You Do Not Have Diabetes Insipidus
Based on your laboratory values and clinical presentation, you do not meet diagnostic criteria for diabetes insipidus. Your serum osmolality of 300 mOsm/kg with urine osmolality of 170 mOsm/kg and normal serum sodium of 143 mmol/L represents an appropriate physiologic response to mild dehydration, not diabetes insipidus 1.
Why This Is Not Diabetes Insipidus
Your Lab Values Rule Out the Diagnosis
Diabetes insipidus requires the pathognomonic triad of polyuria, polydipsia, AND inappropriately dilute urine (osmolality <200 mOsm/kg H₂O) combined with high-normal or elevated serum sodium 1, 2.
Your urine osmolality of 170 mOsm/kg is borderline and occurred in the context of transient increased fluid intake from multivitamins, not persistent pathologic polyuria 1.
True diabetes insipidus patients cannot concentrate their urine even when dehydrated—your subsequent dark yellow urine demonstrates intact urinary concentrating ability, which definitively excludes diabetes insipidus 1, 3.
Your 24-hour urine output of 2-2.5 liters is below the diagnostic threshold of >3 liters per 24 hours required for diabetes insipidus in adults 1, 3.
Your Clinical Course Confirms Normal Physiology
The resolution of your polyuria after stopping the multivitamin, along with return to concentrated (dark yellow) urine, demonstrates normal ADH function 1, 2. Patients with true diabetes insipidus cannot achieve this spontaneous correction 4, 5.
Your ability to sleep through the night without urinating or drinking is incompatible with diabetes insipidus—nocturnal polyuria with night waking is a hallmark feature of organic diabetes insipidus 3.
The transient nature of your symptoms (3 days of multivitamin use) does not fit the persistent, unrelenting polyuria characteristic of diabetes insipidus 4, 6.
What Actually Happened
Transient Osmotic Diuresis from Multivitamins
Your colorless, high-volume urine during multivitamin use likely represented osmotic diuresis from water-soluble B vitamins (particularly B2/riboflavin) and other excretable compounds, not ADH deficiency 1.
The rapid normalization after discontinuing multivitamins confirms this was a reversible, exogenous cause of increased urine output 2.
Normal Physiologic Variation in Urine Concentration
Morning urine is normally more concentrated (dark yellow) after overnight fasting, while daytime urine varies based on fluid intake—this is exactly what you're experiencing 1.
Your urine void volumes of 200-300 mL are completely normal; diabetes insipidus patients often have much larger individual void volumes 7.
Addressing Your Kidney Function Concerns
Your creatinine fluctuation from 1.27 to 0.9 (eGFR 48 to 78) represents normal variation related to meat intake and hydration status, not kidney disease 1.
Red meat consumption 2-3 hours before labs can transiently elevate creatinine through creatine metabolism, and the rapid normalization the next day confirms this 1.
This degree of fluctuation does not indicate chronic kidney disease or diabetes insipidus-related renal complications 1.
Your Anxiety and Sedentary Lifestyle
Clinical anxiety can cause perceived polydipsia and increased attention to urinary symptoms (hypervigilance), but your objective measurements do not support pathologic polyuria 1.
Sedentary lifestyle in bed may alter your perception of normal urinary frequency compared to more active individuals 7.
Critical Distinction: What Would Indicate Diabetes Insipidus
If you actually had diabetes insipidus, you would experience:
Persistent polyuria >3 liters/24 hours that does NOT resolve with stopping multivitamins 1, 3.
Inability to produce concentrated (dark yellow) urine even when restricting fluids—your kidneys would be unable to respond appropriately 1, 4.
Mandatory night waking to urinate and drink, often multiple times 3.
Serum sodium trending toward or exceeding 145 mmol/L with persistently dilute urine <200 mOsm/kg 1, 2.
Severe thirst that is unrelenting and distressing, not just preference for fluids 4, 6.
No Further Testing Needed
You do not require water deprivation testing, copeptin measurement, or pituitary MRI because your clinical presentation and laboratory values do not meet diagnostic criteria for diabetes insipidus 1, 2, 3.
Your normal serum osmolality of 289 mOsm/kg from your previous evaluation further supports normal ADH function 2.
Recommendation
Continue your current medications for anxiety, maintain adequate but not excessive fluid intake based on thirst, and reassure yourself that your urinary pattern is physiologically normal. 1, 7 If polyuria were to recur persistently (>3 liters/24 hours for multiple days) with inability to concentrate urine, then reevaluation would be warranted 1.