TREATMENT OF LEAD ENCEPHALOPATHY WITH BAL (2.3-DIMERCAPTOPROPANOL)
Authors: ENNIS JULIUS M. , HARRISON HAROLD E. 
Published: December 2021

BAL is apparently effective in lowering the mortality rate in children with severe lead encephalopathy. The severity of the residua of severe lead encephalopathy may also be reduced by BAL treatment. No conclusive effects of therapy could be demonstrated in subacute mild cases of lead encephalopathy. The toxic effects of BAL in this series have been limited to nausea and vomiting which were never severe enough to contraindicate continuation of treatment. There was no evidence of exacerbation of symptoms in mild cases of lead poisoning treated with BAL. As has previously been shown, BAL administration increases the urinary excretion of lead for a limited time, and this effect can be repeated in the same patient after an interval. The concentrations of lead in blood fall spontaneously following removal of children with lead poisoning from their source of exposure by admission to the hospital. The rate of decrease in blood lead is not influenced by BAL administration.

The case histories of nine patients with severe lead encephalopathy treated with BAL are summarized below:

Case No. 1: J. B., a 3 yr. old Negro girl, was admitted to BCH. She began to sit up at 8 mo. of age, walked at 11 mo. and talked in sentences at 1½ yr. For some time before admission, she had been seen to eat paint off the wall at home. Three weeks before admission, she had rubella, and 4 days before admission began to have fever and persistent vomiting, became drowsy and remained so until admission. On admission she did not respond to ordinary stimuli. When a lumbar puncture was performed, she had a convulsion which persisted for some minutes, after which she became comatose and remained so for 4 days. Physical examination: she was seen to have a stiff neck, papilledema, and weakness of the left arm and leg. Laboratory examinations revealed albuminuria, glycosuria, and anemia with basophilic stippling of the erythrocytes. Blood lead concentration was 0.15 mg./100 gm. blood. Cerebrospinal fluid protein was 78 mg./100 cc. Roentgenogram of long bones revealed a dense line at the metaphyseal ends. BAL treatment was begun shortly after admission and continued for 10 days. On the 5th day, she began to respond to stimuli, and a bilateral squint was noted at this time. On the 6th day, she was able to take fluids by mouth. Until about the 14th day, it was thought that she could not see but at the time of discharge, 21 days after admission, she had apparently recovered except for a residual weakness of the left leg, and VI and VII left cranial nerve pareses. Eight months after discharge, the left leg paresis was no longer detectable, but slight left facial weakness was still present. She had developed frequent convulsive seizures which were controlled by phenobarbital as long as it was continued. She was not seen again for 3 yr., at which time she had had 3 convulsions which occurred 3 mo. after phenobarbital had been discontinued. She is still a severe behavior problem, hyperactive, restless and distractible. She appears duller than her age of 6 yr., but is physically normal except for a slight left facial paralysis. She was placed on anticonvulsant therapy and has had no further convulsions. Psychometric examination revealed an I.Q. of 62.

Case No. 2: N.D., a 2 yr. old white girl, was admitted to HLH. For the year prior to admission, she had been eating paint from the walls. For 1 wk. prior to admission, she had been vomiting and was anorexic. Three hours before admission, she developed severe generalized convulsions which continued up to admission, following which she lapsed into coma. Physical examination revealed a comatose child with a right-sided hemiplegia, who was slightly dehydrated. Laboratory examination revealed slight albuminuria, glycosuria, hematuria and casts in the urine. Hgb. was 8 gm./100 cc. blood, and there was basophilic stippling of the erythrocytes. Blood lead concentration was 0.33 mg./ 100 gm. blood. Cerebrospinal fluid protein was 81 mg./l00 cc., and there were 11 lymphocytes/cmm. Roentgenograms of long bones revealed evidences of heavy metal deposition. She remained comatose throughout her hospitalization. Twenty-four hours after admission, BAL therapy was begun without any change in her condition, and she died on the 3rd hospital day.

Case No. 3: A. S., an 18 mo. old Negro girl, was admitted to BCH with a severe left-sided convulsion. She had walked and said a few words at 1 yr. For 5 mo. prior to admission, she had been in the habit of going to the window sill and chewing paint off the wood. For 1 mo. before admission, she had been vomiting intermittently. Four days prior to admission, she became fretful, listless and anorexic, and was vomiting forcefully after each feeding. On the day of admission, she was taken to the HLH Dispensary and while waiting to be seen had a severe left-sided convulsion, which lasted 10 mm. and recurred shortly afterwards. She was admitted to BCH in this condition. Laboratory examination on admission revealed the following: Urine was normal, Hgb. was 8.0 gm./100 cc. blood, RBC count 4.7 million/cmm., WBC count was 12.4 thousand/cmm., and basophilic stippling of the erythrocytes was noted. Cerebrospinal fluid pressure was 310 mm. H2O, and the fluid contained protein 105 mg./100 cc. and 66 lymphocytes/cmm. Blood lead concentration was 0.21 mg./100 gm. blood. Roentgenograms of long bones revealed changes consistent with a diagnosis of lead deposition (Fig. 2).

On admission she was placed on BAL therapy. Subsequent blood and urine lead determinations are shown in chart 2. For 3 days after admission, she continued to convulse in spite of large doses of [SEE FIG. 2. IN SOURCE PDF]anticonvulsant drugs, and thereafter she was semicomatose until the 5th day when she began to recognize people, and she then improved throughout the remainder of her hospital stay. At the time of her discharge 1 mo. later, she appeared well except for left hemi-paresis. Since discharge she has had recurrent left-sided convulsions, and on 2 occasions was readmitted to the hospital. On her 2nd hospitalization 10 mo. later, she had no evidence of lead encephalopathy, but roentgenograms of the long bones revealed 2 lines of increased density (Fig. 2), and the blood lead concentration was .098 mg./100 gm. of blood. She was given another course of BAL with determinations of blood and urine lead concentrations which are shown in chart 3. Ten months after admission EEGs revealed "abnormal EEG, hemispheres out of phase, spike seizure discharges, cortical damage with convulsive tendency." A PEG suggested right cerebral atrophy (Fig. 1). She was placed on dilantin and phenobarbital, and since that time has had 2 left-sided convulsions lasting for a few minutes, both associated with an upper respiratory infection and both occurring when anticonvulsant therapy had been omitted. Physical examination at the present time reveals no abnormalities. At the age of 3 yr. and 3 mo. she acts "sort of wild at times and screams for no reason." She has an I.Q. of 79 with a basal age of 2½ yr.

Case No. 4: S. H., a 2 yr. old Negro boy, was admitted to BCH. He sat up at 6 mo., walked at 1 yr. and said words at 15 mo. For at least 1 mo. prior to admission, he had been nibbling on paint and plaster at home. He was well until 4 days before admission when vomiting after each feeding began which continued until admission. He had become drowsy and 2 days before admission his eyes were noted to be crossed; just before admission he became semistuporous. On admission he was irritable, had a high-pitched cry and did not respond to spoken words. When attempts were made to have him walk, he was seen to be ataxic. He had a left internal strabismus, blurring of both discs and marked nuchal rigidity. The plantar reflexes were extensor, and there was weakness of the left arm and leg. The blood lead level was 0.51 mg./100 gm. blood. Spinal fluid pressure was over 300 mm. H2O. Roentgenogram of the long bones showed evidence of heavy metal deposition. He was started on BAL on the 2nd hospital day. He was semicomatose from admission and his condition remained almost unchanged until he died on the 6th hospital day.

Case No. 5: R. E., an 18 mo. old Negro boy, was admitted to Sydenham Hospital. He had been walking and talking well before admission. For 5 mo. before admission, he had been seen eating painted plaster. Three weeks before admission, he became irritable, anorexic and hyperactive. His physician had made a diagnosis of lead poisoning and had started him on treatment with sodium citrate. Twelve hours before admission, he began to vomit forcibly and within a few hours developed severe left-sided convulsions followed by coma. He was admitted in a convulsion which recurred within the hour. His temperature rose to 39.2° C. shortly after admission, his respirations were shallow and rapid. Blood pressure was 136/70 mm.Hg, and papilledema was noted. Laboratory examination revealed Hgb. 9.2 gm./100 cc., WBC count 28.28 thousand/cmm., and there was basophilic stippling of the erythrocytes. Spinal fluid protein was elevated and the fluid contained 86 cells/cmm. Blood lead concentration was .34 mg./100 gm. blood. Roentgenograms of long bones showed evidence of heavy metal deposition. He was started on BAL therapy which was continued for 4 days. He remained comatose for more than 20 hours and was semicomatose or stuporous for 2 more days. On the 3rd day he began to improve rapidly and by the 5th day he was completely asymptomatic. Blood lead concentration fell to 0.17 mg./100 gm. blood on the 12th day. At the time of discharge, he was considered completely well, and when seen again 9 mo. later, he appeared normal mentally and physically. He was not a behavior problem and his mother was satisfied with his development. No psychometric examination was performed.

Case No. 6: E. C., a 4 yr. old Negro girl, was admitted to BCH with a chief complaint of persistent vomiting. She sat up at 6 mo., walked at 14 mo., and talked at the end of her 2nd yr. For 8 mo. prior to admission, she had been seen to eat plaster and also paint off window sills. Two weeks before admission, she began to vomit persistently, and 1 wk. before admission she became irritable and drowsy. Three days before admission, she was seen at HLH and given intravenous fluids for her dehydration. Concentration of lead was 0.15 mg./100 gm. blood. Physical examination on admission revealed no abnormality except evidences of malnutrition. She was irritable and uncooperative and refused to eat. Laboratory examination revealed an albuminuria and glycosuria and acetonuria with numerous cellular and hyalin casts. Hgb. 8.5 gm./100 cc. with RBC count 3.8 million/cmm. Blood lead concentration was 0.12 mg./100 gm. blood. On the 4th hospital day, she was placed on BAL therapy but she continued to vomit and refused fluids and was, unfortunately, allowed to become dehydrated. On the 6th day of treatment, she developed marked generalized convulsions and extreme opisthotonus. Spinal fluid at this time revealed a protein of 50 mg. with 24 lymphocytes/cmm. and increased pressure. The following day, she remained semi-comatose. BAL dosage was increased to 4 mg./kg. body weight, and she was maintained on parenteral fluids for 2 days and then fed by gavage for 2 days. After 3 days, she began to respond but still behaved in a bizarre fashion, repeating phrases, crying out in fright, apparently because of hallucinations. Her vision appeared very poor; she could not focus on any object and her movements were incoordinated. These signs gradually cleared and at the time of discharge, she was apparently well, was not vomiting, was cheerful and mentally clear. The total duration of BAL therapy was 14 days and she was discharged 3 days after therapy was finished. At the time of discharge, blood lead concentration had fallen to .10 mg./100 gm. blood. Since discharge, she has had several tonic convulsions followed by a period of unconsciousness. EEG revealed "moderately abnormally slow encephalogram for age, consistent with encephalopathy and convulsive tendency." Phenobarbital and dilantin® therapy have controlled the convulsions. Her mother considers her more difficult to handle than other children. She is restless and distractible. She has an outgoing and appealing manner and gives the impression of being bright, but psychometric examination revealed an I.Q. of 78.

Case No. 7: J. S., a 4 yr. old Negro boy, was admitted to BCH. He had sat up at 6 mo., walked at 12 mo., and talked at 14 mo. Since the 2nd year of life, he had been eating pieces of paint from the window sill. Five months before admission, he became fretful and babyish. His speech gradually became incoherent and unintelligible. He "forgot" his toilet and eating habits and was no longer able to repeat his nursery rhymes. At the same time, he became more mischievous and unmanageable. Two months previously, he was seen at HLH Dispensary with these complaints. A lumbar puncture was done and spinal fluid gave a positive Pandy reaction. Blood lead determination showed a concentration of 0.17 mg./100 gm. blood. He was placed on sodium citrate 1 gm. 3 times daily. No apparent change was noted until shortly before admission. One week before admission, he had had an upper respiratory infection with fever. He was, otherwise, well until the night of admission when he had a generalized convulsion. He was admitted to the BCH in this condition. Convulsive movements continued for a total of 10 or 11 hr. and he remained comatose for 24 hr. Blood pressure on admission was 156/64 mm.Hg. Laboratory examination revealed albuminuria, glycosuria and occasional red blood cells and casts in the urine. Hgb. was 9.2 gm./100 cc.; RBC count was 5.1 million/cmm. Blood lead concentration was 0.11 mg./100 gm. blood. Cerebrospinal fluid showed a pressure of 200 mm./H2O and protein of 70 mg./100 cc. Roentgenogram of long bones showed a zone of increased density at the metaphyseal ends. He was placed on BAL therapy and subsequent blood and urine lead levels are shown in chart 4. From the 2nd to the 4th day, he was semistuporous and did not respond to environmental stimuli. He slowly improved so that at the time of discharge, he appeared responsive but dull. He would say only a few words. His blood pressure returned to normal over a period of a few days. Since discharge from hospital, he had one generalized convulsion and was placed on phenobarbital therapy. Electroencephalography done 3 mo. later showed "moderately abnormal sleep frequencies for age consistent with diffuse cortical involvement." Intellectually he is improving gradually so that his mother believes he is at the level achieved prior to his illness. He has faulty articulation but otherwise speaks fairly well. Psychometric examination revealed an I.Q. of 69. Because of his fairly rapid improvement, hope was expressed that he may do better when retested later.

Case No. 8: A. B., a 2 yr. old Negro boy, was admitted to HLH. His development had apparently been normal until the present illness. For 3 mo. prior to admission, he had been observed to eat plaster and paint off the walls. Twelve days before admission, he developed an upper respiratory infection and at the same time began to vomit. The vomiting had become more persistent in the few days prior to admission. The day before admission he became drowsy. He had periods of looking oddly into space and seemed disoriented. On admission, he was semistuporous, responding only to painful stimuli. He lay in a position of opisthotonus. Neck was stiff, reflexes were sluggish, no papilledema was seen but there was engorgement of the retinal veins. Blood pressure was 140/55 mm.Hg. Laboratory examination revealed albuminuria and Hgb. 8 gm./100 cc. on admission which fell to 5.5 gm./100 cc. Spinal fluid pressure was 600 mm. H2O and the fluid gave a positive Pandy reaction. The blood lead concentration was 0.33 mg./100 gm. of blood. He was placed on BAL therapy and the changes in concentration of lead in blood and urine are shown in chart 5. Daily lumbar punctures were done in order to lower the intracranial pressure and over a period of 6 days the pressure fell to within normal limits. He remained semistuporous for 2 days. His hypertension persisted for 2 days, and the fullness of the retinal veins persisted for 3 days. Stiffness of the neck persisted for at least 5 days. He continued to vomit throughout the period of treatment with BAL. Towards the end of this period the vomiting was related directly in time to the injection of BAL and disappeared completely when treatment was stopped. At the time of discharge, no abnormalities were noted. When seen 2 mo. after discharge, he was apparently well.

Case No. 9: I. J., an 18 mo. old Negro boy, was admitted to HLH. He sat at 6 mo., walked at 9 mo. and could say a few words prior to his illness. Three months before admission, he had several generalized convulsions from which he quickly recovered. For 3 wk. before admission, he was observed eating plaster and he was thought to be pale. Six hours before admission, he had a severe generalized convulsion which persisted until he was admitted in a comatose state. Spinal fluid pressure was 210 mm. H2O, and the fluid had a protein content of 72 mg./100 cc. Blood lead concentration was 0.23 mg./100 gm. blood. Roentgenograms of the long bones showed evidence of heavy metal deposition.

Shortly after admission, he had another convulsion which persisted for several minutes. BAL therapy was begun shortly thereafter. He remained comatose for 24 hr., semicomatose for another 48 hr. On the 4th day of treatment, he was sitting up in bed and was able to take feedings. Blood lead concentration fell to 0.134 mg./100 gm. blood within a few days, and urinary lead concentrations were increased followed BAL therapy. At the time of discharge, 13 days after treatment was begun, no abnormalities could be discovered.

The following case, although not in the severe group, is included to demonstrate the changes in urinary lead excretion following BAL administration.

Case No. 10: V. C., a 3 yr. old Negro girl, was admitted to HLH. She had apparently developed well until 2 mo. prior to admission, when she contracted measles. Since that time she was seen to eat paint off window sills and pieces of broken plaster. She vomited intermittently throughout this time, had severe abdominal pain, anorexia and constipation, and was quite irritable. Ten days before admission, she developed ataxia and generalized weakness, and had several moderately severe generalized convulsions. Her irritability became more severe and she was hospitalized because of the increase in vomiting and because she had become completely unmanageable. Laboratory examination on admission showed RBC count of 3.1 million/cmm., Hgb. 7.2 gm./100 cc. Cerebrospinal fluid proteins were 50 mg./100 cc., and there were 16 lymphocytes/cmm. spinal fluid. Roentgenograms of long bones showed evidence of heavy metal deposition. Blood lead concentration was 0.22 mg./100 gm. blood. On examination she was found to be awake but completely uncooperative and mentally quite dull. When she tried to walk she had a staggering gait and fell to the left. She was unable to feed herself for the first few days in hospital. She was placed on BAL therapy for a total of 4 days. Concentrations of lead in blood and urine following treatment are shown in chart 6. The vomiting persisted for 3 days and the ataxia was still present on discharge. Since the time of discharge, she has had 2 episodes of convulsions and was placed on anticonvulsant therapy. Psychometric examination was done and she was found to be moderately retarded.