2   Why would the service user have been prescribed lithium for her bipolar disorder?

3   What would be your role in monitoring and caring for this service user while commencing her lithium in the assessment unit?

4   List the factors you would evaluate as a nurse to ensure the efficacy of lithium

5   What reasons may the service user have for not taking her medicine?

ANSWERS

1 What could have caused the service user’s bipolar disorder?

A THE CHOLINERGIC SYSTEM

Lower than normal levels of choline have been found in the erythrocytes of bipolar patients, prompting researchers to believe that an imbalance between cholinergic and catecholaminergic activity is important in the pathophysiology of bipolar disorder. Further evidence implicating the cholinergic system in bipolar disorder is the antimanic properties of cholinergic agonists and the modulation of manic symptoms by the cholinesterase inhibitor phygostigmine (Manji and Lenox 2000).

THE MONOAMINE SYSTEM

The monoamine hypothesis of depression states that the condition is caused by depleted levels of the monoamine (noradrenaline, serotonin and/or dopamine) in the central nervous system (CNS). While this simplistic model is known not to provide an understanding of the patho-etiology of mood disorders, it continues to have value in providing service users with an explanation of the biochemical basis of mood dysregulation.

Substantial evidence for the role of serotonin in patients with bipolar disorder comes from the study of serotonin receptors. Several studies have shown an increase in the density of serotonin 2 receptors in the platelets and brain of depression patients (Delgado 2000).

One of the most convincing rationales for the role of dopamine in bipolar disorder is the vital role it plays in the reward and/or incentive motivational circuitry. In fact, loss of motivation is one of the key features of depression. The most consistent biochemical finding in depression is the reduced concentration of homovanillic acid (HVA), a major dopamine metabolite, in the cerebrospinal fluid.

A function for dopamine in the aetiology of bipolar disorder is suggested by the role that dopamine agonists have in precipitating mania. It has been postulated that dopamine abnormalities are involved in the hyperactivity associated with the severe stages of mania; whereas noradrenaline is associated with hypomania – as observed in bipolar II disorder (Cousins et al. 2009).

THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS

The hypothalamic-pituitary-adrenal (HPA) axis is involved in the stress response and abnormalities in the this axis have long been implicated in mood disorders. Increased HPA axis activity has been associated with mixed-maniac states, depression and classic manic episodes (Manji and Lenox 2000). Following neurotransmitter release and binding at the post-synaptic membrane, a secondary messenger signalling cascade occurs that ultimately elicits the cellular response. This is an extremely complex pathway and dysfunction in these second messenger mechanisms have been implicated in the pathoetiology of bipolar disorder. Some agents involved in these responses include cyclic adenosine monophosphate (AMP), protein kinases and phosphoinositol (Rang et al. 2011).

GENETIC FACTORS

There is a well-recognized genetic component to the aetiology of bipolar disorder. Multiple family studies have shown that there is higher prevalence of bipolar disease in family members of service users with bipolar disorder, compared with psychiatrically healthy controls. The lifetime risk of bipolar disorder in first-degree relatives of a patient with this condition is 40–70% for a monozygotic twin and 5–10% for all other first-degree relatives (Muller-Oerlinghausen et al. 2002). In this case study, the service user’s father has a tendency to mood swings and there is an assumption that her grandmother was possibly diagnosed with the disease, although the family will not discuss this.

ENVIRONMENTAL FACTORS

Evidence suggests that environmental factors play a significant role in the development and course of bipolar disorder (Serretti and Mandelli 2008). There is fairly consistent evidence from prospective studies that recent life events and interpersonal relationships contribute to the likelihood of onsets and recurrences of bipolar mood episodes. In this case study there is evidence that the service user has been exposed to mood swings from her father that may have complicated her relationship with him.

2 Why would the service user have been prescribed lithium for her bipolar disorder?

A Lithium has been established for more than 50 years as one of the most effective therapies for bipolar mood disorder. However, researchers have never been entirely sure exactly how it operates in the human brain. Lithium stabilizes the neuronal membrane so that it becomes less excitable. It does this by suppressing the production of inositol, which is a simple sugar-like compound present in the normal diet (Ketter 2005).

3 What would be your role in monitoring and caring for this service user while commencing her lithium in the assessment unit?

A The nurse’s role in monitoring and caring for the service user is as follows.

•   Monitoring her mental and emotional status. The nurse should observe her for mania and/or extreme depression (lithium should prevent mood swings). The service user should be requested to keep a symptom log, to document her response to the medication.

•   Monitoring her lithium levels. Lithium salts have a narrow therapeutic/toxic ratio and should therefore not be prescribed unless facilities for monitoring plasma concentrations are available. Doses are adjusted to achieve plasma concentrations of 0.8 to 1.00mmol/L (NICE 2006). Overdose usually occurs with plasma concentrations over 1.5mmol/L, and these may prove fatal. Toxic effects include tremor, ataxia, dysarthria, nystagmus, renal impairment, confusion and convulsions. If these potentially hazardous signs occur, treatment should be stopped. Lithium levels should be checked 12 hours post-dose and five days following starting therapy. Levels are then checked weekly until they have been stable for four weeks. Once stabilized, levels are checked every three months. The nurse should consider more frequent monitoring (e.g. every two months) if a service user has been prescribed any interacting medication or if they develop renal, thyroid or cardiac disease (Calderdale and Huddersfield and North Kirklees and Wakefield Area Prescribing Committee 2011).

•   Monitoring her electrolyte balance. Lithium is a salt affected by dietary intake of other salts such as sodium chloride. Insufficient dietary salt intake causes the kidneys to conserve lithium, increasing serum levels.

•   Requesting the service user to monitor dietary salt intake and consume sufficient quantities, especially during illness or physical activity. The service user should be reminded to avoid activities that cause excessive perspiration.

•   Checking that she is not receiving any other drugs that can impair renal function or induce hyponatraemia, such as diuretics (particularly thiazides) (Kripalani et al. 2009).

•   Measuring her fluid intake and output. Weight should be measured daily until stabilization and the legs and ankles observed for any signs of oedema (short-term changes in weight are a good indicator of fluctuations in fluid volume). Excess fluid volume increases the risk of heart failure; pitting oedema may signal heart failure (Kripalani et al. 2009).

•   Monitoring her renal status by arranging a full blood count and measuring differential, blood urea nitrogen, creatinine and uric acid levels. Urinalysis should be carried out on a regular basis, as lithium can cause degenerative changes in the kidney, which increases drug toxicity. Service users should immediately report anuria, especially when accompanied by lower abdominal tenderness, distension, headache and diaphoresis. Service users should report any nausea, vomiting, diarrhoea, flank pain or tenderness, and any changes in urinary quantity and quality (e.g. sediment) (Kripalani et al. 2009).

•   Monitoring her cardiovascular status and vital signs, including apical pulse and status. Lithium toxicity may cause muscular irritability resulting in cardiac dysrhythmias or angina. The drug should be used with caution in service users with any history of coronary artery or heart disease. Service users should be advised to report immediately any palpitations, chest pain or other symptoms suggestive of myocardial infarction (MI) (Shultz and Videbeck 2008).

•   Monitoring her GI status (lithium may cause dyspepsia, diarrhoea or a metallic taste in the mouth). Service users should be instructed to take the drug with food to reduce stomach upset and report distressing gastrointestinal (GI) symptoms (Shultz and Videbeck 2008).

•   Monitoring her metabolic status. Lithium may cause goitre with prolonged use and false-positive results on thyroid tests. Service users should be instructed to report any symptoms of goitre or hypothyroidism: enlarged mass on neck, fatigue, dry skin or oedema (Shultz and Videbeck 2008).

4 List the factors you would evaluate as a nurse to ensure the efficacy of lithium

A

•   She should demonstrate stabilization of mood, including absence of mania and suicidal depression.

•   She should initiate normal activities of daily living and report an improvement in mood.

•   Episodes of harm directed at herself or others should decrease as the drug begins to take effect.

•   She should be able to fall and stay asleep.

•   She should be able to demonstrate understanding of the drug’s action by accurately describing potential side-effects and precautions against them (Shultz and Videbeck 2008).

5 What reasons may the service user have for not taking her medicine?

A

•   She said she felt ‘terrific’ before she left the assessment unit so she may think she no longer needs the medicine on an ongoing basis. Service users do not always see the need for prophylaxis.

•   She may feel that the medication takes away her creativity. Bipolar disorder has been associated with creativity, goal striving and positive achievements. There is significant evidence to suggest that many people with creative talents have also suffered from some form of bipolar disorder, and it is often proposed that creativity and bipolar disorder are linked (Lam et al. 2004). Therefore it might well be worth this service user discussing lowering the dose with her GP.

•   She may have felt that the medication gave her unacceptable side-effects such as fine hand movements that are difficult to control. She should be encouraged to keep a daily record of any side-effects. The dose could be adjusted, taken in different dosing patterns, or extended release formulations could be discussed.

•   She may feel that taking medication is a sign of personal weakness, sickness and lack of control. Discussing sleep–wake monitoring, charting of moods, cognitive restructuring and coping with family stress could all help her feel that she has some degree of control rather than none.

•   There are widespread problems with social stigma, stereotypes and prejudice against individuals with a diagnosis of bipolar disorder. In this case there is a definite stigma attached to her grandmother’s problems. This may be reinforced by taking medication for the disorder (NIMH 2011).

•   She may feel that the medication is being used as a form of control by her parents and that she is giving in to her parents or spouse by agreeing to take lithium.

•   She may be having problems with her memory and can’t remember to take her medication on a regular basis. Using prompts such as alarms or pill boxes can be helpful here (Miklowitz 2011).