The histopathology of drugs of abuse.

The use of drugs for recreational purposes is widespread. The drugs used can be divided into groups including stimulants (cocaine, amphetamines, etc.), opiates and opioids (heroin, oxycodone, methadone, fentanyl, etc.), sedatives (benzodiazepines and related substances) and miscellaneous drugs, including ketamine and cannabis (marijuana). These drugs can have profound effects on all organ systems in the body. The method of administration, whether by injection or inhalation, can cause localized and systemic effects, including the transmission of infection and granulomata at the site of injection and in the lungs. Suppurative abscesses from injection can result in systemic amyloidosis. Stimulants have profound effects on the cardiovascular and cerebrovascular systems, with enlarged hearts with fibrosis seen microscopically and cerebral infarction and haemorrhage. Crack cocaine use is also associated with changes in the pulmonary system, including carbon pigmented intra-alveolar macrophages, emphysema and pulmonary arterial changes. Cannabis use is associated with brown pigmented macrophages in the lung as well as changes in the respiratory tract epithelium. Opiates/opioids are associated with inhalational pneumonitis and hypoxic brain damage due to their respiratory depressant effects. Heroin use has been associated with focal segmental glomerulonephritis (heroin-associated nephropathy: HAN). 3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) use is associated with changes in the cardiovascular system. Its use can lead to hyperpyrexia, which results in systemic changes. Ketamine abuse has been associated with cystitis. Drugs of abuse may affect testicular function. In analysing the effects of drugs at autopsy a systematic approach to sampling of histology is required.