What should you know about terminal dehydration?

Dehydration happens when the body loses more fluid than it replaces. Severe dehydration can affect circulation, alertness, kidney function and the balance of salts in the body. The word terminal may be used to describe a critical stage, but its meaning depends on the clinical context and the person’s underlying illness. Causes can include vomiting or diarrhoea from gastroenteritis, heat exhaustion, inability to drink, or illness affecting kidney or urinary function. Dark urine, cloudy urine, constipation, extreme thirst, dry mouth, dizziness, weakness and reduced urination may occur, but serious dehydration can also cause confusion or unusual sleepiness.

Treat this as urgent rather than trying to manage a critical presentation alone. If the person is awake and able to swallow, offer small, frequent sips of an appropriate rehydration drink while arranging medical help. Do not force drinks into someone who is drowsy, vomiting repeatedly or unable to swallow, because they may choke. Note when they last urinated, recent vomiting or diarrhoea, heat exposure, medicines and any kidney condition. Medical teams may assess circulation, blood tests, kidney function and the need for fluids by another route.

Call emergency services for confusion, fainting, collapse, severe weakness, difficulty waking, seizures, rapid breathing, inability to keep fluids down, no urine, or signs of shock such as cold, clammy skin. Seek prompt care for worsening dizziness, very dark urine, persistent diarrhoea or vomiting, severe abdominal or back pain, or dehydration after heat exposure. Children, older adults and people with kidney, heart or other serious illness can deteriorate quickly.

Ask what caused the fluid loss, how severe it is, which fluids are suitable, and how kidney function and salts will be monitored. Ask which symptoms should trigger a return to emergency care and how to prevent another episode when drinking is difficult.