Sometimes patients don’t fit the mold of Alzheimer Disease (AD). They have a clinical course with symptoms and signs atypical for AD. They could have Lewy Body Disease, Frontotemporal Lobar Degeneration (FTD), Cerebrovascular Disease, or other diseases listed below.
The three questions: “Have we got the right diagnosis? ; Are we treating with the right drugs and non-drug therapies?; and are we forgetting something? (blaming everything on the primary diagnosis and ignoring other possibilities) must always be asked.
One Red Flag is a rapid, unexplained decline. This presentation suggests that brain MRI, EEG, Spinal Tap, screening blood work, and possibly other testing to try to find the cause of such a rapid decline.
Another Red Flag is presentation of dementia at an age younger than would be expected. In addition to the testing mentioned above, testing for autoimmune causes of brain dysfunction, as well as for prion causes, such as Creutzfeldt-Jakob disease, would be appropriate.
It’s complicated! If prominent fluctuations are present, Lewy Body Disease, toxins or electrolyte disturbances, over-medication, untreated sleep disorders, and psychiatric illnesses, along with intracranial hypotension and autoimmune encephalitis (the body’s immune system attacking the brain), may need to be looked for. Epilepsy, with amnesia, can also be evaluated, even if the office EEG is normal, with ambulatory EEG monitoring.
Screening for drugs is often important, including narcotics, sedatives, and anticholinergic medications used to treat tremor. Alcoholism and thiamine deficiency are important to consider as well, and these can precipitate Wernicke’s encephalopathy, with its eye movement abnormalities, and ultimately Korsakoff’s syndrome, with loss of memory and confabulation (invented memories).
Syphilis is decreasing in first world countries, but should be considered in patients who engage in high-risk behaviors, such as IV drug use, multiple sexual partners with people with other STD’s. And patients who are immuno-compromised with drug therapy, lymphoma, or AIDS are at risk for rarer infections of the brain.
When someone does not fit the mold of slowly progressive memory decline typical of Alzheimer’s Disease, then more extensive, and possibly repeat, imaging and other evaluation need to be considered. Normal Pressure Hydrocephalus, with its memory loss, gait problems, and urinary incontinence, can be a reversible cause of cognitive decline. Even when they do fit the clinical mold, recent studies show there is a 30% chance they will not have AD, unless imaged with PET.
Sleep problems, either with or without observed apneas (stopping breathing, sometimes with a witnessed snort), need to be considered because of their profound effect on cognitive function. Likewise, mood disorders, hearing impairment, and medication overuse also need to be considered. Sleep apnea and sleep deprivation can cause abnormal amyloid plaque deposition just by itself, and this can be prevented with CPAP treatment (see sleep module.)
What makes it so complicated sometimes is that patients don’t read our classifications! They have overlap conditions that affect their quality of life. For instance, people with Alzheimer Disease can have sleep apnea, medication effects, electrolyte disturbances, seizures, and autoimmune thyroiditis. They can also develop urinary tract infections or pneumonia that can markedly worsen their confusion. However, sometimes after treatment of the infection, they are left with worsening that does not recover when the infection resolves.
This is why patients with dementia, as with other medical disorders, must be viewed each and every time they are seen with an open mind.
