**3.2 Bipolar illness**

PPD has also been implicated in psychiatric patients with bipolar I disorder in a manic state whose increase in fluid intake can lead to hyponatremia [8]. As defined by DSM 5, a manic episode is a distinct period of abnormally and persistently elevated, expansive or irritable mood with increased activity or energy lasting at least 1 week that is not attributable to physiological effects of substances with three or more of the following symptoms present including inflated self-esteem,

decreased need for sleep, pressured speech, flight of ideas, distractibility, increased goal directed activity, and excessive involvement in activities that have a high potential for painful consequences such as gambling, sexual indiscretions, and unrestrained buying sprees. The presence of mania distinguishes bipolar I from bipolar II; in bipolar I a patient must meet criteria for a manic episode, which may have been preceded or followed by a hypomanic or major depressive episode. Additionally, as defined by DMS 5 [1], bipolar disorder type II is diagnosed when the individual meets criteria for a current or past hypomanic episode and a current or past major depressive episode. A hypomanic episode is defined by DSM 5 [1] as a distinct period of abnormally and persistently elevated, expansive or irritable mood with increased activity or energy lasting at least 4 days with three or more of the following symptoms present including inflated self-esteem, decreased need for sleep, pressured speech, flight of ideas, distractibility, increased goal directed activity, and excessive involvement in activities that have a high potential for painful consequences such as gambling, sexual indiscretions, and unrestrained buying sprees. Major depressive episode includes 5 or more of the following symptoms over a 2-week period that represent a change from previous functioning such as depressed mood, diminished interest in activities, significant change in weight, insomnia or hypersomnia, psychomotor agitation or retardation, loss of energy, feelings of worthlessness, decreased ability to concentrate, and recurrent thoughts of death.

### **3.3 Obessive compulsive disorder (OCD)**

Obsessive-compulsive disorder as defined by DSM 5 [1] is characterized by the presence of obsessions, compulsions or both. Obsessions are recurrent or persistent intrusive thoughts that cause marked anxiety or distress that individuals try to ignore or suppress by performing compulsions such as repetitive behaviors or mental acts including hand washing, praying, or checking behaviors. The obsessions and compulsions are time consuming, and distressing, and are not attributed to another medical condition. An interesting case of an Indian woman has been reported in the literature, where her behaviors of excessive water intake, intrusiveness, excessive washing, cleaning, checking and perfectionism led to a diagnosis of OCD. She had experienced recurrent seizures with no benefit from antiepileptic medication, and only after further assessment it was discovered that her urge to drink excessive water led to consumption of 7 L of water producing hyponatremia and seizure [11]. This case is important because it highlights how a psychiatric condition (OCD) can present as a neurological emergency [11].
