Complication (medicine)

See also: Adverse event

A complication in medicine, or medical complication, is an unfavorable result of a disease, health condition, or treatment. Complications may adversely affect the prognosis of a disease. Complications generally involve a worsening in severity of disease or the development of new signs, symptoms, or pathological changes, which may become widespread throughout the body, affecting other organ systems. Thus, complications may involve the development of new diseases resulting from a previously existing disease. Complications may also arise as a result of various treatments.

The development of complications depends on a number of factors, including the degree of vulnerability, susceptibility, age, health status, and immune system condition.

Knowledge of the most common and severe complications of a disease, procedure, or treatment allow for prevention and preparation for treatment in the event that they should occur.

Complications are not to be confused with sequelae, which is a residual effect that occurs after the acute phase of an illness or injury. Sequelae can appear early or weeks to months later and are a result of the initial injury or illness. For example, a scar resulting from a burn or dysphagia resulting from a stroke would be considered sequelae. In addition, complications should not be confused with comorbidities, which are diseases that occur concurrently, but that have no causative association.

Complications

Iatrogenic Complications

Iatrogenic complications (from Greek, "brought forth by the healer") refers to medical treatments provided by physicians, including drugs or surgery with adverse effects that produce new health problem(s). An adverse event is an injury caused by medical management instead of the underlying disease. Adverse events can be preventable or non-preventable, but ultimately result in a need for additional treatment. Preventable adverse events are usually the result or accumulating medical errors. According to the National Center for Health Statistics, as of 2014, medical errors are the third leading cause of death in the US.

Medical errors can fall into various categories listed below:

• Medication: Medication medical errors include wrong prescription, impaired delivery, or improper adherence. The process of prescribing medication is a complex process that relies on the accurate transfer of information through various parties. Prevention methods include increased use of electronic prescription, pre-packaging unit dosing, and ensuring medical literacy among patients.
• Surgical: Surgery-related medical errors can be anesthesia-related, but most often include wrong-site and wrong-patient procedural errors. Preventative measures include following and double-checking standardized surgical protocol before, during, and after procedures. Universal surgical protocols include verification of patient identity and proper site-marking.
• Diagnostic: Diagnostic errors include misdiagnosis, wrong diagnosis, and over diagnosis. Diagnostic errors are often the result of patient characteristics and physician bias.
• Machine interface: Errors in this category refer to mistakes in human interaction with tools or machines. Machine-related errors can be reduced by standardizing and clear differentiation in design of products.
• Transition and handoff: Errors in this category can occur person-to-person or site-to-site during transfer, and can be managed by adhering to hand-off protocol.
• Human factors, teamwork, and communication: Errors in this category highlight the impact of culture and relationships on communication. These concepts can play a role in other categories of medical errors. Preventative measures include cultivating a "culture of safety", which includes creating an environment where people feel comfortable discussing concerns, feedback, and errors with fear of punishment.

  

  Image of a urinary catheter, which is a common cause of healthcare associated infections.

• Healthcare-associated infections (HAIs): HAIs are most commonly caused by indwelling devices (urinary catheters, central lines) or previous surgical procedures. Clostridium difficile is the most common bacterial source. The most effective preventative measure is hand-hygiene.

Cardiovascular Complications

Complications of Atrial Fibrillation

Atrial fibrillation is a type of arrhythmia characterized by rapid and irregular heart rhythms due to irregular atrial activation by atrioventricular (AV) nodal conduction. In the pathogenesis of atrial fibrillation, there is no effective pumping of blood into either the pulmonary or systemic circulation from the left ventricle of the heart because the left and right ventricles (lower chambers of the heart) do not fill properly from the irregular contraction of the left and right atria (upper chambers of the heart).

A patient with atrial fibrillation may experience symptoms of fatigue, dizziness or lightheadedness, heart palpitations, chest pain, and shortness of breath. The heart does not effectively pump blood into the pulmonary or systemic vasculature, and causes the blood to remain within the chambers of the heart. The blood collecting within the heart can develop into a blood clot (thrombus) and therefore atrial fibrillation is associated with an increase in risk of developing a thrombus. The thrombus can also develop into an embolus and then travel into the systemic circulation. The embolus can enter the brain and therefore atrial fibrillation is associated with an increase in risk of having a stroke.

Other Examples

• Thrombosis in the heart or brain, causing stroke or acute myocardial infarction can be complications of blood coagulation disorders, phlebitis (inflammation of the veins), endocarditis and artificial heart valves.

Metabolic Complications

• Diabetes Mellitus, also known simply as diabetes, is a disorder of the regulation of blood glucose levels. There are two types of chronic diabetes mellitus: type I and type II. Both lead to abnormally high levels of blood glucose (a common type of sugar) as the body isn't able to properly uptake the sugar into tissues. Diabetes requires a life-long consistent monitoring of food intake, blood sugar levels, and physical activity. Diabetes mellitus may present a series of complications in an advanced or more severe stage, such as:
  • Cardiovascular disease. Adults with diabetes are significantly more likely to die from heart disease than are those without diabetes. Diabetes is associated with risk factors for various cardiovascular diseases including obesity, insulin resistance, high blood cholesterol and triglyceride content, and high blood pressure. These conditions increase risk of thrombosis, atherosclerosis (blockage of coronary arteries leading to inadequate supply of oxygen to parts of the heart), and hypertension which can lead to myocardial infarction, coronary artery disease (CAD), and others.
  • Diabetic Neuropathy. Hyperglycemia can eventually cause damage to nerves in the distal extremities (peripheral neuropathy), thighs and hips (radiculoplexus neuropathy), face (mononeuropathy), and internal organs (autonomic neuropathy). Initial symptoms may present as numbness, tingling, pain, muscular weakness, loss of reflexes or proper bodily functions, and many others.
  • Diabetic Nephropathy. Excessive amounts of certain solutes passing through the kidneys for prolonged periods of time can lead to kidney damage. Diabetic nephropathy is specifically characterized by abnormally high levels of urinary albumin excretion. This affects approximately 40% of patients with type I or type II diabetes.
  • Diabetic Retinopathy. Chronic or prolonged type I and type II diabetes can lead to damage in the blood vessels of the retina due to hyperglycemia (excessive blood glucose). Damage and blockage of the vessels causes microaneurysms, tears, and leakage of fluid into the back of the eye. This can eventually lead to abnormal blood vessel growth, nerve damage, or excessive pressure buildup in the eye. Symptoms initially present as blurred vision but can lead to more serious complications such as blindness, glaucoma, retinal detachment, and vitreous hemorrhage.
  • Foot damage. Diabetes mellitus can lead to poor vascular blood flow to the extremities. Injury of the foot with inadequate blood flow can progress to ulcers and become infected. Individuals with diabetic neuropathy may not notice the damage and may develop gangrene(tissue necrosis due to inadequate blood supply).

    

    Commonly referred to as "diabetic foot," wounds and ulcers are a common complication of elevated blood sugar levels in diabetes.

  • Skin conditions. Insulin insensitivity in the case of type II diabetes can cause prolonged increases in blood insulin. Insulin normally binds to insulin receptors but in excess amounts may bind to insulin-like growth factor (IGF) receptors in epithelial tissue. This can cause excessive proliferation of keratinocytes and fibroblasts. This presents as acanthosis nigricans, a thickening and darkening of areas of the skin such as the armpits, necks, hands, and face. Other skin conditions include diabetic dermopathy, digital sclerosis, eruptive xanthomatosis, and others.

Neurologic/Psychiatric Complications

• Hepatic encephalopathy is a possible complication of liver cirrhosis.
• Significant intellectual, physical, and developmental disability are common complications of untreated hydrocephalus.

• Suicide is a common complication of many disorders and conditions that consistently affect a person's life negatively, such as major depressive disorder, posttraumatic stress disorder, schizophrenia, anxiety disorders, or substance abuse.
• Complications of outpatient drugs are very common and many patients experience worry or discomfort due to them.
• Paradoxical reaction to a drug; that is, a reaction that is the opposite to the intended purpose of the drug. An example is benzodiazepines, a class of psychoactive drugs considered minor tranquilizers with varying hypnotic, sedative, anxiolytic, anticonvulsant, and muscle relaxant effects; paradoxically they may also create hyperactivity, anxiety, convulsions etc. in susceptible individuals.

Surgical/Procedural Complications

Image of a surgical site infection caused by stitching

• Puerperal fever was a common complication of childbirth, contributing to the high mortality of mothers before the advent of antisepsis and antibiotics.
• Erectile dysfunction and urinary incontinence which may follow prostatectomy.
• Malignant hyperthermia can be a reaction to general anesthetics, as a complication in a surgery.
• Fractured ribs and sternum may be a complication of cardiopulmonary resuscitation attempts.

Other Examples of Complications

• Sepsis (infection of the blood) may occur as a complication of a bacterial, viral, or fungal infection.
• Miscarriage is the most common complication of early pregnancy.
• Eczema vaccinatum is a rare and severe complication of smallpox vaccination in people with eczema.

See also

• Adverse effect
• Classification of Pharmaco-Therapeutic Referrals
• Diagnosis
• Iatrogenesis
• Late effect
• Nocebo
• Placebo
• Prognosis
• Sequela

Further reading

• Coventry, Brendon J (2014). Surgery: Complications, Risks and Consequences. Book series, seven volumes. Springer. {{cite book}}: Unknown parameter |name-list-format= ignored (|name-list-style= suggested) (help)
• Mulholland, Michael W.; Doherty, Gerard M. (2006). Complications in Surgery. Lippincott Williams and Wilkins. ISBN 978-0-7817-5316-6. {{cite book}}: Unknown parameter |name-list-format= ignored (|name-list-style= suggested) (help)
• Gawande, Atul (2002). Complications: A Surgeon's Notes on an Imperfect Science. Macmillan. {{cite book}}: Unknown parameter |name-list-format= ignored (|name-list-style= suggested) (help)