Posts Tagged ‘X-ray computed tomography’
For non emergency cases, doctors used to
- patiently listen to the patients’ expression of symptoms.
- examine pulse rate.
- check with Stethoscope.
- dilate pupils
- ask the patient about his diet,bowel movement.
- check the tongue and throat.
- Check tummy.
- ask for medications taken.
- ask those who accompany whether the patient had previous history.
- ask for family history.
Only then the Doctor starts diagnosing.
Now, after hearing hastily the symptoms, and in certain cases ask the patient what medicine he/she had taken the last time,starts writing a string of medicines and recommend a plethora of tests.
Tests such as CT scans and ultrasounds add to hospital bills, but doctors said that such tests given right after patients showed up in emergency rooms only helped with diagnosis in roughly one of three cases, the study — published in the Archives of Internal Medicine — said.
There is also research showing that the radiation from multiple CT scans might increase the risk of cancer over the long term.
To see whether such scans were really helpful, researchers led by Ami Schattner of Kaplan Medical Center in Rehovot, Israel, followed all the patients who showed up at the emergency room of a teaching hospital and were subsequently admitted.
“Basic clinical skills remain a powerful tool, sufficient for achieving an accurate diagnosis in most cases,” Schattner and his colleagues wrote.
“Physicians may count more on their clinical faculties when making decisions about patients.”
|Immediate||Nausea and vomiting||5–50%||50–100%||75–100%||90–100%||100%|
|Time of onset||2–6h||1–2h||10–60m||<10m||immediate|
|Diarrhea||None||Slight (10%)||Heavy (10%)||Heavy (90%)||Heavy (100%)|
|Time of onset||—||3–8h||1–2h||>1h||<30m|
|Headache||Slight||Mild (50%)||Moderate (80%)||Severe (80–90%)||Severe (100%)|
|Time of onset||—||4–24h||3–4h||1–2h||<1h|
|Fever||Slight–None||Moderate (50%)||High (100%)||Severe (100%)||Severe (100%)|
|Time of onset||—||1–3h||>1h||>1h||>30m|
|CNS function||No impairment||Cognitive impairment 6–20 h||Cognitive impairment <20 h||Rapid incapacitation||Seizures,Tremor, Ataxia|
|Latent Period||28–31 days||7–28 days||>7 days||none||none|
Dizziness and disorientationHypotension;
Vomiting; Severe diarrhea;
|Mortality without medical care||0–5%||5–100%||95–100%||100%||100%|
|Mortality with medical care||0–5%||5–50%||50–100%||100%||100%|
Japanese authorities are trying to prevent total meltdown at three nuclear reactors that were damaged in Friday's tsunami. Engineers are flooding the reactors to cool them down, then venting the radioactive steam to prevent a dangerous build-up in pressure. Thousands have been evacuated, and helicopters have detected radioactive particles 60 miles from the reactors. How can the evacuees tell if they've been exposed to dangerous levels of radiation?
With a blood test. Nuclear plant workers, radiologists, and rescue workers can wear badges or special rings that tell them how much radiation is in their environment. Post hoc measurement is tougher, though. Public health workers may pass a device over the patient's clothing. The air enters an oxygen- or argon-filled chamber, and the machine detects reactions between the gas and radioactive particles. Another option is to take a swab of the patient's nose and mouth and perform a similar experiment. If either of these methods uncover radiation exposure, doctors then draw blood. Absorption of more than 500 millisieverts of radiation can depress white blood cell levels.
At this time, it doesn't look like anyone in Japan has taken in this much radiation. The highest reported absorption so far is just 106 msv. To put that into perspective, workers at the Chernobyl plant absorbed more than 5,000 msv, and those were the survivors. Even 500 msv is fairly benign. White blood cell counts typically rebound within a couple of days, and the patient's increased lifetime risk of cancer is barely worth mentioning. The average American has a one-in-two chance of developing some form of cancer. One-time exposure to 500 msv raises those odds to about one-in-1.9999.
On the off chance that an unfortunate nuclear plant worker shows signs of significant radiation exposure, treatment would depend on the type of radioactive particle involved. Radioactive cesium can be treated with a chelating agent, a chemical that binds to the particle and ushers it out of the body via urine. Those who inhale a dose of radioactive iodine aren't as lucky. While it can be treated prophylactically with potassium iodide tablets, there's no effective remedy after the exposure. The victim has to wait for his body to process the contaminant.
Radiation Exposure Monitoring (REM) facilitates the collection and distribution of information about estimated patient radiation exposure resulting from imaging procedures.
Radiation poisoning, radiation sickness or a creeping dose, is a form of damage to organ tissue caused by excessive exposure to ionizing radiation. The term is generally used to refer toacute problems caused by a large dosage of radiation in a short period, though this also has occurred with long term exposure. The clinical name for radiation sickness is acute radiation syndrome (ARS) as described by the CDC. A chronic radiation syndrome does exist but is very uncommon; this has been observed among workers in early radium source production sites and in the early days of the Soviet nuclear program. A short exposure can result in acute radiation syndrome; chronic radiation syndrome requires a prolonged high level of exposure.
Radiation exposure can also increase the probability of developing some other diseases, mainlycancer, tumours, and genetic damage. These are referred to as the stochastic effects of radiation, and are not included in the term radiation sickness.
The use of radionuclides in science and industry is strictly regulated in most countries. In the event of an accidental or deliberate release of radioactive material, either evacuation or sheltering in place are the recommended measures. For information on the effects of lower doses of radiation, see the article on radiation orders of magnitude.
A gray (Gy) is a unit of radiation dose absorbed by matter. To gauge biological effects the dose is multiplied by a ‘quality factor’ which is dependent on the type of ionising radiation. Such measurement of biological effect is called “dose equivalent” and is measured in sievert (Sv). For electron and photon radiation (e.g. gamma), 1 Gy = 1 Sv.
Annual limit on intake (ALI) is the derived limit for the amount of radioactive material taken into the body of an adult worker by inhalation or ingestion in a year. ALI is the intake of a given radionuclide in a year that would result in:
- a committed effective dose equivalent of 0.05 Sv (5 rems) for a “reference human body”, or
- a committed dose equivalent of 0.5 Sv (50 rems) to any individual organ or tissue,
whatever dose is the smaller.[9
Signs and symptoms
Radiation sickness is generally associated with acute (a single large) exposure. Nausea and vomiting are usually the main symptoms.The amount of time between exposure to radiation and the onset of the initial symptoms may be an indicator of how much radiation was absorbed, as symptoms appear sooner with higher doses of exposure. The symptoms of radiation sickness become more serious (and the chance of survival decreases) as the dosage of radiation increases. A few symptom-free days may pass between the appearance of the initial symptoms and the onset of symptoms of more severe illness associated with higher doses of radiation. Nausea and vomiting generally occur within 24–48 hours after exposure to mild (1–2 Sv) doses of radiation. Radiation damage to the intestinal tract lining will cause nausea, bloody vomiting and diarrhea. This occurs when the victim’s exposure is 200 rems (1 Sv = 100 rems) or more. The radiation will begin to destroy the cells in the body that divide rapidly, including blood, GI tract, reproductive and hair cells, and harm the DNA and RNA of surviving cells. A direct quantitative relationship exists between the degree of the neutropenia that develops after exposure to radiation and the increased risk of developing systemic infection (sepsis). Headache, fatigue, and weakness are also seen with mild exposure. Moderate (2–3.5 Sv of radiation) exposure is associated with nausea and vomiting beginning within 12–24 hours after exposure. In addition to the symptoms of mild exposure, fever, hair loss, infections, bloody vomit and stools, and poor wound healing are seen with moderate exposure. Nausea and vomiting occur in less than 1 hour after exposure to severe (3.5–5.5 Sv) doses of radiation, followed by diarrhea and high fever in addition to the symptoms of lower levels of exposure. Very severe (5.5–8 Sv of radiation) exposure is followed by the onset of nausea and vomiting in less than 30 minutes followed by the appearance of dizziness, disorientation, and low blood pressure in addition to the symptoms of lower levels of exposure. Severe exposure is fatal about 50% of the time. Severe sepsis is the cause of death in most cases. See criticality accident for a number of incidents in which humans have been accidentally exposed to such levels of radiation.
Longer term exposure to radiation, at doses less than that which produces serious radiation sickness, can induce cancer as cell-cycle genes are mutated. The probability cancer will develop is a function of radiation dose. In radiation-induced cancer the disease, the speed at which the condition advances, the prognosis, the degree of pain, and every other feature of the disease are not functions of the radiation dose to which the person is exposed.
Since tumors grow by abnormally rapid cell division, the ability of radiation to disturb cell division is also used to treat cancer (seeradiotherapy), and low levels of ionizing radiation have been claimed to lower one’s risk of cancer (see hormesis).
Organisms causing sepsis
The systemic infections can be endogenous originating from the oral and gastrointestinal bacterial flora, and exogenous originating from a breached skin and environment following trauma.
The organisms causing endogenous infections are generally Gram negative bacilli such as Enterobacteriacae (i.e. Escherichia coli, Klebsiella pneumoniae, Proteus spp.), Pseudomonas aeruginosa, and Enterococcus spp. (of gastrointestinal origin) and Streptococcus spp. (of oral cavity source).
Exposure to higher doses of radiation is often associated with anaerobic infections due to Gram negative bacilli and gram positive cocci. Fungal infections can also emerge in those who fail antimicrobials and are still febrile for over 7-10 days.
Exogenous infections can be caused by organisms that colonize the skin such as Staphylococcus aureus or Streptococcus spp. and organisms that are acquired from the environment such as Pseudomonas spp.
Patients are best advised to seek detailed information from Doctors on Tests on the necessity and relevance of the tests before they take the tests.
They rate cars. They rate electronics. And now Consumer Reports is hoping its product-rating system will better inform consumers about why they should avoid some common heart-disease screening tests.
Blood pressure and cholesterol screenings are definitely helpful, the nonprofit group said in the report. But electrocardiograms and C-reactive protein testing are not a good idea for healthy people, it concluded.
“It’s worrisome that healthy people are getting tests they may not need because a prevention test that is not reliable can lead to a cascade of unnecessary, costly, and in some cases risky follow-up tests and treatment,” Dr. John Santa, director of the Consumer Reports Health Ratings Center, said in a statement about the report.
“It’s easier to understand the benefits than the risks,” he said in an interview Wednesday.
The magazine’s ratings are based on advice from the U.S. Preventive Services Task Force, a government-sponsored group of physicians without medical industry ties. The task force reviews and rates the scientific evidence behind some proposed procedures. (Task force recommendations on mammograms and prostate tests have been controversial the past few years.) Consumer Reports updated and added to the task force advice on cardiovascular screening tests.
Consumer Reports is also providing a heart-risk calculator on its Web site. People who type in their age, gender and cardiovascular risk profiles, such as hypertension or high cholesterol, can see their 10-year risk of having a heart attack, stroke or other cardiovascular event, and the suggested screenings.
Most healthy people, the magazine said, should only test for blood pressure, cholesterol and possibly blood glucose. But it was uncertain whether benefits outweigh risks in screening healthy people for C-reactive protein or clogged peripheral arteries. And it said risks almost certainly outweigh benefits in testing healthy people for clogged carotid arteries, abdominal aortic aneurysms and heart EKGs.
In the interview, Dr. Santa described one example of the cascade effect.
“Let’s say a nonspecific finding on an EKG that suggests you could have a problem,” he said. “The next thing you know, a CT scan is going to be suggested, so you’re going to be exposed to some significant radiation. And let’s say that the CT scan doesn’t completely exclude a problem. Well, now you’re talking about an angiogram that has a 1 or 2 percent significant side effect.
“And then of course, if you had an angiogram, let’s say you had a coronary artery that’s 50 percent blocked. Well, now wait a minute, we now know that blockage itself is not significant. There’s a lot more to having a heart problem. But it’s awful hard to look at that blockage and tell a cardiologist not to do something. But in fact all the evidence for angioplasty and heart surgery is that they help people who have chest pain, and the degree to which they help people with no symptoms at all is very, very limited, and it may not help at all. This cascade can happen quickly.”
The X-rays are helping to build up a 3D picture of this ferocious predator, called a pliosaur, which terrorized the oceans 150m years ago.
The 2.4m-long (7.9ft) fossil skull was recently unearthed along the UK’s Jurassic coast, and is thought to belong to one of the biggest pliosaurs ever found.
The scans could establish if the giant is a species that is new to science.
Pliosaurs are aquatic mammals belonging to the plesiosaur family. Paddle-like limbs would have powered their huge bulky bodies through the water, and they had enormous crocodile-like heads, packed full of razor-sharp teeth.