What is a symptom?
In medicine, a symptom (Greek symptoma = a happening, befall) refers to a change in body function or sensation, like weakness or pain, as experienced by a patient (1). It is subjective meaning that it cannot be verified or measured independently and has to be reported by the patient.
A patient’s description of the symptoms, its intensity and duration is recorded in the medical history, but the signs of the disease has to be monitored and assessed for accurate diagnosis and monitoring the progression of a disease. To establish a diagnosis a physician will, apart from subjective symptoms, often need to check for objective signs of disease with physical examination of the patient and medical investigations.
Symptoms may be acute (sudden, newly appearing), chronic (long lasting), remittent (temporary decreasing in severity), intermittent (ceasing completely and beginning again; from Latin inter- + mittere = to let go), or relapsing (recurring after a period of improvement; from Latin re- = back + labi = to slip). Symptoms may also be imagined (psychogenic) and to the patient can be as real as symptoms associated with actual disease. This should be differentiated from signs of disease that are due to the effect of the mind (psychosomatic). For example – thinking of a stressful event in one’s life can raise the blood pressure and this high blood pressure can be verified independently.
Common Symptoms in Disease
- Pain : feeling of severe discomfort which can be excruciating.
- Nausea : feeling of wanting to vomit.
- Fatigue : state of extreme tiredness.
- Bloated : sensation of feeling full in the stomach or abdomen and must be differentiated from distension which is visible enlargement of the abdomen.
- Itching : the sensation of discomfort, but not pain, that urges a person to scratch the affected area. It is best described as a sensation similar to a crawling insect of the skin although the exact term for this sensation is formication.
Symptomatic disease appears with symptoms, and asymptomatic disease without symptoms.
What is a sign in medicine?
Sign of disease, such as rash or high blood pressure, refers to an objective evidence of a disease as detected by a physician during a physical examination of the patient, or by a medical investigation. With regards to disease and medicine, the word ‘sign’ needs to be differentiated from ‘symptom’. A sign can be confirmed, assessed and monitored by others. A symptom is only experienced and therefore reported by the patient and cannot be independently verified. It is subjective.
For example, nausea is a symptom because the patient feels like they need to vomit. This cannot be verified independently. However, vomiting is a sign because it can be seen independently by others.
Some Common Signs of Disease
Different diseases will present with a wide variety of signs and even symptoms. These signs depend on the organ or system affected in the disease and any other concomitant effects. Some of these signs include :
- Fever : a higher than normal body temperature usually exceeding 37.8 degrees Celsius.
- Lymphadenopathy : swollen or enlarged lymph node usually greater than 1 centimeter in diameter.
- Edema : visible swelling of a part of the body due to fluid accumulation.
- Rash : an inflamed area of the skin usually dry, red and raised. Various skin rashes may differ in presentation.
- Hemorrhage : bleeding from a blood vessel, usually an artery, due to a tear or rupture.
- Discoloration : variation from the normal color and may refer to the skin, sclera of the eyes or mucous membranes of the mouth, anus or genitalia.
- Pallor : paleness of the skin often due to impaired blood circulation.
- Cyanosis : bluish discoloration of the areas mentioned under discoloration due to reduced oxygen availability.
What do signs of disease mean?
Signs of a disease means that the body is not functioning at the optimal level and some pathogenic process has begun in the affected area. Since signs of a disease can be independently verified, it should be monitored closely by a physician as it is a reliable indication of the progression of a disease or improvement due to successful treatment. The absence of any signs of a disease, despite the report of symptoms, should not mean that a diseases state is not present. In various diseases, a patient may first experience symptoms and only later as the disease progresses will various signs become evident.
What is a medical diagnosis?
A medical diagnosis (Greek dia = apart; gnosis = knowledge, insight), short Dx, is the physician’s conclusion about which disease, disorder, injury or state his patient is affected by. Only a registered physician or appropriately qualified health care practitioner can make a medical diagnosis.
Based on the diagnosis, the physician will the decide on the most appropriate treatment and commence with it accordingly. However, not every diagnosis is accurate. With the scores of different medical conditions, may of which with similar clinical features, a misdiagnosis can be made by even the most experienced physician. This is where the advancements in technology related to medical science has proved to be the greatest asset to the physician. Various diagnostic investigations helps a doctor make the final diagnosis.
Diagnostic procedures includes clinical assessment asking a patient for symptoms by taking a medical history, finding signs of the disease by a physical examination, checking results of medical investigations and making a diagnosis from the collective data.
Diagnostic investigations include blood, sputum, urine or stool tests, imaging studies like X-ray, ultrasound, CT, MRI or more invasive techniques like a biopsy. The purpose of these investigations is to accurately assess the disease process at a cellular or even molecular levels and correlate this data with the medical history and physical examination.
Differential diagnosis, short DD, is a list of diseases that seem to be possible causes of a patient’s symptoms at certain in the process of diagnosis. By excluding each disease on the differential diagnosis list one by one, the final remaining disease is the most likely diagnosis. This process of elimination or exclusion is often necessary when a disease cannot be confirmed by diagnostic investigations. For example, IBS (irritable bowel syndrome) is a diagnosis reached when other diseases are excluded as possible causes of gastrointestinal symptoms.
On the other hand, medical diagnostic investigations these days have advanced to a stage where a physician can accurately diagnose a condition without eliminating all other diseases. For example, a DD in a patient coughing blood includes: chronic bronchitis, lung cancer, pulmonary embolism, injury of the chest and a combination of a chest X-ray, sputum sample, related blood tests and a biopsy will conclusively confirm the diagnosis.