Here is the list with the most often conditions that start with letter “D“:
- Delayed sleep-phase syndrome
- Dengue fever
- Dental fluorosis
- Depersonalization disorder
- Down Syndrome
Deafness (hearing impairment) refers to conditions in which individuals are fully or partially unable to detect or perceive at least some frequencies of sound. It can be classified as: conductive deafness which is an impairment resulting from dysfunction in any of the mechanisms that normally conduct sound waves through the outer ear, the eardrum or the bones of the middle ear; sensori-neural deafness which is one resulting from dysfunction in the inner ear, especially the cochlea where sound vibrations are converted into neural signals, or in any part of the brain that subsequently processes these signals. The vast majority of human sensorineural hearing loss is associated with abnormalities in the hair cells of the organ of Corti in the cochlea. This dysfunction may be present from birth due to genetic or developmental abnormalities, or arise through trauma or disease during the lifetime of an individual. Other important causes include age, long-term exposure to high environmental noise, medication side effects, exposure to ototoxic chemicals, physical trauma. Hearing aids, which amplify the incoming sound, may alleviate some of the problems caused by hearing impairment, but are often insufficient. Cochlear implants artificially stimulate the cochlear nerve by providing an electric impulse substitution for the firing of hair cells. Cochlear implants are not only expensive, but require sophisticated programming in conjunction with patient training for effectiveness.
A 2005 study achieved successful regrowth of cochlea cells in guinea pigs. It is important to note, however, that the regrowth of cochlear hair cells does not imply the restoration of hearing sensitivity as the sensory cells may or may not make connections with neurons that carry the signals from hair cells to the brain.
Dehydration occurs when there the body is lacking a sufficient amount of water. Vomiting, diarrhea, overuse of diuretics and excessive sweating with decreased water intake are all common factors contributing to dehydration. Certain disorders such as diabetes and Addison’s disease can increase the loss of urine, also leading to dehydration. Symptoms of dehydration may include: thirst, dry mouth, dry skin, sunken eyes, reduced skin elasticity, reduced amount of urine or dark colored urine, feeling light headed, confusion, anxiety, low blood pressure, loss of consciousness.
Dehydration can be prevented. Fluid intake should be increased on hot days and during exercise. In the case of mild dehydration, drinking plenty of water may be all that is needed to cure dehydration. If electrolytes are lost, they need to be replaced. Sports drinks are made to replace electrolytes that have been lost during intense exercise. Drinking a sports drink that supplies electrolytes can help to prevent, as well as treat mild dehydration. Severe dehydration requires medical treatment. For severe dehydration, doctors usually give fluids intravenously.
Delayed sleep-phase syndrome (DSPS), also known as delayed sleep-phase disorder (DSPD) is a circadian rhythm sleep disorder, a chronic disorder of the timing of sleep, peak period of alertness, the core body temperature rhythm, hormonal and other daily rhythms, compared to the normal population and relative to societal requirements. People with DSPS generally fall asleep some hours after midnight and have difficulty waking up in the morning.
Often, people with the disorder report that they cannot sleep until early morning, but fall asleep at about the same time every “night”. Unless they have another sleep disorder such as sleep apnea in addition to DSPS, patients can sleep well and have a normal need for sleep. Therefore, they find it very difficult to wake up in time for a typical school or work day. If, however, they are allowed to follow their own schedules ( e.g. sleeping from 4 a.m. to noon, they sleep soundly, awaken spontaneously, and do not experience excessive daytime sleepiness).
The syndrome usually develops in early childhood or adolescence. An adolescent version disappears in adolescence or early adulthood; otherwise DSPS is a lifelong condition. Depending on the severity, it can be to a greater or lesser degree treatable.
Treatment, a set of management techniques, is specific to DSPS. It is different from treatment of insomnia, and recognizes the patients’ ability to sleep well on their own schedules, while addressing the timing problem. Success, if any, may be partial; for example, a patient who normally awakens at noon may only attain a wake time of 10 or 10:30 with treatment and follow-up. Being consistent with the treatment is paramount. Treatments include:
Light therapy with a full spectrum lamp or portable visor, usually 10,000 lux for 30–90 minutes at the patient’s usual time of spontaneous awakening, or shortly before (but not long before), which is in accordance with the phase response curve (PRC) for light. The use of an LED light therapy device can reduce this to 15-30 minutes. Sunlight can also be used.
Dim lights in the evening, sometimes called darkness therapy. Just as bright light upon awakening should advance one’s sleep-phase, bright light in the evening and night delays it.
Melatonin taken an hour or so before usual bedtime may induce sleepiness. Taken this late, it does not, of itself, affect circadian rhythms, but a decrease in exposure to light in the evening is helpful in establishing an earlier pattern.
Modafinil (Provigil) is approved in the US for treatment of shift-work sleep disorder, which shares some characteristics with DSPS, and a number of clinicians are prescribing it for DSPS patients.
A strict schedule and good sleep hygiene are essential in maintaining any good effects of treatment. With treatment, some people with mild DSPS may sleep and function well with an early sleep schedule. Caffeine and other stimulant drugs to keep a person awake during the day may not be necessary, and should be avoided in the afternoon and evening, in accordance with good sleep hygiene.
Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging. It may be static, the result of a unique global brain injury, or progressive, resulting in long-term decline due to damage or disease in the body. Although dementia is far more common in the geriatric population, it may occur in any stage of adulthood. Dementia is a non-specific illness syndrome (does not have a strict set of signs and symptoms) in which affected areas of cognition may be memory, behavior, attention, language, and problem solving. It is normally required to be present for at least 6 months to be diagnosed.
There exist some brief tests (5–15 minutes) that have reasonable reliability and can be used in the office or other setting to screen cognitive status. Examples of such tests include the abbreviated mental test score (AMTS), the mini mental state examination (MMSE), Modified Mini-Mental State Examination (3MS), the Cognitive Abilities Screening Instrument (CASI), and the clock drawing test. Scores must be interpreted in the context of the person’s educational and other background, and the particular circumstances. Also routine blood tests are also usually performed to rule out treatable causes.
Except for the treatable types listed above, there is no cure to this illness. Cholinesterase inhibitors are often used early in the disease course. Cognitive and behavioral interventions may also be appropriate. Educating and providing emotional support to the caregiver (or carer) is of importance as well.
Medications – Acetylcholinesterase inhibitors: Tacrine (Cognex), donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon) are approved by the United States Food and Drug Administration (FDA) for treatment of dementia induced by Alzheimer’s disease; N-methyl-D-aspartate Blockers: Memantine (Namenda) is a drug representative of this class. It can be used in combination with acetylcholinesterase inhibitors; Antidepressant drugs; Anxiolytic drugs.
Dengue fever, also known as breakbone fever, is an acute febrile infectious disease caused by the dengue virus. Typical symptoms include headache, a petechial rash, and muscle and joint pains. Dengue is usually transmitted by the mosquito. Treatment of acute dengue is supportive, using either oral or intravenous rehydration for mild or moderate disease and blood transfusions for more severe cases. Rates of infection have increased dramatically over the last 50 years with approximate 50–100 million people being infected yearly. The disease has become global and is currently endemic in more than 110 countries with 2.5 billion people living in areas where it is prevalent.
Infections from dengue virus range from asymptomatic, to a simple fever, to life threatening. The incubation period (time between exposure and onset of symptoms) is 4–10 days. Most infections are very mild, and many probably experience no symptoms at all. Most commonly symptoms include: sudden onset fever, headache (typically behind the eyes), muscle and joint pains, and a rash; the nickname “break-bone fever” comes from the associated muscle and joints pains.
There are no specific treatments for the dengue fever virus. Treatment depends on the symptoms that a person has and may vary from continuing to drink fluids such as oral rehydration solution at home with close follow up, to admission to hospital for carefully titrated intravenous fluids and/or blood transfusions.
Dental fluorosis is condition caused by a child receiving too much fluoride during tooth development. The critical period of exposure is between 1 and 4 years old; children over age 8 are not at risk. In its mild form, which is the most common, fluorosis appears as tiny white streaks or specks that are often unnoticeable. In its severest form, which is also called mottling of dental enamel, it is characterized by black and brown stains, as well as cracking and pitting of the teeth. The severity of dental fluorosis depends on the amount of fluoride exposure, the age of the child, individual response, as well as other factors including nutrition.
Dental fluorosis occurs because of the excessive intake of fluoride, either through fluoride in the water supply, naturally occurring or added to it or through other sources. The damage in tooth development occurs between the ages of 3 months to 8 years, from the overexposure to fluoride. Dental fluorosis can be cosmetically treated by a dentist. The cost and success can vary significantly depending on the treatment. Tooth bleaching, microabrasion, and conservative composite restorations or porcelain veneers are commonly used treatments. Generally speaking, bleaching and microabrasion are used for superficial staining, whereas the conservative restorations are used for more unaesthetic situations.
Dentophobia (dental fear) refers to the fear of dentistry and of receiving dental care. A pathological form of this fear (specific phobia) is variously called dental phobia, odontophobia, dentophobia, dentist phobia, or dental anxiety. However, it has been suggested that the term “dental phobia” is often a misnomer, as many people with this condition do not feel their fears to be excessive or unreasonable and resemble individuals with post-traumatic stress disorder, caused by previous traumatic dental experiences.
Dermatomyositis (DM) is a connective-tissue disease related to polymyositis (PM) that is characterized by inflammation of the muscles and the skin. The cause is unknown, but it may result from either a viral infection or an autoimmune reaction. In the latter case it is a systemic autoimmune disease. Many people diagnosed with dermatomyositis were previously diagnosed with infectious mononucleosis and Epstein-Barr virus. he main symptoms include skin rash and symmetric proximal muscle weakness which may be accompanied by pain. The pain may resemble the type experienced after strenuous exercise. Some dermatomyositis patients have little pain, while in others the pain may be severe. It is important to remember that this condition varies from person to person in many ways. Also in many cases muscle may deteriorate and render the patient temporarily paralyzed unable to walk, run, get out of bed or even swallow food and liquids.
Depersonalization disorder (DPD) is a dissociative disorder in which the sufferer is affected by persistent or recurrent feelings of depersonalization and/or derealization. Diagnostic criteria include persistent or recurrent experiences of feeling detached from one’s mental processes or body. The symptoms include a sense of automation, going through the motions of life but not experiencing it, feeling as though one is in a movie, feeling as though one is in a dream, feeling a disconnection from one’s body, out-of-body experience, a detachment from one’s body, environment and difficulty relating oneself to reality. It usually affects teenagers. Although depersonalization disorder is an alteration in the subjective experience of reality, it is by no means related to psychosis, as sufferers maintain the ability to distinguish between their own internal experiences and the objective reality of the outside world. During episodic and continuous depersonalization, sufferers are able to distinguish between reality and fantasy, and do not represent a risk to society since their grasp on reality remains stable at all times.
Depression is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities. The general term depression is often used to denote the disorder; but as it can also be used in reference to other types of psychological depression, it is avoided in favor of more precise terminology for the disorder in clinical and research use. Major depression is a disabling condition which adversely affects a person’s family, work or school life, sleeping and eating habits, and general health. In the United States, around 3.4% of people with major depression commit suicide and up to 60% of people who commit suicide had depression or another mood disorder.
The diagnosis of major depressive disorder is based on the patient’s self-reported experiences, behavior reported by relatives or friends, and a mental status examination. Typically, patients are treated with antidepressant medication and, in many cases, also receive psychotherapy or counseling although the effectiveness of medication for mild or moderate cases is questionable.
Biological, psychological, and social factors all play a role in causing depression. The diathesis–stress model specifies that depression results when a preexisting vulnerability, or diathesis, is activated by stressful life events. The preexisting vulnerability can be either genetic, implying an interaction between nature and nurture, or schematic, resulting from views of the world learned in childhood.
The three most common treatments for depression are psychotherapy, medication and electroconvulsive therapy. Psychotherapy is the treatment of choice for people under 18, while electroconvulsive therapy is only used as a last resort. Care is usually given on an outpatient basis, while treatment in an inpatient unit is considered if there is a significant risk to self or others.
Treatment options are much more limited in developing countries, where access to mental health staff, medication, and psychotherapy is often difficult.
Diabetes is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. This high blood sugar produces the classical symptoms of polyuria (frequent urination), polydipsia (increased thirst) and polyphagia (increased hunger). There are three main types of diabetes:
Type 1 diabetes: results from the body’s failure to produce insulin, and presently requires the person to inject insulin. (Also referred to as insulin-dependent diabetes mellitus, IDDM for short, and juvenile diabetes.) Type 1 diabetes mellitus is characterized by loss of the insulin-producing beta cells of the islets of Langerhans in the pancreas leading to insulin deficiency. This type of diabetes can be further classified as immune-mediated or idiopathic. The majority of type 1 diabetes is of the immune-mediated nature, where beta cell loss is a T-cell mediated autoimmune attack. There is no known preventive measure against type 1 diabetes, which causes approximately 10% of diabetes mellitus cases in North America and Europe.
Type 2 diabetes: results from insulin resistance, a condition in which cells fail to use insulin properly, sometimes combined with an absolute insulin deficiency. (Formerly referred to as non-insulin-dependent diabetes mellitus, NIDDM for short and adult-onset diabetes.)
Gestational diabetes: is when pregnant women, who have never had diabetes before, have a high blood glucose level during pregnancy. It may precede development of type 2 DM.
Down Syndrome is a chromosomal condition caused by the presence of all or part of an extra 21st chromosome. It is named after John Langdon Down, the British physician who described the syndrome in 1866. The condition was identified as a chromosome 21 trisomy by Jérôme Lejeune in 1959. Down syndrome is a chromosomal condition characterized by the presence of an extra copy of genetic material on the 21st chromosome.
The effects and extent of the extra copy vary greatly among people, depending on genetic history, and pure chance. The incidence of Down syndrome is estimated at 1 per 733 births, although it is statistically more common with older parents (both mothers and fathers) due to increased mutagenic exposures upon some some older parents’ reproductive cells (however, many older parents produce children without the condition). Other factors may also play a role. Often Down syndrome is associated with some impairment of cognitive ability and physical growth and a particular set of facial characteristics. Individuals with Down syndrome tend to have a lower-than-average cognitive ability, often ranging from mild to moderate disabilities.
Treatment of individuals with Down Syndrome depends on the particular manifestations of the condition. For instance, individuals with congenital heart disease may need to undergo major corrective surgery soon after birth. Other individuals may have relatively minor health problems requiring no therapy.