term care (correctional institutions, nursing homes, mental institutions, other long-term residential facilities)

Age of Patient	Group	Recommendation
< 35 years of age	with risk factor	treat if reaction to 5TU PPD >= 10
	with risk factor and recent TB contact, HIV infected, or has radiographic evidence of old TB	treat if reaction to 5TU PPD >= 5
	no risk factor, high incidence group	treat if PPD >= 10 mm
	no risk factor, low incidence group	treat if PPD >= 15 mm
>= 35 years of age	with risk factor	treat if reaction to 5TU PPD >= 10
	with risk factor and recent TB contact, HIV infected, or has radiographic evidence of old TB	treat if reaction to 5TU PPD >= 5
	no risk factor, high incidence group	do not treat
	no risk factor, low incidence group	do not treat

 

Anergy testing is no longer performed routinely since it has proven to be unreliable in many patients.

 

Treatment:

(1) A patient with risk factors should be treated unless there is evidence of previous adequate therapy.

(2) Children are treated with isoniazid 10 mg/kg per day, up to 300 mg qd.

(3) Adults are treated with isoniazid 300 mg qd; if necessary intermittent treatment with INH 900 mg twice weekly can be used.

(4) If HIV infection or a table abnormal chest radiograph consistent with past tuberculosis treatment is given for 12 months of continuous therapy (patients with HIV infection may receive lifelong treatment).

(5) Other groups are treated for at least 6 months, up to 12 months.

(6) Pyridoxine supplementation with 10-25 mg qd is recommended if age > 65 years or with pregnancy, diabetes mellitus, chronic renal failure, alcoholism, treatment with anticonvulsants or malnutrition.

(7) If exposure was to a drug-resistant strain of M. tuberculosis, then consult with infectious disease expert.

(8) Patients receiving INH who are over 35 or who are daily drinkers should be monitored for hepatoxicity .