Urgent considerations
See Differentials for more details
Rapid assessment and stabilisation of a patient with AMS is mandatory, to include the immediate assessment of airway, breathing, circulation, and vital signs. This includes checking for and treating reversible causes of the altered mental condition (e.g., giving oxygen, thiamine, glucose, naloxone), obtaining an accurate temperature measurement, ordering emergency head computed tomography (CT) if signs of trauma are present, giving empirical antibiotics (and/or antivirals) if fever is present, and taking other basic manoeuvres appropriate to the circumstances. Thiamine should be administered before glucose if Wernicke encephalopathy is suspected.
Acute neurological events
New-onset stroke or transient ischaemic attack, traumatic head injury, epidural or subdural haematoma, subarachnoid haemorrhage, seizures, meningitis, encephalitis, brain abscesses, and neurosyphilis can result in AMS.[11] Neurological assessment is prudent, with CT and/or magnetic resonance imaging (MRI).
Investigations in patients with signs of hypertensive encephalopathy should focus on any signs of end-organ damage. In cases of acute hypertensive emergency, the initial goal of therapy is to reduce mean arterial blood pressure (BP) by no more than 25% (within minutes to 1 hour), and then, if the patient is stable, to 160/100 to 110 mmHg within the next 2 to 6 hours.[12][13]
Delirium (an acute, fluctuating level of consciousness and cognition characterised by inattentiveness and disorganised thinking) is a medical emergency that requires immediate work-up.[8][14] History or signs indicating a general medical condition, such as infection, metabolic disturbance, or pharmacological toxicity, can sometimes be elucidated. Initial tests to order include full blood count (FBC), metabolic profile, fasting blood glucose, urinalysis, and urine culture. Further investigations and management are guided by clinical history and examination. Delirium in older patients admitted to hospital is frequently persistent (up to 21% of older patients at 6 months following discharge).[15] Patients with persistent delirium have consistently been shown to have worse clinical outcomes, including greater risk of losing their independence and being placed in long-term care.[15]
Severe systemic infection
Considering occult infections (central nervous system, skin, heart, lung, abdomen, genitourinary) is imperative, given that early recognition and treatment of sepsis or septic shock is key to improving outcomes.[16][17][18] AMS may be the only identifiable sign of urinary tract infections and pneumonia in older people. Urinalysis and chest x-ray should be obtained as part of every work-up. Brain abscesses can also present with AMS, and can be identified by CT or MRI scans of the head.
Sepsis
A spectrum of disease, where there is a systemic and dysregulated host response to an infection.[19] Presentation ranges from subtle, non-specific symptoms (e.g., feeling unwell with a normal temperature) to severe symptoms with evidence of multi-organ dysfunction and septic shock. Patients may have signs of tachycardia, tachypnoea, hypotension, fever or hypothermia, poor capillary refill, mottled or ashen skin, cyanosis, newly altered mental state, or reduced urine output.[17] Sepsis and septic shock are medical emergencies.
Risk factors for sepsis include:[17]
age under 1 year
age over 75 years
frailty
impaired immunity (due to illness or drugs)
recent surgery or other invasive procedures
any breach of skin integrity (e.g., cuts, burns)
intravenous drug misuse
indwelling lines or catheters
pregnancy or recent pregnancy.
Early recognition of sepsis is essential because early treatment improves outcomes.[17][18][Evidence C][Evidence C] However, detection can be challenging because the clinical presentation of sepsis can be subtle and non-specific. A low threshold for suspecting sepsis is therefore important. The key to early recognition is the systematic identification of any patient who has signs or symptoms suggestive of infection and is at risk of deterioration due to organ dysfunction. Several risk stratification approaches have been proposed. All rely on a structured clinical assessment and recording of the patient’s vital signs.[17][20][21][22][23] It is important to check local guidance for information on which approach your institution recommends. The timeline of ensuing investigations and treatment should be guided by this early assessment.[22]
Treatment guidelines have been produced by the Surviving Sepsis Campaign and remain the most widely accepted standards.[18][24] Recommended treatment of patients with suspected sepsis is:
Measure lactate level, and re-measure lactate if initial lactate is elevated (>2 mmol/L [>18 mg/dL]).
Obtain blood cultures before administering antibiotics.
Administer broad-spectrum antibiotics (with methicillin-resistant Staphylococcus aureus [MRSA] coverage if there is high risk of MRSA) for adults with possible septic shock or a high likelihood for sepsis.
For adults with sepsis or septic shock at high risk of fungal infection, empirical antifungal therapy should be administered.
Begin rapid administration of crystalloid fluids for hypotension or lactate level ≥4 mmol/L (≥36 mg/dL). Consult local protocols.
Administer vasopressors peripherally if the patient is hypotensive during or after fluid resuscitation to maintain MAP ≥65 mm Hg, rather than delaying initiation until central venous access is secured. Noradrenaline is the vasopressor of choice.
For adults with sepsis-induced hypoxaemic respiratory failure, high-flow nasal oxygen should be given.
Ideally, these interventions should all begin in the first hour after sepsis recognition.[24]
For adults with possible sepsis without shock, if concern for infection persists, antibiotics should be given within 3 hours from the time when sepsis was first recognised.[18] For adults with a low likelihood of infection and without shock, antibiotics can be deferred while continuing to closely monitor the patient.[18]
For more information on sepsis, please see our topics [Related Topic: Sepsis in adults ] and [Related Topic: Sepsis in children].
Gastrointestinal
Appendicitis and acute mesenteric ischaemia are surgical emergencies that can be fatal if not identified and treated.
Appendicitis causes constant mid-abdominal pain that later moves to the right lower quadrant. The pain is usually worse on movement. Anorexia, nausea, and vomiting are common. One classic sign is right lower quadrant abdominal tenderness (McBurney's sign). There may be localised rebound tenderness, especially if the appendix is anterior. The goal of treatment is to remove the infected appendix. Once the diagnosis of acute appendicitis is made, patients should be given nothing by mouth. Intravenous maintenance fluids should be started and appendectomy performed without delay.
The majority of patients with an ischaemic bowel experience pain, which can vary depending on the type and segment of bowel involved. Haematochezia, melaena, and diarrhoea frequently occur. Perceived pain may be out of proportion to tenderness appreciated on physical examination. Adequate fluid resuscitation and supplemental oxygen should be administered to optimise tissue perfusion and oxygenation. Initial resuscitation should also aim to relieve any acute heart failure and correct any cardiac arrhythmias. Invasive monitoring and inotropic support may be appropriate. Nothing-by-mouth status should be enforced, with nasogastric tube decompression for symptomatic relief.
Empirical antibiotics suitable for enteric coverage are administered to all patients according to local antimicrobial guidelines, as ischaemia can lead to significant bacterial translocation due to damage to the normal intestinal mucosal barrier.
With the emergence of interventional radiology, endovascular treatment may be considered for haemodynamically stable patients where available. If there are clinical signs of peritonitis, or radiographic or laboratory evidence suggestive of infarction or perforation, exploratory laparotomy or laparoscopy must proceed urgently and include resection of non-viable intestine.
Cardiac events
Acute chest pain warrants rapid clinical assessment, as underlying disease can be life-threatening. Continuous monitoring of pulse, BP, and oxygen saturation is standard care. If the patient is in pain or breathless, or oxygen saturation is <90%, high-flow oxygen should be given. Morphine (intravenous) may also be necessary to relieve severe pain.
Initial investigations include a 12-lead ECG, chest x-ray, cardiac biomarkers, FBC, and renal profile. The patient may need to be transferred to an intensive care setting. Once the patient is stable, further tests, such as a ventilation-perfusion scan, echocardiogram, CT, or angiography, should be requested to confirm clinical suspicion.
Psychiatric events
The assessment of an acutely psychotic patient includes a thorough history and physical examination, as well as laboratory tests. Based on the initial findings, further diagnostic tests may be warranted. Organic causes must be considered and excluded before the psychosis is attributed to a primary psychotic disorder. The most common cause of acute psychosis is drug toxicity from recreational, prescription, or non-prescription drugs. Patients with structural brain conditions, or a toxic or metabolic process presenting with psychosis, usually have other physical manifestations that are readily detectable by history, neurological examination, or routine laboratory tests.
Respiratory disorders
AMS is commonly associated with hypoxia that is usually secondary to an underlying disease, such as systemic infection, pulmonary embolism, severe asthma attack, COPD, cardiac failure or arrhythmia, or carbon monoxide poisoning. Pulse oximetry and arterial blood gases can confirm the presence of hypoxia.
Medication effects
It is essential to establish whether new medications have been started, an existing medication has been recently changed, or a medication has been stopped abruptly.[25] Enquiries should include questions about non-prescription medications and surreptitious alcohol use. Medication reconciliation is mandatory in the emergency department, as certain withdrawal states can be fatal if missed.
Toxidromes
A toxicology screen (for both prescription and illicit drugs) and an alcohol level should be ordered whenever substance abuse is suspected. Accidental poisoning should be considered in all young children with acute mental status changes, and management should be dictated based on the suspected toxin. Withdrawal syndromes should also be considered. Rapid diagnosis and urgent treatment of all toxidromes is imperative. Consideration must be given to illicit drug use (e.g., opiate, amfetamine, and benzodiazepine abuse).
Endocrinopathies
Myxoedema coma typically occurs in older patients with underlying hypothyroidism. Adrenal crisis can occur in patients with Addison's disease during stress, trauma, or infection or, more commonly, in those taking corticosteroids. Thyroid function tests and serum cortisol levels should be considered as part of the work-up for AMS.
Adrenal crisis should be treated immediately, even if a laboratory diagnosis has not yet been made. Intravenous hydrocortisone is given if adrenal crisis is clinically suspected.
Intravenous fluids should be administered to correct hypotension and dehydration. This may be the most important component in the immediate resuscitation of a critically ill patient. Careful monitoring of BP, fluid status, and serum sodium and potassium levels should be maintained. Glucose should be administered when necessary to correct hypoglycaemia, but care should be taken to avoid worsening hyponatraemia. The use of normal saline supplemented with dextrose 5% is helpful in this regard.
Metabolic abnormalities
Patients with life-threatening cases of sodium, potassium, and calcium abnormalities may present with AMS. Metabolic abnormalities may be secondary to renal or liver disease. A metabolic work-up is essential.
Glucose abnormalities
Both hypoglycaemia and hyperglycaemia can present with confusion and reduced consciousness. Plasma glucose should be the first test in any patient presenting with AMS, as it is quick and easy to measure and readily treatable. If the test is not immediately available, empirical glucose should be given.
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