Black foot disease is caused by Arsenic

NEET PG
#1

Black foot disease is caused by
a) Arsenic
b) Cadmium
c) Lead
d) Mercury
Correct Answer - A
Ans. is ‘a’ i.e., Arsenic
Chronic arsenic exposure can cause ‘black foot disease’ a severe
form of peripheral vascular disease, causing gangrene of lower
limbs.
Arsenic poisoning may be acute or chronic.
Acute arsenic poisoning
It can present in any of the two ways :

  1. Gastrointestinal type : It is the common form and resembles
    bacterial gastroenteritis (e.g. cholera). There is garlic adour with
    hemorrhagic gastroenteritis and necrosis of intestinal mucosa. There
    is tenesmus and anal irritation. Dehydration may cause acute
    circulatory collapse, with hypotension, oliguria and acute tubular
    necrosis (ATN).
  2. Fulminant narcotic form : Large dose of arsenic is rapidly absorbed
    without producing GI symptoms. These are giddiness, headache,
    myalgia, formication, vertigo and death in 2-3 hours.
    Postmortem appearance include :
  3. Red velvety mucosa of stomach and submucous petechial
    haemorrhage.
  4. Subendocardial petechial haemorrhage.
  5. Fatty degeneration of liver, kidney and heart.
    Chronic arsenic poisoning
    Chronic arsenic poisoning has four stages :
  6. First stage (nutritional and gastrointestinal disturbances) : The
    earliest sign is gradual emaciation. There is loss of appetite, nausea
    and intermittent vomiting and diarrhea.
  7. Second stage (catarrhal changes) : It resembles common cold, i.e.
    conjunctivitis, running nose and eyes, coughing etc.
  8. Third stage (skin rash) : There is classical ‘rain drop pigmentation’,
    i.e. patchy brown pigmentation of skin. At initial stages, there is a
    vesicular eruption which may resemble nettle rash. Hyperkeratosis
    of palms and soles occur. There are white transverse bands
    crossing the nails, known as Mee’s line, and indicate periods of
    arrested growth due to interference with normal metabolism. There
    is alopecia and exfoliative dermatitis.
  9. Fourth stage (nervous disturbances) : There is sensory and motor
    (i.e. mixed) polyneuropathy, with painful paresthesia of hands and
    feet and muscle tenderness.
    There may be evidence of liver (fatty liver) and kidney damage and
    bone marrow suppression (causing anemia and other cytopenias).
    Heart may also be involved.
    Chronic arsenic exposure can also cause ‘black foot disease’ a
    severe form of peripheral vascular disease, causing gangrene of
    lower limbs.
    Arsenic is carcinogenic, can cause cancers of skin (squamous cell
    carcinoma and basal cell carcinoma), lung, liver, bladder, kidney,
    larynx and lymphoid system (leukemia).