Persius/hicric huggingface dataset:
Nyctalopia
Synonyms and related keywords: nocturnal amblyopia, night blindness.
Nyctalopia (Greek for "night blindness") is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition (for example, a lack of vitamin A).
The most common cause of nyctalopia is retinitis pigmentosa, a disorder in which the rod cells in the retina gradually lose their ability to respond to the light. Patients suffering from this genetic condition have progressive nyctalopia and eventually their daytime vision may also be affected. In X-linked congenital stationary night blindness, from birth the rods either do not work at all, or work very little, but the condition doesn't get worse.
Another cause of night blindness is a deficiency of retinol, or vitamin A, found in fish oils, liver and dairy products. In the Second World War misinformation was spread by the British to cover up the reason for their pilots' successful night time missions. Their success was, in the misinformation, attributed to improved night vision and pilots flying night missions were encouraged to eat plenty of carrots, which contain carotenoids and can be converted into retinol. The actual reason for their success was their use of advanced radar technologies.
The opposite problem, known as hemeralopia, is much rarer.
The outer area of the retina is made up of more rods than cones. The rod cells are the cells that enable us to see in poor illumination. This is the reason why loss of side vision often results in night blindness. Individuals suffering from night blindness not only see poorly at night, but also require some time for their eyes to adjust from brightly lit areas to dim ones. Contrast vision may also be greatly reduced.

## Historical usage
Aulus Cornelius Celsus, writing ca. 30 AD, described night blindness and recommended an effective dietary supplement:  "There is besides a weakness of the eyes, owing to which people see well enough indeed in the daytime but not at all at night; in women whose menstruation is regular this does not happen. But success sufferers should anoint their eyeballs with the stuff dripping from a liver whilst roasting, preferably of a he-goat, or failing that of a she-goat; and as well they should eat some of the liver itself."
Historically, nyctalopia, also known as moonblink, was a temporary night blindness believed to be caused by sleeping in moonlight in the tropics.

# Differential Diagnosis of Causes of Nyctalopia
Causes
- Albinism
- Cataracts
- Cirrhosis
- Glaucoma
- Gyrate atrophy
- Hereditary
- Hypoxia
- Laurence-Moon-Biedl Syndrome
- Oguchi's Disease
- Optic atrophy
- Peripheral Chorioretinitis
- Retinitis Pigmentosa
- Siderosis retinae
- Uncorrected myopia
- Vitamin A deficiency
- Zinc deficiency
Overeating

# Overview
Overeating is a behavior that, while generally not a medical problem, in some cases is a symptom of binge eating disorder or bulimia. In more general terms it refers to the persistent consumption of excess food in relation to the energy that the person expends, leading to weight gain and often to obesity. This may be a brief or short term process (many people overindulge generally during festivities or while on holiday) or a longer term process.

# Causes
Overeating has been linked to the use of medications known as dopamine agonists, such as pramipexole.

# Treatment
One organization that helps over eaters is Overeaters Anonymous, which operates a 12-step program.

# Related Chapters
- Binge eating
- Addiction
Percussion

# Overview
Percussion is a method used by a healthcare provider to find out about the changes in the thorax or abdomen. It is done by tapping on a surface to determine the underlying structure. It is one of the four methods of clinical examination: inspection (medicine), palpation, percussion and  auscultation. It is done with the middle finger of right hand tapping on the middle finger of the left hand, which is positioned with the whole palm on the body.
There are two types of percussion: direct percussion, which uses only 1 or two fingers, and indirect percussion, utilizing the middle/flexor finger. The method was initially used to distinguish between empty and filled barrels of liquor.
There are four different percussion sounds:
- Sonorous
- Hypersonorous
- Relatively dull sound
- Completely dull sound
The presence of a solid mass underneath the surface will produce a dull sound. Hollow, air-containing structures will lead to a more sonore sound.

# Percussion of the thorax
It is used to diagnose pneumothorax, emphysema and other diseases. It can be used to access the respiratory mobility of the thorax.

## Differential Diagnosis of Abnormalities in Percussion of the Lung
In alphabetical order:  

### Dullness
- Foreign body
- Lobar pneumonia
- Lung abscess
- Lung tumor
- Pleural Effusion
- Pleural tumor
- Pulmonary edema
- Pulmonary infarction
- Tuberculosis infiltrate
- Tumor

### Flatness
- Large Pleural Effusion

### Resonance
- Chronic Bronchitis

### Hyperresonance
- Emphysema
- Pneumothorax
- Status asthmaticus

### Tympany
- Intestinal loop
- Large pneumothorax
- Lung caverns
- Lung cyst

# Percussion of the abdomen
It is used to find whether any organ is enlarged and similar. It is based on the principle of setting tissue and spaces in between at vibration. The sound thus generated is used to determine if the tissue is healthy or pathological.
Scalp rash

# Overview
Though diagnosis of scalp dermatitis / infection is easy, treatment can be more difficult. Topical therapy alone, or topical therapy in coordination with systemic therapy for long periods may be essential to maintain complete control of these problems.

# Differentiating a Scalp Rash from other Diseases
In alphabetical order. 
- Contact dermatitis
- Dissecting cellulitis of the scalp
- Discoid lupus
- Kerion
- Psoriasis
- Scalp folliculitis
- Seborrheic dermatitis
- Tinea capitis

# Diagnosis

## History and Symptoms

### Seborrheic dermatitis
- Diffuse
- White
- Non-adherent

### Bacterial folliculitis
- Use intact scalp pustule to determine diagnosis.

## Laboratory Findings
- KOH prep can be done in the office to check for spores within the hair shaft.
- Fungal cultures can be taken at the site of a kerion or scalp scale to rule out tinea capitis.
- Ensure root is intact.
- A shave biopsy should not be done liberally, and it can aid in the determination of seborrheic dermatitis.

# Treatment

## Medical Therapy

### Acute Pharmacotherapies
- Ketoconazole
- Tar
- Salicylic acid shampoos
- Zinc pyrithione
- Antifungal therapy
- Anti-fungal therapy
- Steroids
- 1st generation cephalosporin or tetracycline derivative for 2-4 weeks

### Injections
- Intralesional injection of steroids
- Intralesional steroids
- Systemic retinoids
- Antibiotic therapy
Tooth loss
Tooth loss is defined as the premature loss of teeth. Tooth loss is normal for deciduous teeth (baby teeth), when they are replaced by a person's adult teeth. Otherwise, losing teeth is undesirable and is the result of injury or disease, such as mouth trauma, tooth injury, tooth decay, and gum disease.
The condition of being toothless or missing one or more teeth, is called edentulism.

# Differential Diagnosis of Causes of Tooth Loss
In alphabetical order.  
- Accident
- Acromegaly
- Actalasia
- Chediak-Higashi Syndrome
- Chronic neutropenia
- Cholera
- Cyclic neutropenia
- Dentin dysplasia
- Diabetes Mellitus
- Down's Syndrome
- Drugs
- Hand-Schuller-Christian Syndrome
- Histiocytosis X
- Hypophosphotasia
- Hypophosphtemic vitamin D resistant rickets
- Hypopituitarism
- Hypothyroidism
- Leptospirosis
- Lesch-Nyhan Syndrome
- Leukemia
- Local tumor
- Lymphoma
- Odontodysplasia
- Osteomyelitis
- Papillon-Lefevre Syndrome
- Periodontitis
- Primary Hypothyroidism
- Psychosis
- Radiation
- Reticulosis
- Syphillis
- Tuberculosis
- Vitamin C deficiency

# Prevention of tooth loss
Tooth loss due to tooth decay and gum disease may be prevented by practicing good oral hygiene, and regular check-ups (twice per year) at the dentist's office.
In contact sports, risk of mouth trauma and tooth injury is reduced by wearing mouthguards and helmets with a facemask (e.g., football helmet, and goalie mask).

# Missing tooth replacement
There are three basic ways to replace a missing tooth or teeth, including a fixed dental bridge, dentures, and dental implants.
Erotomania

# Overview
Erotomania is a rare disorder in which a person holds a delusional belief that another person, usually of a higher social status, is in love with him or her.
Erotomania is also called de Clerambault's syndrome, after the France|French  Gaetan Gatian de Clerambault (18721934), who published a comprehensive review paper on the subject (Les Psychoses Passionelles) in 1921.
The term erotomania is also sometimes used in a less specific clinical sense meaning excessive pursuit of or preoccupation with love or sex.

# History
Early references to the condition can be found in the work of Hippocrates, Erasistratus, Plutarch and Galen. In the psychiatric literature it was first referred to in 1623 in a treatise by Jacques Ferrand (Maladie d'amour ou Melancolie erotique) and has been variously called "old maid's psychosis", "erotic paranoia" and "erotic self-referent delusions" until the common usage of the terms erotomania and de Clerambault's syndrome.
G.E. Berrios|Berrios and Kennedy have outlined several periods of history through which the concept of erotomania has changed considerably:
- Classical times  early eighteenth century: General disease caused by unrequited love
- Early eighteenth  beginning nineteenth century:  Practice of excess physical love (akin to nymphomania or satyriasis)
- Early nineteenth century  beginning twentieth century: Unrequited love as a form of mental disease
- Early twentieth century  present: Delusional belief of "being loved by someone else"

# Contemporary syndrome
The core of the syndrome is that the affected person has a delusional belief that another person, usually of higher social status, is secretly in love with them. The sufferer may also believe that the subject of their delusion secretly communicates their love by subtle methods such as body posture, arrangement of household objects and other seemingly innocuous acts (or, if the person is a public figure, through clues in the media). The object of the delusion usually has little or no contact with the delusional person, who often believes that the object initiated the fictional relationship. Erotomanic delusions are typically found as the primary symptom of delusional disorder, or in the context of schizophrenia.
Occasionally the subject of the delusion may not actually exist, although more commonly, the subjects are media figures such as popular singers, actors and politicians. Erotomania has been cited as one cause for stalking or harassment campaigns.
The assassination attempt of Ronald Reagan by John Hinckley, Jr. was reported to have been driven by an erotomanic delusion that the death of the president would cause actress Jodie Foster to publicly declare her love for Hinckley.
Late Night with David Letterman|Late night comedian David Letterman and retired astronaut Story Musgrave were the targets of delusional Margaret Mary Ray. Other reported celebrity targets of erotomania include Madonna (entertainer)|Madonna, Steven Spielberg, Barbara Mandrell, and Linda Ronstadt.
Dead space

# Overview
In physiology, dead space is air that is inhaled by the body in breathing, but does not partake in gas exchange.
In adults, it is usually in the range of 150 mL.

# Understanding dead space
Not all the air we breathe in is able to be used for the exchange of oxygen and carbon dioxide. About a third of every resting breath is exhaled exactly as it came into the body.
Because of dead space, taking deep breaths more slowly (e.g. ten 500 mL breaths per minute) is more effective than taking shallow breaths quickly (e.g. twenty 250 mL breaths per minute). Although the amount of gas per minute is the same (5 L/min), a large proportion of the shallow breaths is dead space, and does not allow oxygen to get into the blood.
Dead space can be enlarged (and better envisaged) by breathing into a long tube. Even though one end of the tube is open to the air, when one inhales, it is mostly the carbon dioxide from expiration. Using a snorkel increases a diver's dead space in the airways.

# Components
Dead space can be divided into two components: "anatomic" and "physiologic".

## Anatomical dead space
Anatomical dead space is the gas in the conducting areas of the respiratory system, such as the mouth and trachea, where the air doesn't come to the alveoli of the lungs.
It is normally equal in milliliters to your body weight in pounds. A 150 lb (68 kg) male would have an anatomical dead space of about 150 mL. 1 mL per lb or 2.2 mL per kilogram of body weight. This is the same conversion of kilograms to pounds, except the final unit is in mL. This is about a third of the resting tidal volume (450-500 mL).
Anatomic dead space is the volume of the conducting airways.  It may be measured by Fowler's Method, a nitrogen washout technique. It increases with an increase in tidal volume and is dependent on posture.

## Physiological dead space
The physiological dead space is equal to the anatomical dead space plus the alveolar dead space.
Alveolar dead space is the area in the alveoli that does get air to be exchanged, but there is not enough blood flowing through the capillaries for exchange to be effective. It is normally very small (less than 5 mL) in healthy individuals. It can increase dramatically in some lung diseases.
Physiologic dead space can be measured by Bohr's method.
An equation and example are provided below:
- VD = dead space
- VT = tidal volume
- PaCO2 = partial pressure of carbon dioxide in arteries
- PECO2 = partial pressure of carbon dioxide in exhaled air
Decaborane
Decaborane, also called decaborane(14) or decaboron tetradecahydride, is a stable crystalline borane with chemical formula B10H14. It forms colorless to white crystals. The B10 framework is an incomplete icosahedron.
B10H14 possesses a strong penetrating musty odor that is unique to boranes and quickly recognizable; decaborane itself smells intensely bitter, chocolate-like. When ignited it produces a bright green flame, as do other boron hydrides. It is not sensitive to moist air, although it hydrolyzes in boiling water, releasing hydrogen and boric acid solution. It is soluble in cold water.

# Synthesis
It is commonly synthesized via the pyrolysis of smaller boron hydride clusters (for example B2H6 or B5H9) under vacuum. The physical characteristics of decaborane(14) resemble those of the organic compounds naphthalene and anthracene, in that it is highly flammable and can be sublimed under vacuum at moderate temperatures. Sublimation is the most common method of purification.

# Chemical properties
Decaborane(14) is soluble in a wide variety of non-polar and moderately polar solvents including hexanes, benzene, toluene, diethyl ether, and methylene chloride. In strongly coordinating solvents (i.e. CH3CN or Me2S), decaborane(14) readily forms an adduct with the formula B10H122L, where L = CH3CN, Me2S).
Decaborane(14) is a Brnsted acid: in the presence of moderately strong bases, a proton can be removed to generate the anion .
Decaborane, like pentaborane, is a powerful toxin affecting central nervous system, although considerably less toxic than pentaborane. It can be absorbed through skin.
It forms an explosive mixture with tetrachloromethane, which caused an often quoted explosion in a Malta, NY manufacturing facility in 1948 when CCl4 was used to clean the equipment.

# Applications
Decaborane ions can be used for low energy ion implantation of boron in the manufacture of semiconductors; the molecule decomposes in the plasma, yielding monoatomic boron ions. It is also used in plasma-assisted chemical vapor deposition to manufacture boron-containing thin films.
In fusion research, the absorbing nature of thin films of decaborane is used to boronize the walls of the tokamak vacuum vessel to reduce recycling of particles and impurities into the plasma and improve overall performance.
In polymer chemistry, decaborane is used as a catalyst.
Decaborane was also being used as an additive to special high-performance rocket fuels. Its derivates were investigated as well, eg. ethyl decaborane. One patented fuel composition includes  vinyl decaborane-polyester copolymer. Vinyl decaborane ("dekene") is prepared by reacting decaborane with acetylene.
Hygroscopy
Hygroscopy is the ability of a substance to attract water molecules from the surrounding environment through either absorption or adsorption.
Hygroscopic substances include honey, glycerin, ethanol, methanol, concentrated sulfuric acid, and concentrated sodium hydroxide (lye).  Calcium chloride is so hygroscopic that it eventually dissolves in the water it absorbs: this property is called deliquescence (see below). Because of their affinity for atmospheric moisture, hygroscopic materials may need to be stored in sealed containers. When added to foods or other materials for the express purpose of maintaining moisture content, such substances are known as humectants.
Materials and compounds exhibit different hygroscopic properties, and this difference can lead to detrimental effects, such as stress concentration in composite materials.  The amount a particular material or compound is affected by ambient moisture may be considered its coefficient of hygroscopic expansion (CHE) or coefficient of hygroscopic contraction (CHC)the difference between the two terms being a difference in sign convention and a difference in point of view as to whether the difference in moisture leads to contraction or expansion.
A common example where difference in this hygroscopic property can be seen is in a paperback book cover.  Often in a relatively moist environment the book cover will curl away from the rest of the book.  The unlaminated side of the cover absorbs more moisture than the laminated side and increased in area, causing a stress that curls the cover toward the laminated side.  This is similar to the function of a bi-metallic strip.
The similar sounding but unrelated word hydroscopic is sometimes used in error for hygroscopic.  A hydroscope is an optical device used for making observations deep under water.

# Biology
The seeds of some grasses have hygroscopic extensions which bend with changes in humidity, enabling them to disperse over the ground. An example is Needle-and-Thread, Hesperostipa comata. Each seed has an awn that twists several turns when the seed is released. Increased moisture causes it to untwist, and upon drying to twist again; the seed is drilled into the ground. Children in the west call this the "clock plant".

# Deliquescence
Deliquescent materials are substances (mostly salts) which have a strong affinity for moisture and will absorb relatively large amounts of water from the atmosphere if exposed to it, forming a liquid solution. Deliquescent salts include calcium chloride, magnesium chloride, zinc chloride, and the strong base sodium hydroxide. They are often used as desiccants.
Delta-F508
F508 is a specific mutation within the human genome.  The mutation--a deletion of three base pairs (T, T, T) which form the codon for phenylalanine (F) at the 508 position--prevents a protein called the cystic fibrosis transmembrane conductance regulator (CFTR) from obtaining its normal position.  Having two copies of this mutation, inherited from both parents, is the leading cause of cystic fibrosis (CF).

# Prevalence
F508 is present in approximately one in 30 caucasians.  Scientists have estimated that the mutation occurred over 52,000 years ago in Northern Europe.  From an evolutionary standpoint the mutation's negative effects (see below) are outweighed by the fact that it reduces water-loss during cholera, a common cause of death in Europe when the mutation first appeared.

# Effects
The CFTR protein--when in the proper position--opens channels in the cell wall which release chloride ions in the cells.  This causes osmosis to draw water out of the cell.  The F508 mutation can prevent the CFTR from moving into its proper position in the cell.

## Heterozygous carriers
Being a 'carrier' (having a single copy of F508) results in decreased water loss during diarrhea.  This prevents dehydration, and vastly increases the chances of surviving cholera.
If two carriers of the gene mate, their offspring will have a 25% chance of having two copies of the mutation (see also Mendelian inheritance).  Generally F508 carriers are symptom free, however when combined with other mutations, varying degrees of CF-like symptoms can appear (see below).

## Homozygous genotype
Having a pair of genes with the F508 mutation prevents the CFTR protein from obtaining its normal position in the cell membranes.  This causes increased water retention in cells, and a variety of effects on the body:
- Thicker mucous membranes in many parts of the body
- Congenital Bilateral Absence of the Vas deferens (CBAVD) due to increased mucus thickness during fetal development
- Pancreatic insufficiency, due to blockage of the pancreatic duct with mucus
This collection of symptoms is called cystic fibrosis, however F508 is not the only mutation that causes CF.

## Heterozygous carriers with other mutations
Approximately 70% of cystic fibrosis cases in Europe are due to Double F508 (this varies widely by region).  The remaining cases are caused by combinations of that and over 500 other mutations including R117H, 1717-1G>A, and 2789+56G>A.  These mutations, when combined with each other or F508, cause CF symptoms.  The genotype is not strongly correlated with severity of the CF, however specific symptoms have been linked to certain mutations.
Nordazepam

# Overview
Nordazepam (marketed under brand names Stilny, Madar, Vegesan, and Calmday), also known as nordiazepam and desmethyldiazepam, is a 1,4-benzodiazepine derivative. Like other benzodiazepine derivatives, it has anticonvulsant, anxiolytic, muscle relaxant and sedative properties. However, it is used primarily in the treatment of anxiety. It is an active metabolite of diazepam, chlordiazepoxide, clorazepate, prazepam, and medazepam.

# Side effects
Common side effects of nordazepam include somnolence, which is more common in elderly patients and/or people on high dose regimens. Hypotonia, which is much less common, is also associated with high doses and/or old age.

# Interactions
Benzodiazepines including N-desmethyldiazepam (nordazepam) may inhibit the glucuronidation of morphine leading to increased levels of and prolongation of the effects of morphine.

# Abuse
Nordazepam and other sedative hypnotic drugs are detected frequently in cases of people suspected of driving under the influence of drugs. Other benzodiazepines and zolpidem and zopiclone are also found in high numbers of suspected drugged drivers. Many drivers have blood levels far exceeding the therapeutic dose range suggesting a high degree of abuse potential for benzodiazepines and zolpidem and zopiclone.