Common Symptoms and How They Are Caused

1. Fever

Fever is a common symptom of infectious disease, immunological disease, tissue destruction, reaction to incompatible blood products, cancers and metabolic disorders. Stimulations called pathogens induce fever. Prostaglandin E2, a sensory neuron, senses pathogens and passes the signal to hypothalamus, a part of the brain, which responses by incresing body temperature. Fever also involves vascular restriction leading to less heat loss, thermogenesis in brown adipose tissue leading to higher heat generation, and raised metabolic rate. If these responses are still not effective, the patient will begin to shiver fore more heat and even higher metabolic rate.

2. Nausea

Nausea and vomiting are responses to various signals ranging from toxins to disturbances in balance sensing organs; more specifically, the factors include motion sickness, certain medication, stress, and injection of toxins. Some causes of nausea delay the symptom more than others do. Food posioning causes nausea to happen up to eight hours later after meal, while foodborne bacteria cause the symptom to happen even later. Generally vomiting is sufferable but harmless; however sometimes vomiting can cause dehydration. Children is especially subjected to dehydration caused by vomiting.

3. Headache

Headaches are classified into primary ones and secondary ones. Primary headaches are not caused by diseases and are thus safer, whereas secondary headaches are caused by dangerous diseases like infection, brain bleed or tumors. Also, since brain does not have pain receptors, the pain is sensed by other body parts on neck and head such as veins and neck muscles. Unlike secondary headaches, primary headaches are caused by reasons yet unknown, although several theories account for the causes. In general, improving lifestyle and taking medicines reduce primary headaches.

4. Runny Nose

Runny nose, or rhinorrhea, occurs when mucus fills up the nasal cavity. The secretion cells produce mucus faster than ithe body can process it, and as the result the mucus eventually blocks the nasal cavity. Rhinorrhea can also cause headache and ear pain by increasing the pressure in head. During colder seasons, nose needs to warm up more air, and the body responses to the need by increasing mucus secretion to protect the nasal cavity from increased air flow. During infection, the mucus functions as a barrier between the bacteria and the lung. The treatment of rhinorrhea is usually unnecessary since the mucus is mostly protective and will stop on its own after a few days.

5. Diarrhea

Diarrhea is defined as having at least three liquid defecations in one day. Research shows diarrhea has evolved to be a defensive mechanism by which the body flushes away pathogens. Thus, diarrhea is better not inhibited during sickness. However, diarrhea may lead to severe dehydration which can be lethal. Maintaining a healthy diet and taking oral rehydration solution, water solution of small amounts of salt and sugar, minimize the effect of dehydration. Maintaining proper sanitation, using clean water, and ingesting enough zinc can prevent diarrhea by eliminating pathogens and reinforcing the immune system.

More Information

Fever Facts

Nausea Facts

Headache Facts

Runny Nose Facts

Diarrhea Facts