Burtonian Lines: Cause, Mechanism, Symptoms

In this post on Burtonian lines or Burton’s line, you get to know about its causes, principle, source of origin, and other signs and symptoms related to lead poisoning like saturnism, coli, etc. along with a case study.

This post also has a FAQ section which further enriches your knowledge on Burton’s line.

You can also check our MCQ section in various subfields in forensic science and our Higher Order Thinking Question (HOTs) Section further enriches your knowledge for the preparation of various entrance examinations.

What is the Burtonian line?

The burtonian line is defined as a stippled blue color line seen on the gingival surface i.e. the coupling place of gums and teeth.

Burtonian lines are also called burton’s line or blue lead line gums caused by chronic lead poisoning.

These Burton lines are especially seen on canine teeth of the upper jaw and, within a week of exposure.

Note 1: It is noted that it is not seen on the teeth surface but the sub-epithelium surface of the junction of teeth and gums.

Population has Sign and symptoms:

These stippled blue line gums are seen only 50-70 % of patients suffering from chronic lead poisoning.

Why Burtonian lines is caused?

As stated earlier, burton lines are caused by chronic lead poisoning.

Burton line is caused by a reaction between circulating lead with the Sulphur ions released by bacterial decomposition in the oral activity.

This results in the deposition of the compound called lead sulfide at the junction of the teeth and gums.

Note 2: The natural color of lead sulfide is white in color but due to oral activity, it color changes to blue. And with the passage of time, it changes to purple-blue or bluish-black in color.

Mechanism of how lead poisoning cause Burton lines.

Mechanism of lead poisoning is divided into three major stages. These are:

  1. Inhibition and Lead Circulation
  2. The production of Hydrogen Sulfide in mouth
  3. Burtonian Lines Formation

Stage 1: Inhibition and Lead Circulation

When lead mixed with the blood, it combines with sulfhydryl groups and interferes with ferrochelatase, δ-ALA dehydratase, mitochondrial oxidative phosphorylation ATPases which is a calcium-dependent messenger.  

This inhibits the body to make hemoglobin, which may further drive to disease like anemia.

Stage 2: The production of Hydrogen Sulfide in mouth

The production of hydrogen sulfide in the mouth is possible due to the presence of various molecules, like volatile sulfur compounds, short-chain fatty acids, polyamines, and indoles.

And major bacteria that responsible for the production of hydrogen sulfide are genera Neisseria, Fusobacterium, Porphyromonas and SR1 (Abscondita Bacteria).

Stage 3: Burtonian Lines Formation

Due to the amalgamation of hydrogen sulfide from bacterial activity with circulating lead leads to the formation of the stippled blue line also known as Burtonian or Burton’s line.

burtonian-lines-mechanism and caused
Mechanism of how lead poisoning cause Burtonian lines.

Sources of Chronic lead Poisoning

As Burtonian lines are caused by chronic lead poisoning, so in this section, only covers sources that cause chronic lead poisoning:

Note 3: Chronic lead poisoning results from a daily intake of 1–2 mg of lead.

  1. Inhaled or Ingested: One of the most common sources is ingestion of lead-dust which is generally seen in industrial works.
  2. Lead Paints Dust: Lead carbonate called white lead is used for the manufacturing of paints. And it is the most common source of lead poisoning in children because of their tendency to put things in the mouth.
  3. Occupations exposure: Occupation like painters, workers at the white lead industry, plumbers, glass polishers, and glass blowers all are encountered with the fumes of lead.
  4. Tetraethyl lead from Petrol: Tetraethyl Lead is used as an anti-knocking agent in petrol and gasoline.
  5. Cosmetics and sindoor: A red color compound of lead called lead tetroxide or vermilion, generally used as a sindoor in India, can be absorbed through the scalp. And the use of hair dyes and cosmetics containing lead.
  6. From beverages and food: Absorption from drinking water stored in lead bottles, processed food packed within lead containers.

Symptoms apart from Burtonian Lines

There are many key symptoms to register a person as a patient of lead poisoning.  These are:

  1. Anemia
  2. Colic
  3. Foot drop or Wrist drop or Lead palsy

Symptom 1: Anemia

Due to impairment in heme synthesis and increased fragility of RBCs.

RBCs fragility get increased in case of lead poisoning due to the loss of intracellular potassium. It can be understood as the increased permeability of the cell membrane to potassium.

Symptom 2: Colic

It is a late symptom, seen in the small and large intestine, ureters and blood vessels.

And the pain in muscular contraction and relaxation which might be very serve termed as saturnine colic.

Symptom 3: Foot drop or Wrist drop or Lead Palsy

It is rare symptoms seen less than 10% of lead poisoning case. It occurs due to degeneration of nerves and muscles groups.

Note 4: lead poisoning peripheral smear:
It is a peripheral blood smear test, performed on a person suspected of exposure to excess atmospheric lead.
It is performed because the person doesn’t show any symptoms related to lead poisoning.

Burtonian lines in other metals:

Blue-line on gums (Mercury): In the case of mercury poisoning, the blue line is very rarely seen but person loosening of teeth are seen.

Bluish-colored lips (Iron Poisoning): Blue lips, palms of hands along with fingerprints are the late symptoms of an iron overdose. But the blue gums are not majorly seen in iron poisoning.

Copper Poisoning: Apart from the blue line, a more greenish line on the gums at the base of teeth just like burtonian line.

Bismuth Blue Gums: The blue gums in case of bismuth poisoning is called bismuth line or Bismuthia. It is commonly seen in people who have ingested bismuth compounds.

The color is not only seen on gums but also on the skin, and have bluish-gray skin’s pigment granules.

Case Study on Burtonian Lines

Burton’s line in a 44-year adult battery worker

In India, a 44-year-old male was diagnosed with chronic lead poisoning.

Case history:

He started to work as child labor in a battery-recycling unit since the age of 10 years. After the passage of years, he owned the shop and hired two more laborers.

The shop doesn’t possess any health-related precautions. They don’t even use the mask. He regularly used to work with molten lead without any protection and mask.

Even he eats his meal at the workplace without washing his hands, this was also a possibility of accidental ingestion of microparticles of lead through the passage of these years.

Even he uses the workplace as his overnight stay and for sleep and without changing his clothes.  

For a long time, he remained asymptomatic i.e. no particular signs and symptoms of the disease. He was initially treated for his symptoms of pain before knowing the root cause of the problem.

But later when his condition got worse, he goes through full diagnosis where subsequent investigations revealed that he was suffering from chronic lead poisoning.

Key symptoms that were seen:

Asymptomatic: Patient doesn’t show any symptoms related to lead poisoning for a long period of time.

This is common in case of lead poisoning.  For this, a peripheral blood smear test is performed to check the lead level in the blood.

Colic: At prolonged exposure for 34 years, his body showed late symptoms like joint pain, muscular contraction, small intestine, and epigastrium.

Burtonian Lines: Burton’s blue lines were seen in this case but after a long period of exposure.

Bottom-line of case study

As a patient for a long period remained asymptomatic. And he used to take medication for his joints pains and epigastrium without aware of the actual reason.

So, the patient is unaware of the ill-effects and he isn’t able to correlate his joint pain, epigastrium and burtonian lines with chronic lead poisoning.

FAQ Section on Burtonian Line

Q1. Industrial worker with blue lines on the gingival surface, most probably due to:

Lead poisoning

Q2. Other names of Burtonian lines are:

Burton’s line or blue lead line gums

Q3. Which enzymes are inhibited by lead in the heme synthesis pathway?

Ferrochelatase and δ-ALA dehydratase

Q4. Which cells shows basophilic stippling?

Red Blood Cells (RBC’s)

Q5. Which chemical compound of lead is responsible for Burtonian lines?

Lead Sulfide (PbS)

Q6. In case of chronic lead poisoning, the levels of which amino acid is elevated

δ-aminolevulinic acid

Q7. Bacteria that are responsible for the production of Hydrogen Sulfide in the mouth.

Neisseria, Fusobacterium, Porphyromonas, and SR1 (Abscondita Bacteria).

Q8. What is the lead compound used as an anti-knocking agent that can cause lead poisoning?

Tetraethyl Lead

Q9. Blue-line gums in case of Bismuth poisoning is called:

Bismuthia or Bismuth Blue Gums.


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