Criteria

A group of Japanese experts has proposed a set of diagnostic criteria and a 13-item severity scale for polydipsia.[66] Published in 2021, these tools are emerging and have yet to be validated in randomized controlled trials or in clinical practice, and should therefore be used with caution until further evidence is available.

Proposed polydipsia diagnostic criteria[66]

Evaluate the following items based on the previous year. For patients under sedation/physical restraint, evaluation is based on status before the start of sedation/restraint.

Criteria A

  • I-1. Excessive drinking (e.g., compulsive repetitive drinking behavior, water-drinking behavior that cannot be stopped, drinking dirty water, and witnessing of frequent drinking or carrying cups around)

  • I-2. Abnormal normalized diurnal weight gain (≥2.5%)

    • Note: cut-off values are quoted in the polydipsia severity scale.

  • II-1. Low serum sodium level (<134 mEq/L) or low serum osmolality (<275 mOsm/L)

    • Note: cut-off values are quoted in the polydipsia severity scale.

  • II-2. Low urine specific gravity (<1.008)

    • Note: cut-off values are quoted in the polydipsia severity scale.

  • III. Development or exacerbation of psychiatric symptoms

    • Note: this can be a supportive item to help the diagnostic evaluation only with multiple recurrence, along with either I or II.

Criteria B

  • It is essential that the polydipsia cannot be explained by a medical condition (e.g., diabetes insipidus), and that hyponatremia cannot be explained solely by any physical disease, or drugs such as diuretics.

  • Definitive polydipsia can be diagnosed if ≥1 items of I are present, with the presence of II-1 and II-2.

  • Probable polydipsia can be diagnosed if II-1 and II-2 are present, without the presence of I.

Proposed polydipsia severity scale[66]

Evaluate the following items based on the past week. The maximum total score is 59.

  • Excessive drinking

    • Rarely occurs (e.g., less than once a week) - score 1

    • Sometimes occurs (e.g., a few times a week) - score 3

    • Occurs most of the time (e.g., almost every day) - score 4

  • Drinking dirty water

    • If yes - score 5

  • Abnormal normalized diurnal weight gain

    • ≥2.5% - score 3

    • ≥4% - score 5

  • Low serum sodium level

    • 130 mEq/L - score 2

    • 129-125 mEq/L - score 3

    • 124-120 mEq/L - score 5

    • <120 mEq/L - score 7

  • Low serum osmolality

    • <275 mOsm/L - score 3

  • Low urine specific gravity

    • <1.008 - score 2

  • Disturbance of consciousness

    • Confusion/twilight state - score 6

    • Loss of consciousness - score 7

  • Seizure

    • If yes - score 7

  • Wobble/gait disturbance/fall

    • If yes - score 5

  • Development or exacerbation of psychiatric symptoms

    • If yes - score 4

  • Polyuria

    • If yes - score 3

  • Incontinent

    • If yes - score 3

  • Vomiting

    • If yes - score 4

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