Symptoms and signs of flu

The symptoms of fluA viral infection affecting the respiratory system., and the extent of these symptoms, vary from person to person.

Classic symptoms include a high temperature, muscleTissue made up of cells that can contract to bring about movement. aches and pains, coughing and sore throat. In some people, having fluA viral infection affecting the respiratory system. may just result in a mild respiratory illness, similar to having a cold. In fact, some research suggests that up to half of all fluA viral infection affecting the respiratory system. infections may cause few if any symptoms. Other people might experience a state of exhaustion, without characteristic signs and symptoms, while in some, the condition may be so severe as to be fatal. [1-3]

The severity of the disease may also depend on the type of influenzaA viral infection affecting the respiratory system. virusA microbe that is only able to multiply within living cells. responsible. For example, influenzaA viral infection affecting the respiratory system. types A and B cause very similar illnesses, while influenzaA viral infection affecting the respiratory system. type C tends to cause a milder illness more similar to the common cold.[4]

The more severe symptoms of fluA viral infection affecting the respiratory system. and fever often last from 7-10 days, although weakness and fatigue may be felt for weeks afterwards

Symptoms of flu

The first sign of fluA viral infection affecting the respiratory system. is often a high fever, which, although it comes down gradually, can last for about a week. This fever usually starts suddenly, and can be as high as 40.0°C or 104°F.[1]

Other symptoms and signs of fluA viral infection affecting the respiratory system. infectionInvasion by organisms that may be harmful, for example bacteria or parasites. may include:[1,2,5,6]

  • Severe muscleTissue made up of cells that can contract to bring about movement. pain (myalgiaPain in the muscles.) and joint pain (arthralgiaPain in the joints.)
  • Loss of appetite (anorexiaA loss of appetite resulting in weight loss. Anorexia nervosa is a psychological illness in which self-starvation leads to weight loss.)
  • Weight loss
  • Sore throat
  • Flushing
  • Generalised or frontal headache
  • Dry cough
  • Chills
  • Weakness and fatigue
  • Chest pain beneath the breastbone, or on breathing in
  • A feeling of general discomfort (malaiseGeneral feeling of being unwell. )
  • Pain on moving the eyes, or on looking at bright lights (photophobiaAn abnormal sensitivity to light.)
  • Shivering and a cold sensation.

People with fluA viral infection affecting the respiratory system. often experience symptoms so suddenly that they can actually pinpoint the hour that they started feeling unwell.[5] The more severe symptoms of fluA viral infection affecting the respiratory system. and fever often last from 7-10 days, although weakness and fatigue may be felt for weeks afterwards.[5,6]

Symptoms such as fever, muscleTissue made up of cells that can contract to bring about movement. pain and cough can be caused by other virusesMicrobes that are only able to multiply within living cells. as well as influenzaA viral infection affecting the respiratory system. virusesMicrobes that are only able to multiply within living cells.. Other possible causes of symptoms similar to those caused by fluA viral infection affecting the respiratory system. include infectionInvasion by organisms that may be harmful, for example bacteria or parasites. with respiratory syncytial virusA microbe that is only able to multiply within living cells., parainfluenza virusesMicrobes that are only able to multiply within living cells. and rhinovirus.[3]

Distinguishing between flu and the common cold

Sometimes people find it difficult to distinguish fluA viral infection affecting the respiratory system. from the common cold; as a general rule, however, people with fluA viral infection affecting the respiratory system. tend to be much more unwell.

Other clues are that fluA viral infection affecting the respiratory system. tends to come on abruptly, whereas the common cold comes on more gradually. Also, a high fever is often seen with fluA viral infection affecting the respiratory system., whereas a fever is rarely seen with a common cold and if fever is present, it is usually mild.[1]

Symptoms such as joint and muscleTissue made up of cells that can contract to bring about movement. pain, headache and loss of appetite are common with fluA viral infection affecting the respiratory system. but unlikely with the common cold. In addition, symptoms such as sneezing and a sore throat are rarely seen with fluA viral infection affecting the respiratory system., though they are frequently seen with a cold.[1]

References: 
  1. Montalto NJ. An office-based approach to influenzaA viral infection affecting the respiratory system.: clinical diagnosisThe process of determining which condition a patient may have. and laboratory testing. Am Fam Physician. 2003;67:111-8.
  2. Zambon MC. Epidemiology and pathogenesis of influenzaA viral infection affecting the respiratory system.. Journal of Antimicrobial Chemotherapy. 1999;44:3-9.
  3. Stott DJ, Kerr G and Karman WF. Nosocomial transmission of influenzaA viral infection affecting the respiratory system.. Occup Med. 2002;52:249-53.
  4. Teo SSS, Nguyen-Van-Tam JS and Booy R. Influenza burden of illness, diagnosisThe process of determining which condition a patient may have., treatment, and prevention: what is the evidence in children and where are the gaps? Arch Dis Child. 2005;90:532-6.
  5. Newton DW, Treanor JJ and Menegus MA. Clinical and laboratory diagnosisThe process of determining which condition a patient may have. of influenzaA viral infection affecting the respiratory system. virusA microbe that is only able to multiply within living cells. infections. Am J Managed Care. 2000;6(suppl):S265-75.
  6. Taubenberger JK and Morens DM. The pathology of influenzaA viral infection affecting the respiratory system. virusA microbe that is only able to multiply within living cells. infections. Annu Rev Pathol. 2008;3:499-522.