Skip to Main Content

++

Introduction

++

In its beginning the malady is easier to cure but difficult to detect, but later it becomes easy to detect but difficult to cure.

Niccolò Machiavelli (1469–1527), On Tuberculosis

++

Bacterial infections can present diagnostic brain-teasers, and a high index of suspicion is needed to pinpoint the diagnosis. Many are rarely encountered, thus making diagnosis more difficult yet demanding vigilance and clinical flexibility.

++

The list includes:

++

  • tuberculosis

  • infective endocarditis

  • syphilis

  • septicaemia

  • the zoonoses (e.g. brucellosis, Lyme disease)

  • clostridial infections: tetanus, gas gangrene, puerperal infection, botulism, pseudomembranous colitis

  • hidden suppuration: abscess, osteomyelitis

  • mycoplasma infections: atypical pneumonia

  • Chlamydia infections: psittacosis, non-specific arthritis, pelvic inflammatory disease, trachoma, atypical pneumonia

  • legionnaire disease

  • Hansen disease

++

Chlamydia and rickettsial organisms have been confirmed as being small bacterial organisms.

++
Tuberculosis
++

Tuberculosis (TB), caused by Mycobacterium tuberculosis, still has a worldwide distribution with a very high prevalence in Asian countries where 60–80% of children below the age of 14 years are affected.1 This has special implication in Australia, where large numbers of Asian migrants are settling. The WHO estimates that one-third of the world's population is infected by the tubercle bacillus. It remains a deadly disease with about 2 million people worldwide dying of TB every year and 8 million new cases a year.

++ Clinical features
++

TB can be a mimic of other diseases and a high level of suspicion is necessary to consider the diagnosis, especially if there are only extrapulmonary manifestations. There may be no symptoms or signs, even in advanced disease. Ideally patients should be referred early for specialist management.

++

Diagnostic triad

DxT malaise + cough + weight loss ± fever/night sweats (± erythema nodosum) pulmonary TB

++
Primary infection
++

The primary infection usually involves the lungs. Transmission is by droplet infection. The focus is usually subpleural in the upper to mid zones and is almost always accompanied by lymph node involvement.

++

Erythema nodosum may accompany the primary infection (see FIG. 29.1). Primary TB is symptomless in most cases although there may be a vague, ‘not feeling well’ illness associated with a cough. In most people this pulmonary focus heals but leaves some surviving tubercle bacilli, even if it becomes calcified (the Ghon focus).

++
FIGURE 29.1

Classic erythema nodosum involving the legs of a patient with pulmonary tuberculosis

Graphic Jump Location
++
Progressive primary tuberculosis
++

If the immune response is inadequate, progressive primary TB develops, with constitutional and pulmonary symptoms. Rarely, haematogenous spread can occur to the lungs (‘miliary tuberculosis'), to the pleural space (tuberculosis pleural effusion) or to extrapulmonary sites such as the meninges and bone.

++
Latent TB infection (LTBI)
...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

Murtagh Collection Full Site: One-Year Subscription

Connect to a suite of general practice resources from one of the most influential authors in the field. Learn the breadth of general practice, including up-to-date information on diagnosis and treatment, as well as key clinical skills like communication.

$145 USD
Buy Now

Pay Per View: Timed Access to all of Murtagh Collection

48 Hour Subscription $34.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.