Have you RULED O²uT medical illness in the presumptive psychiatric patient?

What a practitioner might identify and report as “psychiatric” symp­toms or signs cannot always be explained in terms of psychological stress or a psychiatric disorder. In fact, a range of medical¹ and neurologic² illnesses can mani­fest in ways that appear psychiatric in nature. Common examples are sleep and thyroid dis­orders; deficiencies of vitamin D, folate, and B₁₂; Parkinson’s disease; and anti-N-methyl-d-aspartate receptor autoimmune encephalitis.

People who have a medical illness with what appear to be psychiatric manifesta­tions often elude identification and diagno­sis because they do not visit a health care provider for any of several reasons, includ­ing difficulty obtaining health insurance. Instead, they might seek care in an emer­gency room (ER).

When such patients present for evalu­ation, it is easy—especially in a fast-paced ER—to miss the underlying cause of their illness. Some are then treated on the assump­tion that their diagnosis is psychiatric, while their medical illness goes unidentified.³

We propose a mnemonic, RULED O2uT, as a reminder in the ER (and any other set­ting) of the need to rule out physical illness before treating a patient for a psychiatric dis­order. To demonstrate how the work-up of a patient whose medical illness was obscured by psychiatric signs and symptoms could benefit from applying RULED O2uT, we also present a case.

CASE REPORT
A man with a medical illness who presented with psychiatric symptoms

Mr. Z, in his late 40s, is brought to the ER by his sister for evaluation of depressed mood of 6 to 8 months’ duration. He has no psychi­atric history.

On evaluation, Mr. Z does not remember an event or stressors that could have triggered depression. He describes complete loss of moti­vation for activities of daily living, such as per­sonal grooming. He has stopped leaving the house and meeting friends and family members.

Mr. Z’s sister is concerned for his well-being because he has been living without heat and electricity, which were disconnected for non­payment. Mr. Z reveals that he has not seen his primary care physician “for 20 or 25 years,” although he recently sought care in the ER of another hospital because of mild gait instabil­ity for several months.

Mr. Z has a blunted affect, with linear and goal-directed thought processes. He denies suicidal ideation. Laboratory testing, includ­ing a comprehensive metabolic panel, com­plete blood count, and urine toxicology and urinalysis, are negative.

A non-contrast CT scan of the head reveals foci of low attenuation in the left frontal corona radiata. Follow-up MRI of the brain, with and without contrast, shows extensive supratentorial and infratentorial demyelinat­ing lesions consistent with multiple sclerosis (MS). Several cerebral lesions in the white mat­ter are consistent with active demyelination.

Mr. Z is admitted to the neurology service and started on methylprednisolone for MS. The psychiatry consultation-liaison team pre­scribes sertraline, 50 mg titrated to 100 mg, for depression.

Detailed history means better overall evaluation
Mr. Z presented to the busy ER with psy­chiatric symptoms. It was easy to make a diagnosis of depression and refer him to the outpatient psychiatrist. However, a detailed history provided pertinent information about Mr. Z such as no regular medical check-ups, no family history of mental ill­ness, and gait disturbance in absence of physical injury. This enabled the physicians to conduct a thorough evaluation including a neurologic examination, laboratory tests, and imaging of the brain.

The 8 components of RULED O²uT
Rx interactions. Review medications that the patient is taking or recently stopped tak­ing, to rule out drug−drug interactions and adverse effects.

Unusual presentation. Be mindful of any unusual presentation. For example, sud­den onset of psychiatric symptoms with seizures or hypersensitivity to the sun with depression or psychosis.

Labs. Obtain appropriate blood work, including:
• comprehensive metabolic panel
• complete blood count
• thyroid-stimulating hormone (myx­edema, thyrotoxicosis)
• delta-aminolevulinic acid and porpho­bilinogen (acute intermittent porphyria)
• antinuclear antibody (systemic lupus erythematosus)
• B12 level
• fluorescent treponemal antibody absorption test (neurosyphilis)
• serum ceruloplasmin and copper (Wilson’s disease).

Examination. Perform a thorough exami­nation, including a proper neurological exam. This is especially important when you see signs, or the patient reports symp­toms, that cannot be explained by depres­sion alone. An abnormality or change in gait, for example, might be a consequence of injury or a manifestation of MS, stroke, or Parkinson’s disease. Additional testing, such as CT of the head or lumbar puncture, might be appropriate to supplement or clar­ify findings of the exam. Mr. Z’s neurologic exam revealed weakness in his left leg with variability in reflexes.

Drugs. Ensure that a patient presenting with new-onset psychosis is not taking dopa­minergic medications or steroids and, based on results of a toxicology screen, is not under the influence of stimulants or hallucinogens.

Onset and Office. Determine:
• the time since onset of symptoms; this is crucial to differentiate psychiatric disor­ders and ruling out a nonpsychiatric cause of the patient’s presentation
• if the patient gets a regular medi­cal check-up with her (his) primary care physician.