Hypokalemia can result from one or more of these medical conditions:

Mild hypokalemia is often without symptoms, although it may cause elevation of blood pressure, and can provoke the development of an abnormal heart rhythm. Severe hypokalemia, with serum potassium concentrations of 2.5–3 meq/l (Nl: 3.5–5.0 meq/l), may cause muscle weakness, myalgia, tremor, and muscle cramps (owing to disturbed function of skeletal muscle), and constipation (from disturbed function of smooth muscle). With more severe hypokalemia, flaccid paralysis and hyporeflexia may result. Reports exist of rhabdomyolysis occurring with profound hypokalemia with serum potassium levels less than 2 meq/l. Respiratory depression from severe impairment of skeletal muscle function is found in many patients.

If a tuberculosis infection does become active, it most commonly involves the lungs (in about 90% of cases). Symptoms may include chest pain and a prolonged cough producing sputum. About 25% of people may not have any symptoms (i.e. they remain "asymptomatic"). Occasionally, people may cough up blood in small amounts, and in very rare cases, the infection may erode into the pulmonary artery or a Rasmussen's aneurysm, resulting in massive bleeding. Tuberculosis may become a chronic illness and cause extensive scarring in the upper lobes of the lungs. The upper lung lobes are more frequently affected by tuberculosis than the lower ones. The reason for this difference is not clear. It may be due to either better air flow, or poor lymph drainage within the upper lungs.

Tuberculosis may infect any part of the body, but most commonly occurs in the lungs (known as pulmonary tuberculosis). Extrapulmonary TB occurs when tuberculosis develops outside of the lungs, although extrapulmonary TB may coexist with pulmonary TB.

General signs and symptoms include fever, chills, night sweats, loss of appetite, weight loss, and fatigue. Significant nail clubbing may also occur.

Anisocoria is a condition characterized by an unequal size of the eyes' pupils. Affecting 20% of the population, it can be an entirely harmless condition or a symptom of more serious medical problems.

Autoimmunity is the system of immune responses of an organism against its own healthy cells and tissues. Any disease that results from such an aberrant immune response is termed an "autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, sarcoidosis, systemic lupus erythematosus (SLE), Sjögren's syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis (RA), ankylosing spondylitis, polymyositis (PM), dermatomyositis (DM) and multiple sclerosis (MS). Autoimmune diseases are very often treated with steroids.

Anisocoria is a common condition, defined by a difference of 0.4 mm or more between the sizes of the pupils of the eyes.

Anisocoria has various causes:

- Physiological anisocoria: About 20% of normal people have a slight difference in pupil size which is known as physiological anisocoria. In this condition, the difference between pupils is usually less than 1 mm.

- Horner's syndrome

- Mechanical anisocoria: Occasionally previous trauma, eye surgery, or inflammation (uveitis, angle closure glaucoma) can lead to adhesions between the iris and the lens.

- Adie tonic pupil: Tonic pupil is usually an isolated benign entity, presenting in young women. It may be associated with loss of deep tendon reflex (Adie's syndrome). Tonic pupil is characterized by delayed dilation of iris especially after near stimulus, segmental iris constriction, and sensitivity of pupil to a weak solution of pilocarpine.

- Oculomotor nerve palsy: Ischemia, intracranial aneurysm, demyelinating diseases (e.g., multiple sclerosis), head trauma, and brain tumors are the most common causes of oculomotor nerve palsy in adults. In ischemic lesions of the oculomotor nerve, pupillary function is usually spared whereas in compressive lesions the pupil is involved.

- Pharmacological agents with anticholinergic or sympathomimetic properties will cause anisocoria, particularly if instilled in one eye. Some examples of pharmacological agents which may affect the pupils include pilocarpine, cocaine, tropicamide, MDMA, dextromethorphan, and ergolines. Alkaloids present in plants of the genera "Brugmansia" and "Datura", such as scopolamine, may also induce anisocoria.

- Migraines

Diagnosis of autoimmune disorders largely rests on accurate history and physical examination of the patient, and high index of suspicion against a backdrop of certain abnormalities in routine laboratory tests (example, elevated C-reactive protein). In several systemic disorders, serological assays which can detect specific autoantibodies can be employed. Localised disorders are best diagnosed by immunofluorescence of biopsy specimens. Autoantibodies are used to diagnose many autoimmune diseases. The levels of autoantibodies are measured to determine the progress of the disease.

Symptoms show considerable variation but usually include:

An initial state of "DAZE" with some constriction of the field of consciousness and narrowing of attention, inability to comprehend stimuli, disorientation. Followed either by further withdrawal from the surrounding situation to the extent of a dissociative stupor or by agitating and over activity.

The signs are: Tachycardia (increased heart rate), Sweating, Hyperventilation (increased breathing).

The symptoms usually appear within minutes of the impact of the stressful stimulus and disappear within 2–3 days.

Factitious disorder imposed on self, also known as Munchausen syndrome, is a factitious disorder wherein those affected feign disease, illness, or psychological trauma to draw attention, sympathy, or reassurance to themselves. Munchausen syndrome fits within the subclass of factitious disorder with predominantly physical signs and symptoms, but patients also have a history of recurrent hospitalization, travelling, and dramatic, extremely improbable tales of their past experiences. The condition derives its name from Baron Munchausen.

Factitious disorder imposed on self is related to factitious disorder imposed on another, which refers to the abuse of another person, typically a child, in order to seek attention or sympathy for the abuser. This drive to create symptoms for the victim can result in unnecessary and costly diagnostic or corrective procedures.

Diagnosing factitious disorder imposed on self requires a clinical assessment. Clinicians should be aware that those presenting with symptoms (or persons reporting for that person) may malinger, and caution should be taken to ensure there is evidence for a diagnosis. Lab tests may be required, including complete blood count (CBC), urine toxicology, drug levels from blood, cultures, coagulation tests, assays for thyroid function, or DNA typing. In some cases CT scan, magnetic resonance imaging, psychological testing, electroencephalography, or electrocardiography may also be employed. A summary of more common and reported cases of factitious disorder (Munchausen syndrome), and the laboratory tests used to differentiate these from authentic disease is provided below:

There are several symptoms that together point to factitious disorder, including frequent hospitalizations, knowledge of several illnesses, frequently requesting medication such as pain killers, openness to extensive surgery, few or no visitors during hospitalizations, and exaggerated or fabricated stories about several medical problems. Factitious disorder should not be confused with hypochondria, as people with factitious disorder syndrome do not really believe they are sick; they only want to be sick, and thus fabricate the symptoms of an illness. It is also not the same as pretending to be sick for personal benefit such as being excused from work or school.

People may fake their symptoms in multiple ways. Other than making up past medical histories and faking illnesses, people might inflict harm on themselves by consuming laxatives or other substances, self-inflicting injury to induce bleeding, and altering laboratory samples.” Many of these conditions do not have clearly observable or diagnostic symptoms and sometimes the syndrome will go undetected because patients will fabricate identities when visiting the hospital several times. Factitious disorder has several complications, as these people will go to great lengths to fake their illness. Severe health problems, serious injuries, loss of limbs or organs, and even death are possible complications.

Deaf-mute is a term which was used historically to identify a person who was either deaf using a sign language or both deaf and could not speak. The term continues to be used to refer to deaf people who cannot speak an oral language or have some degree of speaking ability, but choose not to speak because of the negative or unwanted attention atypical voices sometimes attract. Such people communicate using sign language. Some consider it to be a derogatory term if used outside its historical context; the preferred term today is simply "deaf".

OCD can present with a wide variety of symptoms. Certain groups of symptoms typically occur together. These groups are sometimes viewed as dimensions or clusters that may reflect an underlying process. The standard assessment tool for OCD, the Yale–Brown Obsessive Compulsive Scale (Y-BOCS), has 13 predefined categories of symptoms. These symptoms fit into three to five groupings. A meta analytic review of symptom structures found a four factor structure(grouping) to be most reliable. The observed groups included a "symmetry factor", a "forbidden thoughts factor", a "cleaning factor" and a "hoarding factor". The "symmetry factor" correlated highly with obsessions related to ordering, counting, symmetry as well as repeating compulsions. The "forbidden thoughts factor" correlated highly with intrusive and distressing thoughts of a violent, religious or sexual nature. The "cleaning factor" correlated highly with obsessions about contamination and compulsions related to cleaning. The "hoarding factor" only involved hoarding related obsessions and compulsions, and was identified as being distinct from other symptom groupings.

While OCD has been considered a homogenous disorder from a neuropsychological perspective, many of the putative neuropsychological deficits may be due to comorbid disorders. Furthermore, some subtypes have been associated with improvement in performance on certain tasks such as pattern recognition(washing subtype) and spatial working memory(obsessive thought subtype). Subgroups have also been distinguished by neuroimaging findings and treatment response. Neuroimaging studies on this have been too few, and the subtypes examined have differed too much to draw any conclusions. On the other hand, subtype dependent treatment response has been studied, and the hoarding subtype has consistently responded least to treatment.

Obsessive–compulsive disorder (OCD) is a mental disorder where people feel the need to check things repeatedly, perform certain routines repeatedly (called "rituals"), or have certain thoughts repeatedly. People are unable to control either the thoughts or the activities for more than a short period of time. Common activities include hand washing, counting of things, and checking to see if a door is locked. Some may have difficulty throwing things out. These activities occur to such a degree that the person's daily life is negatively affected. Often they take up more than an hour a day. Most adults realize that the behaviors do not make sense. The condition is associated with tics, anxiety disorder, and an increased risk of suicide.

The cause is unknown. There appear to be some genetic components with both identical twins more often affected than both non-identical twins. Risk factors include a history of child abuse or other stress inducing event. Some cases have been documented to occur following infections. The diagnosis is based on the symptoms and requires ruling out other drug related or medical causes. Rating scales such as the Yale–Brown Obsessive Compulsive Scale (Y-BOCS) can be used to assess the severity. Other disorders with similar symptoms include anxiety disorder, major depressive disorder, eating disorders, tic disorders, and obsessive–compulsive personality disorder.

Treatment involves counselling, such as cognitive behavioral therapy (CBT), and sometimes medication, typically selective serotonin reuptake inhibitors (SSRIs). CBT for OCD involves increasing exposure to what causes the problems while not allowing the repetitive behavior to occur. While clomipramine appears to work as well as SSRIs, it has greater side effects. Atypical antipsychotics may be useful when used in addition to an SSRI in treatment-resistant cases but are also associated with an increased risk of side effects. Without treatment, the condition often lasts decades.

Obsessive–compulsive disorder affects about 2.3% of people at some point in their life. Rates during a given year are about 1.2% and it occurs worldwide. It is unusual for symptoms to begin after the age of thirty-five, and half of people develop problems before twenty. Males and females are affected about equally. In English the phrase "obsessive–compulsive" is often used in an informal manner unrelated to OCD to describe someone who is excessively meticulous, perfectionistic, absorbed, or otherwise fixated.

Warning signs of the disorder include:

- A child who has one or more medical problems that do not respond to treatment or that follow an unusual course that is persistent, puzzling, and unexplained.

- Physical or laboratory findings that are highly unusual, discrepant with patient's presentation or history, or physically or clinically impossible.

- A parent who appears medically knowledgeable, fascinated with medical details and hospital gossip, appears to enjoy the hospital environment and expresses interest in the details of other patients' problems.

- A highly attentive parent who is reluctant to leave their child's side and who themselves seem to require constant attention.

- A parent who appears unusually calm in the face of serious difficulties in their child's medical course while being highly supportive and encouraging of the physician, or one who is angry, devalues staff and demands further intervention, more procedures, second opinions, and transfers to other more sophisticated facilities.

- The suspected parent may work in the health care field themselves or profess an interest in a health-related job.

- The signs and symptoms of a child's illness may lessen or simply vanish in the parent's absence (hospitalization and careful monitoring may be necessary to establish this causal relationship).

- A family history of similar or unexplained illness or death in a sibling.

- A parent with symptoms similar to their child's own medical problems or an illness history that itself is puzzling and unusual.

- A suspected emotionally distant relationship between parents; the spouse often fails to visit the patient and has little contact with physicians even when the child is hospitalized with a serious illness.

- A parent who reports dramatic, negative events, such as house fires, burglaries, or car accidents, that affect them and their family while their child is undergoing treatment.

- A parent who seems to have an insatiable need for adulation or who makes self-serving efforts for public acknowledgment of their abilities.

- A patient who inexplicably deteriorates whenever discharge is planned.

In factitious disorder imposed on another, a caregiver makes a dependent person appear mentally or physically ill in order to gain attention. To perpetuate the medical relationship, the caregiver systematically misrepresents symptoms, fabricates signs, manipulates laboratory tests, or even purposely harms the dependent (e.g. by poisoning, suffocation, infection, physical injury). Studies have shown a mortality rate of between 6% and 10%, making it perhaps the most lethal form of abuse.

At the time of diagnosis, the average age of the persons affected was 4 years. Slightly over 50% were aged 24 months or younger, and 75% were under 6 years old. The average duration from onset of symptoms to diagnosis was 22 months. By the time of diagnosis, 6% of the affected persons were dead, mostly from apnea (a common result of smothering) or starvation, and 7% suffered long-term or permanent injury. About half of the affected had siblings; 25% of the known siblings were dead, and 61% of siblings had symptoms similar to the affected or that was otherwise suspicious. The mother was the perpetrator in 76.5% of the cases, the father in 6.7%.

Most present about 3 medical problems in some combination of the 103 different reported symptoms. The most frequently reported problems are apnea (26.8% of cases), anorexia / feeding problems (24.6% of cases), diarrhea (20%), seizures (17.5%), cyanosis (blue skin) (11.7%), behavior (10.4%), asthma (9.5%), allergy (9.3%), and fevers (8.6%). Other symptoms include failure to thrive, vomiting, bleeding, rash and infections. Many of these symptoms are easy to fake because they are subjective. A parent reporting that their child had a fever in the past 24 hours is making a claim that is impossible to prove or disprove. The number and variety of presented symptoms contribute to the difficulty in reaching a proper MSbP diagnosis.

Aside from the motive (which is to gain attention or sympathy), another feature that differentiates MSbP from "typical" physical child abuse is the degree of premeditation involved. Whereas most physical abuse entails lashing out at a child in response to some behavior (e.g., crying, bedwetting, spilling food), assaults on the MSbP victim tend to be unprovoked and planned.

Also unique to this form of abuse is the role that health care providers play by actively, albeit unintentionally, enabling the abuse. By reacting to the concerns and demands of perpetrators, medical professionals are manipulated into a partnership of child maltreatment. Challenging cases that defy simple medical explanations may prompt health care providers to pursue unusual or rare diagnoses, thus allocating, even more, time to the child and the abuser. Even without prompting, medical professionals may be easily seduced into prescribing diagnostic tests and therapies that are at best uncomfortable and costly, and at worst potentially injurious to the child. If the health practitioner instead resists ordering further tests, drugs, procedures, surgeries, or specialists, the MSbP abuser makes the medical system appear negligent for refusing to help a poor sick child and their selfless parent. Like those with Munchausen syndrome, MSbP perpetrators are known to switch medical providers frequently until they find one that is willing to meet their level of need; this practice is known as "doctor shopping" or "hospital hopping".

The perpetrator continues the abuse because maintaining the child in the role of patient satisfies the abuser's needs. The cure for the victim is to separate the child completely from the abuser. When parental visits are allowed, sometimes there is a disastrous outcome for the child. Even when the child is removed, the perpetrator may then abuse another child: a sibling or other child in the family.

Factitious disorder imposed on another can have many long-term emotional effects on a child. Depending on their experience of medical interventions, a percentage of children may learn that they are most likely to receive the positive maternal attention they crave when they are playing the sick role in front of health care providers. Several case reports describe Munchausen syndrome patients suspected of themselves having been MSbP victims. Seeking personal gratification through illness can thus become a lifelong and multi-generational disorder in some cases. In stark contrast, other reports suggest survivors of MSbP develop an avoidance of medical treatment with post-traumatic responses to it. This variation possibly reflects broad statistics on survivors of child abuse in general, where around 30% go on to also become abusers even though a significant percentage do not.

The adult care provider who has abused the child often seems comfortable and not upset over the child's hospitalization. While the child is hospitalized, medical professionals must monitor the caregiver's visits to prevent an attempt to worsen the child's condition. In addition, in many jurisdictions, medical professionals have a duty to report such abuse to legal authorities.

Psychopathy, sometimes considered synonymous with sociopathy, is traditionally defined as a personality disorder characterized by persistent antisocial behavior, impaired empathy and remorse, and bold, disinhibited, egotistical traits. Different conceptions of psychopathy have been used throughout history. These conceptions are only partly overlapping and may sometimes be contradictory.

Hervey M. Cleckley, an American psychiatrist, influenced the initial diagnostic criteria for antisocial personality reaction/disturbance in the "Diagnostic and Statistical Manual of Mental Disorders" (DSM), as did American psychologist George E. Partridge. The DSM and "International Classification of Diseases" (ICD) subsequently introduced the diagnoses of antisocial personality disorder (ASPD) and dissocial personality disorder (DPD) respectively, stating that these diagnoses have been referred to (or include what is referred to) as psychopathy or sociopathy. The creation of ASPD and DPD was driven by the fact that many of the classic traits of psychopathy were impossible to measure objectively. Canadian psychologist Robert D. Hare later repopularized the construct of psychopathy in criminology with his Psychopathy Checklist.

Although no psychiatric or psychological organization has sanctioned a diagnosis titled "psychopathy", assessments of psychopathic characteristics are widely used in criminal justice settings in some nations, and may have important consequences for individuals. The study of psychopathy is an active field of research, and the term is also used by the general public, popular press, and in fictional portrayals. While the term is often employed in common usage along with the related but distinct "crazy", "insane", and "mentally ill", there is a distinction between those with psychosis and psychopathy.

Psychopathy is a personality disorder which has symptoms expressed over a wide range of settings. Socially, it expresses extensive callous and manipulative self-serving behaviors with no regard for others, and often is associated with repeated delinquency, crime and violence, but may also present itself in other, maybe even successful social settings. Mentally, impairments in processes related to affect (emotion) and cognition, particularly socially related mental processes, have been found in those with the disorder which suggest that their destructive social behavior is borne from these aberrant mental processes. Developmentally, symptoms of psychopathy have been identified in young children with conduct disorder, and is suggestive of at least a partial constitutional factor that influences its development.

It is sometimes used to refer to other hearing people in jest, to chide, or to invoke an image of someone who refuses to employ common sense or who is unreliable. "Deaf and dumb", "semi-deaf" and "semi-mute" are other historic references to deaf people.

In the past "deaf-mute" was used to describe deaf people who used sign language, but in modern times, the term is frequently viewed as offensive and inaccurate. From antiquity (as noted in the Code of Hammurabi) until recent times, the terms "deaf-mute" and "deaf and dumb" were sometimes considered analogous to "stupid" by some hearing people.

The simple identity of "deaf" has been embraced by the community of signing deaf people since the foundations of public deaf education in the 18th century and remains the preferred term of reference or identity for many years. Within the deaf community there are some who prefer the term "Deaf" (upper-case D) to "deaf" (lower-case) as a description of their status and identity.

Classification as a deaf-mute has a particular importance in Jewish law. Because historically it was thought impossible to teach or communicate with them, deaf-mutes were not moral agents, and therefore were unable to own real estate, act as witnesses, or be punished for any crime. However, today when techniques for educating deaf people are known, they are no longer classed as such.