Arsenic Flashcards
Approach to arsenic
What is arsenic ?
Arsenic is a nearly tasteless, odorless metalloid that causes significant acute and chronic toxicity
What are the different forms of arsenic ?
Elemental and organic forms have little to no toxicity.
whereas inorganic compounds, including arsenite (trivalent or As 3+ ) and arsenate (pentavalent or As 5+ ), are highly toxic.
How is arsenic absorbed ?
Due to its water solubility, pentavalent arsenic (arsenate) is more readily absorbed through mucous membranes, such as the GI tract, than is trivalent arsenic (arsenite), which penetrates the skin more readily due to its increased lipid solubility.
In acute toxicity :
clinical effects usually develop within minutes to hours of ingestion.
Severe gastroenteritis with nausea, vomiting, and cholera-like diarrhea is the hallmark of acute poisoning and may last several days to weeks, frequently necessitating hospitalization.
Patients may complain of a metallic taste.
Hypotension and tachycardia s ary to volume depletion, capillary leak, and myocardial dysfunction occur in moderate to severe cases.
Subacute toxicity :
survivors of acute poisonings and patients who are poisoned slowly may develop subacute toxicity, typically presenting with complaints of weakness, muscle aches, abdominal pain, memory loss, personality changes, periorbital and extremity edema, or skin rash, often with a history of gastroenteritis occurring 1 to 6 weeks earlier.
Subacute toxicity :
Central Neuro logic symptoms include headache, confusion, delirium, and personality changes. Chronic encephalopathy with delirium, hallucinations, disorientation, agitation, and confabulation resembling Korsakoff’s syndrome may occur. Peripheral neuropathy develops in a stocking-glove distribution and is initially sensory, with motor symptoms developing later. Patients with severe poisoning can develop an ascending paralysis mimicking Guillain-Barré syndrome.
Dermatologic manifestations vary and include morbilliform rash, alopecia, and desquamation. Mees lines (1- to 2-mm–wide transverse white lines in the nails) due to disrupted keratinization of the nail matrix may be seen 4 to 6 weeks after an acute ingestion.
Chronic exposure
hypertension, peripheral vascular disease, diabetes mellitus, e dermoid cancer, respiratory tract cancer, hepatic angiosarcoma, and, possibly, leukemia. Dermatologic manifestations are prominent and include hyperpigmentation, hyperkeratosis of the palms and soles, Bowen’s disease, and squamous and basal cell carcinomas. Perforation of the nasal septum has been found in workers exposed occupationally to arsenic.
When to consider Arsenic ?
diagnosis of chronic arsenic toxicity should be considered in a patient with a peripheral neuropathy, typical skin manifestations, or recurrent bouts of unexplained gastroenteritis.
Diagnostic testing ?
24-hour urine collection
