Neuritis is a general term for inflammation of a nerve or the general inflammation of the peripheral nervous system. Symptoms depend on the nerves involved, but may include pain, paresthesia (pins-and-needles), paresis (weakness), hypoesthesia (numbness), anesthesia, paralysis, wasting, and disappearance of the reflexes.

Causes of neuritis include:

Those with diseases or dysfunctions of their nerves may present with problems in any of the normal nerve functions. Symptoms vary depending on the types of nerve fiber involved.In terms of sensory function, symptoms commonly include loss of function ("negative") symptoms, including , tremor, impairment of balance, and gait abnormality. Gain of function (positive) symptoms include tingling, pain, itching, crawling, and pins-and-needles.

Motor symptoms include loss of function ("negative") symptoms of weakness, tiredness, muscle atrophy, and gait abnormalities; and gain of function ("positive") symptoms of cramps, and muscle twitch (fasciculations).

In the most common form, length-dependent peripheral neuropathy, pain and parasthesia appears symmetrically and generally at the terminals of the longest nerves, which are in the lower legs and feet. Sensory symptoms generally develop before motor symptoms such as weakness. Length-dependent peripheral neuropathy symptoms make a slow ascent of leg, while symptoms may never appear in the upper limbs; if they do, it will be around the time that leg symptoms reach the knee. When the nerves of the autonomic nervous system are affected, symptoms may include constipation, dry mouth, difficulty urinating, and dizziness when standing.

While inclusion criteria for Rud syndrome have varied considerably, the major manifestations includes congenital ichthyosis, hypogonadism, small stature, mental retardation, and epilepsy. Ocular findings were inconsistently reported and included strabismus, blepharoptosis, blepharospasm, glaucoma, cataract, nystagmus, and retinitis pigmentosa. Other systemic includes metabolic, bony, neurologic, and muscular abnormalities.

Rud syndrome is a poorly characterized disorder, probably of X-linked recessive inheritance, named after Einar Rud who described 2 patients with the case in 1927 and 1929. It was argued that all reported cases of Rud syndrome are genetically heterogeneous and significantly differ from the original case reports of Rud and that the designation Rud syndrome should be eliminated and that the patients with such diagnosis should be reassigned to other syndromes, such as Refsum disease and Sjögren-Larsson syndrome.Some consider Rud syndrome and Sjögren-Larsson syndrome the same entity and that Rud syndrome doesn't exist.

Causes of the one and a half syndrome include pontine hemorrhage, ischemia, tumors, infective mass lesions such as tuberculomas, and demyelinating conditions like multiple sclerosis.

The one and a half syndrome is a rare weakness in eye movement affecting both eyes, in which one cannot move laterally at all, and the other can move in only one lateral direction (inward or outward). More formally, it is characterized by ""a conjugate horizontal gaze palsy in one direction and an internuclear ophthalmoplegia in the other"". The most common manifestation of this unusual syndrome is limitation of horizontal eye movement to abduction (moving away from the midline) of one eye (e.g. right eye in the diagram on the right) with no horizontal movement of the other eye (e.g. left eye in the diagram on the right). Nystagmus is also present when the eye on the opposite side of the lesion is abducted. Convergence is classically spared as cranial nerve III (oculomotor nerve) and its nucleus is spared bilaterally.

In medicine, a prodrome is an early sign or symptom (or set of signs and symptoms), which often indicate the onset of a disease before more diagnostically specific signs and symptoms develop. It is derived from the Greek word "prodromos", meaning "running before". Prodromes may be non-specific symptoms or, in a few instances, may clearly indicate a particular disease, such as the prodromal migraine aura.

For example, fever, malaise, headache and lack of appetite frequently occur in the prodrome of many infective disorders. A prodrome can be the early precursor to an episode of a chronic neurological disorder such as a migraine headache or an epileptic seizure, where prodrome symptoms may include euphoria or other changes in mood, insomnia, abdominal sensations, disorientation, aphasia, or photosensitivity. Such a prodrome occurs on a scale of days to an hour before the episode, where an aura occurs more immediate to it.

Prodromal labour, mistakenly called "false labour," refers to the early signs before labour starts.

Any fracture in elbow region or upper arm may lead to Volkmann's ischemic contracture, but it is especially associated with supracondylar fracture of the humerus.

Volkmann's contracture results from acute ischaemia and necrosis of the muscle fibres of the flexor group of muscles of the forearm, especially the flexor digitorum profundus and flexor pollicis longus. The muscles become fibrotic and shortened.

The condition is caused by obstruction on the brachial artery near the elbow, possibly from improper use of a tourniquet, improper use of a plaster cast, or compartment syndrome. It is also caused by fractures of the forearm bones if they cause bleeding from the major blood vessels of the forearm.

Psychiatric disorders of childbirth are mental disorders developed by the mother related to the delivery process itself. They overlap with the Organic prepartum and postpartum psychoses and other psychiatric conditions associated with having children. ; symptoms include rage, or in rare cases, neonaticide.

There are many distinct forms of psychosis which start during pregnancy (prepartum) or after delivery (postpartum). In Europe and North America, only one – polymorphic psychosis (postpartum psychosis)– is commonly seen. Postpartum bipolar disorder, referred to in the DSM-5 as bipolar, peripartum onset, is a separate condition with no psychotic features. Historically, about one quarter of psychoses after childbirth were 'organic' and would now be classified as a form of delirium. This means that a severe mental disturbance, usually in the form of delirium, develops as a complication of a somatic illness.

A prodrome for schizophrenia is the period of decreased cognitive functioning that is postulated to correlate with the onset of psychotic symptoms. The concept has been reconsidered as the pathways to emerging psychosis have been investigated since the mid-1990s. One example of the international paradigms aimed at researching the prodrome is the North American Prodrome Longitudinal Study (NAPLS). This study is concerned with brain development, hormones, and neuropsychological functions that may play a role in risk for and prevention of mental illness in young adulthood. The term at risk mental state is sometimes preferred, as a prodromal period cannot be confirmed unless the emergence of the condition has occurred. (Also see early psychosis.)

Prodrome, or psychosis risk syndrome as it is also known, is a proposed syndrome to be used in the "DSM-5" (2013) of psychiatry. It is also defined as "the aura that precedes a psychotic break by up to two or three years." Patients with this condition "still have 'insight' – a pivotal word in psychiatric literature, indicating that a patient can still recognize an altered worldview as a sign of illness, and not a revelation." Prodrome is also sometimes called "attenuated psychotic symptoms syndrome." Chairman of the DSM-IV Task Force, Allen Frances, has criticised the concept of Psychosis Risk Syndrome on the grounds of a high rate of inaccuracy, the potential to stigmatize young people given this label, the lack of any effective treatment, and the risk of children and adolescents being given dangerous antipsychotic medication.

About one third of patients with prodrome are diagnosed with schizophrenia or other psychosis in a few years. In the North American Prodrome Longitudinal Study, researchers found that 35 percent of "patients had a psychotic break within two and a half years of enrolling at a clinic." 65 percent "found that their symptoms passed or plateaued." A psychotic break is made statistically more likely (43% vs. 35%) if the patient abuses certain drugs.

Netherton syndrome is characterized by chronic skin inflammation, universal pruritus (itch), severe dehydration, and stunted growth. Patients with this disorder tend to have a hair shaft defect (trichorrhexis invaginata), also known as "bamboo hair". The disrupted skin barrier function in affected individuals also presents a high susceptibility to infection and allergy, leading to the development of scaly, reddish skin similar to atopic dermatitis. In severe cases, these atopic manifestations persist throughout the individual's life, and consequently post-natal mortality rates are high. In less severe cases, this develops into the milder ichthyosis linearis circumflexa.

Netherton syndrome has recently been characterised as a primary immunodeficiency, which straddles the innate and acquired immune system, much as does Wiskott-Aldrich syndrome. A group of Netherton patients have been demonstrated to have altered immunoglobulin levels (typically high IgE and low to normal IgG) and immature natural killer cells. These Natural Killer cells have a reduced lytic function; which can be improved with regular infusions of immunoglobulin (see 'Treatment'); although the mechanism for this is not clear.

Patients are more prone than healthy people to infections of all types, especially recurrent skin infections with staphylococcus. They may have more severe infections; but are not as vulnerable to opportunistic pathogens as patients with true Natural Killer cell deficiency-type SCID.

WE is characterized by the presence of a triad of symptoms;

1. Ocular disturbances (ophthalmoplegia)

2. Changes in mental state (confusion)

3. Unsteady stance and gait (ataxia)

This triad of symptoms results from a deficiency in vitamin B which is an essential coenzyme. The aforementioned changes in mental state occur in approximately 82% of patients' symptoms of which range from confusion, apathy, inability to concentrate, and a decrease in awareness of the immediate situation they are in. If left untreated, WE can lead to coma or death. In about 29% of patients, ocular disturbances consist of nystagmus and paralysis of the lateral rectus muscles or other muscles in the eye. A smaller percentage of patients experience a decrease in reaction time of the pupils to light stimuli and swelling of the optic disc which may be accompanied by retinal hemorrhage. Finally, the symptoms involving stance and gait occur in about 23% of patients and result from dysfunction in the cerebellum and vestibular system. Other symptoms that have been present in cases of WE are stupor, low blood pressure (hypotension), elevated heart rate (tachycardia), as well as hypothermia, epileptic seizures and a progressive loss of hearing.

Interestingly, about 19% of patients have none of the symptoms in the classic triad at first diagnosis of WE; however, usually one or more of the symptoms develops later as the disease progresses.

Arterial occlusion may be due to thrombi, amniotic fragments or air embolism. Postpartum cerebral angiopathy is a transitory arterial spasm of medium caliber cerebral arteries; it was first described in cocaine and amphetamine addicts, but can also complicate ergot and bromocriptine prescribed to inhibit lactation. Subarachnoid haemorrhage can occur after miscarriage or childbirth. Epidural anaesthesia can, if the dura is punctured, lead to leakage of Cerebrospinal fluid and subdural haematoma. All these can occasionally present with psychiatric symptoms.

The syndrome is a combined manifestation of two namesake disorders, Wernicke's encephalopathy and Korsakoff's psychosis. It involves an acute Wernicke-encephalopathy phase, followed by the development of a chronic Korsakoff's syndrome phase.

Villitis of unknown etiology, abbreviated VUE, is an inflammatory process that involves the chorionic villi (villitis) whose cause (etiology) is not known. VUE is associated with recurrent miscarriage and intrauterine growth restriction, and recurs in subsequent pregnancies.

Volkmann's contracture is a permanent flexion contracture of the hand at the wrist, resulting in a claw-like deformity of the hand and fingers. Passive extension of fingers is restricted and painful.

Histomorphologically, VUE is characterized by a lymphocytic infiltrate of the chorionic villi without a demonstrable cause. Plasma cells should be absent; the presence of plasma cells suggests an infective etiology, e.g. CMV infection.

The condition may be a sign of various disease states, including but not exclusive to the following:

- Cancers

- Lymphoma

- Leukemia

- Infections

- HIV/AIDS

- Tuberculosis

- Mycobacterium avium-intracellulare infection

- Infectious mononucleosis

- Fungal infections (histoplasmosis, coccidioidomycosis)

- Lung abscess

- Infective endocarditis

- Brucellosis

- Pneumocystis pneumonia (most often - in immunocompromised individuals)

- Endocrine disorders

- Menopause

- Premature ovarian failure

- Hyperthyroidism

- Diabetes mellitus (nocturnal hypoglycemia)

- Endocrine tumors (pheochromocytoma, carcinoid)

- Orchiectomy

- Rheumatic disorders

- Takayasu's arteritis

- Temporal arteritis

- Other

- Obstructive sleep apnea

- Gastroesophageal reflux disease

- Chronic fatigue syndrome

- Fibromyalgia

- Granulomatous disease

- Chronic eosinophilic pneumonia

- Lymphoid hyperplasia

- Diabetes insipidus

- Prinzmetal's angina

- Anxiety

- Pregnancy

- Drugs

- Antipyretics (salicylates, acetaminophen)

- Antihypertensives

- Dinitrophenol - a common side effect

- Phenothiazines

- Drug withdrawal: ethanol, benzodiazepines, heroin (and other opiates),

- Over-bundling

- Autonomic over-activity

- IBD (inflammatory bowel disease) - Crohn's disease/ulcerative colitis

Netherton syndrome is a severe, autosomal recessive form of ichthyosis associated with mutations in the "SPINK5" gene. It is named after Earl W. Netherton (1910–1985), an American dermatologist who discovered it in 1958.

Night sweats, also known as nocturnal hyperhidrosis, is the occurrence of excessive sweating during sleep. The person may or may not also suffer from excessive perspiration while awake.

One of the most common causes of night sweats in women over 40 is the hormonal changes related to menopause and perimenopause. This is a very common occurrence during the menopausal transition years.

While night sweats might be relatively harmless, it can also be a sign of a serious underlying disease. It is important to distinguish night sweats due to medical causes from those that occur simply because the sleep environment is too warm, either because the bedroom is unusually hot or because there are too many covers on the bed. Night sweats caused by a medical condition or infection can be described as "severe hot flashes occurring at night that can drench sleepwear and sheets, which are not related to the environment". Some of the underlying medical conditions and infections that cause these severe night sweats can be life-threatening and should promptly be investigated by a medical practitioner.

Among the signs of subacute bacterial endocarditis are:

- Malaise

- Weakness

- Excessive sweat

- Fever

Patients can develop two clinical phases: an acute septic phase and a chronic eruptive phase associated with skin lesions. In the acute phase (also known as Oroya fever or "fiebre de la Oroya"), "B. bacilliformis" infection is a sudden, potentially life-threatening infection associated with high fever and decreased levels of circulating red blood cells (i.e., hemolytic anemia)and transient immunosuppression. "B. bacilliformis" is considered the most deadly species to date, with a death rate of up to 90% during the acute phase, which typically lasts two to four weeks. Peripheral blood smears show anisomacrocytosis with many bacilli adherent to red blood cells. Thrombocytopenia is also seen and can be very severe. Neurologic manifestations (neurobartonellosis) are altered mental status, agitation, or even coma, ataxia, spinal meningitis, or paralysis. It is seen in 20% of patients with acute infection, in which the prognosis is very guarded with an about 50% mortality. The most feared complication is overwhelming infection mainly by Enterobacteriaceae, particularly "Salmonella" (both "S. typhi" and " S. "non-"typhi", as well as reactivation of toxoplasmosis and other opportunistic infections .

The chronic manifestation consists of a benign skin eruption with raised, reddish-purple nodules (angiomatous tumours). The bacterium can be seen microscopically, if a skin biopsy is silver stained (the Warthin–Starry method).

"Acanthamoeba spp." causes mostly subacute or chronic granulomatous amoebic encephalitis (GAE), with a clinical picture of headaches, altered mental status, and focal neurologic deficit, which progresses over several weeks to death. In addition, "Acanthamoeba spp." can cause granulomatous skin lesions and, more seriously, keratitis and corneal ulcers following corneal trauma or in association with contact lenses.

"B. henselae" is the etiologic agent for peliosis hepatis, which is defined as a vascular proliferation of sinusoid hepatic capillaries resulting in blood-filled spaces in the liver in HIV patients and organ transplant recipients. Peliosis hepatis can be associated with peliosis of the spleen, as well as bacillary angiomatosis of the skin in HIV patients.

Diagnosis of subacute bacterial endocarditis can be done by collecting three blood culture specimens over a 24-hour period for analysis, also it can usually be indicated by the existence of:

- Osler's nodes

- Roth's spots

- Nail clubbing