H1N1 (Swine Flu): Inflamed, Flooded Lungs Trigger Death; Pregnant Women and 1918 Flu – Long Term Health Impacts on Their Babies
THE NEW DISEASE – FLAARDS – FLU A ASSOCIATED ACUTE RESPIRATORY DISEASE SYNDROME
The medical journal Critical Care and Resuscitation has just released a study in the September issue that notes that H1N1 is most dangerous when it causes the lungs to become inflamed, flood with fluid and fail to function. While a majority of people infected with the virus have a mild illness, a small number develop life-threatening disease, intensive-care specialists Steven Webb and Ian Seppelt said. The doctors described the most common of three main complications from the pandemic strain as flu A-associated acute respiratory disease syndrome, or “flaards.”
Hospitals in the Northern Hemisphere are bracing for a surge in flu cases in coming weeks, spurred by colder weather that promotes its spread. In Australia, flu patients occupied a quarter of beds in intensive-care units last winter and 178 died. Intensive-care doctors in Australia and New Zealand are pooling data on more than 400 swine flu cases to describe disease patterns and treatment strategies, and inform the Northern Hemisphere countries about what to expect this winter. ‘Canary in the Coal Mine’ “ICUs are the ‘canary in the coal mine’,” Webb and Seppelt wrote in the editorial. “It is only by documenting the severe cases requiring intensive care that it is possible to get an idea of the overall impact of this new disease.”
In Victoria, Australia’s second most-populous state, the pandemic virus sickened about 5 percent of the population, with 0.3 percent of infected patients being hospitalized, health officials said in a study yesterday in the Medical Journal of Australia. One in five people admitted to the hospital were transferred to ICU, mostly because of severe respiratory failure. Eighty-five percent of critically ill patients survived after staying an average of nine days in ICU. Almost three- quarters of these patients required mechanical ventilation to breathe and 7 percent needed to have their blood pumped through an artificial lung in a procedure known as extracorporeal membrane oxygenation, or ECMO.
In most cases, flu remains in the nose, throat and bronchi, where it causes a runny nose, sore throat and cough until the body’s immune systems eliminates it, usually within a week. The new H1N1 strain may be at least 1,000 times more adept than seasonal flu at infiltrating the lower branches of the airway, said Yoshihiro Kawaoka, a virologist at the University of Tokyo, who has studied the viruses in non-human primates. In severe cases, influenza can damage the capillaries surrounding the tiny grape-like sacs, known as alveoli, where gas is exchanged through the blood. Damaged alveoli can bleed, causing pulmonary hemorrhage and blood clots.
Inflammatory chemicals are produced by the immune system to fight the infection and repair the damage. An over-exuberant response can worsen the effect by filling the lungs with fluid and cause permanent scarring that restricts the lungs.
Life-threatening infection may be more common in people with underlying health conditions, including morbid obesity, type-2 diabetes, cancer, a weakened immune system and chronic lung disease, they said. Pregnant women and those who recently gave birth also appear at higher risk. Still, “many patients with flaards are young and previously well,” they said. In Australia, the median age of people dying from seasonal flu is 83. With the novel H1N1 virus, it is 51 years, the health department said in a report last week.
ProMED Digest V2009 #458 www.promedmail.org
PREGNANT WOMEN IN 1918 – THE IMPACT OF THE FLU ON THEIR BABIES
The famous 1918 Spanish Flu affected babies in the womb, causing them to have higher rates of heart disease later in life, notes a new Canadian study. Men exposed to the H1N1 strain in utero were also slightly shorter than boys born months before or after the 1918 flu, a phenomenon suggesting growth retardation. The findings, from researchers who looked at more than 100,000 people born in and around the lethal 1918-19 “Spanish flu” pandemic, searching for evidence of excess heart disease and other chronic illnesses, comes as major medical groups in Canada are urging pregnant women to get vaccinated against human swine flu.
Today’s H1N1 human swine flu is a distant cousin to the older strain. The 1918 flu was “notoriously virulent,” sickening one-third of the U.S. across all age groups and killing about 0.6 per cent of the population, according to the study, published in the Journal of Developmental Origins of Health and Disease. “There is particular concern for the current swine flu which seems to target pregnant women.”
Earlier studies by some of the same researchers showed that babies born in the first part of 1919, who were exposed in the womb to the flu at its worst, had “development impairment or lifetime health issues.”
Studies in animals have shown that infecting pregnant mice with various respiratory viruses can lead to abnormal cognitive and behavioural problems in their offspring. Other studies have linked more recent, 20th century flus with an increased risk of schizophrenia and autism. The risk of schizophrenia was three-times higher in babies exposed prenatally to influenza in the U.S. during 1959 to 1966.