Medical diagnosis is the process of determining which disease or condition explains a person's symptoms and signs. It is most referred to as diagnosis with the medical context being implicit; the information required for diagnosis is collected from a history and physical examination of the person seeking medical care. One or more diagnostic procedures, such as diagnostic tests, are done during the process. Sometimes posthumous diagnosis is considered a kind of medical diagnosis. Diagnosis is challenging, because many signs and symptoms are nonspecific. For example, redness of the skin, by itself, is a sign of many disorders and thus does not tell the healthcare professional what is wrong, thus differential diagnosis, in which several possible explanations are compared and contrasted, must be performed. This involves the correlation of various pieces of information followed by the recognition and differentiation of patterns; the process is made easy by a sign or symptom, pathognomonic. Diagnosis is a major component of the procedure of a doctor's visit.
From the point of view of statistics, the diagnostic procedure involves classification tests. The first recorded examples of medical diagnosis are found in the writings of Imhotep in ancient Egypt. A Babylonian medical textbook, the Diagnostic Handbook written by Esagil-kin-apli, introduced the use of empiricism and rationality in the diagnosis of an illness or disease. Traditional Chinese Medicine, as described in the Yellow Emperor's Inner Canon or Huangdi Neijing, specified four diagnostic methods: inspection, auscultation-olfaction and palpation. Hippocrates was known to make diagnoses by smelling their sweat. A diagnosis, in the sense of diagnostic procedure, can be regarded as an attempt at classification of an individual's condition into separate and distinct categories that allow medical decisions about treatment and prognosis to be made. Subsequently, a diagnostic opinion is described in terms of a disease or other condition, but in the case of a wrong diagnosis, the individual's actual disease or condition is not the same as the individual's diagnosis.
A diagnostic procedure may be performed by various health care professionals such as a physician, physical therapist, healthcare scientist, dentist, nurse practitioner, or physician assistant. This article uses diagnostician as any of these person categories. A diagnostic procedure does not involve elucidation of the etiology of the diseases or conditions of interest, that is, what caused the disease or condition; such elucidation can be useful to optimize treatment, further specify the prognosis or prevent recurrence of the disease or condition in the future. The initial task is to detect a medical indication to perform a diagnostic procedure. Indications include: Detection of any deviation from what is known to be normal, such as can be described in terms of, for example, physiology, pathology and human homeostasis. Knowledge of what is normal and measuring of the patient's current condition against those norms can assist in determining the patient's particular departure from homeostasis and the degree of departure, which in turn can assist in quantifying the indication for further diagnostic processing.
A complaint expressed by a patient. The fact that a patient has sought a diagnostician can itself be an indication to perform a diagnostic procedure. For example, in a doctor's visit, the physician may start performing a diagnostic procedure by watching the gait of the patient from the waiting room to the doctor's office before she or he has started to present any complaints. During an ongoing diagnostic procedure, there can be an indication to perform another, diagnostic procedure for another concomitant, disease or condition; this may occur as a result of an incidental finding of a sign unrelated to the parameter of interest, such as can occur in comprehensive tests such as radiological studies like magnetic resonance imaging or blood test panels that include blood tests that are not relevant for the ongoing diagnosis. General components which are present in a diagnostic procedure in most of the various available methods include: Complementing the given information with further data gathering, which may include questions of the medical history, physical examination and various diagnostic tests.
A diagnostic test is any kind of medical test performed to aid in the diagnosis or detection of disease. Diagnostic tests can be used to provide prognostic information on people with established disease. Processing of the answers, findings or other results. Consultations with other providers and specialists in the field may be sought. There are a number of methods or techniques that can be used in a diagnostic procedure, including performing a differential diagnosis or following medical algorithms. In reality, a diagnostic procedure may involve components of multiple methods; the method of differential diagnosis is based on finding as many candidate diseases or conditions as possible that can cause the signs or symptoms, followed by a process of elimination or at least of rendering the entries more or less probable by further medical tests and other processing until, aiming to reach the point where only one candidate disease or condit
Cranial nerves are the nerves that emerge directly from the brain, in contrast to spinal nerves. 10 of the cranial nerves originate in the brainstem. Cranial nerves relay information between the brain and parts of the body to and from regions of the head and neck. Spinal nerves emerge sequentially from the spinal cord with the spinal nerve closest to the head emerging in the space above the first cervical vertebra; the cranial nerves, emerge from the central nervous system above this level. Each cranial nerve is present on both sides. Depending on definition in humans there are twelve or thirteen cranial nerves pairs, which are assigned Roman numerals I–XII, sometimes including cranial nerve zero; the numbering of the cranial nerves is based on the order in which they emerge from the brain, front to back. The terminal nerves, olfactory nerves and optic nerves emerge from the cerebrum or forebrain, the remaining ten pairs arise from the brainstem, the lower part of the brain; the cranial nerves are considered components of the peripheral nervous system, although on a structural level the olfactory and trigeminal nerves are more considered part of the central nervous system.
Most humans are considered to have twelve pairs of cranial nerves, with the terminal nerve more canonized. They are: the olfactory nerve, the optic nerve, oculomotor nerve, trochlear nerve, trigeminal nerve, abducens nerve, facial nerve, vestibulocochlear nerve, glossopharyngeal nerve, vagus nerve, accessory nerve, hypoglossal nerve. Cranial nerves are named according to their structure or function. For example, the olfactory nerve supplies smell, the facial nerve supplies motor innervation to the face; because Latin was the lingua franca of the study of anatomy when the nerves were first documented and discussed, many nerves maintain Latin or Greek names, including the trochlear nerve, named according to its structure, as it supplies a muscle that attaches to a pulley. The trigeminal nerve is named in accordance with its three components, the vagus nerve is named for its wandering course. Cranial nerves are numbered based on their rostral-caudal position. If the brain is removed from the skull the nerves are visible in their numeric order, with the exception of the last, CN XII, which appears to emerge rostrally to CN XI.
Cranial nerves have paths outside the skull. The paths within the skull are called "intracranial" and the paths outside the skull are called "extracranial". There are many holes in the skull called "foramina" by. All cranial nerves are paired, which means that they occur on both the right and left sides of the body; the muscle, skin, or additional function supplied by a nerve on the same side of the body as the side it originates from, is referred to an ipsilateral function. If the function is on the opposite side to the origin of the nerve, this is known as a contralateral function. Intracranial course of cranial nerves is important regarding diagnosis of various intracranial lesions like brain tumors and intracranial arterial aneurysms. Dysfunction of one or more cranial nerves indicates stimulation by some lesion. For example an acoustic schwanoma may cause disturbance in hearing but with further growth of tumor it may involve other cranial nerves and the patient may present with pain resembling trigeminal neuralgia when the tumor involves trigeminal nerve or diplopia due to abducent nerve involvement facial palsy with facial nerve compression.
These findings along with cerebellar signs will suggest the diagnosis of a cerebellopontine angle lesion. A patient presenting with ptosis may have a posterior communicating artery aneurysm compressing the oculomotor nerve during its intracranial course. Facial pain in the distribution of any one or all divisions of trigeminal nerve suggests stimulation of trigeminal nerve roots by a near by vessel; the cell bodies of many of the neurons of most of the cranial nerves are contained in one or more nuclei in the brainstem. These nuclei are important relative to cranial nerve dysfunction because damage to these nuclei such as from a stroke or trauma can mimic damage to one or more branches of a cranial nerve. In terms of specific cranial nerve nuclei, the midbrain of the brainstem has the nuclei of the oculomotor nerve and trochlear nerve; the fibers of these cranial nerves exit the brainstem from these nuclei. Some of the cranial nerves have sensory or parasympathetic ganglia of neurons, which are located outside the brain.
The sensory ganglia are directly correspondent to dorsal root ganglia of spinal nerves and are known as cranial sensory ganglia. Sensory ganglia exist for nerves with sensory function: V, VII, VIII, IX, X. There are parasympathetic ganglia, which are part of the autonomic nervous system for cranial nerves III, VII, IX and X; the trigeminal ganglia of the trigeminal nerve occupies a space in the dura mater called Trigeminal cave. This ganglion contains the cell bodies of the sensory fibers of the three branches of the trig
In medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is associated. Asymptomatic infections are called subclinical infections. Other diseases might be considered subclinical if they present some but not all of the symptoms required for a clinical diagnosis; the term clinically silent is used. Knowing that a condition is asymptomatic is important because: It may develop symptoms and so require watch and wait or early treatment, it may become benign. It is required that a person undergoes treatment so it does not cause medical problems such as high blood pressure and hyperlipidaemia. Be alert to possible problems: asymptomatic hypothyroidism makes a person vulnerable to Wernicke-Korsakoff syndrome or beri-beri following intravenous glucose; the affected person may be infectious and unknowingly spread the infection to others. An example of an asymptomatic disease is Cytomegalovirus, a member of the herpes virus.
"It is estimated that 1% of all newborns are infected with CMV, but the majority of infections are asymptomatic." In some diseases, the proportion of asymptomatic cases can be important. For example, in multiple sclerosis it is estimated that around 25% of the cases are asymptomatic, being these cases detected postmortem or just by coincidence while treating other diseases. Asymptomatic conditions may not be discovered; some people may remain asymptomatic for a remarkably long period of time. If a patient is asymptomatic, precautionary steps must be taken. A patient's individual genetic makeup may prevent the onset of symptoms; some diseases are defined only clinically, like AIDS being opposed to HIV infection. Therefore, it makes no sense to speak about "asymptomatic AIDS"; this concept of clinically defined diseases is related in some way to the concept of syndrome. These are conditions for which there is a sufficient number of documented individuals that are asymptomatic that it is clinically noted.
For a complete list of asymptomatic infections see subclinical infection. Symptomatic Subclinical infection