• Patient Participation in Urine Specific Gravity Screening for Arginine Vasopressin Deficiency in an Inpatient Neurosurgical Clinic
• Idiopathic Arginine Vasopressin Deficiency With Mild and Reversible Hypercalcemia
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• Evaluation of fluid status in patients with acromegaly through bioelectrical impedance vector analysis: a cross-sectional study
• A Case of Anterior Pituitary Hypofunction and Central Diabetes Insipidus That Occurred after the Extended Right Hepatectomy for Cystic Duct Cancer
• BMI trajectories in the first 3 months after childhood craniopharyngioma resection: a plea for early management of BMI changes
• Does clonidine stimulate copeptin in children?
• Outcomes in surgical management of microprolactinomas: an international multi-institutional series

(*formerly known as Central Diabetes Insipidus*)

Deficiency results in:

• Polyuria
• Polydipsia
• Hypotonic urine
• Risk of hypernatremia and dehydration

Common causes:

• Postoperative (esp. pituitary surgery)
• Traumatic brain injury
• Pituitary tumor/hypothalamic tumors
• Idiopathic or genetic

see Water Deprivation Test

– Progressive fluid restriction – Measure: body weight, plasma osmolality, urine osmolality – Administer desmopressin (DDAVP) when appropriate

* Pituitary MRI to rule out structural causes * Look for loss of posterior pituitary bright spot

Red flags (first 72h post-surgery):

• Urine output >250 mL/h for 2–3 h
• Urine SG <1.005 g/mL
• Rising serum sodium >145 mmol/L

Patient self-monitoring strategy:

• Use urine dipsticks (e.g., Combur-10)
• Cut-off ≥1.015 g/mL reliably excludes hypotonic urine

→ Reduces need for nurse-led testing by ~50% ¹⁾.

It advances the concept of patient-participatory diagnostics and offers a replicable approach to screen for AVP-D. With thoughtful implementation, it has the potential to optimize workflows and empower patients, though accuracy limitations and clinical oversight remain essential.

Self-monitoring of urine specific gravity (SG) offers a non-invasive, accessible method for early identification of Arginine vasopressin deficiency (AVP-D) — particularly useful in the early postoperative period after pituitary surgery.

To enable patients to detect hypotonic urine (SG < 1.005 g/mL), a hallmark of AVP-D, using simple tools and clear thresholds, reducing reliance on continuous nurse monitoring.

1. Frequency: Every 2–4 hours during the first 72h post-op (or as indicated) 2. Record:

1. Urine SG using dipstick
2. Time of measurement
3. Urine volume (if known)

3. Interpretation:

1. If SG < 1.005 → Alert nurse or clinician
2. If SG ≥ 1.015 → No action needed

4. Look for associated symptoms:

1. Excessive thirst (polydipsia)
2. Frequent urination (polyuria)
3. Light-colored or clear urine
4. Dizziness or fatigue

• Reduces nurse-led SG testing by ~50% ²⁾
• Promotes early detection of AVP-D
• Encourages patient engagement and education
• Minimizes unnecessary interventions

• Patients must be briefly trained on dipstick use and interpretation
• Not suitable for:
  1. Patients with cognitive impairment
  2. Pediatric patients (without caregiver)
  3. Severe visual deficits
• Always confirm low SG findings with clinical review and serum sodium

Antidiuretic hormone (ADH) appears as a hyperintensity (HI) on T1-weighted magnetic resonance imaging in:

• The pituitary stalk
• The posterior lobe of the pituitary gland

Key findings:

• Disappearance of HI in the posterior lobe is a marker of ADH deficiency, often observed in DI.
• Appearance of HI in the stalk suggests disturbances in ADH transport.

³⁾

* An increase in serum sodium ≥2.5 mmol/L is a positive marker of postoperative diabetes insipidus with:

• 80% specificity

* A serum sodium ≥145 mmol/L postoperatively indicates DI with:

• 98% specificity

These thresholds help identify patients at risk and guide early treatment decisions after endoscopic transsphenoidal surgery (ETSS).

⁴⁾