Description of specialty

The specialty of infectious diseases and tropical medicine encompasses the diagnosis and treatment of people with a wide variety of infections, only some of which are ‘infectious’ in the commonly understood sense of the word. Previously associated with fever hospitals, infectious diseases units are now fully integrated into the general, acute hospital and closely allied with acute medical specialties.

Physicians in the specialty help hospitals deal with problems relating to healthcare-associated infections and, at the same time, are at the forefront of efforts to recognise and contain emerging infections like the Ebola virus and pandemic influenza. The specialty is also involved in providing travel medicine advice for people visiting the tropics and for assessing travellers returning to the UK with health problems. Most infectious diseases physicians are actively engaged in research and other academic activities.

Acute admissions

Most inpatients arrive from the community as acute admissions to infectious diseases wards. A variety of conditions such as gastroenteritis, bacterial pneumonia, meningitis, skin and soft tissue infections are managed in addition to more complex conditions such as HIV, malaria and tuberculosis. Although a proportion of patients may present with infections, they may end up with a non-infective diagnosis, such as connective tissue disease or malignancy.

Due to the nature of the diseases dealt with, infectious diseases physicians see a large number of vulnerable patients, such as asylum seekers and recent immigrants, homeless people, injecting drug users and overseas visitors. The majority of acute admissions come from GPs or the emergency department. Others may be referred from other hospital services or admitted as tertiary referrals from outlying hospitals. A few, such as people with HIV, may self-refer. Some of the more vulnerable patients may be referred by social services, the voluntary sector or prisons.

Immunosuppressed patients

In addition to treating patients with community-acquired infections such as pneumonia, pyelonephritis and cellulitis, the specialty is increasingly involved in managing the infective complications of a growing number of immunosuppressed patients. Advances in treatments for cancer and autoimmune diseases mean that more patients survive but are prone to infections, many of which are unusual. 

Over the past two decades HIV infections have increased substantially. New patients continue to present late with infectious complications of HIV and these can be complex to manage. In addition, the welcome success of antiretroviral therapy (ART) has dramatically increased survival in patients with HIV, so the numbers seen in the clinic continue to increase, putting pressure on services. Many infectious diseases physicians treat increasing numbers of hepatitis virus-infected patients (hepatitis B and C). At the same time, increasing problems with antibiotic resistance are changing the face of healthcare-associated infection. The specialty has to cope with the problems of methicillin-resistant Staphylococcus aureus (MRSA) and new strains of Clostridium difficile, as well as multidrug-resistant Gram-negative infections and resistant tuberculosis. Finally, increasing numbers of travellers from the UK and migrants to the UK increase the number of tropical infections such as malaria, that are imported.