Disease states are the primary cause of homeostasis failure, an inability to maintain physiological balance within the internal environment of the body. Due to the processes involved with disease, the functioning of tissues and organs are altered in such a way that it causes severe maladjustment, namely in diseases affecting renal and immune system function. Certain mechanisms are initiated that work to defend the body against invading pathogens, but the system can sometimes mistakenly fight itself. As human beings age, the capabilities of organ systems wane, interfering with homeostatic functioning as evidenced by Alzheimer's disease and heart arrhythmia.
Sudden failure of kidney function may cause serious issues due to homeostasis failure, as these important organs help the blood to remove harmful toxins and maintain efficient fluid and electrolyte levels. Tumors and kidney stones may prevent urine from being excreted as result of the formation of urinary duct blockages, while certain types of medication may also disturb the action of kidneys. In the case of hemorrhage, blood circulation to the kidneys decreases leading to acute kidney failure, characterized by edema, nausea, and seizures. Coma can also result.
Temperature regulation mechanisms become disrupted due to the presence of infectious agents within the body, especially in those with suppressed immune function. Fever is one of the important ways in which the body fights against infection as the hypothalamus raises internal temperature, causing chills and fatigue. Normal body temperature ranges around 98.6° Fahrenheit (37° Celsius), but a fever typically develops at about 100° Fahrenheit (38° Celsius). Even though a fever can be brought under control with drugs referred to as antipyretics and other interventions, the most effective treatment rids the body of the offending pathogen.
The immune system's ability to distinguish between itself and true pathogens sometimes can interfere with treatment. For example, a patient receiving an organ transplant or blood transfusion might experience a reaction that could lead to homeostasis failure because the immune system presents many ways in which mechanisms designed to protect the human body can fail. Sometimes hypersensitivity develops, an excessively excitable immune response to an antigen that would normally cause no reaction such as with an allergic reaction to a bee sting.
Changes that occur in the course of aging lead to decreased functioning in older people. The declining capacity of various systems in the human body, although most apparent in the elderly, may start much earlier in life such as with Alzheimer's disease. Systems of the body decline at different points, causing homeostasis failure as result of decreased nerve functioning and that of other organs.