INTRODUCTION: INJECTION USE IN THE UNITED STATES
An estimated 424,000 persons in the United States, aged 12 or older, injected heroin, cocaine, methamphetamines or other stimulants during 2005.1 These needles and syringes are usually shared with other injection drug users,which may result in the transmission of infectious diseases and skin and bone infections.
This article is designed to increase knowledge among healthcare professionals about the common diseases which may be acquired through injection drug use (IDU), and the screening and patient education that could reduce the transmission of disease among individuals who inject drugs.
Injection Drug Use
In an era when disease prevention is an integral part of primary care medicine, a significant, but often overlooked concept is the epidemiologic impact of injection drug use on the spread of deadly diseases. Morbidity and mortality among injection drug users results either from infection introduced through the process of injection, from contaminants added to the drug mixture, from sequelae of the drug usage itself, from drug overdose, or from violence associated with drug use.
To appreciate the depth of impact beyond the drug user, one must examine and understand the injection drug culture. For the IDU, the daily focus is the acquisition and use of their drug of choice. Although illicit drugs may be introduced into the body orally or nasally, for many persons the preferred method is injection. The term injection drug use (IDU) encompasses three routes: intravenous (IV), subcutaneous and intramuscular.
The intravenous route (“mainlining”) is often preferred, because this is the fastest way to achieve the desired response from the drug. The IV route is most popular because when a bolus of drug is introduced into the vein, the user experiences a rapid and powerful euphoria. On the average, the desired response can be achieved within 15-30 seconds, compared to intranasal use, which produces the desired effects within 3-5 minutes.2
When injecting, if the vein is missed or if the vein cannot be penetrated because of excessive venous destruction, the drug may be injected under the skin, or subcutaneously (“skin popping”), or inside the muscle, or intramuscularly (“muscling”). Injection drug users may inject themselves or have someone else inject them. As needle possession is illegal in most states, and clean syringes are not available legally to those without medical prescriptions, there is a high probability that users will share equipment. This substantially increases the transmission of infectious diseases and skin and bone infections.3
An estimated 424,000 persons in the United States aged 12 or older injected heroin, cocaine, methamphetamines, or other stimulants during 2005.1 Unfortunately, the injecting drug user may transmit Infectious diseases through syringe/needle sharing or sexual transmission. Pregnant women can transmit HIV and other infectious diseases through perinatal transmission. Preventing both the acquisition and transmission of diseases becomes paramount in providing medical care for this patient population.
Infectious Disease: HIV, Hepatitis C and B
Injection drug use greatly enhances the introduction of pathogens and various other contaminants into the body through needle sharing or lack of sterile preparation and injection techniques. Skin infection, bone infections, systemic bacterial infections and hepatitis B and C are just a few of the diseases caused or transmitted by IDU.
Injection drug use has been clearly demonstrated to have a strong association, through the sharing of syringes and needles, with transmission of the Human Immunodeficiency Virus (HIV) which leads to Acquired Immune Deficiency Syndrome (AIDS). Data published by the Centers for Disease Control note that 24.6% of 478,488 persons living with HIV/AIDS in 2005 in the United States were identified as having a transmission risk of IDU.4 In New Jersey, 30% of 33,623 persons living with HIV/ AIDS in 2006 were identified as IDU. An additional 1,748 persons were infected with HIV/AIDS by an IDU partner. This included approximately 1,350 women who could potentially transmit the HIV to an unborn child.5
Hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV). For some people, the infection becomes chronic, leading to liver failure, liver cancer, or cirrhosis, a condition that causes permanent scarring of the liver11 and can be transmitted via used syringes/needles. In 2005, a total of 5,494 confirmed acute cases of hepatitis B were identified, and 15% of the patients reported IDU as a risk factor. After accounting for asymptomatic infection and underreporting, approximately 51,000 new infections of hepatitis B occurred in the United States.6 It is estimated that 1.25 million persons in the United States are chronically infected with hepatitis B, and approximately 5,000 persons have died because of chronic liver disease related to hepatitis B.8
Hepatitis C is transmitted via used syringes/ needles which contain the virus. This virus attacks the liver, and patients may have no symptoms. The hepatitis C virus (HCV) causes the liver to become inflamed, which interferes with its ability to function. Over time, hepatitis C infection can lead to liver cancer, liver failure or cirrhosis.6 In 2005, a total of 671 confirmed acute cases of hepatitis C were identified in the United States. The risk factor for this disease was IDU in 50% of the cases. However, after accounting for asymptomatic infection and underreporting, approximately 20,000 new infections may have actually occurred.7 Overall, the prevalence of hepatitis C in the United States is 1.6% (95% CI, 1.3% to 1.9%), equating to an estimated 4.1 million (CI, 3.4 million to 4.9 million) hepatitis C positive persons nationwide. A total of 48.4% of hepatitis C-positive persons between 20 and 59 years of age reported a history of injection drug use, the strongest risk factor for HCV infection.8 An estimated 8,000-10,000 deaths have occurred because of chronic liver disease related to hepatitis C.9 Of note, concurrent infection with hepatitis C and HIV is common in the United States, affecting 15% to 30% of HIV-infected individuals, and resulting in an accelerated sequelae of cirrhosis of the liver and end stage liver disease.10
Skin and soft tissue infections are common infections among injecting drug users, with Staphylococcus aureus (S. aureus), the most common bacterial pathogen for these patients.12 This organism can cause severe infections such as endocarditis and bacteremia. S. aureus is carried in the nose and on the body, and is associated with an increased risk of subsequent S. aureus infections. Patients who are active IDUs have a higher rate of colonization with S.aureus than the general population.15 In a community sample of urban poor residents of San Francisco, 22.8% were colonized with S. aureus, and 12% of the samples were community-acquired methicillin-resistant Staphylococcus aureu (MRSA). The main risk factor for having MRSA was attributed to IDU, with samples from these patients about ten times more likely to have MRSA than non-IDU.14 A cross-sectional study among IDU in San Francisco found that 32% of patients had an abscess or cellulitis15 when they were examined.
Musculoskeletal infections occur in IDU patients as the organism may travel in the blood and be ‘seeded’ in bone, causing osteomyelitis, and septic arthritis. The only symptom may be pain in uncommon places such as the sacroiliac or sternoclavicular joint, and the vertebral spine or knee.16