DISEASES

A. baumannii is an opportunistic bacterium with a range of different diseases, each with their own symptoms. Some possible types of A. baumannii infections include:

• Pneumonia
• Bloodstream Infections
• Meningitis
• Wound and surgical site infections, including flesh eating bacterium necrotizing fasciitis
• Urinary Tract Infections

Symptoms of A. baumannii infections are often indistinguishable from other opportunistic infections caused by other opportunistic bacteria - including Klebsiella pneumoniae and Streptococcus pneumoniae.

Symptoms of A. baumannii infections in turn range from fevers and chills, rash, confusion and/or altered mental states, pain or burning sensations when urinating, strong urge to urinate frequently, sensitivity to bright light, nausea (with or without vomiting), muscle and chest pains, breathing problems, and cough (with or without yellow, green, or bloody mucus). In some cases, A. baumannii may present no infection or symptoms, as with colonizing an open wound or tracheostomy site.

Acne, also known as acne vulgaris, is a long-term skin disease that occurs when hair follicles are clogged with dead skin cells and oil from the skin. It is characterized by blackheads or whiteheads, pimples, oily skin, and possible scarring. It primarily affects areas of the skin with a relatively high number of oil glands, including the face, upper part of the chest, and back. The resulting appearance can lead to anxiety, reduced self-esteem and, in extreme cases, depression or thoughts of suicide.Genetics is thought to be the primary cause of acne in 80% of cases. The role of diet and cigarette smoking is unclear, and neither cleanliness nor exposure to sunlight appear to play a part. In both sexes, hormones called androgens appear to be part of the underlying mechanism. Another frequent factor is excessive growth of the bacterium Propionibacterium acnes, which is normally present on the skin.Many treatment options for acne are available, including lifestyle changes, medications, and medical procedures. Eating fewer simple carbohydrates such as sugar may help. Treatments applied directly to the affected skin, such as azelaic acid, benzoyl peroxide, and salicylic acid, are commonly used. Antibiotics and retinoids are available in formulations that are applied to the skin and taken by mouth for the treatment of acne. However, resistance to antibiotics may develop as a result of antibiotic therapy. Several types of birth control pills help against acne in women. Isotretinoin pills are usually reserved for severe acne due to greater potential side effects. Early and aggressive treatment of acne is advocated by some in the medical community to decrease the overall long-term impact to individuals.In 2015, acne was estimated to affect 633 million people globally, making it the 8th most common disease worldwide. Acne commonly occurs in adolescence and affects an estimated 80–90% of teenagers in the Western world. Lower rates are reported in some rural societies. Children and adults may also be affected before and after puberty. Although acne becomes less common in adulthood, it persists in nearly half of affected people into their twenties and thirties and a smaller group continue to have difficulties into their forties.

Rosacea is a long-term skin condition that typically affects the face. It results in redness, pimples, swelling, and small and superficial dilated blood vessels. Often the nose, cheeks, forehead, and chin are most involved. A red enlarged nose may occur in severe disease, a condition known as rhinophyma.

The cause of rosacea is unknown. Risk factors are believed to include a family history of the condition. Factors that may potentially worsen the condition include heat, exercise, sunlight, cold, spicy food, alcohol, menopause, psychological stress, or steroid cream on the face. Diagnosis is based on symptoms.

While not curable, treatment usually improves symptoms. Treatment is typically with metronidazole, doxycycline, or tetracycline. When the eyes are affected azithromycin eye drops may help. Other treatments with tentative benefit include brimonidine cream, ivermectin cream, and isotretinoin. Dermabrasion or laser surgery may also be used. The use of sunscreen is typically recommended.

Rosacea affects somewhere between one and ten percent of people. Those affected are most often 30 to 50 years old and female. Caucasians are more frequently affected. The condition was described in The Canterbury Tales in the 1300s, and possibly as early as the 200s BCE by Theocritus.

A vestibular schwannoma (VS) is a benign primary intracranial tumor of the myelin-forming cells of the vestibulocochlear nerve (8th cranial nerve). A type of schwannoma, this tumor arises from the Schwann cells responsible for the myelin sheath that helps keep peripheral nerves insulated. Although it is also called an acoustic neuroma, this is a misnomer for two reasons. First, the tumor usually arises from the vestibular division of the vestibulocochlear nerve, rather than the cochlear division. Second, it is derived from the Schwann cells of the associated nerve, rather than the actual neurons (neuromas).Approximately 2,000 to 3,000 cases are diagnosed each year in the United States (6 to 9 per million persons). Comprehensive studies from Denmark published in 2012 showed an annual incidence of 19-23 per million from 2002 to 2008, and over the last 30 years, the reported incidence has been increasing, until the last decade in which an approximation of the true incidence may have been found. Most recent publications suggest that the incidence of vestibular schwannomas has been rising because of advances in MRI scanning. Most cases are diagnosed in people between the ages of 30 and 60, and men and women appear to be affected equally. Most vestibular schwannomas occur spontaneously in those without a family history. One confirmed risk factor is a rare genetic mutation called NF2.The primary symptoms of vestibular schwannoma are unexplained progressive unilateral hearing loss and tinnitus and vestibular (disequilibrium) symptoms. Treatment of the condition is by surgery or radiation and often results in substantial or complete hearing loss in the affected ear. Observation (non-treatment) over time also usually results in hearing loss in the affected ear.

Human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). Following initial infection, a person may not notice any symptoms or may experience a brief period of influenza-like illness. Typically, this is followed by a prolonged period with no symptoms. As the infection progresses, it interferes more with the immune system, increasing the risk of developing common infections such as tuberculosis, as well as other opportunistic infections, and tumors that rarely affect people who have working immune systems. These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS). This stage is often also associated with unintended weight loss.HIV is spread primarily by unprotected sex (including anal and oral sex), contaminated blood transfusions, hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding. Some bodily fluids, such as saliva and tears, do not transmit HIV. Methods of prevention include safe sex, needle exchange programs, treating those who are infected, and male circumcision. Disease in a baby can often be prevented by giving both the mother and child antiretroviral medication. There is no cure or vaccine; however, antiretroviral treatment can slow the course of the disease and may lead to a near-normal life expectancy. Treatment is recommended as soon as the diagnosis is made. Without treatment, the average survival time after infection is 11 years.In 2016, about 36.7 million people were living with HIV and it resulted in 1 million deaths. There were 300,000 fewer new HIV cases in 2016 than in 2015. Most of those infected live in sub-Saharan Africa. From the time AIDS was identified in the early 1980s to 2017, the disease has caused an estimated 35 million deaths worldwide. HIV/AIDS is considered a pandemic—a disease outbreak which is present over a large area and is actively spreading. HIV originated in west-central Africa during the late 19th or early 20th century. AIDS was first recognized by the United States Centers for Disease Control and Prevention (CDC) in 1981 and its cause—HIV infection—was identified in the early part of the decade.HIV/AIDS has had a great impact on society, both as an illness and as a source of discrimination. The disease also has large economic impacts. There are many misconceptions about HIV/AIDS such as the belief that it can be transmitted by casual non-sexual contact. The disease has become subject to many controversies involving religion including the Catholic Church's position not to support condom use as prevention. It has attracted international medical and political attention as well as large-scale funding since it was identified in the 1980s.

Acrylamide is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.

Acrylamide is considered a potential occupational carcinogen by U.S. government agencies and classified as a Group 2A carcinogen by the IARC. The Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health have set dermal occupational exposure limits at 0.03 mg/m³ over an eight-hour workday. In animal models, exposure to acrylamide causes tumors in the adrenal glands, thyroid, lungs, and testes. Acrylamide is easily absorbed by the skin and distributed throughout the organism; the highest levels of acrylamide post-exposure are found in the blood, non-exposed skin, kidneys, liver, testes, and spleen. Acrylamide can be metabolically-activated by cytochrome P450 to a genotoxic metabolite, glycidamide, which is considered to be a critical mode of action to the carcinogenesis of acrylamide. On the other hand, acrylamide and glycidamide can be detoxified via conjugation with glutathione to form acrylamide- and isomeric glycidamide-glutathione conjugates, subsequently metabolized to mercapturic acids and excreted in urine. Acrylamide has also been found to have neurotoxic effects in humans who have been exposed. Animal studies show neurotoxic effects as well as mutations in sperm.

Actinic keratosis (AK) is a pre-cancerous area of thick, scaly, or crusty skin. These growths are more common in fair-skinned people and those who are frequently in the sun. They are believed to form when skin gets damaged by ultraviolet (UV) radiation from the sun or indoor tanning beds, usually over the course of decades. Given their pre-cancerous nature, if left untreated they may turn into a type of skin cancer called squamous cell carcinoma. Untreated lesions have up to a 20% risk of progression to squamous cell carcinoma, so treatment by a dermatologist is recommended.

Actinic keratoses characteristically appear as thick, scaly, or crusty areas that often feel dry or rough. Size commonly ranges between 2 and 6 millimeters in size, but they can grow to be several centimeters in diameter. Notably, AKs are often felt before they are seen, and the texture is sometimes compared to sandpaper. They may be dark, light, tan, pink, red, a combination of all these, or have the same color as the surrounding skin. Given the causal relationship between sun exposure and AK growth, they often appear on a background of sun-damaged skin and in areas that are commonly sun-exposed, such as the face, ears, neck, scalp, chest, backs of hands, forearms, or lips. Because sun exposure is rarely limited to a small area, most people who have an AK have more than one.

Diagnosis is suspected clinically on physical exam by a physician or other health care provider, but can be confirmed by looking at cells from the lesion under a microscope in a biopsy procedure. Multiple treatment options for AK are available. Photodynamic therapy (PDT) is one option the treatment of numerous AK lesions in a region of the skin, termed field cancerization. It involves the application of a photosensitizer to the skin followed by illumination with a strong light source. Topical creams, such as 5-fluorouracil or imiquimod, may require daily application to affected skin areas over a typical time course of weeks. Cryotherapy is frequently used for few and well-defined lesions, but undesired skin lightening, or hypopigmentation, may occur at the treatment site. By following up with a dermatologist, AKs can be treated before they progress to skin cancer. If cancer does develop from an AK lesion, it can be caught early with close monitoring, at a time when treatment is likely to have a high cure rate.

Angle closure is defined as the apposition of iris to the trabecular meshwork, which results in increased intraocular pressure (IOP). In acute angle closure (AAC), the process occurs suddenly with a dramatic onset of symptoms, including blurred vision, red eye, pain, headache, and nausea and vomiting. The sudden and severe IOP elevation can quickly damage the optic nerve, resulting in acute angle-closure glaucoma (AACG).

AAC is a true ophthalmic emergency, and a delay in treatment can result in blindness. While immediate treatment can sometimes minimize the amount of visual loss, the best treatment is to stop its occurrence in susceptible individuals

Autoimmune neuropathies present with a broad range of symptoms, including subacute progression, asymmetric or multifocal deficits, and selective involvement of motor, sensory, or autonomic nerves. The overlap of symptoms among syndromes often makes diagnosis difficult. Presumptive diagnosis is based on patient history and clinical presentation. Initial laboratory testing aims to rule out underlying etiologies, including potential infection, metabolic disturbances, and brain tumors; if nothing is uncovered, further evaluation, including imaging, nerve conduction studies, and cerebrospinal fluid (CSF) analysis may be required. Autoimmune neuropathies can also arise as paraneoplastic disorders in the setting of cancer; refer to the Paraneoplastic Neurological Syndromes and Associated Disorders topic for more information. The detection of an autoantibody in the right clinical setting provides some evidence that the peripheral nerve disturbance is immune mediated and may direct treatment, but antibody testing cannot be used as the sole diagnostic tool.

Acute flaccid paralysis (AFP) is a rare but serious neurological illness which is normally due to inflammation of the spinal cord, known as acute flaccid myelitis (AFM).

AFP and AFM causes weakness of the arms, legs or face. In the past, AFP was commonly due to poliovirus infection.

Acute generalized exanthematous pustulosis (AGEP) (also known as pustular drug eruption and toxic pustuloderma) is a rare skin reaction that in 90% of cases is related to medication administration.

AGEP is characterized by sudden skin eruptions that appear on average five days after a medication is started. These eruptions are pustules, i.e. small red white or red elevations of the skin that contain cloudy or purulent material (pus).^:124 The skin lesions usually resolve within 1–3 days of stopping the offending medication. However, more severe cases are associated with a more persistent disorder that may be complicated by secondary skin infections and/or involvement of the liver, lung, and/or kidney.

SCARs disorders are regarded as the drug-induced activation of T cells which then initiate innate immune responses that are inappropriately directed against self tissues. Studies on the DRESS syndrome, SJS, SJS/TEN, and TEN indicate that many individuals are predisposed to develop these reactions to a particular drug based on their genetically-determined expression of particular human leukocyte antigen (i.e. HLA) alleles or T cell receptors and/or their efficiencies in adsorbing, distributing to tissues, metabolizing, and/or eliminating) a particular SCARS-inducing drug. Evidence for these predispositions in AGEP has not been as well-established.

Acute inflammatory demyelinating polyradiculoneuropathy is an inflammatory disease of the peripheral nervous system characterized by lymphocytic and macrophagic infiltration with destruction of myelin. The condition is often designated as the Landry-Guillain-Barré-Strohl syndrome or Guillain-Barré syndrome (GBS) in recognition of the descriptions provided by these authors. An acute, ascending, predominantly motor paralysis with respiratory failure and death was first reported by Landry in 1859 (Landry 1859). In 1916 G Guillain and JA Barré, then French army neurologists, along with A Strohl reported 2 patients with acute polyradiculoneuritis and introduced the concept of "albuminocytologic dissociation" in the cerebrospinal fluid as a laboratory marker to distinguish this disorder from other neuropathies and from poliomyelitis (Guillain et al 1916).

Acute lymphoblastic leukemia (ALL) is a cancer of the lymphoid line of blood cells characterized by the development of large numbers of immature lymphocytes. Symptoms may include feeling tired, pale skin color, fever, easy bleeding or bruising, enlarged lymph nodes, or bone pain. As an acute leukemia, ALL progresses rapidly and is typically fatal within weeks or months if left untreated.

In most cases, the cause is unknown. Genetic risk factors may include Down syndrome, Li-Fraumeni syndrome, or neurofibromatosis type 1. Environmental risk factors may include significant radiation exposure or prior chemotherapy. Evidence regarding electromagnetic fields or pesticides is unclear. Some hypothesize that an abnormal immune response to a common infection may be a trigger. The underlying mechanism involves multiple genetic mutations that results in rapid cell division. The excessive immature lymphocytes in the bone marrow interfere with the production of new red blood cells, white blood cells, and platelets. Diagnosis is typically based on blood tests and bone marrow examination.

ALL is typically treated initially with chemotherapy aimed at bringing about remission. This is then followed by further chemotherapy typically over a number of years. Additional treatments may include intrathecal chemotherapy or radiation therapy if spread to the brain has occurred. Stem cell transplantation may be used if the disease recurs following standard treatment. Additional treatments such as immunotherapy are being studied.

ALL affected about 876,000 people globally in 2015 and resulted in about 111,000 deaths. It occurs most commonly in children, particularly those between the ages of two and five. In the United States it is the most common cause of cancer and death from cancer among children. ALL is notable for being the first disseminated cancer to be cured. Survival for children increased from under 10% in the 1960s to 90% in 2015. Survival rates remain lower for babies (50%) and adults (35%).

Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal cells that build up in the bone marrow and blood and interfere with normal blood cells. Symptoms may include feeling tired, shortness of breath, easy bruising and bleeding, and increased risk of infection. Occasionally spread may occur to the brain, skin, or gums. As an acute leukemia, AML progresses rapidly and is typically fatal within weeks or months if left untreated.Risk factors include smoking, previous chemotherapy or radiation therapy, myelodysplastic syndrome, and exposure to the chemical benzene. The underlying mechanism involves replacement of normal bone marrow with leukemia cells, which results in a drop in red blood cells, platelets, and normal white blood cells. Diagnosis is generally based on bone marrow aspiration and specific blood tests. AML has several subtypes; for which treatments and outcomes may vary.AML, typically is initially treated with chemotherapy aimed at inducing remission. People may then go on to receive additional chemotherapy, radiation therapy, or a stem cell transplant. The specific genetic mutations present within the cancer cells may guide therapy, as well as determine how long that person is likely to survive. Arsenic trioxide may be tried in cases that have recurred following usual treatments.AML affected about one million people globally in 2015 and resulted in 147,000 deaths. It most commonly occurs in older adults. Males are affected more often than females. AML is curable in about 35% of people under 60 years old and 10% over 60 years old. Older people who are not healthy enough to receive intensive chemotherapy have a typical survival of 5–10 months. It accounts for roughly 1.8% of cancer deaths in the United States.