Assess any injuries and ongoing safety and support. Emergency accommodation may be needed if the victim's home is not safe. A brief history of when and where the assault took place, who put what where, and contraception or condom use will inform immediate treatment.

Ask whether the victim wants to report the assault to the police. Early referral to a sexual assault service assists forensic testing. A forensic assessment involves careful documentation of injuries and testing for the presence of foreign DNA; the findings are compiled in a court medicolegal report. Even if the victim is unsure about wanting to report the assault, if there is any possibility of a complaint being made forensic assessment will preserve evidence in case a formal report is made to police at a later date. Ask about the possibility of drug-assisted rape, which is becoming increasingly common worldwide.14 Early forensic referral may facilitate detection of commonly used drugs (eg, flunitrazepam, ketamine) in the victim's blood or urine. Testing must be performed in a police laboratory to preserve continuity of court evidence. If the patient keeps a spot urine specimen, this can be handed directly to the police.

A thorough general and genital examination should be performed and any injuries documented. Although most sexual assault services use speculums for examining women, this depends on both the woman (comfort versus her need to know all is normal) and the practitioner (expertise and requirement for testing), and should be discussed with the woman before examination. Similarly, the use of a proctoscope may be required. Victims are often afraid that there has been genital damage which will make it obvious to others that they have been raped. Feedback that everything looks normal, as is usually the case,15 can be very reassuring.

Tests for forensic purposes, sexually transmissible infections and pregnancy are performed according to need. If a woman is being transferred to a sexual assault service for forensic assessment after unprotected vaginal rape, the initial dose of the emergency contraceptive pill should be given first.

Forensics: If the victim is willing for the police to be involved, he or she should be referred immediately to an expert sexual assault service for forensic assessment (a list is provided at the end of this article). If a victim is undecided about reporting the assault, forensic specimens may be stored while a formal complaint is considered.

DNA evidence left on or in the body of a victim, particularly in moist areas, degrades quickly over 2–10 days.16,17 Therefore, forensic assessments need to be made as soon as possible, but within 10 days of an assault. If proceeding to a forensic assessment, advise victims not to shower (or to clean their teeth or rinse their mouths if the assault was oral), and ensure all clothes worn during the assault remain unwashed. As DNA evidence degrades quickly if moist, ask the victim to store underclothes worn during the assault in paper (not plastic) bags.

In remote areas, timely expert forensic assessment is difficult. Most sexual assault services provide 24-hour phone assistance by doctors experienced in forensic medicine to discuss assessment. After discussion, some practitioners in remote areas may decide to perform forensic assessments, but this can be a difficult decision, as the practitioner may later be required to give evidence in court. Sexual assault services in Western Australia suggest a compromise solution that entails wiping the victim's vulval and/or anal area with sterile gauze, air-drying it, putting it into a labelled sterile container and handing it directly to local police for forensic testing before the victim's transfer for forensic assessment.18

Pregnancy risk: Depending on the victim's contraceptive and menstrual history, testing urine or serum might be useful to direct therapy and follow-up.

Sexually transmissible infections: Baseline testing of sexual assault victims for sexually transmissible infections (STIs) in Australia varies with local clinical practice. In some Queensland sexual assault services serum is held in case STI testing is requested or required later (M Mobbs, Visiting Medical Officer, Brisbane Sexual Assault Service, personal communication). Baseline testing usually occurs in sexual assault services and communities with known high STI risk. As victims of sexual assault have higher rates of STIs compared with the general population,19 opportunistic screening is worthwhile if follow-up can be organised. Under Australian law, a rape victim's sexual history is inadmissible in court and this includes any history of STI. Thus, possible court prejudice is not a reason to withhold testing. See Box 4 for screening test recommendations. Note PAP smears are not generally included.

The HIV/STI status of the perpetrator is usually unknown. In the absence of any better indicators, ethnicity or culture is sometimes used as a proxy for HIV/STI risk. The purpose of this judgement of risk is not to vilify minority groups, but to assess the victim's risk of infection on the basis of often very limited information about the perpetrator. Treatment recommendations alter for victims assaulted by anyone thought to be from a high risk group (see Box 5).

The National HIV/AIDS Strategy states that community prevalence of HIV and STIs is higher in certain groups, including African and South-East Asian people, homosexual and bisexual men, and injecting drug users.21 Rates of STI are high in northern Australia, including in Indigenous communities,22,23 while HIV prevalence is higher in inner Sydney than elsewhere in Australia.24 As the risk of sexual transmission of hepatitis C virus (HCV) is low,25 tests are usually only performed in high risk situations (eg, assault with bleeding injuries, or assault by known HCV-positive assailant).

Although the risk of HIV from one act of unprotected intercourse is very small, if the assault was penetrative unprotected vaginal or anal rape victims should be advised to use condoms until follow-up testing at three months. Most victims are concerned about HIV risk, even though they may not admit it.7 The vast majority will not require HIV prophylaxis, as the risk of transmission from an HIV-positive assailant is very small (see Box 6) and the chance that the perpetrator was HIV positive far smaller.

Sexual assault is a frightening and sometimes life-threatening violent experience and counselling should be offered to all. Even if victims do not wish to attend counselling, it is important that they know where they can go for help, as memories can surface later (eg, at first childbirth) and can impair future functioning.27 Family and partners may also require counselling, or referral may be needed for domestic violence issues. Safety after rape can require moving house if the rapist lives with the victim, or knows where he or she lives. Emergency housing may be needed, as may other forms of immediate support, such as certificates for absence from work and support letters for school.

If the assault was unprotected vaginal rape, or if there was any possibility that this occurred (eg, victim lost consciousness, was intoxicated or is unsure), then emergency contraception can be offered up to three, and possibly up to five, days after the assault.28 The progesterone-only regimen is recommended over the Yuzpe method because it is more effective with fewer side effects. Give the first dose as soon as possible, as efficacy halves with each 12-hour interval after the assault.29

Progesterone-only method: 750 μg levonorgestrel orally; repeat 12 hours later. A 750 μg tablet (Postinor-2, Schering Pty Ltd) is now available in Australia, or 25 30-μg tablets (Microval, Wyeth Australia Pty Ltd; or Microlut, Schering Pty Ltd) can be used for each dose.

Yuzpe method: 100 μg oestradiol orally; repeat 12 hours later. Use two 50-μg oestrogen-containing combined oral contraceptive tablets for each dose. This regimen should only be used if the progesterone-only method is not tolerated or unavailable.

For unprotected vaginal or anal assault, victims are offered single-dose prophylaxis with azithromycin for chlamydia (see Box 5). They are also offered prophylactic hepatitis B vaccine if likely to be non-immune.

Treatment varies according to community prevalence of STIs and perceived individual risk. In tropical areas of Australia, or if the perpetrator is considered at high risk of being infected, prophylaxis may also be added for gonorrhoea, occasionally syphilis, and passive vaccination with hepatitis B immune globulin30 may also be given if the recipient is not immune.

For victims at high risk of having acquired HIV infection (eg, rape by someone from an area of high HIV prevalence), urgent phone consultation with an infectious diseases or sexual health physician about post-exposure prophylaxis for HIV is recommended (see Box 7).