Children who present with an episode of altered mental status, whether transient or persistent, present a diagnostic challenge for practitioners. This article describes some of the more common causes of altered mental status and delineates a rational approach to these patients. This will help practitioners recognize the life-threatening causes of these frightening presentations as well as help avoid unnecessary testing for the more benign causes.
Key points
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Although altered mental status (AMS), transient or persistent, can cause a great deal of anxiety for patients and providers, a rational approach to these patients is essential to avoid underuse or excessive use of testing.
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An age-based approach is important, because the various diseases are common in different age groups.
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In patients with transient AMS, differentiating true syncope from other causes is the first step; a stepwise approach, guided by the history and physical examination, can then proceed.
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Persistent AMS, on the other hand, is a life-threatening presentation and time is of the essence.
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The differential diagnosis is broad and, rather than trying to recall long lists of highly specific causes, it is more helpful to consider broad categories of disease: structural lesions, insufficient delivery of appropriate substrate to the brain, metabolic imbalance, inflammation, infection, and abnormal electrical activity.
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Maintaining a broad differential and evaluating for multiple diseases simultaneously is critical in the care of these patients.
Introduction: nature of the problem
Altered mental status (AMS), whether transient (t-AMS) or persistent (p-AMS), presents a diagnostic challenge. With a broad differential diagnosis, a wide range of severity, and potential involvement of any organ system, this presentation is complicated by an inability of the patient to give an accurate history. For the purposes of this article, the term AMS is used to describe any change in the way a patient interacts with their environment. What is distinguished is the concept of t-AMS and p-AMS, because the differential is different for these presentations.
For teaching purposes, mnemonics have been developed to help clinicians consider all possible causes of AMS. This long list of possible diagnoses is cumbersome and difficult to remember. Instead, it may be simpler to consider broader categories of disease. For the brain to function normally, it requires adequate perfusion with appropriate delivery of oxygen, nutrients, and balanced electrolytes. In addition, there cannot be structural disease; masses, blood, and excessive cerebrospinal fluid (CSF), which can all impede normal function. It cannot be plagued by infection or inflammation, and electrical activity has to be organized. Some causes more commonly cause t-AMS (moments of inadequate perfusion, abnormal electrical activity), whereas others cause persistent symptoms (structural, metabolic, or infectious).
A detailed description of all causes of AMS is beyond the scope of this article; trauma and toxicology are not discussed. Instead, a description of some of the more common causes is delineated. As these potential causes are reviewed, there are some key themes that must be considered. First, the differential diagnosis for AMS changes with age ( Table 1 ). Second, t-AMS is common and usually benign, whereas p-AMS is less common, carries a higher morbidity and mortality, and requires rapid diagnosis and treatment. There is no substitute for a thorough history and physical examination with these patients; it is essential for guiding diagnostic workup.
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