The kidneys filter waste products and balance the body’s internal environment. When they fail—either suddenly from acute kidney injury (AKI) or progressively from end-stage renal disease (ESRD)—this balance cannot be maintained. Dialysis is a necessary medical intervention that takes over these functions, cleaning the blood of toxins and regulating fluid levels. Without this treatment, the body rapidly descends into a state of chemical and volume imbalance.
The Immediate Physiological Crisis
When kidney filtration stops, two immediate crises develop simultaneously. The first is uremic toxicity, caused by the accumulation of nitrogenous waste products that build up to toxic levels, affecting every system of the body. The second crisis is overwhelming fluid overload, as the body cannot excrete consumed water. This excess volume stresses the circulatory system and leads to systemic congestion. These effects are compounded by dangerous electrolyte and acid-base imbalances. A primary life-threatening imbalance is hyperkalemia, a dangerous rise in blood potassium levels. This rise disrupts the heart’s electrical signaling. The blood also becomes severely acidic, a condition known as metabolic acidosis, because the kidneys fail to remove hydrogen ions.
Systemic Impact on Major Organs
The chemical and volume crises quickly cause severe symptoms across the body’s organ systems. The cardiovascular system suffers significantly. Fluid overload forces fluid into the lungs, resulting in pulmonary edema. This congestion causes severe shortness of breath and respiratory distress, creating a sensation akin to drowning. The excess fluid volume also leads to severe hypertension and heart failure, as the heart struggles to pump against the overwhelming pressure.
Unchecked hyperkalemia directly interferes with the heart’s rhythm, causing a progressive slowing of the heart rate and conduction blocks that lead to fatal arrhythmias. The neurological system is severely affected by uremic toxins, leading to a condition known as uremic encephalopathy. Early symptoms include confusion, disorientation, and profound lethargy, often accompanied by muscle twitching and restlessness. As toxin levels increase, the patient can progress to seizures and irreversible coma. Uremic poisoning also affects the gastrointestinal tract, causing severe and persistent nausea, vomiting, and a complete loss of appetite.
The Progression and Final Outcome
The timeline for survival without dialysis is variable, but the outcome is uniformly fatal. For patients with a sudden and complete loss of function, such as severe acute kidney injury, death can occur within days. For individuals with end-stage renal disease who retain some minimal function, this progression may extend to a few weeks.
The final moments are typically triggered by one of three acute complications. The most common cause of death is a cardiac event, specifically cardiac arrest resulting from refractory hyperkalemia. The excessive potassium overwhelms the heart’s electrical system. Another common pathway is respiratory failure caused by unmanageable pulmonary edema. The fluid in the lungs prevents oxygen exchange, leading to suffocation. The third outcome is death from irreversible coma and multi-organ failure driven by severe uremic encephalopathy.