Learn — Immune & communicable diseases

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HIV — stages and management

HIV is a retrovirus that infects and progressively destroys CD4 T-lymphocytes, so that cell-mediated immunity fails and the patient becomes vulnerable to opportunistic infections and to certain cancers; AIDS is the late stage defined by a CD4 count below 200 cells per cubic millimetre or by an AIDS-defining illness. With modern antiretroviral therapy it has become a chronic treatable condition in which an adherent patient has a near-normal life expectancy and, once the viral load is undetectable, does not transmit the virus sexually, which is why testing, immediate treatment and adherence support are the whole of management.

Transmission is by unprotected sexual contact (the commonest route in India), by blood through contaminated needles, sharps injuries and unscreened transfusion, and from mother to child in pregnancy, delivery and breastfeeding; it is not spread by sharing food, utensils, toilets, mosquitoes or casual contact, and that reassurance is part of the nursing role.
The natural history is acute seroconversion illness (a glandular-fever-like illness 2 to 4 weeks after infection, with a very high viral load and high infectivity), then clinical latency lasting years, then symptomatic disease and AIDS; WHO clinical staging runs from 1 (asymptomatic) to 4 (AIDS-defining conditions).
Diagnosis in India follows the NACO algorithm at an ICTC: three different rapid antibody tests based on different antigens or principles on the same sample, all three reactive for a positive diagnosis, with pre-test and post-test counselling and written informed consent; the older ELISA-then-Western-blot sequence is no longer the Indian pathway. Infants under 18 months need a DNA-PCR because maternal antibody persists.
The window period is the interval before antibodies are detectable — up to about 3 months with antibody tests and shorter with fourth-generation antigen-antibody assays — so a negative test in a recent exposure is repeated rather than trusted.
Test and treat is national policy: antiretroviral therapy is offered to every person living with HIV regardless of CD4 count. The standard first-line regimen is the single daily fixed-dose tablet TLD — tenofovir disoproxil fumarate 300 mg, lamivudine 300 mg and dolutegravir 50 mg.
Drug monitoring: tenofovir needs creatinine monitoring for renal tubular toxicity and reduced bone density; dolutegravir causes weight gain, insomnia and headache and produces a small benign rise in creatinine by blocking its tubular secretion; adherence above 95% is what preserves the regimen, and missed doses drive resistance.
Treatment success is measured by viral load, not by symptoms: suppression to below the detectable limit is the target, and an undetectable viral load means the virus is not transmitted sexually. A persistently detectable load triggers adherence counselling and then a switch to second-line therapy.
Opportunistic infections track the CD4 count: Pneumocystis jirovecii pneumonia and oesophageal candidiasis below 200, cerebral toxoplasmosis and cryptococcal meningitis below 100, Mycobacterium avium complex and CMV retinitis below 50; tuberculosis occurs at any CD4 count and is the commonest opportunistic infection and cause of death in India.
Prophylaxis and co-management: co-trimoxazole preventive therapy for patients with a low CD4 count or advanced disease, which also covers toxoplasmosis; the four-symptom tuberculosis screen (current cough, fever, weight loss, night sweats) at every visit, with TB preventive therapy when it is negative; and when TB and HIV coexist, TB treatment starts first and antiretroviral therapy is added within the first weeks, with immune reconstitution inflammatory syndrome anticipated as the patient improves.
Prevention of parent-to-child transmission: lifelong antiretroviral therapy for every pregnant woman with HIV regardless of CD4 count, institutional delivery with avoidance of unnecessary instrumentation, infant nevirapine prophylaxis, early infant diagnosis by DNA-PCR at 6 weeks, and exclusive breastfeeding for 6 months with the mother on treatment rather than mixed feeding.
Occupational exposure: wash the site with soap and water without squeezing, scrubbing or applying bleach or antiseptic, report immediately, and start post-exposure prophylaxis with a three-drug regimen for 28 days as soon as possible and within 72 hours, with follow-up testing; the risk from a percutaneous exposure to HIV-positive blood is about 0.3%. Standard precautions are applied to every patient, not to those known to be positive.
Confidentiality is a legal duty: the HIV and AIDS (Prevention and Control) Act 2017 prohibits discrimination, requires informed consent for testing, and forbids disclosure of a person's status without consent — including in handover, on the bed head ticket and to family.

Wasting syndrome

HIV wasting syndrome is the involuntary loss of more than 10% of baseline body weight together with either chronic diarrhoea for 30 days or more, or chronic weakness with documented fever for 30 days or more, in the absence of any concurrent illness other than HIV that would explain it. It is an AIDS-defining, WHO stage 4 condition, and it differs from simple starvation because the loss falls disproportionately on lean body mass rather than on fat, so appetite alone will not restore it.

The mechanism is multifactorial: cytokine-driven hypermetabolism, reduced intake from oral and oesophageal candidiasis, painful mouth ulcers, nausea and depression, malabsorption from chronic gut infection, the metabolic cost of untreated opportunistic infection, and household food insecurity.
Chronic diarrhoea in these patients is usually infective — Cryptosporidium, Cystoisospora, microsporidia, Giardia, Mycobacterium avium complex, CMV colitis — so the stool workup is part of the nutritional assessment, not separate from it.
Tuberculosis is the single commonest cause of wasting and fever in an Indian patient with HIV, and it must be actively excluded with the four-symptom screen and upfront NAAT before the weight loss is attributed to the syndrome itself.
Assessment is objective and repeated: weight at the same time on the same scale, body mass index, mid-upper arm circumference, a 24-hour dietary recall, and a swallowing and mouth examination; serum albumin falls in inflammation and is a poor marker of nutritional status on its own.
Antiretroviral therapy is the single most effective treatment, because it removes the driving inflammation and allows lean mass to be rebuilt; the syndrome has become uncommon where treatment is available, so unexplained weight loss in a patient already on therapy should raise the question of tuberculosis, another opportunistic infection or treatment failure rather than of the syndrome.
Nutritional support is high-energy and high-protein, given as small frequent meals with energy-dense local foods, oral nutritional supplements between meals, micronutrient supplementation, and enteral tube feeding when intake stays inadequate; treat oral and oesophageal candidiasis with fluconazole so that eating stops being painful.
Food and water safety matter more than in other patients: boiled or safely treated drinking water, freshly cooked hot food, avoidance of raw salads, unpasteurised milk and street food, and scrupulous hand hygiene, because a further gut infection undoes weeks of gain.
Progressive resistance exercise as tolerated is what actually restores lean body mass; feeding alone tends to add fat, and this is the point most often missed in the answer to an examination question.
Practical support closes the loop: link the patient to nutrition and social welfare support and to the ART centre's counselling services, treat depression, and involve the family so that food reaches the patient rather than only the prescription.
Wasting is distinguished from the lipodystrophy of older antiretroviral drugs, in which fat is lost from the face and limbs and gained centrally while total weight may not fall, and from cancer cachexia in lymphoma or Kaposi sarcoma.

Healthcare-associated infections (HAI)

A healthcare-associated infection is one that a patient acquires while receiving care and that was neither present nor incubating on admission, conventionally one appearing 48 hours or more after admission, up to 3 days after discharge, or within 30 days of surgery (or up to 90 days where an implant was placed). They are the clearest measure of nursing safety in a hospital, because almost every one of them is driven by a device, a procedure or a break in technique, and almost every one of them is preventable by a bundle of nursing actions.

The four that account for most of the burden are catheter-associated urinary tract infection, central line-associated bloodstream infection, ventilator-associated pneumonia and surgical site infection; urinary infection dominates in general wards and ventilator and line infections dominate in intensive care.
Hand hygiene is the single most effective measure. WHO's five moments are before touching a patient, before a clean or aseptic procedure, after body fluid exposure risk, after touching a patient, and after touching the patient's surroundings; alcohol-based handrub takes 20 to 30 seconds and soap and water 40 to 60 seconds.
Soap and water, not alcohol rub, is mandatory when hands are visibly soiled and after caring for a patient with Clostridioides difficile or norovirus, because alcohol does not kill spores; contact precautions and a dedicated commode go with it.
The central line bundle: hand hygiene, maximal sterile barrier precautions at insertion (cap, mask, sterile gown, gloves and a full-body drape), 2% chlorhexidine in alcohol skin antisepsis allowed to dry, avoidance of the femoral site in adults with subclavian preferred, scrubbing the hub for at least 15 seconds before every access, and daily review with prompt removal of a line that is no longer needed.
The urinary catheter bundle: insert only for a valid indication, aseptic insertion with a sterile closed system, keep the bag below bladder level and never on the floor, keep the tubing free of kinks and dependent loops, secure the catheter, do not routinely irrigate or use prophylactic antibiotics, empty with a clean container per patient, and review the need every single day.
The ventilator bundle: head of bed elevated 30 to 45 degrees, daily sedation interruption with an assessment of readiness to extubate, oral care with an antiseptic, subglottic secretion drainage, maintaining cuff pressure, avoiding unnecessary circuit changes, and peptic ulcer and venous thromboembolism prophylaxis.
Transmission-based precautions are added to standard precautions: contact precautions with gown and gloves for MRSA, VRE, carbapenem-resistant organisms and C. difficile; droplet precautions with a surgical mask within about a metre for influenza, pertussis, meningococcus, mumps and rubella; airborne precautions with an N95 respirator and a negative-pressure or well-ventilated single room for tuberculosis, measles and chickenpox.
Standard precautions apply to every patient regardless of diagnosis — hand hygiene, gloves for contact with blood and body fluids, gown and eye protection when splashing is likely, safe injection practice with one needle, one syringe, one time, no recapping (or a one-handed scoop if unavoidable), and immediate disposal of sharps at the point of use.
Biomedical waste segregation at the point of generation under the 2016 Rules: yellow for human anatomical, soiled and microbiological waste and expired drugs, red for contaminated recyclable plastics such as tubing, catheters and syringes without needles, white puncture-proof containers for sharps, and blue for glassware and metallic implants.
Surveillance and stewardship complete the picture: infection rates are reported per device-day rather than as raw counts, an outbreak is investigated when a cluster of the same organism appears, antimicrobial stewardship with de-escalation on culture results limits multidrug resistance, and staff protection includes hepatitis B vaccination and post-exposure prophylaxis.
Environmental and personal measures that are easy to lose: cleaning and disinfection of high-touch surfaces, dedicated or disinfected shared equipment such as stethoscopes and BP cuffs, bare below the elbows with short clean nails and no rings or wristwatches, and no artificial nails for clinical staff.

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