HIV tb co infection according to park spam textbook

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HIV-TB Co-infection

Park's Textbook of Preventive and Social Medicine

Overview

HIV and TB are bidirectional killers. HIV damages the immune system and accelerates TB from a harmless latent infection to a life-threatening active disease. The estimated 10% lifetime activation rate of dormant TB in a normal person rises to 10% per year when HIV is superimposed. TB is already the most common opportunistic infection killing HIV-positive people worldwide.

Even in HIV-positive cases, TB can be cured with timely diagnosis and proper treatment. Correct TB treatment gives an HIV-positive person with TB on average two additional years of life.

Epidemiological Impact: How HIV and TB Interact

Reactivation of latent infection - People co-infected with TB and HIV are 25-30 times more likely to develop active TB disease than those infected with TB alone. HIV disables the immune system, allowing TB bacilli to multiply rapidly. (Studies in Rwanda, USA, Zaire, and Zambia found HIV-positive individuals are 30-50 times more likely to develop active TB than HIV-negative people.)
Primary infection - HIV-positive individuals are more vulnerable to new TB infection because their weakened immune system cannot contain it. New TB infection in PLHIV can progress to active disease very quickly.
Recurring infection - People with HIV who have been cured of TB may be at higher risk of getting TB again, either due to reinfection or relapse.
Community-level impact - More people in the community become infectious, more die unless treated, and additional social discrimination occurs. Community education is needed to convey that TB is curable and patients are no longer infectious after the first few weeks of treatment.

Diagnosis of TB in People with HIV

Diagnosis is more difficult in advanced HIV infection because:

(a) Sputum smear negativity - HIV-positive people with pulmonary TB have a higher frequency of negative sputum smears. Sputum culture may be needed to confirm the diagnosis.

(b) False-negative tuberculin skin test (TST) - The TST relies on measuring the immune response. If the immune system is damaged by HIV, it may not respond even though the person is infected with TB. This leads to a higher frequency of false-negative TST results.

(c) Less cavitation on chest X-ray - Cavities form due to the immune response causing lung tissue destruction. In HIV patients with a compromised immune system, there is less tissue destruction and hence less cavitation, making radiology less useful.

(d) More extrapulmonary TB - Cases of extrapulmonary TB are more common in co-infected individuals.

Integrated TB-HIV services include:

HIV screening at RNTCP designated microscopy centres
Early detection of TB in PLHIV using an expanded 4-symptom screening algorithm: current cough, weight loss, fever, or night sweats (not just cough alone)
Upfront CBNAAT (Cartridge-Based Nucleic Acid Amplification Test) for presumptive TB in PLHIV
Intensified case finding at ART, Link ART centres, and targeted intervention projects for high-risk groups (injection drug users, female sex workers, MSM)
Early detection of HIV-infected drug-resistant TB patients
Strengthened activities for children and pregnant women

Treatment of HIV-Infected TB Patients

Start anti-TB treatment first, then initiate ART as soon as TB treatment is tolerated (between 2 weeks and 2 months)
ART must be offered to all patients with HIV and TB, and all patients with HIV and MDR-TB, irrespective of CD4 cell count
MDR-TB treatment is the same as for HIV-negative patients; however, treatment is more difficult and adverse events are more common, requiring rigorous monitoring
TB treatment alone (without ART) does not significantly increase CD4 cell count or decrease HIV viral load
HAART in TB-HIV patients leads to:
- Sustained reduction in HIV viral load
- Immunological reconstitution
- Decreased AIDS-defining illness and mortality
All HIV-infected TB patients must also receive co-trimoxazole preventive therapy (CPT) to reduce mortality by preventing opportunistic infections

Immune Reconstitution Inflammatory Syndrome (IRIS)

Occasionally, patients with HIV-related TB may experience a temporary exacerbation of symptoms, signs, or radiographic manifestations of TB after beginning TB treatment. This is called a paradoxical reaction (IRIS).

Mechanism: Immune restitution from simultaneous antiretroviral and TB medication administration.

Features:

High fever
Lymphadenopathy
Expanding intra-thoracic lesions
Worsening chest X-ray findings

Management:

Diagnose IRIS only after excluding TB treatment failure
For severe paradoxical reactions: prednisone 1-2 mg/kg for 1-2 weeks, then gradually tapering doses

Isoniazid Preventive Therapy (IPT) for PLHIV

IPT is one of the "3-Is" globally recommended for preventing TB among HIV-infected individuals:

3-Is = Intensified case finding, Isoniazid preventive therapy, Infection control

Key points about IPT:

Most effective bactericidal anti-TB drug available
Prevents progression of latent TB to active disease (reactivation) and also prevents TB reinfection
All children with HIV who have completed TB treatment should receive INH for an additional 6 months
Children living with HIV aged >12 months who are unlikely to have active TB on symptom-based screening should receive IPT: 10 mg/kg/day for 6 months
IPT does not increase risk of INH-resistant TB later; concern about resistance should not be a barrier to providing IPT

Source: Park's Textbook of Preventive and Social Medicine, Chapter on Tuberculosis (HIV-TB Co-infection section), pp. 234-236, and Chapter on AIDS.

Exam oriented

Here is the exam-oriented summary of HIV-TB Co-infection from Park's textbook:

HIV-TB Co-infection - Exam Notes

Park's Textbook of Preventive & Social Medicine

🔑 High-Yield One-Liners

Fact	Value
TB is the ___ most common OI killing HIV+ve people	Most common
Lifetime TB activation in normal person	10% over lifetime
Lifetime TB activation with HIV superimposed	10% per year
HIV+ve person is ___ times more likely to develop active TB	25-30 times (Park Ch. TB) / 30-50 times (Park Ch. AIDS)
Extra years of life with correct TB treatment in HIV+ve	2 additional years

Epidemiological Impact - 4 Ways HIV & TB Interact (PPRR)

#	Type	Key Point
1	Primary infection	HIV weakened immunity → rapid progression to active disease
2	Progression (reactivation)	Latent TB → active TB, 25-30× more likely
3	Recurring infection	Post-cure TB - relapse or reinfection more common
4	Ripple in community	More active cases → more deaths unless treated

Why Diagnosis is Difficult in HIV - 4 Reasons (SFCC)

Letter	Feature
S	Sputum smear negative (higher frequency) → need culture
F	False-negative TST (damaged immune system can't respond)
C	Cavitation less on CXR (less immune response = less tissue destruction)
C	Common extrapulmonary TB

Integrated TB-HIV Diagnosis - Key Points

4-symptom screening in PLHIV (not just cough):

Cough + Weight loss + Fever + Night sweats
Upfront CBNAAT for all presumptive TB in PLHIV
HIV screening at RNTCP designated microscopy centres

Treatment - Most Asked Points

Question	Answer
Start TB treatment or ART first?	TB treatment first
When to start ART after TB Rx?	2 weeks to 2 months (as soon as TB treatment is tolerated)
ART given based on CD4?	No - irrespective of CD4 count (ALL HIV-TB patients get ART)
Additional drug for PLHIV with TB?	Co-trimoxazole preventive therapy (CPT)
TB treatment alone increases CD4?	No significant increase without ART

IRIS (Immune Reconstitution Inflammatory Syndrome)

Also called: Paradoxical reaction
When: After starting TB treatment in HIV+ve patients
Mechanism: Immune restitution from simultaneous ART + anti-TB drugs
Features: High fever, lymphadenopathy, expanding intra-thoracic lesions, worsening CXR
Diagnosis: Exclude TB treatment failure first
Treatment: Severe cases → Prednisone 1-2 mg/kg for 1-2 weeks, then taper

Isoniazid Preventive Therapy (IPT) - 3 I's

3 I's = Intensified case finding + IPT + Infection control

Point	Detail
Purpose	Prevents latent TB → active TB (reactivation) + prevents reinfection
Dose in children (HIV+ve, >12 months)	INH 10 mg/kg/day × 6 months
Post TB treatment in HIV+ve children	Additional 6 months INH
IPT causes INH resistance?	No - not a barrier to giving IPT
Eligibility	Symptom screen negative + no contact with TB case

Quick Recall Box

HIV + TB → TB Rx FIRST → ART in 2 wk–2 months → CPT always
IRIS = paradoxical worsening → Prednisone if severe
IPT = INH 10 mg/kg/day × 6 months in HIV+ve children
TST = FALSE NEGATIVE in HIV (immune system damaged)
CXR = LESS CAVITATION in HIV (less tissue destruction)
25-30× more likely to get TB if HIV+ve
10% per year activation (vs 10% per lifetime normally)

Exam tip: The most commonly asked facts are - (1) 25-30× risk, (2) start TB first then ART at 2 wk-2 months, (3) ART irrespective of CD4, (4) IRIS mechanism and treatment, (5) 4-symptom screening, (6) IPT dose.

Chemoprophylaxis of hiv from parks textbook

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Chemoprophylaxis of HIV

Park's Textbook of Preventive & Social Medicine

Overview

Chemoprophylaxis for HIV covers three distinct areas:

Post-Exposure Prophylaxis (PEP)
Co-trimoxazole Preventive Therapy (CPT)
Isoniazid Preventive Therapy (IPT) (for TB in PLHIV - covered in HIV-TB co-infection)

1. Post-Exposure Prophylaxis (PEP)

PEP = A comprehensive set of services to prevent HIV infection developing in an exposed person, including first aid, counselling, risk assessment, HIV testing, and short-term (28 days) antiretroviral drugs.

Key Time Point

Must be initiated as early as possible, ideally within 72 hours of exposure
Beyond 72 hours - PEP is not effective

Eligibility - WHEN to Give PEP

Give PEP for:

Type	Examples
Parenteral/mucous membrane exposure	Sexual exposure, eye/nose/oral splash
Risky body fluids	Blood, blood-stained saliva, breast milk, genital secretions, CSF, amniotic, rectal, peritoneal, synovial, pericardial, pleural fluids

Do NOT give PEP when:

Situation
Exposed person is already HIV positive
Source is established HIV negative
Exposure to non-risky fluids: tears, non-blood-stained saliva, urine, sweat

Exam tip: HIV status of the exposed person should NOT be a barrier to initiating PEP. In emergency situations - start PEP first, test later.

PEP Drug Regimen

Preferred 3-Drug Regimen (Adults & Adolescents):

Option	Drugs	Dose
Option 1	Raltegravir (RAL) + TDF + FTC (Truvada)	RAL 400 mg BD + TDF 300 mg/FTC 200 mg OD
Option 2	Dolutegravir (DTG) + TDF + FTC	DTG 50 mg OD + TDF 300 mg/FTC 200 mg OD

DTG is a once-daily alternative to RAL
3-drug regimen is now recommended for all exposures (severity of exposure no longer needs assessment)
Duration: 28 days

Special Circumstances (2-Drug Regimen):

Only when recommended ARVs unavailable, or concern about adherence/toxicity - consult expert.

Children < 10 years:

Preferred third drug: LPV/r (Lopinavir/ritonavir)
Alternatives: ATV/r, RAL, DRV, EFV, NVP

PEP - Special Populations

Population	Action
Women of childbearing potential	Pregnancy test before PEP
Non-pregnant woman on DTG	Counsel to use effective contraception during PEP
Pregnant woman exposed to DTG in 1st trimester	Monitor for neural tube defects

2. Co-trimoxazole Preventive Therapy (CPT)

Co-trimoxazole = Fixed dose combination of Sulfamethoxazole + Trimethoprim Covers bacterial, fungal, and protozoan infections

In Adults (including pregnant women)

Indication	Recommendation
WHO stage 3 or 4 disease	Give CPT regardless of CD4
CD4 ≤ 350 cells/mm³	Give CPT
Malaria / severe bacterial infections endemic area	Give CPT regardless of CD4 or WHO stage

When to STOP CPT in adults:

Clinically stable on ART + immune recovery + viral suppression
Exception: continue in malaria/severe bacterial infection endemic settings regardless

In Children & Adolescents

Group	Recommendation
All HIV-infected children	Give CPT irrespective of clinical/immune conditions
Priority: < 5 years	Give regardless of CD4 or stage
WHO stage 3/4 or CD4 ≤ 350	High priority at any age
Endemic malaria/bacterial setting	Continue till adulthood irrespective of ART
Low prevalence setting, age ≥ 5 years	Can stop if stable on ART ≥ 6 months + CD4 > 350

In HIV-Exposed Infants

Point	Detail
Start CPT	From 4-6 weeks of age
Continue until	HIV infection excluded by age-appropriate test after complete cessation of breastfeeding