Isolates that are multi-resistant to any other combination of anti-TB drugs but not to INH and RMP are not classed as MDR-TB. As of Oct 2006, "Extensively drug-resistant tuberculosis" (XDR-TB) is defined as MDR-TB that is resistant to quinolones and also to any one of kanamycin, capreomycin, or amikacin. The old case definition of XDR-TB is MDR-TB that is also resistant to three or more of the six classes of second-line drugs. This definition should no longer be used, but is included here because many older publications refer to it. The principles of treatment for MDR-TB and for XDR-TB are the same. The main difference is that XDR-TB is associated with a much higher mortality rate than MDR-TB, because of a reduced number of effective treatment options. The epidemiology of XDR-TB is currently not well studied, but it is believed that XDR-TB does not transmit easily in healthy populations, but is capable of causing epidemics in populations which are already stricken by HIV and therefore more susceptible to TB infection. Epidemiology of drug-resistant TB
A 1997 survey of 35 countries found rates above 2% in about a third of the countries surveyed. The highest rates of drug-resistant TB were in the former USSR, the Baltic states, Argentina, India and China, and was associated with poor or failing national Tuberculosis Control programmes.
Alport syndrome is a genetic disorder affecting around 1 in 5,000-10,000 children, characterized by glomerulonephritis, end-stage kidney disease, and hearing loss. Alport syndrome can also affect the eyes, though the changes do not usually affect vision, except when changes to the lens occur in later life. Blood in urine is universal. Proteinuria is a feature as kidney disease progresses.The disorder was first identified in a British family by the physician Cecil A. Alport in 1927. Alport syndrome once also had the label hereditary nephritis, but this is misleading as there are many other causes of hereditary kidney disease and nephritis. Alport syndrome is caused by an inherited defect in type IV collagen—a structural material that is needed for the normal function of different parts of the body. Since type IV collagen is found in the ears, eyes, and kidneys, this explains why Alport syndrome affects different seemingly unrelated parts of the body (ears, eyes, kidneys, etc.). Depending on where the mutation is located in the genome, Alport syndrome can present itself in many forms. This includes X-linked Alport syndrome (XLAS), autosomal recessive Alport syndrome (ARAS), and autosomal dominant Alport syndrome (ADAS). Signs and symptoms
These descriptions refer to classic Alport syndrome, which usually causes significant disease from young adult or late childhood life. Some individuals, usually with milder mutations or carrier status, develop disease later, or show only some of the features of classic disease. Chronic kidney disease
Blood in urine is a usual feature of Alport syndrome from early infancy, identifiable on urine dipsticks.