Clinical Reasoning Tutorial #35: Delirium PDF

Clinical Reasoning – Background Reading CR226 Clinical Reasoning Tutorial #35: Delirium Prepared by Dr. Omer Yusuf, MD FRCPC Session Learning Objectives: At the end of the session, the student will be able to: 1. Define and differentiate delirium and dementia 2. Describe common causes of d...

Clinical Reasoning – Background Reading CR226 Clinical Reasoning Tutorial #35: Delirium Prepared by Dr. Omer Yusuf, MD FRCPC Session Learning Objectives: At the end of the session, the student will be able to: 1. Define and differentiate delirium and dementia 2. Describe common causes of delirium and screening methods for delirium 3. Identify common problems in the diagnosis and management of a patient with dementia 4. Reproduce the provided differential diagnosis for delirium and dementia 5. Make a problem list and management plan for a complex patient 6. Describe illness scripts for: a. Sepsis b. Anticholinergic toxidrome c. Alzheimer’s dementia Student Preparation 1. Read the Delirium background reading document and complete the practice questions 2. Answer a self-directed question Delirium - Introduction Delirium, also commonly called acute confusional state, broadly represents a sudden change in cognition from a person’s baseline. The exact definition of delirium has changed many times. The most current DSM-5 definition includes 5 criteria to meet the medical definition of delirium: A. Disturbance in attention and awareness. This is a required symptom and involves easy distraction, inability to maintain attentional focus, and varying levels of alertness. B. Onset is acute (from hours to days), representing a change from baseline mentation with fluctuations throughout the day C. At least one additional cognitive disturbance (in memory, orientation, language, visuospatial ability, or perception) D. The disturbances (criteria A and C) are not better explained by another neurocognitive disorder E. There is evidence that the disturbances above are a "direct physiological consequence" of another medical condition, substance intoxication or withdrawal, toxin, or various combinations of causes Delirium, like coma, can occur from a large number of potentially dangerous causes. Since many causes are dangerous, a red-flag approach to separating “dangerous” vs “non-dangerous” causes of delirium is not useful; we should try to find and treat the underlying cause. DDx for Coma/delirium The differential diagnosis for altered mental status (whether due to delirium, seizures, or coma) is broad. This is because there are many things that can disrupt normal cognitive function, and even things that aren’t too dangerous (like tap water) CAN became dangerous when taken to an extreme (like how drinking way too much water very quickly can cause hyponatremia and death!). Nevertheless, as it will be your job as clerks, residents, and clinicians to figure out the cause of a patient’s altered mental status so you can begin treatment. 1  Clinical Reasoning – Background Reading CR226 I WATCH DEATH and DIMS – please memorize ONE of these lists to use in your tutorials I WATCH DEATH DIMS Infection: Sepsis (UTI, pneumonia, infective endocarditis), Drugs (therapeutic, intoxication or CNS infections withdrawal): Prescription medications, illicit Withdrawal: Alcohol, barbiturate, sedative-hypnotic drugs, pesticides, solvents, Acute metabolic: Electrolyte disturbance, hepatic failure, environmental/heavy metal exposure, post- renal failure, acidosis, alkalosis anesthesia, alcohol (intox or withdrawal), Trauma: Head injury, postoperative, severe burns sedative hypnotic (intox or withdrawal), CNS pathology: stroke, intracranial hemorrhage, seizures, cerebral vein thrombosis, tumors/metastases, Infection/inflammation: Sepsis, CNS hydrocephalus, vasculitis, encephalitis, meningitis, syphilis infections (meningitis/encephalitis), Hypoxia: Hypotension, cardiac or pulmonary dysfunction vasculitis, syphilis, rheumatological (i.e. lupus (CHF or PE), anemia, carbon monoxide poisoning cerebritis), post-operative Deficiencies: Vitamin B12, thiamine Endocrinopathies: Hyper / hypoglycemia, hyper / Metabolic (largest category): electrolyte hypoadrenocorticism, myxedema, hyperparathyroidism disturbances, organ failure (cardiac, hepatic, Acute vascular: Hypertensive encephalopathy, stroke, renal), endocrinopathies (thyroid, glucose), arrhythmia, shock vitamin deficiencies (B12, thiamine) Toxins or drugs: Prescription drugs, illicit drugs, pesticides, solvents, environmental exposure Structural (“brain” problem): trauma, stroke, Heavy Metals: Lead, manganese, mercury ICH, hydrocephalus, seizures, tumors, hypertensive encephalopathy Adapted from icudelirium.org (accessed June 20, 2021) Adapted from bcemergencynetwork.ca (accessed June 20, 2021) You can use either “I WATCH DEATH” or “DIMS” in future tutorials. I personally prefer “DIMS” because it creates a workflow on how to identify common causes of altered mental status - Drugs: can be identified history, toxidrome or patient’s medication list - Infection: careful head-to-toe exam, identify source (urine, imaging), gather cultures and start empiric antibiotics - Metabolic: order appropriate lab studies including TSH where appropriate - Structural: consider CT brain Similar to Coma, many of these tests will be ordered simultaneously. Above all, it is important to manage unstable patients accordingly (i.e., also consider the ABCs first). Often, patients arrive in the emergency department with undifferentiated delirium. Commonly, patients present with delirium AFTER they are admitted for a clear problem (i.e., after a cholecystectomy, or diagnosed with pneumonia). If the problem is relatively clear, you can consider limiting your testing. Consider the advice below regarding the use of CT scan of the brain in hospitalized patients with delirium: 2  Clinical Reasoning – Background Reading CR226 Choosing Wisely – Canadian Society of Hospital Medicine recommends: Don’t routinely obtain head computed tomography (CT) scans, in hospitalized patients with delirium in the absence of risk factors. Delirium is a common problem among hospitalized patients. In the absence of risk factors for intracranial causes of delirium (such as recent head trauma or fall, new focal neurological findings, and sudden or unexplained prolonged decreased level of consciousness), routine head CT scans are of low diagnostic yield. Guidelines suggest a step-wise approach to the management of new delirium in hospitalized patients and consideration of head CT only in patients with select risk factors. Causes of delirium: sepsis and anticholinergic toxicity Sepsis and anticholinergic toxicity are two common causes of delirium. Sepsis is a very important topic in medicine that we will revisit, so this is only the introduction. Anticholinergic toxicity is an example of a pharmacologic cause of delirium; there are MANY more. SEPSIS Key Features It’s common, dangerous/deadly and responds well to treatment. Old terminology: some people still prefer this definition because it has easy to remember numbers - bacteremia + Systemic inflammatory response syndrome (SIRS) o SIRS: at least 2/4 of Temp >38 or 90, RR >20, WBC >12 or = 65 mmHg ▪ Mean Arterial Pressure = 1/3(SBP) + 2/3(DBP) ▪ a lactate greater than or equal to 2 mmol/L in the absence of hypovolemia Sepsis occurs on a spectrum: mild cases will just barely meet the criteria for organ dysfunction with infection, but otherwise appear well; some patient will present with septic shock and near death. Classically presents with fever, tachycardia, tachypnea and hypotension. There may be an obvious source of infection such as a cough, signs of UTI, or large infected wound. Mental status changes (confusion or obtundation) can occur as part of delirium itself or patients can be obtunded due to inadequate cerebral perfusion. WBC count is often abnormal, but sepsis is often diagnosed before lab results are available. Prevalence Common. Risk Factors Elderly, immunocompromised + Predictors ↑WBC, confusion, tachycardia, fever, source of infection found on history or exam. - Predictors No confusion, no organ dysfunction, afebrile, normal WBC, normal vital signs Rule-in Tests Positive blood culture along with clinical signs of sepsis. Rule-out None. 50% of patients with sepsis will not grow cultures. Some may appear well initially with mild Tests infection, then later develop the signs we associate with sepsis. Confirmatory Treatment should (almost) always start before any lab tests are available. Almost all adult patients in tests whom sepsis is suspected will require: WBC count, blood cultures, urinalysis and urine c+s. Imaging 3  Clinical Reasoning – Background Reading CR226 is often required to assess for potential sources of sepsis, such as x-ray for respiratory causes and CT scan/US for abdominal causes. Cultures can be negative in up to 50% of cases of sepsis, so they are not a rule out test. Lactate will be elevated if metabolic acidosis occurs due to poor perfusion. Oliguria is a sign of poor renal perfusion and using a urinary catheter to monitor urine output can help guide whether treatment is effective ( 75 11.7% 13% MoCA (< 26) 94% 60% 2.35 0.10 > 85 — 31.2% IQCODE 80% 84% 5.2 0.23 MMSE, Mini-Mental Status Exam; MOCA, The Montreal Cognitive Assessment; IQCODE, The Informant Questionnaire on Cognitive Decline in the Elderly. 11  Clinical Reasoning – Background Reading CR226 Evidence-Based Diagnosis Diagnosing is based on the diagnosis of dementia and the presence of features consistent with AD. This can be challenging because patients often have subtle symptoms early in the disease course. 1. AD presents with self-reported memory loss in only a minority of patients. a. Memory loss reported by a spouse, relative, or close friend is more predictive of dementia than self-reported memory loss. b. Memory loss reported by a patient is still predictive dementia but may also be a sign of depression. 2. Behavioral changes and mood changes are commonly recognized by family members. 3. Clinicians may recognize behavioral changes such as increased anxiety, increased somatic complaints, or delusional thinking regarding illness as early symptoms of the disease. A few important points: Alzheimer’s disease is the most common type of dementia. Although the two terms are used interchangeably, they are not the same thing. AD is a specific disease, whereas dementia is broad term used to describe a decline in cognition. In other words, all patients with AD will have dementia, but not all patients with dementia have AD. This becomes important when exploring reversible causes of dementia. Reversible dementias An important issue when diagnosing AD is how much more of a workup should be done? The concern is that when making a clinical diagnosis, potentially reversible dementias might be missed. These reversible dementias include: a. CNS infections b. Hypothyroidism c. Vitamin B12 deficiency d. CNS masses 1. Neoplasms 2. Subdural hematomas e. Normal-pressure hydrocephalus f. Medications To exclude a reversible dementia, most clinicians will order the following tests: a. CBC b. Thyroid-stimulating hormone (TSH) c. Basic metabolic panel and liver biochemical tests d. Vitamin B12 level e. Tests to exclude neurosyphilis f. Consider neuroimaging (MRI or CT) 1. Imaging is not required in most patients with dementia. 2. In practice, most patients will undergo imaging both to assess for diagnoses other than AD and to detect brain atrophy that may support the diagnosis of AD. A few important points: - An important REVERSIBLE dementia is vitamin B12 deficiency. As you recall from Anemia, it causes 12  Clinical Reasoning – Background Reading CR226 a macrocytic anemia, usually with an MVC >100 and hypersegmented PMNs. It is uncommon/rare, but highly treatable with B12 supplementation, so we have a very low threshold for testing. Risk factors include malnutrition, elder age, bariatric surgery, strict vegan diet and crohns. A serum B12 level that is very low is rule-in test. However, there are cases where you might get a “normal” level in the context of a very suspicious case (i.e., a “low-normal” value). Because of vitamin b12’s efficacy and safety, it is sometimes prudent to start treatment in these cases and reassess. - Imaging in dementia is a controversial topic. Neuroimaging might be helpful to detect hydrocephalus, ICH, stroke or tumor. However, its overall yield is low, and if your assessment makes you strongly believe that the patient has AD, then imaging is not necessary. Different physicians have different opinions whether imaging is required for the assessment of dementia, but there is agreement that imaging is indicated when the progression is acute, there are focal neurological signs, young age, or reason to believe that there is a reversible dementia. Communication: how to ask for a consultation (review from tutorial 32) When patients need to be admitted to hospital, or require specialized services/advice, you will need to involve a consultant. For your first few consults, consider taking a few minutes to prepare, and consider following the following steps (adapted from CanadiEM). 1. Offer a polite greeting. No matter how stressed you are, it is important to remain courteous. 2. Describe who you are and what service you are representing. In your tutorial, you will be a medical student calling from the emergency department. 3. Outline the reason for consultation. Sometimes you are calling because you believe a patient needs admission to hospital and you believe that your consultant is the most appropriate service, but other times you are just looking for advice or outpatient follow up. Consider describing at the beginning the nature of the consult. Also, if there is urgent help required, let them know here! 4. Describe the patient, case or dilemma, including what has already been done. This is your case presentation. Notice that there are three other steps before jumping into the presentation – this is to help prime the person on the phone what your desired goal is so they can better appreciate the details of your case. 5. Ask if there is anything else that they would like done and thank the consultant for their help. Before the consultant or their team sees the patient (or the patient is seen in follow-up), there might be a few things that can help the patient. Also, a second reminder to be courteous in your interactions. Self-directed learning activity This week, I will ask that half of your group comes up with a self-directed question (the other half with present next week). You will present your question and answer to your classmates. A good self-directed question: - Can be answered in 2-5 minutes. Nothing shorter or longer please. - Should be relevant to either this tutorial or the most recent tutorial - Should be coordinated with your group to avoid duplication - Should be supported by primary, secondary, or tertiary literature (not your lecture notes) In case you are having a hard time coming up with questions, here are a few that I thought were interesting: - What is qSOFA for sepsis? How helpful (sensitive, spec) is it for sepsis? 13  Clinical Reasoning – Background Reading CR226 - There is some overlap between the presentation of depression in older adults and cognitive impairment/dementia. What is similar, and what is dissimilar, in there presentation? - Is one cognitive test better than another for dementia? Do some have particular strengths? - What are some common, non-anticholinergic medications that are implicated in delirium? Practice questions 1. Which of the following causes of cognitive decline is MOST likely to present with a normal CT scan: A. Vitamin B12 deficiency B. Subdural hematoma C. Hydrocephalus D. Brain tumor E. Subarachnoid hemorrhage 2. An 80-year-old woman is reluctantly brought into a clinic by her family due to their concerns about a gradual decline in her memory over the 18 months. After a thorough history and physical exam, you strongly believe that the patient has Alzheimer’s disease. You have ordered some routine labs, including a TSH and B12 level. While not necessary, a CT scan could be done to: A. Rule-in the most likely diagnosis B. Determine the severity of her illness C. Decide if she can safely undergo a lumbar puncture D. Rule-out items on the differential diagnosis E. Assess for age-related cerebral atrophy 3. A 60-year-old man presents with confusion. Which of the following is the MOST suggestive of sepsis: A. Hypotension B. Disorientation C. An MMSE score of 30 cc/hour is considered a marker of ‘adequate’ renal perfusion. 4. B. The testing threshold is very low for reversible dementias. In other words, we’re willing to test many low probability patients in order to find these few treatable cases. Reversible dementias are not common causes of dementia and often the clinical picture gives no indication that the dementia is from a reversible cause. This makes for a very low pretest probability. A clear explanation of your reasoning will usually satisfy the patient’s family. 5. C. Urinary retention is the only anticholinergic cause on the list, whereas the others are cholinergic effects. 6. E. An ECG is helpful because many substances that cause anticholinergic effects can also cause cardiac conduction abnormalities. 7. B. Infections are very common causes of delirium and UTIs are especially common. Hypothyroidism and low B12 can cause confusion but they wouldn’t present so quickly. Normal pressure hydrocephalus has cognitive changes that are more gradual and subtle. Hypernatremia and other electrolyte abnormalities are listed above as potential causes of delirium but infections are more common precipitants 8. B. remember that the CAM requires acute/fluctuating course AND inattention, plus either disorganized thinking or altered level of consciousness. The stem already tells you that this is acute/fluctuating, and your exam also tells you that there is decreased level of consciousness, so the only thing missing is inattention. 16