On palpating the abdomen during these acute exacerbations, it is found that not only the gastric region, but the whole of the abdomen, is affected. Occasionally the acute pain is referred to the navel, but generally to the lower region of the abdomen; and very frequently the pain is described as running down into the scrotum, whilst there may also be pain complained of as far as the knee-joint, but this last is unusual. There may or may not be well-marked peristalsis taking place, but quite commonly large hardened tumours can be felt in various situations in the abdomen, corresponding to the contracted intestinal walls. Shifting tumours, then, may be regarded rather as a diagnostic sign of the acute forms of lead colic.
The colic rarely commences without some slight prodromal symptoms of dyspepsia or gastric discomfort; generally for two or three days preceding the attack there is loss of appetite, with a distaste for food, and obstinate constipation, particularly a general feeling of languor associated with an unpleasant taste in the mouth. Tanquerel, and later Grissolle[3], among others, described a form of stomatitis which they thought was a prodromal symptom of an attack of lead colic. Our own experience, however, does not at all coincide with these statements.
Very occasionally the sufferer from acute colic may die during a paroxysm due to heart failure, but we have had no experience of such a fatality, although such an occurrence has been recorded on more than one occasion.
After the first acute attack of colic, which generally commences suddenly, often without previous warning, but is as a rule ushered in by irregular and finally complete constipation, or with diarrhœa alternating with constipation, the colic still occurs at irregular intervals; and although the constipation be relieved by enemata or the use of strong purgatives, paroxysmal pain will recur for days, and even weeks. In one particular case colic recurred at intervals for eight weeks, although the bowels were open each day and the patient had been under regular treatment, whilst the anæmia and other general symptoms of poisoning had disappeared.
According to the researches of Meillère[4] and others, lead is stored up in the body in various situations, and is gradually eliminated, such elimination taking place mainly through the fæces, and only to a limited extent through the urine. Probably the elimination of lead through the lower part of the intestine accounts for the recurrent attacks of colic.
Amino[5], Chatin[6], and Harnack[7], regard this colic as due to vaso-constriction taking place in the splanchnic area, and the rapid action of such drugs as atropin, chloroform, and nitroglycerine, support this view. In fact, Mayer[8] in 1881 demonstrated that in lead colic the splanchnic vessels undergo well-marked minute inflammatory changes. Others, from investigations carried on in persons who had died of lead poisoning, regard the acute pain as set up by irritation of the sympathetic nervous system, particularly of the solar plexus, irritation of the nerves in this region presumably setting up reflex colic.
The inhalation of amyl nitrite during an attack of colic will often entirely relieve it, and the pulse will immediately rise to the normal rate. It is difficult, however, in observing a case of colic, to determine whether the colic is preceded by slowing of the pulse and the rise of blood-pressure, or whether the colic is the immediate exciting cause of the constriction of the vessels and the alteration of the pulse-rate.
Chronic Colic.
—The acute form of lead colic frequently passes on to a chronic condition; the attacks become much less intense, and may at times only amount to general discomfort in the abdomen, but the symptoms may last for several weeks, and even months, with no abdominal discomfort for a period of a week or ten days, then recurrence of pain, gradually increasing until it has attained a considerable degree of intensity, and then passing away, only to reappear in two or three days’ time. In such cases of prolonged colic after an interval of two or three weeks, small doses of strychnine or tincture of nux vomica will determine the onset of an attack of colic, showing that the intestinal muscular tissue remains in a state of hypersensibility long after the attack appears to have passed away.
A particular form of colic of long duration with exacerbations and remissions has been known for many years in the French navy, called “seamen’s colic.” Before this time outbreaks had occurred in various parts of the world, and John Hunter[9] described a form of dry bellyache occasioned by drinking certain West Indian wines, the wines in question having been stored in contact with lead—in fact, the vigorous Saxon of John Hunter peculiarly describes this chronic form of lead colic.