​Kembara Xtra - Medicine - Lead Poisoning

​Kembara Xtra - Medicine - Lead Poisoning 
Disease brought on by a high body burden of lead (Pb), a substance whose function in the body is unknown.
Synonym(s): inorganic lead poisoning


Epidemiology 

The majority of workers are adults, aged 1 to 5 years.
Male is more common than female in childhood (1:1)
Prevalence
According to the Centers for Disease Control and Prevention (CDC), half a million American children between the ages of 1 and 5 have blood Pb levels greater than 5 g/dL. Levels differ amongst populations and communities.
● Blood Pb levels under 10 g/dL were recorded in 11,097 children in the United States in 2017, down from 17,246 in 2012. According to CDC estimates, the number of kids with blood Pb levels over 1 g/dL has considerably decreased as a result of Pb poisoning prevention.

Pathophysiology and Etiology 
Ingestion of Pb or inhalation of Pb fumes
Pb takes the place of calcium in bones. Pb disrupts the production of heme, results in interstitial nephritis, and affects neurotransmitters, particularly glutamine. Encephalopathy, convulsions, and coma can result from high Pb levels.
Pb exposure early in life produces methylation modifications that result in epigenetic abnormalities that may predispose to brain dysfunction. Pb breaches the blood-brain barrier by dislodging calcium ions. The developing nervous system is particularly vulnerable to the harmful effects of Pb.

Risk Factors ● Children with pica or with iron deficiency anemia ● Residence in or frequent visitation to deteriorating pre- 1978 housing with Pb-painted surfaces or recent renovation ● Soil/dust exposure near older homes, Pb industries, or urban roads ● Sibling or playmate with current or past Pb poisoning ● Dust from clothing of Pb worker or hobbyist ● Pb dissolved in water from Pb or Pb-soldered plumbing (e.g., Flint, Michigan 2014 to 2015) ● Pb-glazed ceramics leachate (especially with acidic food or drink) ● Folk remedies, spices, and cosmetics – Mexico: Azarcon, Greta – Dominican Republic: litargirio, a topical agent – Asia and Middle East: chuifong tokuwan, pay-loo-ah, ghasard, bali goli, kandu, ayurvedic herbal medicine from South Asia, kohl (alkohl, ceruse), surma, saoott, cebagin ● Hobbies: target shooting, glazed pottery making, Pb soldering, preparing Pb shot or fishing sinkers, stainedglass making, car/boat repair, home remodeling ● Occupational exposure: plumbers, pipe fitters, Pb miners, auto repairers, glass manufacturers, ship builders, printer operators, plastic manufacturers, Pb smelters and refiners, steel welders or cutters, construction workers, rubber product manufacturers, battery manufacturers, bridge reconstruction workers, firing range workers, military and law enforcement ● Dietary: zinc or calcium deficiency ● Imported toys or jewelry with Pb ● Retained bullet fragments, especially if multiple fragments, associated with fracture, or in joints

Child Safety Considerations

Children are especially at danger because the blood-brain barrier does not fully mature until the age of three, which allows more lead to enter the central nervous system (CNS).
 Children's ingested Pb is 40% bioavailable, compared to 10% for adults.
The danger of ingesting Pb is increased by typical childhood habits such frequent hand-to-mouth activity and pica (repeated ingestion of nonfood materials).
pregnant women's issues
Cross-sectional research points to a link between preeclampsia and increased blood Pb.

Prevention 
Provide families with information about Pb sources and ways to reduce exposure. Kids at risk should be screened.
Inform parents of dangerous home modifications.
Using a high-phosphate solution to wet mop and dust (such as powdered automatic dishwasher detergent with 1/4 cup per gallon of water) will help control Pb-bearing dust.
Some states no longer sell high-phosphate detergent.
Use cold water instead of hot water to flush pipes if tap water may be Pb contaminated. Do this for 30 to 60 seconds. If at all feasible, use bottled or distilled water that doesn't contain Pb.
Consider screening pregnant women who are at risk.


Associated Conditions Anemia due to iron deficiency


Background Frequently asymptomatic
Mild-to-moderate toxicity: lethargy, irritability, weariness, paresthesias, and myalgias
- Muscular exhaustion, arthralgia, headache, tremor, difficulty concentrating, vomiting, and abdominal pain
Three main clinical symptoms can indicate severe toxicity:
- Alimentary type: anorexia, metallic taste, constipation, severe abdominal pains brought on by intestinal spasm and occasionally accompanied by rigidity of the abdominal wall
- Neuromuscular kind (adult plumbism's defining feature): peripheral neuritis that affects just the extensor muscles and is typically painless.
The following long-term effects are more common in children with cerebral type or Pb encephalopathy: seizure, coma, and neurologic problems, delayed mental development, and persistent hyperactivity (or other behavioral changes).
Renal failure may result from prolonged exposure.

clinical assessment 

While usually normal, abdominal soreness can be very intense.
A neurologic exam may show encephalopathy or neuropathy.


Multiple Diagnoses 

The neuromuscular type manifests similarly to other polyneuropathies, but the gastrointestinal type may manifest as an acute abdomen.
 Could be mistaken for ADD, intellectual disability, autism, dementia, and other seizure-causing conditions.
Erythropoietic protoporphyria results in an extremely high erythrocyte protoporphyrin content and may be caused by iron-deficiency anemia or (less frequently) hemolytic anemia.

Laboratory Results 
Pb reference value in venous blood >5 g/dL (0.24 mol/L).
The reference value may be lowered by the CDC to greater than 3.5 g/dL (0.17 mol/L). Verify screening capillary Pb levels with a venous sample if they are >5 g/dL (0.24 mol/L).
 Eosinophilia; basophilic stippling on peripheral smear (not diagnostic); somewhat low hemoglobin and hematocrit
In the later stages, renal function is diminished.
If recent intake is suspected, an abdominal radiograph should be performed to look for Pb particles in the intestines. A radiograph of the long bones may reveal metaphyseal abnormalities brought on by growth stop. Not always suggested are movies.
Screening questionnaires are only 60% sensitive in detecting children with increased blood levels, according to preliminary tests (lab, imaging).

Management 

g/dL Blood Level Confirmation period Examining ref value-9 1–3 mo
10–44 1 wk–1 mo
45–59
48 hr 60–69
24 hr ≥70 ASAP as a test for an emergency

Caution 
If Pb levels are greater than 5 g/dL, confirm with additional testing in accordance with the guidelines.
 Request a house inspection from your local public health department if your blood lead levels are consistently above 15 g/dL.
 If a level is high, inform people about Pb exposure sources.
Pb level 5 to 45: thorough medical history and physical examination, follow-up Pb monitoring, thorough examination of home or workplace to determine source of Pb and Pb-hazard reduction, and neurodevelopmental monitoring of iron status, hemoglobin, or hematocrit. Pb level 45 to 69 g/dL: treatment to lower level plus free erythrocyte protoporphyrin, oral chelation therapy, or hospitalization if Pb-safe environment cannot be ensuredPb levels above 70 g/dL: hospitalization for chelation therapy

General Actions 

Take the child away from the exposure source.

Medication: If there is GI tract Pb contamination, delay chelation until the bowel is decontaminated because all chelating agents enhance the absorption of lead by the gut. Consider oral chelation for asymptomatic and Pb >45 and 70; chelation (ideally parenteral) for Pb >70 or symptomatic Pb 70.


Initial Line
Succimer (Chemet), dimercaptosuccinic acid (DMSA), 350 mg/m2 or 10 mg/kg every eight hours for five days, followed by every twelve hours for two weeks. In the event that Pb levels do not settle at 15 g/dL (0.72 mol/L) after two weeks, this may be done again.
Parenteral chelation (start after ensuring sufficient urine output):
- Dimercaprol (British anti-Lewisite [BAL]) 75 mg/m2 given deep intramuscularly, followed by BAL 450 mg/m2/day divided every four hours for five days, as well as Ca edetate calcium disodium (EDTA) 1,500 mg/m2/day continuous IV infusion for five days. Chelation may be repeated after a 2-day interval if there are symptoms or after a 5-day interval if there are no symptoms if the rebound Pb level is less than 45 g/dL (2.17 mol/L).
CaEDTA 1,000 mg/m2/day for five days; repeatable after five to seven days
- Dimercaprol had a stronger impact on lowering Pb levels in adults than CaEDTA.
- Contraindications: Because the medication solution contains peanut oil, BAL should not be administered to patients who have a peanut allergy.
 Diazepam for the early management of seizures; paraldehyde for continued control
Warnings - Succimer: GI distress, rash, nasal congestion, muscle aches, increased liver function tests - BAL: diarrhoea, vomiting, fever, headache, temporary hypertension, hepatocellular damage
Ca EDTA: increased excretion of zinc, copper, and iron; renal failure; significant potential interactions; do not administer vitamins with chelation. A patient with a deficit in glucose-6-phosphate dehydrogenase may experience hemolytic crises as a result of BAL.

Penicillamine (D-penicillamine, Depen, Cuprimine) oral chelation as a second line of treatment
Patients who are allergic to penicillin shouldn't take penicillamine (cross sensitivity is prevalent).
 10 to 15 mg/kg/day administered BID in apple juice or sauce (not FDA-approved)
Penicillamine can result in gastrointestinal distress, renal failure, granulocytopenia, liver dysfunction, anemia, and drug-induced lupus-like syndrome.


Referral 
If parenteral chelation is necessary, take advice into consideration.

Further Treatments 

If the patient's Pb level is above 45, keep them away from potential Pb sources until a thorough home examination has been done.

Alternative Therapies 

Adults with mild to moderate Pb poisoning have been treated with garlic.

Admission 

 Blood Pb concentration >70 g/dL
 Blood Pb level >35 g/dL if symptoms are present.
Unless parenteral chelation or rapid departure from a contaminated environment is necessary, outpatient care is the only option.
Avoid visiting any location that may be contaminated; if the Pb source is in the home, the patient must relocate until the abatement procedure is finished.

Patient Follow-Up Monitoring
Expect a rebound following chelation because Pb will have been released from bone reserves.
7 to 10 days after chelation therapy, check for rebound Pb levels. After that, check in biweekly or monthly.
 Treat any iron or other nutritional deficits that have been found.
● Repeat testing every 1 to 3 months until level 25 g/dL is reached once Pb 35 g/dL. Then, until the level is below 10 g/dL, monitor every 3 to 6 months. Test every 6 to 9 months when 9 g/dL.


Diet 
Avoid drinking too much fluid if you have symptoms.
To lessen Pb absorption, avoid pica and consume enough calcium, iron, zinc, magnesium, and vitamins C and D. 

Prognosis: Chelation usually relieves the symptoms of non-encephalopathic Pb poisoning, but mild CNS toxicity may be persistent or permanent.
Children in preschool with higher Pb levels perform worse in reading and math in elementary school.
At age 11, children with high Pb levels have lower IQ scores and socioeconomic standing as adults.
Permanent sequelae, such as mental retardation, seizure disorder, blindness, and hemiparesis, are present in 25–50% of cases of Pb encephalopathy.

Complications 

Long-term Pb exposure may result in chronic renal failure (Fanconi-like syndrome), gout, or a Pb line (blue-black) on gingival tissue. CNS poisoning may be long-lasting or irreversible.
Pb exposure during pregnancy is linked to low birth weight and early delivery.