Choreoathetosis secondary to lead toxicity

Retained bullets and lead toxicity: a systematic review

INTRODUCTION

Lead toxicity secondary to retained bullet(s) (RB) after a penetrating gunshot wound is a rare but likely underdiagnosed condition, given the substantial number of firearm injuries in the United States. There is currently no consensus on the indications for surveillance, chelation, or surgical intervention.

OBJECTIVE

The purpose of our review is to summarize the literature on systemic lead toxicity secondary to RBs to help guide clinicians in the management of these patients.

METHODOLOGY

The primary literature search was conducted in Medline (PubMed), EMBASE, Cochrane, and CENTRAL using the following MESH terms: "chelation" and "lead poisoning" or "lead toxicity" or "lead" and "bullet" or "missile" or "gunshot", or "bullet".

RESULTS

The search identified 1,082 articles. After exclusions, a total of 142 articles were included in our final review, the majority of which were case reports. Several factors appear to increase the risk of developing lead toxicity including the location of the RB, the presence of a fracture or recent trauma, number of fragments, hypermetabolic states, and bullet retention duration. Particularly, RBs located within a body fluid compartment like an intra-articular space appear to be at a substantially higher risk of developing lead toxicity. Even though patients with lead toxicity from RBs will have similar symptoms to patients with lead toxicity from other sources, the diagnosis of lead poisoning may occur months or years after a gunshot wound. Symptomatic patients with high blood lead levels (BLLs) tended to improve with a combination of chelation and surgical removal of RBs.

CONCLUSIONS

We suggest surveillance with serial BLLs should be performed. Patients with intra-articular RBs appear to be at increased risk of lead toxicity and if possible, early surgical removal of the RBs is warranted, especially given that signs of toxicity are vague, and patients may not have access to follow-up. Long-term chelation should not be used as a surgical alternative and management should be multidisciplinary.

Generalized chorea due to delayed encephalopathy after acute carbon monoxide intoxication

Movement disorder due to delayed encephalopathy after carbon monoxide (CO) intoxication is uncommon. Generalized chorea, presenting as an initial symptom of delayed encephalopathy, is extremely rare. We describe a 60-year-old woman, who had completely recovered from acute CO poisoning, developed mental and behavioral changes, urinary incontinence and generalized chorea 2 weeks thereafter. T2-weighted brain magnetic resonance imaging showed extensive hyperintensity of the bilateral periventricular and subcortical white matter and the globus pallidus. Brain single-photon emission computed tomography (SPECT) with technetium-99 ethylene cysteine dimer showed inhomogeneous perfusion in the cerebral cortex, with decreased uptake in bilateral frontal regions. Delayed encephalopathy after acute CO intoxication was diagnosed, and the symptoms gradually improved after hyperbaric oxygen therapy (HBOT). This case report demonstrates that generalized chorea may be one of the initial presenting symptoms of delayed encephalopathy after acute CO intoxication. We hypothesize that the generalized chorea in our patient may have been caused by the subcortical white matter lesions, which most likely interrupted the basal ganglia-thalamocortical circuits and that HBOT may be the treatment of choice for such patients.

Toxic leukoencephalopathies, including drug, medication, environmental, and radiation-induced encephalopathic syndromes

Toxic leukoencephalopathies can be secondary to the exposure to a wide variety of exogenous agents, including cranial irradiation, chemotherapy, antiepileptic agents, drugs of abuse, and environmental toxins. There is no typical clinical picture, and patients can present with a wide array of signs and symptoms. Involvement of white matter is a key finding in this scenario, although in some circumstances other high metabolic areas of the central nervous system can also be affected. Magnetic resonance (MR) imaging usually discloses bilateral and symmetric white matter areas of hyperintense signal on T2-weighted and fluid-attenuated inversion recovery images, and signs of restricted diffusion are associated in the acute stage. In most cases, the changes are reversible, especially with prompt recognition of the disease and discontinuation of the noxious agent. Either the MR or clinical features may be similar to several nontoxic entities, such as demyelinating diseases, leukodystrophies, hepatic encephalopathy, vascular disease, hypoxic-ischemic states, and others. A high index of suspicion should be maintained whenever a patient presents recent onset of neurologic deficit, searching the risk of exposure to a neurotoxic agent. Getting to know the most frequent MR appearances and mechanisms of action of causative agents may help to make an early diagnosis and begin therapy, improving outcome. In this review, some of the most important causes of leukoencephalopathies are presented; as well as other 2 related conditions: strokelike migraine attacks after radiation therapy syndrome and reversible splenial lesions.