October 04, 2010

Q&A: Diagnosis Of Acute Confusion in a Child

Delirium and confusional states are among the most common mental disorders encountered in patients with medical illness, particularly among those who are older. They are associated with many complex underlying medical conditions and can be hard to recognize. Systematic studies and clinical trials are difficult to perform in patients with cognitive impairment. Recommendations for evaluating and treating delirium are based primarily upon clinical observation and expert opinion.

This article is for Medical Students & Professionals
This is a Question & Answer revision article designed for medical students and professionals preparing for the PLAB, MRCP or USMLE examinations. They are based on actual questions from these examinations. You may find the Acute Confusion article more useful, or one of our many articles on Diseases & Conditions, Medical Syndromes, Health & Wellness or Home Remedies.
In this article:
Evaluation and diagnosis
MCQ exam: clinical scenario
MCQ exam: answer
MCQ exam: explanation

Evaluation and diagnosis

Several key features characterize delirium and confusional states. A disturbance of consciousness and altered cognition are essential components. The condition typically develops over a short period of time and tends to fluctuate during the course of the day. The disturbance is typically caused by a medical condition, substance intoxication, or medication side effect.

There are two important aspects to the diagnostic evaluation of delirium: recognizing that the disorder is present and uncovering the underlying medical illness that has caused delirium.

Careful attention to the key features of acute onset, fluctuating course, altered consciousness, and cognitive decline should readily distinguish delirium from depression, psychotic illness, and dementia. When in doubt, the most useful rule of thumb is to assume delirium and attempt to rule out common medical etiologies. This is true even for patients with known psychiatric illness (including dementia), since they also are susceptible to delirium when acutely ill.

MCQ exam: clinical scenario

A twelve year old girl develops a change in mental status with psychosis over a 24 day period. On examination she is found to be febrile and appears restless. She has a CT scan which is normal. She is admitted but deteriorates over the next 24 hours and passes away in the intensive care unit. An autopsy reveals severe edema, hemorrhages and necrosis confined primarily to the temporal lobes. Histology reveals intranuclear inclusion bodies.

A likely diagnosis is:

a) Herpes encephalitis
b) Child abuse
c) Meningitis
d) Cerebral glioma
e) Infectious mononucleosis

MCQ questions & answers on medicalnotes.info

MCQ exam: answer

The correct answer is A.

MCQ exam: explanation

Clinically, herpes encephalitis is characterized by rapid onset of fever, chills, restlessness, and signs of increased intracranial pressure. The mortality rate of herpes encephalitis is at least 25%. The characteristic gross appearance of herpes encephalitis include edema, hemorrhages and necrosis confined primarily to the temporal lobes. The degree of edema is evidenced by the medial displacement of the uncal gyri. The involvement may be bilateral or may be unilateral.

In the acute stages, microscopic examination reveals vascular destruction with infiltrates of neutrophils and lymphocytes. In the later stages, glial proliferation becomes the prominent feature. The histological feature which characterizes herpes simplex encephalitis is the finding of eosinophilic intranuclear inclusion bodies (Cawdry type A). The inclusions may be seen in neurons, astrocytes, and oligodendroglia. At the ultrastructural level, the nuclear inclusions of herpes simplex are found to contain viral particles with a characteristic bull's eye appearance.

Herpes simplex, a DNA virus, is carried by a majority of the human population. The virus is harbored in the trigeminal ganglia, and produces lesions in the oral mucosa when activated by stress. Herpes simplex encephalitis arises sporadically and does not necessarily occur in people with a history of oral lesions.

1). UpToDate: Diagnosis of delirium and confusional states. Available online: https://www.uptodate.com/contents/diagnosis-of-delirium-and-confusional-states

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