42 year old male smoker begins to feel ill with malaise, general aches, a headache

Discussion in 'Plab 1 and 2 forum' started by Partha Sarkar, Jun 23, 2013.

  1. Q. Five days after a working journey in France a 42 year old male smoker begins to feel ill with malaise, general aches, a headache, and a dry cough. He rapidly develops diffuse bruising and acute renal failure. Investigations reveal a thrombocytopenia. The most likely diagnosis is

    a) Lyme disease

    b) legionnaire\'s disease

    c) tularemia

    d) listeriosis

    e) psittacosis
    Most infections with legionellas are respiratory infections, although other infections can occur, such as wound infections due to contact with contaminated water. The commonest result of infection is an acute pneumonia, Legionnaires disease. After an incubation period of two to ten days the patient begins to feel ill with malaise, general aches, a headache, and a dry cough. Within a day or two their temperature may reach 40 degrees celcius. Patients may become confused and seriously ill. The signs and symptoms may be more those of a septicaemia (a reaction to bacteria in the blood) than respiratory illness, but after another day or two it becomes obvious that the patient has severe respiratory infection. Patients may develop complications such as thrombocytopenia , acute renal failure, or failure of other important organs. The organism may spread via the bloodstream and cause infection elsewhere in the body. Abdominal symptoms such as nausea, vomiting and diarrhoea are quite common. Legionnaires disease is a potentially fatal condition; in the United Kingdom in 1996, the mortality rate was 12%. The disease is treated with antibiotics (such as erythromycin), plus supportive treatment including mechanical ventilation if necessary. About half the cases occurring in the UK are associated with travel abroad, the destinations most frequently associated with Legionnaires disease are (in descending order) Spain, France, Turkey and Greece which are popular destinations for British holidaymakers. More than two thirds of the cases which originate in the UK are associated with urban areas particularly industrial estates, which may be due to a greater concentration of water cooling towers in those areas. Other infections are associated with travel within the UK, and legionella infection may also be acquired in hospital, although this is now rare. There are a number of risk factors for Legionnaires disease. The disease is commoner and/or more severe in men, cigarette smokers, elderly patients, those with pre-existing lung disease and patients with deficient immune systems. Legionellas are commonly found in small numbers in collections of fresh water, but there they probably do no harm. They can survive normal drinking water disinfection, and may enter the mains water supply for homes and industry. Once in the distribution system, they may multiply (particularly if the water temperature is favourable or if the system contains excessive sediment) and susceptible people may be exposed to the organism via sprays generated by water taps or shower heads. This is much less likely to be a problem in domestic water supplies because the turnover of the supply does not allow the water to stagnate and the legionellas to multiply. Air conditioning systems may constitute the greatest hazard. The organisms multiply in the water of cooling towers in which a cascade of water is used to cool air in pipes or vanes. The water does not come into direct contact with the air, but a great deal of it is lost by evaporation or as spray, and as cooling towers are usually situated in the roofs of buildings the clouds of droplets containing legionellas may be drawn into the air intakes of the building or fall on people passing by. Humidification systems have also been incriminated as a source of infection.

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