INJECTION DRUG USERS
Category: Emergency Medicine
Abstract : Injection Drug Users The practice of injection drug use and the lifestyle of the injection drug user (injection drug user), place the indivinjection drug useral at risk for a wide variety of infectious and noninfectious complications. In addition to an increased risk of the human immunodeficiency virus (HIV), hepatitis, and sexually transmitted diseases, the injection drug user's lifestyle is a
Injection Drug Users
The practice of injection drug use and the lifestyle of the injection drug user (injection drug user), place the indivinjection drug useral at risk for a wide variety of infectious and noninfectious complications. In addition to an increased risk of the human immunodeficiency virus (HIV), hepatitis, and sexually transmitted diseases, the injection drug user's lifestyle is also associated with an increased risk of trauma.
The high incidence of homelessness, nutritional deficiencies, smoking and alcohol use, and mental illness further compromise this population's health.
Approximately 2.4 million indivinjection drug userals in the United States have used heroin at some point in their lives, with nearly 130,000 having used it within the past 30 days. The ED is a common point of entry to health care for many injection drug users, with an estimated 14 percent of all drug-related ED episodes involving heroin. Between 1991 and 1996, heroin-related ED episodes more than doubled (from 35,898 to 73,846) and in youths aged 12 to 17 years, heroin-related episodes nearly quadrupled. To adequately evaluate injection drug users, health care providers should be aware of the drugs used in their catchment area as well as their street names.
Patients should be asked about drug type(s) and amount, preparation of materials for injection (e.g., licking needles or use of saliva or tap/toilet water for drug reconstitution), reuse of needles, needle sharing, use of antibiotics, and coincident illness. Socioeconomic issues such as the injection drug user's ability to purchase medications and return for follow-up should also be addressed when making dispositions. The injection drug user should receive nonjudgmental instruction in measures to reduce the risk of complications and infections. Finally, drug rehabilitation (even as a referral) should always be offered.
Pathophysiology
In addition to placing patients at greater risk for immunocompromising infections such as HIV and hepatitis, injection drug user itself has been associated with immune dysfunction. Exaggerated and atypical lymphocytosis, diminished lymphocyte responsiveness to mitogenic stimulation, hypergammaglobulinemia, increased opsonin production, high levels of circulating immune complexes, and reticuloendothelial abnormalities, have been found. Because of this immune stimulation, false-positive syphilis serology, positive Coombs tests, and thrombotic thrombocytopenic purpura have all been described in this population. Given immune dysfunction, febrile injection drug users should be suspected of having infections, even when the fever is low grade and with normal/near-normal white blood counts and erythrocyte sedimentation rates.
Fever
Fever is part of the presenting complaint in the majority of ED visits by injection drug users and is associated with infection in more than two-thirds of patients.4 Prospective studies of febrile injection drug users have found bacteremia in up to 42 percent, pneumonia in 26 to 38 percent, and endocarditis in up to 13 percent of patients. Neither clinical judgment nor derived predictive rules were reliable in identifying those with serious underlying causes of fever.
Noninfectious causes of fever include acute toxic reactions to substances of abuse, reactions to injected adulterants, and withdrawal syndromes. Cocaine and amphetamines can cause fevers acutely, occasionally in excess of 40°C (104°F). Adulterants used to dilute active substances may also cause dramatic febrile reactions accompanied by alteration in mental status and leukocytosis. One syndrome known as "cotton fever" is associated with the use of cotton balls as filters for drug suspensions.
Patients with cotton fever develop a flulike syndrome within hours after injection. Physical findings may include tachypnea, tachycardia, abdominal pain, and inflammatory retinal nodules. Chest radiographs are typically normal, but may demonstrate inflammatory pulmonary granulomata. This syndrome spontaneously resolves within 24 h. While the cause remains unclear, it has been proposed that the acute symptoms are caused by either endotoxin from gram-negative rods introduced by injection or by the pyrogenic effect of injected cotton particulate matter. Patients withdrawing from barbiturates or heroin also may appear acutely ill, with chest and abdominal pain, diaphoresis, tachycardia, and fever.
Because no reliable markers are available to exclude serious illness in the febrile injection drug user, common practice has been to obtain blood cultures and admit such patients for observation, awaiting culture results. In clinically well patients for whom follow-up can be ensured, outpatient evaluation is reasonable as long as an adequate cultures are obtained.
Dyspnea
A wide range of both infectious and noninfectious causes may produce dyspnea and cough in injection drug users. Pneumonia in injection drug users is typically community-acquired. However, other infectious causes for dyspnea include opportunistic infections and septic pulmonary emboli from right-sided endocarditis. The febrile injection drug user presenting with dyspnea, cough, or an abnormal chest radiograph should be placed in respiratory isolation until tuberculosis has been excluded and/or an alternative diagnosis is found.
Noninfectious causes of dyspnea include pneumothorax, hemothorax, toxic reactions to injected substances, and hypersensitivity reaction. Pneumo- and hemothorax are seen most commonly with the practice of "pocket shooting," when drug users inject into veins in the supraclavicular fossa to access the subclavian, jugular, or brachiocephalic vein. Talc lung is a syndrome of progressive respiratory distress and diffuse interstitial infiltrates caused by the injection of the adulterant talc.
Hypersensitivity reactions, associated with both heroin and cocaine injection, present with cough and wheezing and typically respond to inhaled -agonist therapy. Noncardiogenic pulmonary edema is associated with both heroin and cocaine use. Patients may complain of dyspnea or have a low pulse oximetry reading, with the chest radiograph revealing diffuse alveolar infiltrates; treatment is supportive. Finally, septic, air, or needle fragment emboli can produce dyspnea.
Altered Mental Status
Drug intoxication or withdrawal, stroke syndromes, hypoxia, delayed leukoencephalopathy, infectious diseases, mycotic aneurysms, and secondary trauma from either loss of consciousness and fall or drug-related violence may all cause altered mental status in the injection drug user. Central nervous system (CNS) infections may be a result of embolic complications of distant infections (e.g., endocarditis) or of extensions of local infections (e.g., vertebral osteomyelitis). Infections commonly seen in this population include epinjection drug userral abscess, bacterial and fungal meningitis, and brain abscess. Meningococcus, pneumococcus, and Staphylococcus aureus spreading from a primary endocarditis are the common causes for bacterial meningitis. Opportunistic organisms are common in the patient with coincident HIV infection.
Stroke syndromes may be secondary to low-flow states during heroin intoxication, hypertensive hemorrhage from amphetamines, phencyclidine, or cocaine, and embolized vegetations from infectious endocarditis. Delayed leukoencephalopathies, both hypoxic and nonhypoxic, have been reported in injection drug users, but are rare.
Back Pain
Back pain may be the result of an epinjection drug userral abscess, vertebral osteomyelitis, or complications from trauma. In patients with coincident HIV, opportunistic infections may present with a more indolent course. Nontraumatic focal back pain usually requires imagining studies such as computed tomography (CT) and magnetic resonance imaging (MRI) to evaluate for possible infection.
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