Polyuria – Symptoms, Causes, Diagnosis, and Treatments

Introduction

Polyuria is excessive or an abnormally large production or passage of urine (greater than 3 L over 24 hours). However, certain factors such as the use of diuretics and uncontrolled glycaemic levels in Diabetes are frequent causes of this condition.

 In the non-diabetic individual and in the absence of diuretic use, the most frequent causes encountered in clinical practice are chronic polyuria secondary to polydipsia, central Diabetes insipidus and nephrogenic Diabetes insipidus.

TYPES OF POLYURIA

Based on the onset and the duration, polyuria may be

• Transient
• Temporary or
• Permanent.

Occasional polyuria 

Occasional polyuria manifests in specific patient scenarios, as mentioned herewith.

• Increased drinking of clear fluids
• Consumption of foods that contain natural diuretics such as watermelon, alcohol, coffee.
• Stressful and emotional conditions culminate in the increased secretion of adrenaline, noradrenaline and cortisol in the bloodstream.
• Sometimes trivial causes like exposure to cold environments may induce increased enuresis.

The most significant point that is emphasised in all the above-mentioned conditions is that polyuria only lasts for a brief duration.

Only when there is a reversal of the precipitating causes, the polyuria will cease permanently. This will lead to the correction of urine excretion, and the fluid volume becomes normal.

Despite the causes mentioned above, certain pathologic conditions induce polyuria that may last for a brief period of time, such as

• Paroxysmal arrhythmias
• Acute myocardial infarction
• Painful conditions like Ureteric colic and gall bladder colic
• Convulsions

On the contrary, polyuria is considered to be persistent or permanent and further subdivided into two important categories based on the density of urine.

Hypotonic and Isotonic polyuria

The basic and fundamental difference between hypotonic and isotonic polyuria is governed by the osmolality and osmolarity of the urine plasma, which consequently is regulated by the concentration of sodium in the plasma.

Categorically hypotonic polyuria implies that urine osmolality is diminished below 200 mOsm/100 mL.  Hypotonic polyuria is frequently associated with

• Nephrogenic insipidus Diabetes mellitus
• Chronic renal failure secondary to polycystic kidney disease, pyelonephritis
• Certain metabolic and electrolyte abnormalities of sodium and calcium, such as hypokalemia and hypercalcemia.

Causes for polyuria

Polyuria maybe be caused due to

• Urinary tract Infection (more common in Females)
• Uncontrolled Diabetes Mellitus/Diabetes Insipidus
• Alimentary Glycosuria
• Neurogenic bladder
• Pregnancy
• Medications
• Stress
• Excessive water Drinking
• Weather
• RTA (Renal Tubular Acidosis)
• Hypercalcaemia
• Hypokalaemia
• Alcohol

Diabetes Insipidus 

• Severe polyuria
• Hypernatremia
• Serum osmolarity >280
• Urine osmolarity < 280
• Response to Desmopressin (central type)

Alimentary Glycosuria 

• Seen in individuals where blood glucose level rises rapidly after meals (Post gastrectomy)

Medication 

• Diuretics
• Corticosteroids
• Phenothiazine-Psychogenic drug
• SGLT2 inhibitors

Symptoms of UTI

• Burning micturition
• Nausea
• Vomiting
• Lower abdomen pain
• Fever with chills and rigour

Symptoms of overactive bladder

• Urgency
• Urinary frequency
• Nocturia
• Urge incontinence

Diagnostic investigations

The following diagnostic tests are required to know the cause of polyuria.

• Blood sugar  
• UCE
• Urine osmolality
• Serum urea/Creatinine
• Serum Electrolytes
• ABG
• USG Abdomen

Treatment

There is no specific medication to treat polyuria, nor does it have a set course of treatment. Instead, the patient has to work with a doctor to control the disease that causes polyuria.

The primary factor influencing treatment is the cause of polyuria. Identifying the root cause and treating uncontrolled diseases, such as diabetes or congestive heart failure, is the only goal of treatment.

Conclusion

Polyuria is an increase in urination frequency. About one to two litres of urine are normally excreted each day by an adult. Polyuria is the excretion of three litres or more of urine daily. Treatment for polyuria lies in treating the disease or condition causing this symptom. Doctor consultation can help people who experience more frequent urination.

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