Diagnosing different levels of dementia no easy task

Scenario

Mrs. D is a very active 78-year-old widow who lives alone in the home where she has resided for 45 years. She was a high school English teacher and has been retired for the last 10 years. She is independent for activities of daily living and instrumental ADLs. Over the last year, she has noticed her energy level has declined and she needs to take a nap in the middle of the day. She has started making worrisome mistakes while playing her weekly bridge game. Last month she failed to call her daughter for her birthday. A few days ago, she could not remember her 6-month-old grandson's name. She comes to you for evaluation and advice.

Case history

Mrs. D. has a medical history of hypertension, well controlled; and breast cancer that was treated 15 years ago with mastectomy, local radiation therapy and five years of Tamoxifen. Her mother died in her 50s in a motor vehicle crash. Her grandmother had "dementia of old age" when she passed away at 84. Mrs. D.'s physical exam showed a weight increase of 5 pounds since the previous visit and new, trace, pitting edema up to mid-calf bilateral. She scored 29/30 in the Mini Mental State Exam; she lost one point in the three-item recall after five minutes.

Discussion

Memory changes are among the most common cognitive complaints reported by older adults. The early signs of mild cognitive impairment or dementia can be vague and subtle, and settling on a definitive diagnosis is not simple. For patients with a family history of Alzheimer's disease, even minor memory lapses can trigger a consultation with a primary care physician.

It is increasingly important, though, for physicians to note the earliest warning signs and symptoms of dementia, to track its progression and to make a timely diagnosis. After all, intervening during the condition's initial stages can help the patient take advantage of a range of resources to help improve and protect his or her quality of life and compensate for the impairment.

Elderly patients such as Mrs. D. are often disturbed when they realize they are becoming increasingly forgetful or feel they are not as mentally sharp as they used to be. They fear Alzheimer's. And their concerns are not unfounded. Today Alzheimer's disease, the most common cause of dementia, affects an estimated 5 million people in the United States.

Some patients who have such symptoms, though, are diagnosed with MCI. This term describes a condition in which the cognitive decline is greater than what is normally associated with aging. But no clear cutoff point exists on any cognitive scale that would separate MCI from dementia. Currently the impact of cognitive impairment on the patient's ability to perform normal daily activities is being used as a major criteria for the differentiation. MCI is associated with intact ADLs while deterioration of complex IADLs, such as managing finances or organizing work, may be observed.

MCI also is viewed somewhat as a prodromal state of a neurodegenerative disorder such as Alzheimer's. However, although patients with MCI are more likely than others in their peer group to progress, not everyone with this condition develops full dementia.

For patients like Mrs. D. who present with cognition concerns, a complete medical history and physical, as well as clinical laboratory studies, are warranted. An investigation of other conditions that might be reversible causes of these symptoms should be done early in the diagnostic process. In this case, Mrs. D.'s low energy, slight weight gain and new lower extremity edema should trigger a physician to explore factors such as new congestive heart failure, medication side effects, vitamin B-12 deficiency and thyroid disorders. Other possible conditions that can be present with cognitive impairment or mental status changes include alcohol abuse, infections, kidney or liver disease, neurological diseases, and emotional problems such as stress, anxiety or depression.

A complete exam for memory loss should review the patient's use of prescription and over-the-counter medicines, his or her diet and nutrition, past medical problems and general health. In addition to talking with the patient, a physician might seek behavioral information from a family member, caregiver or close friend. Such close contacts will be able to shed light on any coping strategies the patient has adopted to work around or conceal his or her decline. Additionally, they can report evidence of problems or changes in regard to home life, leisure activities or personal care. Genetic testing for the diagnosis of Alzheimer's disease is not recommended for clinical use.

Physicians also should evaluate such patients' mental status for attention, immediate and delayed recall, remote memory and executive function. Screening tests may include the MMSE (originally developed by Folstein, Folstein and McHugh), the Mini-Cog or a challenge involving the number of animals named in one minute, to aid in the diagnosis and/or track the patient's disease progression. In doing so, physicians should keep in mind the circumstances of their patients, especially their level of education.

Mrs. D., for instance, is a smart and educated woman. As a result, though her MMSE score was 29 out of 30, which is in the normal range, her intellect likely would enable her to naturally compensate for any cognitive impairment, and her score may not reflect accurately her impairment. Therefore, referring for neuropsychological studies could be crucial for the evaluation. These examine the patient's complaint of memory loss directly, systematically and in detail.

Neuroimaging studies, either CT or MRI, also should be considered. The yield of clinically significant abnormalities is low, but the likelihood of detecting structural lesions that could explain the cognitive changes is higher in younger patients -- especially for those younger than 60. The likelihood of detecting such lesions also increases with focal neurological signs or symptoms, abrupt onset or rapid decline, and the presence of predisposing conditions, such as metastatic cancer.

Once a patient is diagnosed with MCI or early dementia, he or she will require follow-up and should be under a physician's care. Additionally, it is important that people stay physically and mentally active. For instance, exercise helps the patient maintain healthy weight and promotes healthy sleep while social interaction wards off depression.

According to the National Institute on Aging, the cognitive problems that occur with MCI may not get worse for many years. However, an accurate diagnosis, whether for Alzheimer's disease or other types of dementia, can help an older patient and his or her family to plan for the future. Early diagnosis offers the best chance to slow progression, treat the symptoms, adjust the environment and discuss care options.