Do I have diabetes insipidus given my symptoms of polyuria and low urine osmolality?

Do You Have Diabetes Insipidus?

No, you do not have diabetes insipidus. Your clinical picture is inconsistent with this diagnosis based on multiple key factors: your urine output is normal (2-2.5L/24h), your serum sodium is normal (143 mmol/L), and your symptoms were transient and resolved after stopping the multivitamin 1, 2.

Why Diabetes Insipidus Is Ruled Out

Urine Volume Does Not Meet Diagnostic Criteria

• Diabetes insipidus requires polyuria >3 liters per 24 hours in adults 1, 3, 4.
• Your reported output of 2-2.5L/24h is within normal range and falls well below this threshold 1.
• Individual void volumes of 200-300ml are completely normal 1.

Your Osmolality Pattern Is Inconsistent with DI

• True diabetes insipidus presents with urine osmolality <200 mOsm/kg combined with high-normal or elevated serum sodium—this triad is pathognomonic 1.
• While your urine osmolality was 170 mOsm/kg (which is low), your serum osmolality of 300 mOsm/kg and serum sodium of 143 mmol/L are both normal 1, 2.
• In diabetes insipidus, serum sodium is typically >145 mmol/L due to water loss 1, 3.
• The combination of dilute urine with normal serum sodium suggests transient increased fluid intake or a temporary concentrating defect, not diabetes insipidus 1, 2.

Symptom Resolution Excludes Chronic DI

• Diabetes insipidus is a persistent condition that does not spontaneously resolve 3, 5, 4.
• Your symptoms improved after stopping the multivitamin and you now have concentrated urine (dark yellow), which is physiologically impossible in diabetes insipidus 2, 3.
• Patients with DI cannot concentrate their urine even with dehydration 3, 4.

What Actually Explains Your Symptoms

Transient Polyuria from Multivitamin

• Certain B vitamins (particularly B2/riboflavin) cause bright yellow urine and can increase urine output temporarily through osmotic effects 1.
• Your timeline (symptoms during multivitamin use, resolution after stopping) strongly suggests this was the cause 1.

The Creatinine Fluctuation

• Your creatinine elevation (1.27 with eGFR 48) followed by normalization (0.9 with eGFR 78) the next day is explained by pre-renal factors, not kidney disease 1.
• Eating red meat 2-3 hours before labs can falsely elevate creatinine due to creatine metabolism 1.
• Mild dehydration from increased urination while on the multivitamin could have contributed 6.
• The rapid normalization confirms this was not true kidney dysfunction 1.

Anxiety and Sedentary Lifestyle Effects

• Clinical anxiety can increase perceived urinary frequency without actual polyuria 1.
• Being sedentary in bed may make you more aware of normal bladder sensations 1.
• Not drinking excessively and not waking at night to urinate are both inconsistent with diabetes insipidus 3, 5.

Critical Distinguishing Features You Lack

Patients with diabetes insipidus have these features that you do not:

• Persistent polyuria >3L/24h that continues despite attempts to reduce fluid intake 1, 3.
• Inability to concentrate urine even when dehydrated 3, 4.
• Nocturia requiring multiple awakenings to urinate 3, 5.
• Hypernatremia (sodium >145 mmol/L) if fluid access is restricted 1, 3.
• Symptoms that persist continuously, not transiently 3, 5, 4.

What You Should Do

No Further DI Workup Needed

• You do not require water deprivation testing, copeptin measurement, or desmopressin trials 1, 3, 4.
• These tests are only indicated when polyuria >3L/24h persists with inappropriately dilute urine and elevated serum sodium 1, 3.

Monitor Your Current Status

• Continue observing your urine color and frequency now that the multivitamin is stopped 1.
• If urine remains light yellow to dark yellow and frequency stays normal (not waking at night), this confirms resolution 1.
• Your normal serum sodium (143 mmol/L) and normal kidney function (creatinine 0.9, eGFR 78) require no specific intervention 1.

Address Anxiety Component

• Work with your prescriber to optimize anxiety management, as this may be amplifying your awareness of normal bodily functions 1.
• Consider cognitive behavioral therapy for health anxiety if concerns about medical conditions persist 1.

When to Seek Re-evaluation

Return for medical evaluation only if you develop:

• True polyuria with measured 24-hour urine output >3 liters 1, 3.
• Persistent extreme thirst with inability to satisfy it 1, 3.
• Multiple nighttime awakenings (≥2) specifically to urinate large volumes 3, 5.
• Symptoms of hypernatremia: confusion, weakness, or severe dehydration 1, 2.

Your clinical picture represents a transient, self-limited phenomenon related to multivitamin use, not diabetes insipidus 1, 2.