Hepatitis B

Hepatitis B

David J Mutimer, MBBS, MD, FRCP; Ye Htun Oo, MBBS, PhD, MRCP

atitis B virus (HBV) infection is a global health problem. Around 400 million people are chronically infected with HBV, which is a major cause of liver cirrhosis and liver failure. The interaction between the virus and host immune responses defines the clinical course of infection. The natural history of HBV is not linear, and the clinical spectrum varies from an asymptomatic carrier state to fulminant hepatic failure. Immunization programmes have resulted in a dramatic decline in the incidence and prevalence of chronic hepatitis B infection in many countries. For those with infection, the timing of treatment and the choice of antiviral therapy depend on the patient profile. The main goal of antiviral therapy is to prevent liver cirrhosis. Antiviral treatment is with interferon or nucleoside analogues. Nucleoside analogues are potent oral antiviral drugs that can suppress viral replication to undetectable levels. However, the viral genome can persist in hepatocytes despite sustained and potent suppression. For selected patients with decompensated liver cirrhosis, liver transplantation may be appropriate.

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Getting to know your dermatology drugs

Getting to know your dermatology drugs

Retinoids

The term vitamin A refers to a group of compounds that are necessary for cellular differentiation, organ development and production of the visual pigment in the retina. These compounds also influence immune function and have some anti-inflammatory activity. Except in the retina, the main active form is probably all-trans retinoic acid (tretinoin), the level of which in the cell is dependent on complex interconversions with closely related analogues and various binding and storage proteins. Retinoic acid receptor (RAR) subtypes mediate its effects. There are other receptors, eg retinoic acid receptor (RXR), which bind an isomer, 9-cis retinoic acid. This incompletely understood system is utilised therapeutically by administration of the following agents generically termed retinoids.

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Hair disorders

Hair disorders

The way a person looks is very much influenced by their hair and hairstyle. For many people self-esteem is closely linked to physical appearance and the loss of hair may have a profound affect on a person’s sense of wellbeing. The perceived loss of attractiveness in part explains the anxiety many patients, in particular female patients, feel when they lose their hair. Effective management of patients with a disorder of their hair requires an understanding of the social and cultural importance of hair as well as the anxiety the patient feels. There are numerous disorders that can affect the hair and the diagnosis and management of these conditions can be complex.

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Genital (reproductive) tract infections

Genital (reproductive) tract infections

Balanitis

Inflammation of the glans penis is rare in circumcised males and should be referred for specialist advice. In prepubertal boys, Streptococcus pyogenes is commonly cultured from skin swabs taken when the foreskin is retracted. In adults, bacterial causes are less common than Candida albicans.

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