Can urinary frequency with pale urine, caused by severe caloric restriction, stress, and high anxiety, be managed with electrolyte replenishment, and is it related to my lab results showing hypernatremia, low urine osmolality, and elevated ketones?

Your Symptoms Are Not Diabetes Insipidus—This Is Severe Caloric Restriction with Stress-Induced Urinary Frequency

Your lab results and clinical picture are entirely consistent with severe caloric restriction (300 calories/day or fasting) combined with stress and anxiety, not diabetes insipidus. Your serum osmolality of 300 mOsm/kg with serum sodium of 143 mEq/L indicates you are slightly hyperosmolar, while your urine osmolality of 170 mOsm/kg shows your kidneys are appropriately diluting urine—but the key finding is that your kidneys can still concentrate urine (evidenced by your response to Pedialyte), which rules out diabetes insipidus 1.

Why Your Labs Rule Out Diabetes Insipidus

The diagnostic triad for diabetes insipidus requires high serum osmolality (>295 mOsm/kg), elevated or high-normal serum sodium, AND inappropriately dilute urine (<200 mOsm/kg) that fails to concentrate even with dehydration 1. While your urine osmolality of 170 mOsm/kg appears low, the critical distinction is that you responded to Pedialyte—meaning your kidneys retained the ability to respond to electrolyte and volume changes, which would not occur in true diabetes insipidus 1.

• In diabetes insipidus, patients produce 3-20 liters of urine daily regardless of fluid intake, with urine osmolality persistently <200 mOsm/kg even during dehydration 1
• Your urinary frequency with pale urine while drinking only water on severe caloric restriction represents appropriate renal response to excessive water intake relative to solute intake 2
• Your urine sodium of 39 mEq/L is within normal range and does not suggest pathological urinary losses 1

The Real Culprits: Starvation Ketosis and Psychogenic Polydipsia

Your ketones of 5 mg/dL indicate starvation ketosis from eating only 300 calories daily or fasting completely, which is an expected metabolic response to severe caloric restriction 3. This is not diabetic ketoacidosis (which requires pH <7.3, bicarbonate <15 mEq/L, and glucose typically >250 mg/dL), but rather physiological ketone production from fat breakdown when carbohydrate intake is inadequate 3.

• Your chloride of 107 mEq/L is at the upper limit of normal (98-107 mEq/L), likely reflecting mild volume contraction from inadequate caloric intake 4
• Your eGFR of 99 mL/min/1.73m² and creatinine of 0.68 mg/dL are completely normal, ruling out kidney disease as a cause 1
• Stress, anxiety, and grief (from your relative's death) are well-established triggers for urinary frequency and overactive bladder symptoms, with up to 25.9% of patients with depression/anxiety experiencing bladder dysfunction 5, 6

Why Pedialyte Helped Your Symptoms

Pedialyte contains balanced electrolytes (sodium, potassium, chloride) and glucose, which provided both the solute load your body desperately needed and corrected the relative hypotonicity you created by drinking only water on severe caloric restriction 1. When you consume only water without adequate food (solute), you create a situation where your kidneys must excrete large volumes of dilute urine to maintain osmotic balance 2.

• The electrolytes in Pedialyte increased your effective circulating volume and provided osmotic particles that allowed your kidneys to concentrate urine more effectively 1
• This response proves your kidneys are functioning normally and can respond to osmotic signals—the opposite of diabetes insipidus 1
• Pedialyte will not "bring down" your chloride of 107 mEq/L; in fact, it contains chloride and will maintain or slightly increase it, but this is appropriate given your clinical context 1

Critical Distinction: Psychogenic Polydipsia vs. Diabetes Insipidus

Your presentation is most consistent with psychogenic polydipsia (excessive water drinking driven by anxiety/stress) superimposed on severe caloric restriction 7. In psychogenic polydipsia, patients drink excessive amounts of water (often >3 liters daily) driven by psychological factors, leading to appropriately dilute urine as the kidneys work to excrete the excess water 1.

• Psychogenic polydipsia accounts for 17.9% of patients presenting with polyuria in specialized centers 7
• The key differentiating feature is that patients with psychogenic polydipsia have normal serum sodium at baseline when they can drink freely, and their kidneys can concentrate urine when water intake is restricted—exactly matching your response to Pedialyte 1
• Stress and anxiety activate the hypothalamic-pituitary axis and dysregulate serotonergic pathways, directly affecting bladder sensation and creating urgency/frequency 6

What Your 24-Hour Urine Collection Will Show

Your 24-hour urine collection will likely show increased urine volume (possibly 3-5 liters) with low urine osmolality, but the critical test is whether your serum sodium remains normal or elevated during the collection 1. If your serum sodium stays normal despite high urine output, this confirms psychogenic polydipsia rather than diabetes insipidus 1.

• Complete the collection by emptying your bladder at the start time and discarding that urine, then collecting every drop for exactly 24 hours, including the final void 1
• Maintain your usual fluid intake based on thirst—do not artificially restrict or increase fluids, as this reflects your true physiological state 1
• Avoid electrolyte-containing solutions like Pedialyte during the collection, as they can confound results by providing exogenous sodium load 1

Immediate Management Recommendations

You must increase your caloric intake immediately to at least 1,200-1,500 calories daily with adequate protein (at least 50-60g daily) and carbohydrates to resolve your starvation ketosis and normalize your fluid-electrolyte balance 3. Continuing severe caloric restriction while grieving and experiencing high anxiety is creating a dangerous metabolic situation that mimics but is not diabetes insipidus.

• Resume eating regular meals with adequate carbohydrates to suppress ketone production and provide osmotic particles for normal kidney function 3
• Address your anxiety and grief with appropriate mental health support, as these are likely the primary drivers of your urinary frequency 5, 6
• Continue drinking to thirst rather than forcing excessive water intake, which may be anxiety-driven 1
• Monitor your weight daily—rapid weight loss or gain (>2 pounds/day) suggests ongoing fluid-electrolyte imbalance requiring medical evaluation 1

When to Seek Urgent Medical Attention

Seek immediate medical care if you develop confusion, severe weakness, inability to urinate, or serum sodium >145 mEq/L with inability to access water, as these indicate life-threatening hypernatremic dehydration 1. However, based on your current labs showing serum sodium of 143 mEq/L with normal kidney function, you are not in immediate danger if you resume adequate nutrition and fluid intake.

• If your 24-hour urine collection shows urine output >5 liters with persistently elevated serum sodium despite free water access, further evaluation with plasma copeptin levels may be warranted to definitively rule out diabetes insipidus 1
• The combination of normal kidney function (eGFR 99), appropriate urine sodium (39 mEq/L), and response to Pedialyte makes diabetes insipidus extremely unlikely 1