Acute poisoning –
Acute poisoning with iron occurs mostly in children due to consumption of adult dose of ferrous sulphate or during I.V. injection of iron preparation.
Signs symptoms of acute poisoning –
Within 15 mts. to one hour, there are signs of G.I. tract irritation followed by signs of restlessness, collapse and drowsiness. There are increased rate of respiration and heartbeat. Frequency of vomiting increases with presence of altered blood in the vomitus. Diarrhoea with offensive stool follows. There may be muscular twitching and convulsion. I.V. injection may cause anaphylaxis. Jaundice may develop due to centri- lobular necrosis of liver, and there may be presence of bilirubin, bile salts and high urobilinogen in the urine. Liver damage may lead to hepatic coma. Blood serum contains very high amount of iron being bound with transferrin, the iron binding plasma protein, and also being present as free iron or being loosely bound with other plasma protein. There may be albumin in the urine due to damage of the renal tubules. Pulmonary haemorrhage, increase of the level of serum transaminase, slow delta wave in the E.E.G. are the other features. Necrosis of the upper G.I. tract with pyloric stenosis are the complications. In acute poisoning cases death may occur within 3 to 4 days.
Signs and symptoms of chronic poisoning –
Prolonged treatment of anaemia with heavy dose of ferri-et-amon-citrous may cause iron encephalopathy. Absorption of small amount over years leads to siderosis or lung fibrosis. There will be signs of damage of liver, kidneys (tubules) and G. I. tract.
Absorption, fate and excretion – Iron is efficiently absorbed from the upper part of the intestine, though the greater part of it remains unabsorbed and is excreted with stool. Absorbed part circulate with blood plasma as described above. It is slowly excreted through the kidney.
1. Stomach wash with Na-bicarbonate solution. 2. Demulcent drinks like milk or egg albumin. 3. Desferrioxamine by mouth to neutralize the poison in the stomach. After initial 8 gm. dose by mouth, it is repeated with a daily oral dose of 2-3 gm. or I.V. dose of 1-2 gm., for the absorbed part of the poison. It forms ferrioxamine with iron which is readily excreted through urine. Alternatively, E.D.T.A. or penicillamine may be used in their usual doses. In acute cases if there is shock, pressure agent should be given.
Haemodialysis or peritoneal dialysis may be necessary in acute cases.
Postmortem findings –
Pulmonary haemorrhage, centrilobular necrosis of liver, necrosis of kidney tubules, signs of G.I. tract irritation in acute cases and necrosis of the upper G.I. tract in chronic cases are the usual findings. Serum iron content and serum transaminase level are high.
Medicolegal aspects –
Both acute and chronic poisoning cases are almost always accidental, from over-dose, prolonged therapy or I.V. administration.