Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Leprosy is caused mainly by Mycobacterium leprae, a rod-shaped bacillus that is an
obligate intracellular (only grows inside of certain human and animal cells)
bacterium. M. leprae is termed an "acid fast" bacterium because of its chemical
characteristics. When special stains are used for microscopic analysis, it
stains red on a blue background due to mycolic acid content in its cell walls.
The Ziehl-Neelsen stain is an example of the special staining techniques used to
view the acid-fast organisms under the microscope.
Currently, the organisms cannot be cultured on artificial media. The bacteria
take an extremely long time to reproduce inside of cells (about 12-14 days as
compared to minutes to hours for most bacteria). The bacteria grow best at
80.9 F-86 F, so cooler areas of the body tend to develop the infection. The bacteria
grow very well in the body's macrophages and Schwann cells (cells that cover and
protect nerve axons). M. leprae is genetically related to M. tuberculosis (the
type of bacteria that cause tuberculosis) and other mycobacteria that infect
humans. As with malaria, patients with leprosy produce anti-endothelial
antibodies (antibodies against the lining tissues of blood vessels), but the
role of these antibodies in these diseases is still under investigation.
In 2009, investigators discovered a new Mycobacterium species, M. lepromatosis, which causes diffuse disease (lepromatous leprosy). This new species (determined by genetic analysis) was found in patients located in Mexico and the Caribbean islands.
What are leprosy symptoms and signs?
Unfortunately, the early signs and symptoms of leprosy are very subtle and occur slowly (usually over years). The symptoms are similar to those that may occur with
syphilis, tetanus, and leptospirosis. Numbness and loss of temperature sensation (cannot sense very hot or cold temperatures) are some of the first symptoms that patients experience. As the disease progresses, the sensations of touch, then pain, and eventually deep pressure are decreased or lost. Signs that occur, such as relatively painless ulcers, skin lesions of hypopigmented macules (flat, pale areas of skin), and eye damage (dryness, reduced blinking) are experienced before the large ulcerations, loss of digits, and facial disfigurement develop. This long-term developing sequence of events begins and continues on the cooler areas of the body (for example, hands, feet, face, and knees).
Foot pain may be caused by injuries (sprains, strains, bruises, and fractures), diseases (diabetes, Hansen disease, and gout), viruses, fungi, and bacteria (plantar warts and athlete's foot), or even ingrown toenails. Pain and tenderness may be accompanied by joint looseness, swelling, weakness, discoloration, and loss of function. Minor foot pain can usually be treated with rest, ice, compression, and elevation and OTC medications such as acetaminophen and ibuprofen. Severe pain should be treated by a medical professional.
There are many causes of scalp hair loss. This featured article covers the common ones such as patchy hair loss (alopecia areata, trichotillomania, and tinea capitis), telogen effluvium, and androgenetic alopecia (male-pattern baldness, female-pattern baldness).
Alopecia areata is a condition that causes hair loss on the scalp and sometimes other parts of the body. It is believed to be caused by an abnormality of the immune system that causes the body's immune system to attack the hair follicles. Typically, hair regrows within a year without treatment. Steroid injections, creams, and shampoos may be used during treatment.
Travelers should prepare for their trip by visiting their physician to get the proper vaccinations and obtain the necessary medication if they have a medical condition or chronic disease. Diseases that travelers may pick up from contaminated water or food, insect or animal bites, or from other people include malaria, meningococcal meningitis, yellow fever, hepatitis A, typhoid fever, polio, and cholera.
Aseptic necrosis (avascular necrosis or osteonecrosis) is a condition that develops when blood supply diminishes to an area of bone and causes bone death. Though aseptic necrosis may be painless, pain is often associated when the degenerating bone is used. If caught early, aseptic necrosis may be treated by grafting new bone into the degenerating area. In later stages, joint replacement surgery may be required.
Blindness is the state of being sightless. Causes of blindness include macular degeneration, stroke, cataract, glaucoma, infection and trauma. Symptoms and signs may include eye pain, eye discharge, or the cornea or pupil turning white. Treatment of blindness depends upon the cause of the blindness.
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