HIV and hepatitis

HIV

· human immunodeficiency virus

history

· 1981- AIDS first identified in USA

· 1982 - AIDS first diagnosed in Australia

· 1983 - HIV virus identified

· 1984 - first confirmed case of AIDS through blood transfusion

· 1985 - laboratory test for HIV introduced

· 1985 - HIV screening of blood supply in USA and Australia

epidemiology

Incidence

· 1% of US population is HIV-positive

· 0.1% of Australian population is HIV-positive

· 25% of these have AIDS

· M:F = 20:1

Risk groups

· homosexual - 85%

· drug user - 5%

· heterosexual contact - 5%

· haemophilia - 2%

· blood transfusion - 2%

Surgery

· 20% of AIDS patients require surgery

· up to 10% of ER patients are HIV-positive

Aetiology

Transmission

Sexual intercourse

· anal

· vaginal

Blood-borne

· sharing of infected needles and syringes by infected drug users

· blood or blood products (none since 1985)

· accidental transmission with infected blood in health care setting

Infected mother to child

· before or during birth

· via breast milk

Microbiology

· belongs to retrovirus family

· can reverse RNA of virus into DNA

· thus incorporate into DNA of infected cell

· uses reverse transcriptase

pathogenesis

Immune impairment

· primary impairment is CD4 lymphocyte (T-helper cell)

· also affects

· B lymphocyte

· monocyte/macrophage cell line

· production of gamma interferon and lymphokines

· impairs wound healing

· via CD4 and lymphokine deficiency

· causes platelet deficiency

· autoimmune thrombocytic purpura

· causes neuropathy

· via autoimmune neuritis

· affects bacteriocidal functions of leukocytes

· chemotaxis, phagocytosis and secretion of microbicides

clinical

Natural history

· may develop illness at time of acute infection

· within 2-4 wks of exposure

· mononucleosis-type illness

· lympadenopathy, myalgia, fever, rash

· high viraemia and high risk of transmission

· HIV antibodies appear 3 wks to 4 mths after infection

· usually resolves

· some have persistent lymphadenopathy

· proportion will progress to HIV infection

· median time of 8-10 yrs

· associated with

· progressive failure in immune system

· development of opportunistic infections and neoplasms

· progression follows chronological order

· can be divided into stages depending on CD4 count

· early (CD4 > 500)

· intermediate (CD4 200-500)

· late (CD4 < 200)

Early

· CD4 > 500

· average survival 10.9 yrs

· develop autoimmune disorders

· ITP, Guillaine-Barre syndrome, polymyositis

Intermediate

· CD4 200-500

· develop mild infections, esp. of skin and mucosa

· tinea, dermatitis, herpes

Late

· CD4 < 200

· average survival 1.7 yrs

· develop severe infections and malignancy

· see below

Classification

Group 1

· acute infection

Group II

· asymptomatic infection

Group III

· persistent generalised lymphadenopathy

Group IV

· other diseases

· A - constitutional disease

· B - neurological disease

· C - infectious disease

· D - malignant disease

complications

Opportunistic infection

· pneumocystis carinii

· Mycobacterium avium complex

· toxoplasmosis

· cryptococcal meningitis

Malignant disease

· Kaposi sarcoma

· non Hodgkin’s lymphoma

· primary CNS lymphoma

Bacterial infection

· increased susceptibility

· most common organisms

· Staph aureus

· Strep pneumoniae

· E coli

· most common infections

· pneumonia

· central line phlebitis

· celllitis

· UTI

· usually benign appearance

· not febrile

· not septic

Musculoskeletal disease

Polyarthralgia

· similar to that seen in other viral diseases

· self-limiting

Septic arthritis

· prone to joint sepsis

· may be due to

· conventional organisms

· opportunistic infections

Reiter’s syndrome

· classical presentation

Psoriatic arthritis

· similar pattern to HIV-negative patients

Polymyositis

· proximal muscle weakness

· myalgia

· elevated serum CK

diagnosis

· window period

· time from infection to time antibody test becomes positive

· usually 2-6 weeks

· up to 6 months considered for safety

· antibody tests

· ELISA test (sensitive but not specific)

· Western Blot Test (specific)

surgery

Effect of surgery on patient

Complications

· some risks with HIV infection

· increased risk with AIDS

· problems due to

· impaired defences to common surgical pathogens

· delayed wound healing

· risks are

· increased morbidity of sepsis and wound problems

· increased mortality secondary to these and to generalised poor state

Effect on disease progression

· no evidence that surgery accelerates disease progression

Recommendations

Procedure

· need to assess risk/benefit ratio

· increased risks of death, sepsis and wound problems

· decreased benefits with limited longevity and decreased function

Indicators

· factors that correspond with outcome risk are

1. low CD4 level

· < 100

2. anergy

· decreased delayed hypersensitivity response to skin test with mumps and tetanus

3. thrombocytopaenia

· < 60 000

4. leucopaenia

· PMNs < 1 000

5. low serum albumin

· < 25 g/l

6. AIDS-relaed conditions

· opportunistic infection

· neoplasm

Preparation

· granulocyte-stimulating factor

· platelet transfusion

· treatment of opportunistic infection

· vaccination against measles, mumps and rubella

· stop marrow-suppressing AIDS treatment