28th November 2023

The Confused Patient

We’re often faced with narrowing down differentials for the confused patient. This is important in psychiatry, especially in old age psychiatry, where any one of the following could lead to increased confusion on the background of a diagnosed disorder such as dementia. The following look at confusion is from a physical health perspective and focuses on the topics which pop up in exams. In this section we’ll cover:

• Delirium.
• Normal pressure hydrocephalus.
• Hypercalcaemia.
• Pellagra.

Delirium

As per the ICD-11, in delirium, there is a disturbance in global cognitive function, as well as in attention and orientation. It also often presents with changes in behaviour, emotion, and reversal of the sleep-wake cycle. It develops quickly with a fluctuating course. It is predominantly seen in hospital inpatients, affecting up to 50% of those aged 65 and over in an inpatient setting (British Geriatrics Society, 2019).

Clinicians often split delirium into hypoactive and hyperactive subtypes. Hypoactive delirium is a reduction in activity by the patient; with excessive sleeping, lethargy, apathy, and psychomotor retardation (Meagher, 2009); whereas hyperactive delirium is often marked by psychomotor agitation, aggression, delusions and hallucinations.

Presentation

To diagnose delirium, there needs to be a change in functioning, with the disturbances in the following developing over the course of hours to days:

• Attention.
• Orientation.
• Awareness.
• Emotion.
• Perception – Patients can have illusions and hallucinations.

Causes

A good way of remembering the causes of delirium is by using the ‘PINCH ME’ mnemonic (explored by Pryor and Clarke, 2017):

• Pain.
• Infection.
• Constipation.
• DeHydration.
• Medication.
• Environment – Including not having the correct glasses or hearing aids.

Investigations

As with all pathology, a thorough history and examination (including CAM criteria or 4A’s test) is key to guide further investigations and, ultimately, diagnosis. Bloods, often termed a ‘confusion’ screen, are normally done as standard and includes (National Institute for Health and Care Excellence (NICE) CKS, 2021):

• FBC, U+Es, LFTs, TFTs, Calcium profile, haematinics, TFTs, glucose and HbA1c.

Other investigations are guided by examination but include an infective screen (chest X-ray, urine analysis, blood cultures) and CT head.

Management

Treatment is that of the underlying cause. We can also optimise the environment (e.g. ensuring adequate lighting, correcting sensory impairments, etc.), and pharmacological interventions can be used for particularly problematic behaviour which may cause the patient to be a risk to themselves or a risk to others. In such cases, haloperidol is useful (NICE CKS, 2021).

It is worth noting the high mortality associated with delirium, with 40% of people diagnosed with delirium dying within a year (Kiely et al., 2009).

Normal pressure hydrocephalus

This is a type of communicating hydrocephalus – meaning that there is a blockage of the flow of CSF after it has already entered the ventricles (Relkin et al., 2005).

Presentation

The handy memory aid is ‘wet, wacky and wobbly’ with the classical presentation of Hakim’s triad (Wallenstein and McKhann, 2010):

• Urinary incontinence.
• Mental state changes.
• Ataxia.

Investigations

First line investigations include imaging (normally a CT head), followed by a lumbar puncture (LP) with opening pressure. The CT head may show ventricular enlargement (Damasceno, 2015) with periventricular leukomalacia. There will be a normal opening pressure during the LP and improvement of symptoms following the drainage of fluid.

Management

This depends on whether the patient is deemed fit for surgical intervention or not. If they are, a shunt can be placed; if not, large volume cerebrospinal fluid taps are done. Either way, minimising cardiovascular risk factors is key (BMJ Best practice, 2022).

Hypercalcaemia 

An abnormally high serum calcium level has several causes (Carric and Costner, 2018).

• Secondary to other conditions – Hyperparathyroidism and cancers such as myeloma.
• Secondary to medications – Lithium, thiazide diuretics, and vitamin D supplementation.

Presentation

The handy memory aid is ‘groans, bones, stones, moans, thrones, and psychic overtones’ (Sadiq, Naganathan and Badireddy, 2022), with the classic presentation of:

• Gastrointestinal issues such as constipation with secondary abdominal pain.
• Bone pain.
• Renal stones.
• Tiredness.
• Polydipsia and polyuria.
• Depression, fatigue and confusion.

Management

This includes rehydration with IV fluids and, in more resistant cases, IV bisphosphonate. Ultimately, the underlying cause must be treated.

Pellagra

Pellagra is due to Vitamin B3 (niacin) deficiency. Causes include dietary deficiency, malabsorption and secondary to some medications (including carbamazepine).

Presentation

It is often remembered by the four Ds:

• Dementia.
• Diarrhoea.
• Dermatitis.
• Death (if not effectively managed).

Management

Oral B3 replacement is used, but ideally, the condition should be prevented entirely; be this through the fortification of food in at risk areas (Matapendeu, Dunn and Pagels, 2017) or the use of supplementation when receiving medications known to be associated with niacin deficiency (Prabhu, Dawe and Mponda, 2021). The gastrointestinal symptoms of pellagra can begin to improve within days of treatment, and the psychiatric symptoms within the first week. The skin changes seen are more resistant to treatment (Karthikeyan and Thappa, 2002).