A 4-fold increase has been used to support the diagnosis of subclinical herpes zoster (zoster sine herpete). However, a rising titer secondary to viral exposure rather than reactivation cannot be ruled out.Imaging studies:
Magnetic resonance imaging lesions attributable to herpes zoster were seen in the brain stem and cervical cord in 56% (9/16) of patients. At three months after onset of herpes zoster, 56% (5/9) of patients with an abnormal magnetic resonance image had developed postherpetic neuralgia. Of the seven patients who had no herpes-zoster-related lesions on the magnetic resonance image, none had residual pain. Prevention
Primary prevention
In 1995, the Food and Drug Administration (FDA) approved the Varicella vaccine to prevent chickenpox. Its effect on postherpetic neuralgia is still unknown. The vaccine—made from a weakened form of the varicella-zoster virus—may keep chickenpox from occurring in nonimmune children and adults, or at least lessen the risk of the varicella zoster virus lying dormant in the body and reactivating later as shingles. If shingles could be prevented, postherpetic neuralgia could be completely avoided.In May 2006 the Advisory Committee on Immunization Practices approved a new vaccine by Merck (Zostavax) against shingles. This vaccine is a more potent version of the chickenpox vaccine, and evidence shows that it reduces the incidence of postherpetic neuralgia. The CDC recommends use of this vaccine in all persons over 60 years old.The most effective means of preventing PHN from a herpes zoster infection is prior vaccination with the varicella vaccine.
Extrapulmonary tuberculosis is tuberculosis (TB) within a location in the body other than the lungs. It accounts for an increasing fraction of active cases, from 20 to 40% according to published reports, and causes other kinds of TB. These are collectively denoted as "extrapulmonary tuberculosis". Extrapulmonary TB occurs more commonly in immunosuppressed persons and young children. In those with HIV, this occurs in more than 50% of cases. Notable extrapulmonary infection sites include the pleura (in tuberculous pleurisy), the central nervous system (in tuberculous meningitis), the lymphatic system (in scrofula of the neck), the genitourinary system (in urogenital tuberculosis), and the bones and joints (in Pott disease of the spine), among others. Infection of the lymph nodes, known as tubercular lymphadenitis, is the most common extrapulmonary form of tuberculosis. An ulcer originating from nearby infected lymph nodes may occur and is painless. It typically enlarges slowly and has an appearance of "wash leather". When it spreads to the bones, it is known as skeletal tuberculosis, a form of osteomyelitis. Tuberculosis has been present in humans since ancient times.Central nervous system infections include tuberculous meningitis, intracranial tuberculomas, and spinal tuberculous arachnoiditis.Abdominal infections include gastrointestinal tuberculosis (which is important to distinguish from Crohns disease, since immunosuppressive therapy used for the latter can lead to dissemination), tuberculous peritonitis, and genitourinary tuberculosis.A potentially more serious, widespread form of TB is called "disseminated tuberculosis", also known as miliary tuberculosis. Miliary TB currently makes up about 10% of extrapulmonary cases.