As mentioned, the effects of rising blood levels of wastes and the inability to excrete said wastes and fluid  will have profound effects on almost every system in the body.

Fluid overload (because volume can’t be excreted) will cause problems with

• Cardiovascular: increased blood volume will increase blood pressure and work for the heart. This can push a heart into failure if it can not maintain pumping this excessive volume.
• Pulmonary:  increased blood volume may increase blood pressure in pulmonary circulation. As a result, some plasma-like fluid leaks out of the pulmonary capillaries and into alveolar space, manifesting as  pulmonary edema which can be heard upon auscultation of the chest

Excessive circulating nitrogenous wastes will cause problems with

• Gastrointestinal:  nitrogenous wastes like urea and ammonia are very irritating to tissues that have fluid, given their ability to dissolve in water easily.  Thus, the entire GI tract will be irritated, manifesting in nausea and vomiting.
• Nervous:  Similarly, excessive nitrogenous wastes will dissolve in the cerebrospinal fluid and thus irritate the CNS, manifesting as confusion and  CNS depression (i.e. reduced level of consciousness, altered cognition)

Imbalance of  pH and electrolyte imbalances (because excretion/absorption is impaired) will cause problems with

• Cardiovascular:  disturbances in electrolytes – especially potassium – will have effects on all electrically excitable cells:  especially the heart. Thus electrolyte imbalances due to AKI can cause arrhythmias
• Nervous:  similarly, electrolyte disturbances will affect the CNS  – manifesting in altered cognition, CNS depression, and possibly seizures.
• Pulmonary:  pH imbalances will affect the rate and depth of breathing as the respiratory system tries to maintain pH balance.  AKI prevents acid from being excreted – so a faster breathing rate (tachypnea) will occur causing the body to work harder to breathe.

Section Summary

Review questions