Here is the list of the most common disorders that begin with letter “R“:
- Radiation poisoning
- Raynaud’s phenomenon
- Reactive airway disease
- Reiter’s Syndrome / Reactive Arthritis
- Refusum disease
- Renal agenesis
- Renal Calculi (Kidney Stones)
- Renal failure
- Restless legs syndrome (RLS)
- Rett syndrome
- Reye’s syndrome
- Rh disease
Rabies is a viral disease that causes acute encephalitis (inflammation of the brain) in warm-blooded animals. It is zoonotic (i.e. transmitted by animals), most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms. The rabies virus infects the central nervous system, ultimately causing disease in the brain and death.
The rabies virus travels to the brain by following the peripheral nerves. The incubation period of the disease is usually a few months in humans, depending on the distance the virus must travel to reach the central nervous system. Once the rabies virus reaches the central nervous system and symptoms begin to show, the infection is effectively untreatable and usually fatal within days.
Early-stage symptoms of rabies are malaise, headache and fever, progressing to acute pain, violent movements, uncontrolled excitement, depression, and hydrophobia. Finally, the patient may experience periods of mania and lethargy, eventually leading to coma. The primary cause of death is usually respiratory insufficiency. Worldwide, roughly 97% of rabies cases come from dog bites. In the United States, however, animal control and vaccination programs have effectively eliminated domestic dogs as reservoirs of rabies. In several countries, including Australia, Japan, and the United Kingdom, rabies carried by animals that live on the ground has been eradicated entirely. Concerns exist about airborne and mixed-habitat animals including bats. A small number of bats of three species in the U.K and in some other countries have been found to have European Bat Lyssavirus 1 and European Bat Lyssavirus 2. The symptoms of these viruses are similar to those of rabies and so the viruses are both known as bat rabies.
Radiation poisoning, Radiation sickness or Radiation toxicity, is a constellation of health effects which occur within several months of exposure to high amounts of ionizing radiation. The term generally refers to acute problems rather than ones that develop after a prolonged period.
The onset and type of symptoms that develop depends on the dose of radiation exposure. Relatively smaller doses result in gastrointestinal effects such as nausea and vomiting and symptoms related to falling blood counts such as infection and bleeding. Relatively larger doses can result in neurological effects and rapid death. Treatment of acute radiation syndrome is generally supportive with blood transfusions and antibiotics.
Chronic radiation syndrome has been reported among workers in the Soviet nuclear program due to long term exposures to radiation levels lower than what is required to induce acute sickness. It may manifest with low blood cell counts and neurological problems. Radiation exposure can also increase the probability of developing some other diseases, mainly different types of cancers, however these diseases are not included in the term radiation sickness.
Classically acute radiation syndrome is divided into three main presentations: hematopoietic, gastrointestinal and neurological/vascular. These symptoms may or may not be preceded by a prodrome. The speed of onset of symptoms is related to radiation exposure with greater doses resulting in a shorter delay in symptom onset.
Hematopoietic. This syndrome is marked by a drop in blood cells which results in infections due to low white blood cells, bleeding due to low platelets, and anemia due to low red blood cells.
Gastrointestinal. This syndrome typically occurs at exposure doses of 600–1000 rad (6–10 Gy). Nausea, vomiting, loss of appetite, and abdominal pain are usually seen within one to two hours.
Neurovascular. This syndrome typically occurs at exposure doses greater than 1000 rad (10 Gy). It presents with neurological symptoms such as dizziness, headache, or decreased level of consciousness with an absence of vomiting.
For more detailed information see this article.
Radiophobia is an abnormal fear of ionizing radiation, in particular, fear of X-rays. The term is also used in a non-medical sense to refer to general opposition to the use of nuclear energy.
Fear of ionizing radiation is not unnatural, since it can pose significant risks. However this fear may become abnormal and even irrational, often owing to poor information or understanding, but also as a consequence of traumatic experience.
The term “radiophobia” is also polemically applied to the arguments of proponents of the LNT concept (Linear no-threshold response model for ionizing radiation) of radiation security proposed by the U.S. National Council on Radiation Protection and Measurements (NCRP) in 1949. The “no-threshold” position effectively assumes that even negligible doses of radiation may pose danger. The issue remains controversial.
Raynaud’s phenomenon is a vasospastic disorder causing discoloration of the fingers, toes, and occasionally other areas. This condition can also cause nails to become brittle with longitudinal ridges. Named for French physician Maurice Raynaud (1834–1881), the phenomenon is believed to be the result of vasospasms that decrease blood supply to the respective regions. Emotional stress and cold are classic triggers of the phenomenon.
It comprises both Raynaud’s disease (also known as “Primary Raynaud’s phenomenon”) where the phenomenon is idiopathic, and Raynaud’s syndrome (secondary Raynaud’s), where it is caused by some other instigating factor. Measurement of hand-temperature gradients is one tool used to distinguish between the primary and secondary forms.
It is possible for the primary form to progress to the secondary form.In extreme cases, the secondary form can progress to necrosis or gangrene of the fingertips.
Raynaud’s phenomenon is an exaggeration of vasomotor responses to cold or emotional stress. More specifically, it is a hyperactivation of the sympathetic system causing extreme vasoconstriction of the peripheral blood vessels, leading to tissue hypoxia. Chronic, recurrent cases of Raynaud phenomenon can result in atrophy of the skin, subcutaneous tissues, and muscle. In rare cases it can cause ulceration and ischemic gangrene.
The condition can cause pain within the affected extremities, discoloration (paleness) and sensations of cold and/or numbness. This can often be distressing to those who are not diagnosed, and sometimes it can be obstructive. If someone with Raynaud’s is placed in too cold a climate, it could potentially become dangerous.
The symptoms include several cyclic color changes:
When exposed to cold temperatures, the blood supply to the fingers or toes, and in some cases the nose or earlobes, is markedly reduced; the skin turns pale or white (called pallor), and becomes cold and numb.
When the oxygen supply is depleted, the skin colour turns blue (called cyanosis).
These events are episodic, and when the episode subsides or the area is warmed, the blood flow returns and the skin colour first turns red (rubor), and then back to normal, often accompanied by swelling, tingling, and a painful “pins and needles” sensation.
All three colour changes are observed in classic Raynaud’s. However, not all patients see all of the aforementioned colour changes in all episodes, especially in milder cases of the condition. Symptoms are thought to be due to reactive hyperemias of the areas deprived of blood flow.
In pregnancy, this sign normally disappears due to increased surface blood flow. Raynaud’s has also occurred in breastfeeding mothers, causing nipples to turn white and become extremely painful.
Reactive airway disease is a general term for conditions involving wheezing and allergic reactions.
In time it has evolved to be mistakenly used as a synonym for asthma. Current usage of the term in the medical community is to describe an asthma-like syndrome in infants that may later be confirmed to be asthmatics when they become old enough to participate in diagnostic tests such as the bronchial challenge test.
In pediatrics patients, it is best to avoid use of any other term other than bronchial asthma, although one can call it childhood asthma. The designation such as reactive airway disease, bronchitis, allergic bronchitis, asthmatic bronchitis, and so on, may lead to delay in the acceptance of a diagnosis of asthma, and thence to under-treatment and mismanagement of the disease, finally resulting in an increase in subsequent morbidity and mortality.
Reactive arthritis (Reiter’s Syndrome or Reiter’s arthritis), is classified as an autoimmune condition that develops in response to an infection in another part of the body. Coming into contact with bacteria and developing an infection can trigger the disease. Reiter’s syndrome has symptoms similar to various other conditions collectively known as “arthritis”. By the time the patient presents with symptoms, often time the “trigger” infection has been cured or is in remission in chronic cases, thus making determination of the initial cause difficult.
Commonly known as Reiter’s syndrome, recent political pressure has seen certain institutions utilize “reactive arthritis” but the condition is also known as arthritis urethritica, venereal arthritis and polyarteritis enterica. It is a type of seronegative spondyloarthropathy. The original name “Reiter’s syndrome”, named after the German physician Hans Conrad Julius Reiter for his contributions to identification and description of the disease, has become unpopular in the past decade as Reiter’s history of Nazi party membership, allegations of experimentation in the Buchenwald concentration camp, and prosecution in Nuremburg as a war criminal, have come to light.
The manifestations of Reactive arthritis include the following triad of symptoms: an inflammatory arthritis of large joints including commonly the knee and the back (due to involvement of the sacroiliac joint), inflammation of the eyes in the form of conjunctivitis or uveitis, and urethritis in men or cervicitis in women. Patients can also present with mucocutaneous lesions, as well as psoriasis-like skin lesions such as circinate balanitis, and keratoderma blennorrhagica. Enthesitis can involve the Achilles tendon resulting in heel pain. Not all affected persons have all the manifestations, and the formal definition of the disease is the occurrence of otherwise unexplained non-infectious inflammatory arthritis combined with urethritis in men, or cervicitis in women.
Refsum disease, also known as classic or adult Refsum disease, heredopathia atactica polyneuritiformis, phytanic acid oxidase deficiency and phytanic acid storage disease, is an autosomal recessive neurological disease that results from the over-accumulation of phytanic acid in cells and tissues. It is one of several disorders named after Norwegian neurologist Sigvald Bernhard Refsum (1907–1991).
Individuals with Refsum disease present with neurologic damage, cerebellar degeneration, and peripheral neuropathy. Onset is most commonly in childhood/adolescence with a progressive course, although periods of stagnation/remission occur. Symptoms also include night blindness, ataxia, scaly skin (ichthyosis), difficulty hearing, and eye problems including cataracts.
Refsum disease is a peroxisomal disorder caused by the impaired alpha-oxidation of branched chain fatty acids resulting in buildup of phytanic acid and its derivatives in the plasma and tissues. This may be due to deficiencies of phytanoyl-CoA hydroxylase or peroxin-7 activity. In general, Refsum disease is caused by PHYH mutations.
Renal agenesis is a unilateral or bilateral medical condition in which one or both fetal kidneys fail to develop leading to oligohydramnios, resulting in a 40-fold increase in perinatal mortality.
Bilateral renal agenesis is the uncommon and serious failure of both a fetus’ kidneys to develop during gestation, and is one causative agent of Potter sequence. This absence of kidneys causes oligohydramnios, a deficiency of amniotic fluid in a pregnant woman, which can place extra pressure on the developing baby and cause further malformations. The condition is frequently, but not always the result of a genetic disorder, and is more common in infants born to one or more parents with a malformed or absent kidney. Males are more commonly affected and most infants that are born alive do not live beyond four hours.
Unilateral renal agenesis is much more common, but is not usually of any major health consequence, as long as the other kidney is healthy. It is associated with an increased incidence of mullerian duct abnormalities which are abnormalities of the development of the female reproductive tract and can be a cause of infertility. The odds of a person being born with this condition are roughly 1 in 750. Adults with unilateral renal agenesis have considerably higher chances of hypertension (high blood pressure). People with this condition are advised to approach contact sports with caution.
Renal Calculi (or Kidney stones) are solid concretions or crystal aggregations formed in the kidneys from dietary minerals in the urine. Stones are typically classified by their location in the kidney (nephrolithiasis), ureter (ureterolithiasis), or bladder (cystolithiasis), or by their chemical composition (calcium-containing, struvite, uric acid, or other compounds). Kidney stones are a significant source of morbidity. 80% of those with kidney stones are men. Men most commonly experience their first episode between age 30–40 years, while for women the age at first presentation is somewhat later.
Kidney stones typically leave the body by passage in the urine stream, and many stones are formed and passed without causing symptoms. If stones grow to sufficient size (usually at least 3 millimeters (0.12 in) they can cause obstruction of the ureter. Ureteral obstruction causes postrenal azotemia and hydronephrosis (distension and dilation of the renal pelvis and calyces), as well as spasm of the ureter. This leads to pain, most commonly felt in the flank, lower abdomen and groin (a condition called renal colic). Renal colic can be associated with nausea, vomiting, fever, blood in the urine, pus in the urine, and painful urination. Renal colic typically comes in waves lasting 20 – 60 minutes, beginning in the flank or lower back and often radiating to the groin or genitals. The diagnosis of kidney stones is made on the basis of information obtained from the history, physical examination, urinalysis, and radiographic studies. ultrasound examination and blood tests may also aid in the diagnosis.
Renal failure or kidney failure (formerly called renal insufficiency) describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood. The two forms are acute (acute kidney injury) and chronic (chronic kidney disease); a number of other diseases or health problems may cause either form of renal failure to occur.
Renal failure is described as a decrease in the glomerular filtration rate. Biochemically, renal failure is typically detected by an elevated serum creatinine level. Problems frequently encountered in kidney malfunction include abnormal fluid levels in the body, deranged acid levels, abnormal levels of potassium, calcium, phosphate, and (in the longer term) anemia as well as delayed healing in broken bones. Depending on the cause, hematuria (blood loss in the urine) and proteinuria (protein loss in the urine) may occur. Long-term kidney problems have significant repercussions on other diseases, such as cardiovascular disease.
Restless legs syndrome (RLS) or Willis-Ekbom disease is a neurological disorder characterized by an irresistible urge to move one’s body to stop uncomfortable or odd sensations. It most commonly affects the legs, but can affect the arms, torso, and even phantom limbs. Moving the affected body part modulates the sensations, providing temporary relief.
RLS sensations can most closely be compared to an itching or tickling in the muscles, like “an itch you can’t scratch” or an unpleasant “tickle that won’t stop.” The sensations typically begin or intensify during quiet wakefulness, such as when relaxing, reading, studying, or trying to sleep. In addition, most individuals with RLS have limb jerking during sleep, which is an objective physiologic marker of the disorder and is associated with sleep disruption. Some controversy surrounds the marketing of drug treatments for RLS. It is a “spectrum” disease with some people experiencing only a minor annoyance and others experiencing major disruption of sleep and significant impairments in quality of life.
Retinoblastoma (Rb) is a rapidly developing cancer that develops in the cells of retina, the light-detecting tissue of the eye. In the developed world, Rb has one of the best cure rates of all childhood cancers (95-98%), with more than nine out of every ten sufferers surviving into adulthood.
There are two forms of the disease; a heritable form and non-heritable form (all cancers are considered genetic in that mutations of the genome are required for their development, but this does not imply that they are heritable, or transmitted to offspring). Approximately 55% of children with Rb have the non-heritable form. If there is no history of the disease within the family, the disease is labeled “sporadic”, but this does not necessarily indicate that it is the non-heritable form.
In about two thirds of cases, only one eye is affected (unilateral retinoblastoma); in the other third, tumours develop in both eyes (bilateral retinoblastoma). The number and size of tumours on each eye may vary. In certain cases, the pineal gland is also affected (trilateral retinoblastoma). The position, size and quantity of tumours are considered when choosing the type of treatment for the disease.
The most common and obvious sign of retinoblastoma is an abnormal appearance of the pupil, leukocoria. Other less common and less specific signs and symptoms are: deterioration of vision, a red and irritated eye, faltering growth or delayed development. Some children with retinoblastoma can develop a squint, commonly referred to as “cross-eyed” or “wall-eyed” (strabismus). Retinoblastoma presents with advanced disease in developing countries and eye enlargement is a common finding.
Retinoschisis is an eye disease characterized by the abnormal splitting of the retina’s neurosensory layers, usually in the outer plexiform layer, resulting in a loss of vision in the corresponding visual field in some rarer forms. More common forms are usually asymptomatic.
Rett syndrome is a neurodevelopmental disorder of the grey matter of the brain that affects females more commonly than males. The clinical features include small hands and feet and a deceleration of the rate of head growth (including microcephaly in some). Repetitive hand movements, such as wringing and/or repeatedly putting hands into the mouth, are also noted. People with Rett syndrome are prone to gastrointestinal disorders and up to 80% have seizures. They typically have no verbal skills, and about 50% of individuals affected are not ambulatory. Scoliosis, growth failure, and constipation are very common and can be problematic.
The signs of this disorder are most easily confused with those of Angelman syndrome, cerebral palsy and autism.
Some argue that it is misclassified as an autism spectrum disorder, just as it would be to include such disorders as fragile X syndrome, tuberous sclerosis, or Down syndrome where one can see autistic features.
Reye’s syndrome is a potentially fatal disease that causes numerous detrimental effects to many organs, especially the brain and liver, as well as causing a lower than usual level of blood sugar (hypoglycemia). The exact cause is unknown, and while it has been associated with aspirin consumption by children with viral illness, it also occurs in the absence of aspirin use.
The disease causes fatty liver with minimal inflammation and severe encephalopathy (with swelling of the brain). The liver may become slightly enlarged and firm, and there is a change in the appearance of the kidneys. Jaundice is not usually present.
Early diagnosis is vital; while most children recover with supportive therapy, severe brain injury or death are potential complications.
The precise mechanism by which Reye’s syndrome occurs remains unknown. This serious condition is described as a “syndrome” rather than a disease as the clinical features that physicians use to diagnose it are quite broad.
Rh disease (also known as Rh (D) disease, Rhesus incompatibility, Rhesus disease, RhD Hemolytic Disease of the Newborn, Rhesus D Hemolytic Disease of the Newborn or RhD HDN) is one of the causes of hemolytic disease of the newborn (HDN). The disease ranges from mild to severe, and typically occurs only in some second or subsequent pregnancies of Rh negative women where the fetus’ father is Rh positive,leading to a Rh+ pregnancy. During birth, the mother may be exposed to the infant’s blood, and this causes the development of antibodies, which may affect the health of subsequent Rh+ pregnancies. In mild cases, the fetus may have mild anaemia with reticulocytosis. In moderate or severe cases the fetus may have a more marked anaemia and erythroblastosis (erythroblastosis fetalis). When the disease is very severe it may cause HDN, hydrops fetalis, or stillbirth.
Rh disease is generally preventable by treating the mother during pregnancy or soon after delivery with an intramuscular injection of anti-RhD immunoglobulin (Rho(D) immune globulin).
Most Rh disease can be prevented by treating the mother during pregnancy or promptly (within 72 hours) after childbirth. The mother has an intramuscular injection of anti-Rh antibodies (Rho(D) Immune Globulin), sold under the brand name RhoGAM. This is done so that the fetal Rhesus D positive erythrocytes are destroyed before her immune system can discover them. This is passive immunity and the effect of the immunity will wear off after about 4 to 6 weeks (or longer depending on injected dose) as the anti-Rh antibodies gradually decline to zero in the maternal blood.
It is part of modern antenatal care to give all Rhesus D negative pregnant women an anti-RhD IgG immunoglobulin injection at about 28 weeks gestation (with or without a booster at 34 weeks gestation). This reduces the effect of the vast majority of sensitizing events which mostly occur after 28 weeks gestation. Anti-RhD immunoglobulin is also given to non-sensitized Rhesus negative women immediately (within 72 hours – the sooner the better) after potentially sensitizing events that occur earlier in pregnancy.
Rheumatism or rheumatic disorder is a non-specific term for medical problems affecting the joints and connective tissue. The study of, and therapeutic interventions in, such disorders is called rheumatology.
The term “rheumatism” is still used in colloquial speech and historical contexts, but is no longer frequently used in medical or technical literature; there is no longer any recognized disorder simply called “rheumatism”. Some countries use the word rheumatism to describe fibromyalgia syndrome. The traditional term covers such a range of different problems that to ascribe symptoms to “rheumatism” is not to say very much. Nevertheless, sources dealing with rheumatism tend to focus on arthritis. However, “non-articular rheumatism”, also known as “regional pain syndrome” or “soft tissue rheumatism” can cause significant discomfort and difficulty. Furthermore, arthritis and rheumatism between them cover at least 200 different conditions.
The term “Rheumatic Diseases” is used in MeSH to refer to connective tissue disorders.
A vast number of traditional herbal remedies were recommended for “rheumatism”. Modern medicine, both conventional and complementary, recognises that the different rheumatic disorders have different causes (and several of them have multiple causes) and require different kinds of treatment.
Nevertheless, initial therapy of the major rheumatological diseases is with analgesics, such as paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs), members of which are ibuprofen and diclofenac. Often, stronger analgesics are required.
There has long been said to be a link between “rheumatic” pain and the weather. There appears to be no firm evidence in favour or against; a 1995 questionnaire given to 557 people by A. Naser and others at the Brigham and Women’s Hospital’s Pain Management Center concludes that “changes in barometric pressure are the main link between weather and pain. Low pressure is generally associated with cold, wet weather and an increase in pain. Clear, dry conditions signal high pressure and a decrease in pain”.
Rickets is a softening of bones in children due to deficiency or impaired metabolism of vitamin D, magnesium, phosphorus or calcium, potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries. The predominant cause is a vitamin D deficiency, but lack of adequate calcium in the diet may also lead to rickets (cases of severe diarrhea and vomiting may be the cause of the deficiency). Although it can occur in adults, the majority of cases occur in children suffering from severe malnutrition, usually resulting from famine or starvation during the early stages of childhood. Osteomalacia is the term used to describe a similar condition occurring in adults, generally due to a deficiency of vitamin D. The origin of the word “rickets” is probably from the Old English dialect word ‘wrickken’, to twist. The Greek derived word “rachitis” (ραχίτις, meaning “inflammation of the spine”) was later adopted as the scientific term for rickets, due chiefly to the words’ similarity in sound.
Rubella, commonly known as German measles, is a disease caused by the rubella virus. The name “rubella” is derived from the Latin, meaning little red. Rubella is also known as German measles because the disease was first described by German physicians in the mid-eighteenth century. This disease is often mild and attacks often pass unnoticed. The disease can last one to three days. Children recover more quickly than adults. Infection of the mother by Rubella virus during pregnancy can be serious; if the mother is infected within the first 20 weeks of pregnancy, the child may be born with congenital rubella syndrome (CRS), which entails a range of serious incurable illnesses. Spontaneous abortion occurs in up to 20% of cases.
Rubella is a common childhood infection usually with minimal systemic upset although transient arthropathy may occur in adults. Serious complications are very rare. Apart from the effects of transplacental infection on the developing fetus, rubella is a relatively trivial infection.
Acquired (i.e. not congenital) rubella is transmitted via airborne droplet emission from the upper respiratory tract of active cases (can be passed along by the breath of people sick from Rubella. The virus may also be present in the urine, feces and on the skin. There is no carrier state: the reservoir exists entirely in active human cases. The disease has an incubation period of 2 to 3 weeks.
In most people the virus is rapidly eliminated. However, it may persist for some months post partum in infants surviving the CRS. These children are a significant source of infection to other infants and, more importantly, to pregnant female contacts.
Rubeola is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses. Symptoms include fever, cough, runny nose, red eyes and a generalized, maculopapular, erythematous rash.
Measles (also sometimes known as English Measles) is spread through respiration (contact with fluids from an infected person’s nose and mouth, either directly or through aerosol transmission), and is highly contagious—90% of people without immunity sharing living space with an infected person will catch it. The infection has an average incubation period of 14 days (range six to 19 days) and infectivity lasts from two to four days prior, until two to five days following the onset of the rash (i.e. four to 9 days infectivity in total).
An alternative name for measles in English-speaking countries is rubeola, which is sometimes confused with rubella (German measles); the diseases are unrelated.