ABIM Exam Disease of the Week Profile: Alzheimer Disease
The clever comic strip “Rhymes with Orange” from the September 5, 2013 funny pages mentions Alzheimer’s, a disease found in the Neurology and General Internal Medicine sections of the ABIM Internal Medicine Exam blueprint:
Here, we provide you a brief primer on Alzheimer disease as relevant to the ABIM exam to close out Knowmedge’s #NeuroWeek. Read to the end to find the answer to the question posed in the strip.
Alzheimer disease (AD) is classified as a chronic, progressive, neurodegenerative disorder, resulting in an eventual decline in cerebral functioning. AD is the most common cause of dementia in the US. The disease progression occurs within a decade of onset of disease. The 4.5 million US residents with AD comprise 60-70% of cases of dementia in the country.
Risk Factors Age is the strongest risk factor for the development of AD with individuals rarely developing the illness. Those who do develop AD before the fifth decade may have an autosomal dominant form of AD, seen in just 5% of all cases. Genetics can serve as a risk factor in those cases:
- Presenilin 1 (found on chromosome 14)
- Presenilin 2 (found on chromosome 1)
- Amyloid beta A4 precursor protein (found on chromosome 21)
- Patients with ApoE-4 susceptibility gene may cause sporadic cases of late-onset AD
- A negative, or protective, risk factor is the presence of the ApoE-2 isoform
Symptoms Some of the common signs and symptoms of AD include:
- Memory impairment (often the earliest symptom) or memory loss of recent events and thoughts
- Disorientation or forgetting location of objects
- Name-finding difficulty
- Social and/or occupational impairment
- Declining ability to perform activities of daily living
- Unexplained personality changes
- Diminished executive function
- Loss of interest in usual activities of interest
Workup Often the first step in assessing AD is the administration of the Mini-Mental State Examination (MMSE). In addition, there are some other laboratory studies that can be ordered as part of the workup to rule out other causes of dementia.
A complete blood count can be ordered to rule out anemia. A basic metabolic panel may be checked to rule out sodium, calcium, or glucose abnormalities. As elevated or depressed thyroid states can be associated with dementia, checking a thyroid stimulating hormone (TSH) level is worthwhile. Vitamin B12 deficiency may be inducing dementia symptoms so B12 should be ordered in patients suspected of having AD. If patient has any signs of possible recreational drug use, drug-related dementia needs to be ruled out with a urine drug screen.
Treatment While medications are available against AD, much of the management is non-medical, as shown below:
- Caregiver support
- Detecting and treating depression (a common co-occurrence)
- Preparation of advanced directive
- Home safety evaluation
- Occupational therapist to assess functional capacity
- Crosswords for prevention (according to a 2012 Archives of Neurology study)
Medical Management The use of medications in AD is with the goal of prevent a decline in cognitive function. If medical treatment is indicated, it is usually with cholinesterase inhibitors, such as donepezil or rivastigmine. Medication can be initiated when the diagnosis of mild AD is made. SSRIs are the appropriate choice for AD depression.
Complications As patients lose their cognition, their ability to perform activities of daily living may also be compromised. As a result, certain complications arise including the following:
The ability to hold urine can be affected, leading to incontinence. While it is not indicated, Foley catheter is sometimes placed in such patients which increases the chance of developing urinary tract infections. Dysphagia to liquids and solids increases the risk of aspiration pneumonia. In fact, recurrent episodes of aspiration pneumonia are often the cause of death in patients with severe dementia. Bed sores and muscle contractures may be seen in patients whose AD causes them to be bed-bound or institutionalized.
Answer Answer to question posed in above comic asking for Nine-letter word that begins with “C”, ends in “D” and helps stave off Alzheimer’s: C-R-O-S-S-W-O-R-D
For more Internal Medicine Board (ABIM) exam topics, head over to www.knowmedge.com.
“Rhymes of Orange” comic is created by Hilary Price. Content adapted from MKSAP edition 15, American College of Physicians, 2010 and Epocrates
You can see all the previous ABIM Exam disease of the week blog posts at the Knowmedge Blog. You can also find additional topics and questions directly from the Knowmedge Internal Medicine ABIM Board Exam Review Questions QVault.