Why TB Symptoms Are So Often Missed
Tuberculosis is caused by Mycobacterium tuberculosis — a slow-growing bacterium that replicates over weeks, not hours. This slow growth is the fundamental reason TB symptoms develop insidiously: no single day is dramatically different from the day before. The patient and their family attribute the cough to dust, the weight loss to stress, the night sweats to the heat. By the time the pattern becomes undeniable, months have passed.
In India, this delay is compounded by three factors. First, TB carries social stigma — patients fear that a TB diagnosis will affect their marriage, employment, and social standing. Second, antibiotics are widely available over the counter — patients self-treat cough with amoxicillin or azithromycin, which briefly suppresses secondary bacterial infections but has no effect on TB. The partial improvement reinforces the belief that this is “just a cough.” Third, primary care doctors without chest or ID training may not order GeneXpert as a first-line test, instead treating empirically for months.
The 2–3 Week Rule
Any cough lasting more than 2–3 weeks in India — especially in someone who has been exposed to TB, has HIV, has uncontrolled diabetes, or lives in crowded housing — should be assumed to be TB until GeneXpert is negative. This is not excessive caution: it is the correct clinical threshold given India’s TB burden of 2.8 million new cases per year.
The 7 Symptoms of Tuberculosis
Pulmonary TB — affecting the lungs — is the most common form and the most infectious. Its symptoms are listed below in the order they typically develop. No single symptom is required to be present, and extrapulmonary TB (affecting organs other than the lungs) can present without any respiratory symptoms at all.
Chronic Cough Most Common
Present in over 90% of pulmonary TB cases. The defining feature is duration: the cough of TB does not resolve. It may be dry at first, then become productive. Patients often describe it as “a cough that never fully went away.” If cough lasts more than 2–3 weeks despite basic treatment, send GeneXpert immediately.
Blood in Sputum (Haemoptysis) Serious Signal
Present in approximately 20–30% of pulmonary TB cases. May range from blood-streaked sputum to frank bright red blood. Any haemoptysis requires urgent investigation. While TB is not the only cause (bronchiectasis, lung cancer), it is the most important to exclude in India. Never attribute haemoptysis to a “burst blood vessel from coughing” without a chest investigation.
Night Sweats Constitutional — Key Clue
Drenching night sweats — soaking the clothes and sheets — present in 50–70% of active TB cases. Distinct from normal sweating: the patient wakes up wet. Often dismissed as “the heat” in Surat’s climate. Night sweats alongside chronic cough and weight loss is the classic TB triad. Their presence dramatically raises TB probability.
Unexplained Weight Loss Constitutional — Key Clue
Present in 60–80% of cases. The weight loss of TB is a wasting process — driven by the chronic inflammatory response and the bacteria’s metabolic demands on the host. Typically 5–10 kg over 2–3 months. Weight loss + cough + night sweats = TB until proven otherwise. Many patients notice their clothes fitting differently before they notice the weight loss consciously.
Persistent Low-Grade Fever Constitutional
Evening fever — temperature rising in the late afternoon and evening — is a classic TB feature, present in 40–60% of cases. The fever is often not dramatically high (37.5–38.5°C) and may not be noticed by the patient as “real” fever. They describe feeling “hot” or “feverish” in the evenings. This pattern distinguishes TB from acute bacterial infections which cause sudden high fever.
Chest Pain and Breathlessness Lung Involvement
Chest pain — usually pleuritic (worsened by breathing) — present in 20–30%. Indicates pleural involvement (TB pleuritis). Breathlessness suggests significant lung parenchymal involvement, pleural effusion, or both. In a young patient in India with breathlessness + chest pain + no clear cardiac cause: TB and its complications must be excluded.
Fatigue and Loss of Appetite Constitutional
Profound fatigue — disproportionate to the level of fever — present in 50–70% of cases. Loss of appetite compounds the weight loss. Patients describe inability to do their usual work, sleeping more than usual, and feeling exhausted despite doing little. This combination — fatigue + anorexia + weight loss — without an obvious cause is TB until excluded.
Extrapulmonary TB — When TB Has No Cough
Approximately 15–20% of TB cases in India are extrapulmonary — affecting organs other than the lungs. In HIV-positive patients, this proportion is much higher (40–60%). Extrapulmonary TB presents without cough or respiratory symptoms and is frequently missed because TB is not in the clinician’s differential when there is no chest involvement.
Pulmonary TB — Lungs (80–85%)
Lymph Node TB (Scrofula) — Most Common Extrapulmonary
Miliary TB — Disseminated
TB Meningitis — Neurological
The Correct Test for TB — Not a Chest X-Ray
The most common diagnostic error in TB in India: relying on chest X-ray to exclude TB. A chest X-ray can be entirely normal in early pulmonary TB and in extrapulmonary TB. A normal CXR does not exclude TB.
The correct first-line test is GeneXpert MTB/RIF (CBNAAT) on sputum — a WHO-recommended molecular assay that detects TB DNA and tests for rifampicin resistance simultaneously in under 2 hours. GeneXpert changed TB diagnosis because it is far more sensitive than sputum smear microscopy and provides drug resistance information that guides treatment.
GeneXpert MTB/RIF on sputum
3 sputum samples — spot, early morning, spot — maximise sensitivity. GeneXpert detects TB DNA and tests for rifampicin resistance simultaneously. Sensitivity 88–89% for smear-positive TB, 67–72% for smear-negative. A negative GeneXpert in a strongly suspected case does not exclude TB.
HRCT Chest (not CXR alone)
High-resolution CT chest is far more sensitive than CXR for early TB, pleural disease, and mediastinal lymph nodes. Upper lobe infiltrates + cavities on CXR suggest active TB. HRCT detects tree-in-bud pattern, micro-nodules, and lymphadenopathy that CXR misses. Order HRCT if CXR is normal but clinical suspicion is high.
IGRA (Interferon-Gamma Release Assay)
QuantiFERON-TB Gold or T-SPOT: detects immune sensitisation to TB antigens. Positive IGRA indicates exposure to TB (latent infection) but does not confirm active disease. Used for: household contact investigation; screening immunocompromised patients; TB in healthcare workers. A positive IGRA + clinical symptoms = high suspicion for active TB.
Drug Sensitivity Testing (DST)
GeneXpert detects rifampicin resistance only. Full DST (culture + sensitivity) tests for all first and second-line drugs. MDR-TB (resistant to isoniazid + rifampicin) requires different treatment regimen. XDR-TB (resistant to fluoroquinolones in addition) requires specialist management. Never treat TB without knowing the drug sensitivity pattern.
HIV test: mandatory in every TB workup
TB and HIV are the deadliest co-infection. HIV-positive patients have 20–30× higher risk of developing active TB. TB accelerates HIV progression. Every patient diagnosed with TB must have an HIV test. HIV-positive TB patients require ART initiation within 2 weeks of starting TB treatment and cotrimoxazole prophylaxis.
Who Is at Highest Risk for TB in Surat?
TB is not random. Risk is concentrated in specific groups who share identifiable biological, social, or environmental factors. Knowing which groups are highest risk allows targeted screening and contact investigation.
HIV-Positive Individuals
20–30× higher risk of developing active TB. TB is the leading cause of death in HIV-positive individuals globally. Annual TB screening mandatory.
Uncontrolled Diabetics
Diabetes impairs cellular immunity. 2–3× higher TB risk. Poor glucose control is the single most important modifiable TB risk factor in India.
Household TB Contacts
5–10× higher risk than general population. All household members of a TB patient must be screened. Children under 5 must receive IPT if IGRA positive.
Immunosuppressed Patients
On steroids, biologicals (TNF inhibitors), or post-transplant. TB screening before starting immunosuppression is mandatory.
Healthcare Workers
Occupational exposure to TB patients. Annual screening with IGRA. Prompt investigation of any respiratory symptoms lasting more than 2 weeks.
Crowded Living Conditions
TB spreads through shared indoor air. Crowded housing, dormitories, and prisons dramatically increase transmission risk. Ventilation is the primary environmental control.
TB Is Curable — But Only With the Right Treatment
Standard drug-sensitive TB is cured with a 6-month regimen under the Revised National TB Control Programme (RNTCP): 2 months of HRZE (isoniazid + rifampicin + pyrazinamide + ethambutol) followed by 4 months of HR (isoniazid + rifampicin). Treatment success rates exceed 90% when taken correctly and completely.
The critical failure mode: patients stop treatment when they feel better — typically after 2–3 months — before the 6-month course is complete. The bacteria that survive this incomplete treatment are disproportionately those with natural resistance — and the patient relapses with MDR-TB. This is the single most important cause of drug-resistant TB in India.
MDR-TB (resistant to both isoniazid and rifampicin) requires 18–24 months of treatment with second-line injectable agents. XDR-TB is even harder to treat. Both are preventable by completing the standard 6-month regimen. At SCID-AI, every TB patient is monitored monthly for treatment adherence, side effects, and smear conversion.
Contact Investigation: The Neglected Step
When Dr. Savaj diagnoses TB at SCID-AI, the next step is always household contact investigation. All household members are evaluated — IGRA + CXR for adults; clinical assessment + IGRA for children. Contacts with positive IGRA and no active disease receive isoniazid preventive therapy (IPT) — which reduces TB reactivation risk by 60–90%. This step is consistently neglected in standard care and is one of the most important interventions in TB control.
The Clinical Rule in Surat
In a city with India’s highest TB burden: cough lasting more than 2–3 weeks is TB until GeneXpert is negative. Night sweats + weight loss + cough is the classic triad. A normal chest X-ray does not exclude TB. Three courses of antibiotics for a cough that does not resolve is not “treatment” — it is a 3-month delay in diagnosis. Come to SCID-AI for GeneXpert, not another antibiotic.
