Diagnostic challenges in primary care: Identifying and avoiding cognitive bias

3 stages of presentation. Unlike other forms of dementia, LBD typically presents first with psychiatric symptoms, then with cognitive impairment, and last with parkinsonian symptoms. Additionally, rapid eye movement sleep behavior disorder and often subtle elements of nonmemory cognitive impairment distinguish LBD from both AD and vascular dementia.³² The primary cognitive deficit in LBD is not in memory but in attention, executive functioning, and visuospatial ability.³⁴ Only in the later stages of the disease do patients exhibit gradual and progressive memory loss.

Mistaken for many things. When evaluating patients exhibiting signs of dementia, it’s important to include LBD in the differential, with increased suspicion for patients experiencing episodes of psychosis or delirium. The uniqueness of LBD lies in its psychotic symptomatology, particularly during earlier stages of the disease. This feature helps distinguish LBD from both AD and vascular dementia. As seen in the case, LBD can also be confused with acute delirium.

The uniqueness of Lewy body dementia lies in its psychotic symptomatology, particularly during earlier stages of the disease.

Older adult patients presenting to the ED or clinic with visual hallucinations, delirium, and mental confusion may receive a false diagnosis of schizophrenia, medication- or substance-induced psychosis, Parkinson disease, or delirium of unknown etiology.³⁵ Unfortunately, LBD is often overlooked and not considered in the differential diagnosis. Due to underrecognition, patients may receive treatment with typical antipsychotics. The addition of a neuroleptic to help control the psychotic symptoms causes patients with LBD to develop severe extrapyramidal symptoms and worsening mental status,³⁶ leading to severe parkinsonian signs, which further muddies the diagnostic process. In addition, treatment for suspected Parkinson disease, including carbidopa-levodopa, has no benefit for patients with LBD and may increase psychotic symptoms.³⁷

First-line treatment for LBD includes psychoeducation for the patient and family, cholinesterase inhibitors (eg, rivastigmine), and avoidance of high-potency antipsychotics, such as haloperidol. Although persistent hallucinations and psychosis remain difficult to treat in LBD, low-dose quetiapine is 1 option. Incorrectly diagnosing and prescribing treatment for another condition exacerbates symptoms in this patient population.

Case 4

A 36-year-old Hispanic woman presents to the PCP for her annual physical exam. The patient’s medical record shows 2 previous office visits over the past 2 years—an annual physical exam and an office visit for the flu vaccine. The patient is highly accomplished in her profession, working as a certified public accountant for a major corporation. She is a nonsmoker and reports only casual social drinking and no recreational drug use. The patient is slightly overweight for her height but is otherwise healthy. Previous lab studies are within normal limits.

The patient has been experiencing chronic pain for the past few years after a motor vehicle accident. She has seen a physiatrist and another provider, both of whom found no “objective” causes of her chronic pain. They started the patient on sertraline for depression and an analgesic, both of which were ineffective.

The patient likes to exercise at a gym twice a week by doing light cardio (treadmill) exercise and light weightlifting. Lately, however, she has been unable to exercise due to the pain. At this visit, she mentions having low energy, poor sleep, frequent fatigue, and generalized soreness and pain in multiple areas of her body. The PCP recognizes the patient’s presenting symptoms as significant for FM and starts her on pregabalin and hydrotherapy, with positive results.

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