What are the immediate plans for a suspected tuberculosis (TB) case, particularly in vulnerable populations such as the elderly, young children, or those with compromised immune systems?

Immediate Management of Suspected Tuberculosis

All patients with suspected active TB should undergo immediate chest radiography, respiratory isolation if pulmonary TB is suspected, and collection of at least three sputum specimens for acid-fast bacilli (AFB) smear, culture, and molecular testing, with prompt reporting to the local health department. 1

Initial Clinical Assessment and Risk Stratification

High-Risk Populations Requiring Immediate Action

• Immunocompromised patients (HIV-infected, those on anti-TNF therapy, transplant recipients) warrant immediate evaluation and should not wait for confirmatory testing to initiate isolation 1
• Young children under 4 years and elderly patients require expedited workup due to higher risk of dissemination and atypical presentations 1
• HIV-infected patients with low CD4 counts may have normal chest radiographs despite active disease, necessitating CT imaging if clinical suspicion remains high 1

Clinical Indicators Warranting Immediate Evaluation

• Persistent cough lasting ≥3 weeks, hemoptysis, unexplained weight loss, night sweats, or fever 1
• Recent contact with known TB case, residence in TB-endemic area, or time spent in high-risk congregate settings (prisons, homeless shelters, long-term care facilities) 1
• Newly positive tuberculin skin test (≥5mm in immunocompromised, ≥10mm in high-risk groups, ≥15mm in low-risk populations) with compatible symptoms 2

Immediate Diagnostic Workup

Respiratory Specimen Collection

• Obtain at least three sputum specimens collected on separate days, with at least one early-morning specimen, for AFB smear, culture, and drug susceptibility testing 1
• For children unable to produce sputum: perform three early-morning gastric aspirates (expected yield 50%), which can be done outpatient 1
• For smear-negative cases with high clinical suspicion: consider bronchoalveolar lavage or tissue biopsy, particularly in children when source case is unavailable 1

Imaging Protocol

• Chest radiography (frontal view only) is the initial imaging study; lateral views do not improve TB detection 1
• Look specifically for upper lobe or superior-segment lower lobe fibrocavitary disease, hilar/mediastinal adenopathy, or pleural effusion 1
• CT chest should be obtained when: chest radiograph is equivocal, patient is HIV-positive with CD4 <200, or patient is on anti-TNF medications with normal chest radiograph but high clinical suspicion 1

Molecular Testing

• GeneXpert MTB/RIF should be performed immediately on at least one respiratory specimen as it provides results within 2 hours and detects rifampin resistance 3, 4
• GeneXpert has 86% sensitivity overall and 84% in HIV-positive patients, with 61% detection rate in smear-negative, culture-positive cases 3
• Use GeneXpert as a "rule-in test" not "rule-out test"—negative results do not exclude TB, and full diagnostic workup must continue 5, 4

Additional Testing in High-Risk Pediatric Populations

• Consider urine LAM testing in HIV-positive children and those with severe acute malnutrition as an adjunctive tool (not standalone diagnostic) 6
• LAM testing increases TB detection by 38.5% in intrathoracic TB and 41.6% in lymph node TB when added to standard testing 6
• LAM should only be used as "rule-in" test with specificity of 92-93%; positive Grade 2-3 results strongly support TB diagnosis 6

Immediate Isolation and Infection Control

Respiratory Isolation Criteria

• Initiate airborne isolation immediately for any patient with suspected pulmonary TB who has cough, is undergoing cough-inducing procedures, or has positive AFB smear 1
• Isolation must continue until patient meets ALL criteria: receiving standard multidrug therapy for 2-3 weeks, demonstrates clinical improvement, has three consecutive negative AFB sputum smears collected 8-24 hours apart 1
• More stringent criteria apply for hospitalized patients returning to congregate settings or those with suspected multidrug-resistant TB—require three consecutive negative smears before release from isolation 1

Special Considerations for Children

• Children with typical primary TB (hilar adenopathy without cavitation, negative smear, no pronounced cough) usually do not require isolation 1
• Isolate pediatric patients who have laryngeal or extensive pulmonary involvement, pronounced cough, positive AFB smears, or cavitary disease 1
• Evaluate parents and visitors of all pediatric TB patients immediately, as the source case often resides in the family 1

Public Health Reporting and Contact Investigation

Mandatory Reporting

• Report every suspected and confirmed TB case to local health department within 1 week of diagnosis 1
• Reporting should occur even before culture confirmation when clinical and radiographic findings are consistent with TB 1

HIV Testing

• Perform HIV testing on all TB patients with results determined within 2 months of TB diagnosis 1
• HIV status critically affects treatment duration (minimum 12 months for HIV-infected patients with LTBI) and monitoring requirements 1, 2

Contact Tracing

• Identify and evaluate all close contacts before determining patient is non-infectious, particularly children under 4 years and immunocompromised contacts 1
• Close contacts with ≥5mm tuberculin reaction should receive treatment for latent TB infection 2
• Tuberculin-negative children and adolescents who are close contacts should receive preventive therapy until repeat testing at 12 weeks post-exposure 2

Treatment Initiation Considerations

When to Start Treatment Before Culture Confirmation

• Begin treatment immediately when chest radiography shows upper lobe fibrocavitary disease in appropriate clinical setting, sufficient to warrant isolation pending culture 1
• For children under 4 years with suspected TB: start treatment as soon as diagnosis is suspected due to high risk of dissemination 1
• Infants and young children should receive three-drug regimen (isoniazid, rifampin, pyrazinamide) initially, reserving four-drug therapy for adult-type disease with cavitation 1

Initial Regimen Selection

• Standard four-drug regimen (isoniazid, rifampin, pyrazinamide, ethambutol) for adults and children with adult-type TB until susceptibilities known 1
• Three-drug regimen (omitting ethambutol) acceptable for children with primary TB when drug-susceptible strain is known or suspected 1
• Add ethambutol (15-20 mg/kg/day) as fourth drug in children when epidemiologic circumstances suggest drug resistance, even if too young for routine eye testing 1

Critical Pitfalls to Avoid

• Do not rely solely on chest radiography in immunocompromised patients—normal radiographs occur in AIDS patients with very low CD4 counts despite active disease 1
• Do not use GeneXpert or LAM as rule-out tests—negative results require continuation of full diagnostic workup including culture 6, 5
• Do not delay isolation pending test results—clinical and radiographic findings alone warrant respiratory isolation 1
• Do not treat with single-drug therapy—always use multiple agents to prevent drug resistance, even when starting empirically 2
• Do not assume children are non-infectious—evaluate using same parameters as adults (cavitation, cough, positive smear) 1