16.1 Tuberculosis, HIV, Hepatitis B & C and Needlestick Injuries

Tuberculosis, HIV, Hepatitis B & C and Needlestick Injuries

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Tuberculosis (TB)

Mycobacterium tuberculosis spreads by airborne droplets. Most infected people develop latent TB infection; reactivation risk is higher with HIV, diabetes, CKD, malnutrition, alcohol misuse and immunosuppression (especially anti-TNF biologics and corticosteroids).

Active TB

• Pulmonary: cough for more than 3 weeks, haemoptysis, fever, night sweats, weight loss; chest X-ray may show upper lobe consolidation or cavitation and hilar nodes. Higher-risk groups include people born in high-incidence countries, homeless people, prisoners and people who use drugs.
• Extrapulmonary: lymph nodes (the commonest), pleura, spine (Pott's disease), meninges, genitourinary tract, abdomen and miliary disease.
• Investigations: 3 sputum samples (including one early-morning sample) for smear microscopy (acid-fast bacilli), culture (the gold standard, taking weeks) and rapid nucleic acid amplification testing for TB and rifampicin resistance; tissue samples for extrapulmonary disease; HIV testing for everyone with TB.

Treatment (NICE NG33)

Pyridoxine is given with isoniazid to prevent peripheral neuropathy. Check liver function, renal function and visual acuity at baseline.

Public health: TB is notifiable. People with infectious pulmonary TB are isolated (respiratory precautions) until they have had about 2 weeks of effective treatment; contacts are traced and screened. Directly observed therapy supports people at risk of poor adherence. Drug-resistant TB needs specialist care.

Latent TB & BCG

Latent infection is diagnosed with an interferon-gamma release assay (or Mantoux test) in contacts, migrants from high-incidence countries and people before biologic therapy. Treatment options include 3 months of rifampicin and isoniazid or 6 months of isoniazid. BCG vaccination is offered to babies at higher risk (living in areas with a high TB incidence or with a parent or grandparent from a high-incidence country).

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HIV

• Testing (BHIVA): test anyone with an indicator condition (for example TB, pneumonia, lymphoma, hepatitis B or C, unexplained weight loss, a sexually transmitted infection, shingles in a young person), in sexual health and antenatal services, and widely in areas of high prevalence (including opt-out testing in some emergency departments).
• Primary HIV infection (seroconversion): 2–6 weeks after exposure, a glandular fever-like illness with fever, sore throat, rash, lymphadenopathy and mouth ulcers. A fourth-generation test (antibody plus p24 antigen) may need repeating.
• Advanced HIV: opportunistic infections at low CD4 counts, such as Pneumocystis pneumonia (below 200 cells/mm³; co-trimoxazole prophylaxis), toxoplasmosis and cryptococcal meningitis (below 100), and cytomegalovirus retinitis (below 50).
• Treatment: antiretroviral therapy (ART) for everyone diagnosed, regardless of CD4 count. Effective ART with an undetectable viral load gives near-normal life expectancy and no sexual transmission (U=U).
• Pregnancy: universal antenatal screening; ART to suppress the viral load; vaginal birth is possible if the viral load is undetectable; the baby receives post-exposure prophylaxis; formula feeding is advised in the UK, with specialist support for mothers with an undetectable viral load who choose to breastfeed.
• Prevention: condoms, pre-exposure prophylaxis (PrEP, tenofovir with emtricitabine) for people at higher risk, and post-exposure prophylaxis (PEP): a 28-day course of combination ART, started as soon as possible, ideally within 24 hours and no later than 72 hours.
• Confidentiality and partner notification are discussed in section 15.3.

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Hepatitis B & C

Hepatitis B Serology

Hepatitis B is spread by blood, sexual contact and from mother to baby. Babies of mothers with hepatitis B receive vaccine at birth (plus hepatitis B immunoglobulin if the mother is highly infectious) and complete the schedule. Chronic infection may need tenofovir or entecavir and needs surveillance for cirrhosis and hepatocellular carcinoma. Vaccination is part of the infant schedule and is offered to healthcare workers and other at-risk groups.

Hepatitis C

Usually spread through injecting drug use, contaminated medical equipment, blood products before 1991 or tattoos in unregulated settings; sexual transmission is less common. Most infections become chronic and are often asymptomatic until cirrhosis develops. Test with HCV antibody, then HCV RNA to confirm current infection. Direct-acting antivirals for 8–12 weeks cure over 95% of patients. There is no vaccine.

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Needlestick & Other Occupational Exposures

1. First aid: encourage the wound to bleed (do not suck or scrub), wash with soap and running water, and irrigate splashes to the eyes or mouth with water.
2. Report immediately to occupational health or the emergency department (out of hours) and complete an incident report.
3. Risk assessment: type of exposure (a deep injury with a hollow needle containing blood is highest risk) and the source patient's status. With consent, test the source for HIV, hepatitis B and hepatitis C. A source who lacks capacity can be tested only if it is in their best interests, not solely for the benefit of the injured worker.
4. Approximate transmission risk after percutaneous exposure: hepatitis B up to about 30% (if the source is HBeAg-positive and the worker is not immune), hepatitis C about 0.5–2%, HIV about 0.3%.
5. Post-exposure measures: HIV PEP started as soon as possible (ideally within an hour or two) if the exposure is significant and the source is HIV-positive with a detectable or unknown viral load; hepatitis B vaccine booster or course, with or without hepatitis B immunoglobulin, depending on the worker's immunity and the source; no PEP exists for hepatitis C, so the worker has follow-up testing and early treatment if infected.
6. Follow-up: baseline and later blood tests; safer sex and avoiding blood donation until follow-up testing is complete.