Psychogenic polydipsia (PP), also known as primary polydipsia and potomania, was first described in the 1930s. It is surprisingly common with a prevalence rate between 3 to 25% in institutionalized patients. In this podcast, we will discuss how to accurately diagnose and manage psychogenic polydipsia in patients.
Published On: 07/11/2022
Duration: 11 minutes, 37 seconds
Referenced Article: “Management of Psychogenic Polydipsia,” The Carlat Hospital Psychiatry Report, 2022
Victoria Hendrick, MD, and Zachary Davis, BS, have disclosed no relevant financial or other interests in any commercial companies pertaining to this educational activity.
Dr. Hendrick: Welcome to The Carlat Psychiatry Podcast.
I’m Dr. Victoria Hendrick, the Editor-in-Chief of The Carlat Hospital Psychiatry Report, and a clinical professor at the David Geffen School of Medicine at UCLA. I’m also the director of inpatient psychiatry at Olive View -- UCLA Medical Center.
Zachary Davis And I’m Zachary Davis. I graduated from UC Santa Cruz with a neuroscience degree, and I’m a content-coordinator at Carlat Publishing. I’m also a pre-med student who’ll be applying to medical school over the 2022-2023 application cycle, and I’ll be joining Dr. Hendrick on this podcast.
Psychogenic polydipsia (PP), also known as primary polydipsia and potomania, was first described in the 1930s. It is surprisingly common with a prevalence rate between 3 to 25% in institutionalized patients. In this podcast, we will discuss how to accurately diagnose and manage psychogenic polydipsia in patients. But first, a preview of the CME quiz for this podcast.
Dr. Hendrick: Which of the following medications, when used with an antipsychotic can reduce compulsive drinking?
Zachary Davis: So. Dr. Hendrick, what is psychogenic polydipsia and what are its associated physiological effects?
Dr. Hendrick: Psychogenic polydipsia is characterized by an excessive intake of water. It was mainly observed in patients with psychotic disorders who drank too much water, leading to frequent urination and low sodium levels. The cause is unknown, but these patients may have acquired a defect in hypothalamic thirst regulation. Several psychotropic medications such as phenothiazines like chlorpromazine, SSRIs, carbamazepine, oxcarbazepine, haloperidol, MAOIs, amitriptyline, and valproate are thought to cause or worsen PP. This is most likely due to the uncomfortable sensation of dry mouth caused by the anticholinergic effects. The excessive intake of water leads to a dilution of the blood. On a chemistry panel it will show low sodium (<135 mEq/L) as well as low serum osmolality. In addition, the urine will be diluted, with a urine osmolality <100 mosmol/kg and a low urine sodium level.
Zachary Davis: In what types of patients is psychogenic polydipsia most commonly seen?
Dr. Hendrick: Psychogenic polydipsia or PP is most commonly associated with schizophrenia, with an incidence of 11 to 20%, but it can also be seen in patients with other psychotic disorders, mood disorders, and anxiety disorders. Patients with restrictive eating disorders or substance use disorders also show a higher risk of developing polydipsia due to poor nutrition. An example of this occurs in patients with “beer potomania” who drink to a level at which proper nutrition becomes extremely low. This results in low sodium and other electrolyte abnormalities typical of psychogenic polydipsia. MDMA or “ecstasy” can also cause PP in some users
Zachary Davis: One of the risk factors is nicotine dependence, a common comorbidity in patients with schizophrenia, so smoking cessation can help decrease risk of PP. Small studies have reported that the opioid antagonist naltrexone 50 mg daily, when used adjunctively with an antipsychotic, reduces compulsive drinking.
Zachary Davis: The two other conditions that also cause polydipsia and polyuria are diabetes mellitus and diabetes insipidus. How can clinicians rule out these conditions, and what are the differences in pathophysiology between them?
Dr. Hendrick: In diabetes mellitus, the primary problem is hyperglycemia. This causes polyuria because excess glucose is being dumped into the urine which draws excess water along with it via osmotic diuresis. The excess thirst is a result of the dehydration caused by the polyuria. We can rule this condition out because the key diagnostic features of diabetes mellitus, hyperglycemia and glycosuria, are not expected in psychogenic polydipsia.
In diabetes insipidus, the primary problem is not excess water intake or hypoglycemia, but instead it is lowered secretion or response to ADH (antidiuretic hormone). In nephrogenic diabetes, ADH secretion from the brain is normal, but the kidneys are less sensitive to ADH. This is sometimes caused by long term lithium use, and consequent chronic kidney disease. There will be similar signs to psychogenic polydipsia such as dilute urine, but we can rule diabetes insipidus out because unlike psychogenic polydipsia the serum sodium will be high since the serum is concentrated from free water loss.
Another condition I also want to touch on that is important for providers to rule out when diagnosing patients with psychogenic polydipsia is SIADH (syndrome of inappropriate antidiuretic hormone secretion). SIADH is common in elderly patients taking psychiatric drugs or medications such as oxcarbazepine, carbamazepine, and serotonergic antidepressants. Other risk factors include being female or underweight.These medications cause an overproduction of ADH in the body which causes the kidney to absorb excessive water. As a result the serum becomes dilute, but the urine is concentrated. This is unlike psychogenic polydipsia where the urine is diluted so we can rule SIADH out.
Zachary Davis: What are some of the best treatment strategies to manage PP?
Dr. Hendrick: The most important treatment strategy is fluid restriction, which sounds simple in theory but in practice, not so much. The problem lies in preventing the patient from consuming excessive quantities of water. You can always write an order in the chart to limit a patient’s fluid intake to a certain amount, but on a busy inpatient unit, that’s difficult to enforce. Patients will have access to a bathroom and can find ways to drink water. These patients may need 1:1 supervision to ensure they don’t over consume water and have nursing attendants monitor patients by keeping the door ajar when they use the bathroom.
Zachary Davis: In addition to the fluid restriction strategy it is important that we monitor the progression of psychogenic polydipsia. Providers should try to determine if any of the patient’s medications might have triggered or worsened PP. Medications to look for typically include anticholinergic antipsychotics that cause dry mouth, such as chlorpromazine, haloperidol, or tricyclic antidepressants.
How do we know if water consumption levels are being successfully restricted?
Dr. Hendrick: If water consumption is being successfully restricted, serum sodium will improve rapidly. If the sodium remains low, you can supplement with sodium chloride tablets, 1-3 gm daily.
Zachary Davis: Is the treatment plan the same for all patients with psychogenic polydipsia?
Dr: Hendrick: Well, in severe cases of PP- when serum sodium levels drop to 120 mEq/L and lower patients can show signs of delirium along with seizures and obtundation. Serious cases involving cerebral edema and central herniation can be fatal. We need to place special attention on these patients and have them transferred to a medicine unit for closely monitored sodium repletion using intravenous saline (a 3% saline solution).
Zachary Davis: Dr. Hendrick, what should patients do to prevent recurring episodes of polyuria and/or hyponatremia?
Dr. Hendrick: That's a great question. To prevent recurrent episodes of hyponatremia, patients may need to have sodium levels checked at regular intervals. However, depending on the severity of their psychogenic polydipsia, daily sodium supplements may need to be prescribed as needed.
Zachary Davis: Also, behavioral interventions and group therapeutic strategies have shown promising results in preventing relapses.
Any final thoughts on this topic?
Dr. Hendrick: As providers we should also educate patients who are at risk of developing PP of preventative methods. A risk factor for the development of PP is nicotine dependence, a common comorbidity in patients with schizophrenia, so smoking cessation can help decrease the risk of PP. It has also been found that the administration of 50mg daily of opioid antagonist naltrexone when used alongside an antipsychotic, reduces compulsive drinking.
Dr. Hendrick: This Clinical Update is available for subscribers to read in The Carlat Hospital Psychiatry Report. Hopefully people check it out. Subscribers get print issues in the mail and email notifications when new issues are available on the website. Subscriptions also come with full access to all the articles on the website and CME credits.
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Dr. Hendrick: As always, the links you need are in the episode description. Thanks for listening and have a great day!