Types of Medical Mistakes
There are many ways that your medical care can go wrong.
All of the phases from diagnosis to treatment can have some type of error.
Studies of error types:
An Institute of Medical report
attempts to quantify the types of medical
errors that occur in healthcare settings.
One cited study lists
causes of error as follows:
- technical errors (44%),
- misdiagnosis (17%),
- failure to prevent injury (12%),
- medication errors (10%).
About 70% of all errors were believed to be preventable.
The remainder were presumably non-preventable errors
such as a patient reacting to a drug who had no previous
history of an allergy to the drug.
National Patient Safety Foundation Survey:
The National Patient Safety Foundation (NPSF) commissioned
a phone survey in 1997 to review patient opinions
about medical mistakes.
The findings showed that 42% of people believed they had
personally experienced a medical mistake.
In these cases, the error affected them personally (33%),
a relative (48%),
or a friend (19%).
Of these people, the type of mistake they
had experienced was:
- misdiagnosis (40%),
- medication error (28%),
- medical procedure error (22%),
- administrative error (4%),
- communication error (2%),
- incorrect laboratory results (2%),
- equipment malfunction (1%),
- other error (7%).
Unfortunately, the wording in the study for misdiagnosis
was "misdiagnosis or wrong treatment",
so it is unclear exactly how many were true misdiagnoses
or wrong condition treated
versus the wrong treatment for the correctly diagnosed condition.
In other questions, people reported that they
believed their doctor failed to make
an adequate diagnosis in 9% of cases,
and in another question 8% cited misdiagnosis as a causal
factor in the medical mistake.
The location where the medical error was experienced was
- hospital (48%),
- doctor's office (22%),
- operating room (7%),
- clinic (5%),
- emergency room (5%),
- pharmacy (4%),
- home (3%),
- medical laboratory (1%),
- nursing home (1%),
- other (5%).
When asked to cite what they believed primarily caused the error,
NPSF survey respondents mentioned
- carelessness/negligence (29%),
- untrained staff/incompetence (14%),
- communication (12%),
- misdiagnosis (8%),
- overworked staff (8%),
- misread prescription or pharmacy error (6%),
- other (14%).
Diagnosis mistakes: there are various mistakes
that can cause a misdiagnosis of a condition.
Misdiagnosis can be one of the most costly of medical errors,
leading to delayed, omitted, or inappropriate medical treatments.
- Self-diagnosis mistakes: when you diagnose yourself,
mistakes are very common.
Always seek professional medical advice.
Do not rely on internet health information.
- Not diagnosed: some conditions are not obvious and may be missed,
especially if they have no major symptoms.
- Wrongly diagnosed: you might be diagnosed as having the wrong condition.
- Wrong subtype of disease diagnosed: the diagnosis might have
the correct overall disease, but the wrong subtype.
- Complications not diagnosed: the diagnosed disease
may have various complications that also need to be diagnosed
- Underlying disease not diagnosed: there may actually
be an underlying hidden disease causing the already diagnosed disease.
- Associated diseases not diagnosed:
some types of conditions cluster together, even though
they do not cause each other.
- Failure to diagnose others: infectious diseases
need to be checked in family members and other exposed people;
genetically associated diseases indicate family members
may be at higher risk and may need screening.
Treatment mistakes: There are numerous ways that
an error can occur in medical treatment.
- Self-treatment mistakes: if you try to treat yourself,
mistakes are very common.
Always seek professional medical advice.
- Wrong condition treated: i.e. from a misdiagnosis of the condition
- Wrong choice of treatment plan: the overall strategy used
to treat your condition might not be the best one.
- Wrong type of treatment given
- Wrongly delayed treatment: there might be an undesirable delay
in your treatment, by choice or through non-diagnosis.
- Wrongly performed procedures: all medical events
such as surgeries and tests can have things go wrong.
- Wrong medications: see below.
Prevention mistakes: The failure to prevent a condition
is another type of medical failing.
In certain cases, it is clear that preventive actions should be taken
and failure to do so is a medical mistake.
- Failure to prevent known complications of a diagnosed disease.
- Failure to treat family members or others exposed to an infectious disease.
- Failure to address clear risk factors for various conditions
Surgical procedures are often complex and subject to various errors.
Administration of surgery can also lead to errors.
In some cases, there are known complications or risks of surgery
than are often unavoidable.
- Surgery administration mistakes: wrong-patient, wrong-site, wrong-organ,
equipment left inside.
- Surgical mistakes: the surgeon might make a wrong cut or other mistake.
- Anaesthesia mistakes: too much, too little (waking up).
- Complications from surgery
- Infections from surgery: called "iatrogenic infections"
- Wrong blood type transfusion
A hospital can make errors in any of its varied activities.
There are many staff who can make human mistakes
and overall system problems can also lead to errors.
- Hospital-caused infections: called "nosocomial infections"
- Medication errors in hospitals: ordered medication not given,
wrong dosage, wrong combinations, wrong patient given medication, and so on.
- Wrong procedures: failure to do ordered tests, wrong procedures or tests.
Errors in medication are a major source of medical mistakes.
Medication errors can occur in hospitals or pharmacies,
and the error may be made by any of the staff involved
with choosing or dispensing medication.
- Inappropriate medication: the wrong medication given for a disease
- Wrong medication: the patient gets the wrong medication despite
the doctor prescribing the correct one.
- Drug name mix-ups: several medications have similar-sounding names
and can be mixed up by doctors or pharmacists.
- Wrong medication combinations: there are numerous types of
medications that should not be mixed, because of side effects
- Adverse reactions to medication: Some people have allergic
or other adverse reactions to certain medications.
These are risks and not necessarily avoidable mistakes if the person
has no previous history of a particular adverse reaction.
- Side effects of medication: Almost all medications have
some types of side effects.
Some are mild, some nasty.
It is almost impossible to know up front whether a person will have
side effects from a medication.
- Non-compliance: the failure to follow your medication regimen
can be a mistake made (usually by the patient).
The dispensing of drugs by the pharmacy is a complex and busy activity.
Various errors can occur at the pharmacist.
- Wrongly filled prescriptions
- Wrong drug supplied
- Wrong dosage supplied
- Drug name mix-ups: various drugs have similar names.
Pathology lab errors:
Diagnostic testing done by a pathology laboratory can be subject
to various errors.
Some are administrative or human mistakes;
other "mistakes" are inherent to the limitations of the type of test.
- Wrong biopsy results: visual inspection of cellular slides
- Administrative errors: mixing samples, etc.
- Known test errors and risks: almost all tests
have a small percentage of unavoidable errors (false positives,
- Known limitations of tests
Equipment failure errors:
Physical failures with medical equipment can occur.
- IV drips dislodged
- Dead batteries in equipment
Unnecessary medical treatment:
Excessive medical care can be a form of "mistake" for medical professionals
This can occur with good intentions (to ensure correctness)
or for cynical reasons (to increase income).
- Unnecessary procedures
- Unnecessary tests
- Unnecessary visits
1. Institute of Medicine (IOM), "To Err Is Human: Building a Safer Health System", 2000,online.
» Next page: Medication errors
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