What Is Diabetes Insipidus? Types, Symptoms, Diagnosis, and Treatment

Diabetes insipidus (DI) is distinct from diabetes mellitus. In DI, fluid balance is impaired due to problems with the antidiuretic hormone (ADH)/vasopressin, so the kidneys fail to conserve water and produce large volumes of very dilute urine.

Types of Diabetes Insipidus

• Central — Inadequate ADH production (pituitary dysfunction), often following head injury, tumors, or brain surgery.
  Low ADH
• Nephrogenic — Kidneys do not respond to ADH despite adequate levels; may follow kidney damage or certain drugs.
  ADH resistance
• Gestational — Temporary during pregnancy due to hormonal shifts.
  Pregnancy
• Drug/Toxin-induced — Triggered by medications (e.g., lithium) or toxin exposure impairing renal function.
  Drugs/Toxins

Symptoms

The hallmark features are polyuria (very large volumes of dilute urine, sometimes >10 L/day) and polydipsia (excessive thirst). Ongoing fluid loss leads to dehydration—dry mouth, headaches, fatigue—and frequent nocturia that disrupts sleep. In many people, poor sleep and underhydration further affect daily concentration and performance.

Causes

DI may result from head trauma, brain surgery, or tumors damaging the pituitary; infections (meningitis/encephalitis) interfering with ADH production; genetic conditions, cancer, or kidney damage. Several drugs—most notably lithium—are recognized triggers in susceptible patients. Identifying the cause is crucial to guide treatment.

Diagnosis

Clinicians typically combine urinalysis (concentration and electrolytes) with blood tests (fluid and hormonal status, including ADH) to profile the disorder. A careful medical and medication history helps uncover precipitating factors. When structural disease is suspected, imaging such as MRI or CT is used to evaluate the brain and kidneys. The goal is to classify the DI type and exclude look-alike conditions.

Treatment

Management focuses on restoring fluid balance while addressing the cause. In central DI, desmopressin (synthetic ADH) is often first-line and can be given orally, intranasally, or by injection. Patients are guided to regulate fluid intake to avoid both dehydration and overhydration. For nephrogenic DI, clinicians may adjust offending medications (e.g., discontinue lithium), consider selected diuretics, and tailor nutrition to support renal function. Treating the underlying driver—such as managing tumors or infections—is integral to long-term control.

Prevention & Education

Not all cases are preventable, but simple steps help reduce risk and manage symptoms: keep daily fluids adequate, limit alcohol and caffeine, manage stress, and avoid strenuous activity without proper hydration. For those on higher-risk medications, discuss alternatives or monitoring plans with a healthcare professional. Patient and family education about dehydration warning signs enables faster, safer responses.

Complications

Without treatment, recurrent fluid loss can cause severe dehydration and electrolyte imbalance, affecting vital organs. In extreme situations, kidney failure, neurological injury, infections, and even life-threatening events may occur. Regular follow-up, treatment adherence, and timely access to care help prevent long-term harm.