Abstract
This case illustrates the importance of eliciting the use of alternative and non-prescription medicines when taking histories and also considering lead poisoning in the differential of unexplained abdominal pain.
Case
A previously well 26-year-old Asian man presented acutely with a two-day history of severe, colicky, central upper abdominal pain, associated with vomiting and constipation. There were no precipitating factors and the pain was not relieved by simple analgesia. He was on no prescribed medication and denied taking any other drugs. Clinical examination was unremarkable, as was an abdominal radiograph. Routine haematology and biochemistry blood tests, including blood film, were normal apart from a raised Alanine Transaminase (ALT) at 222 IU/mL. Although in great distress initially, his symptoms resolved spontaneously within two days and he was discharged.
Two weeks later he presented with identical symptoms, having been symptom-free in the interim. ALT was again moderately raised at 180 IU/mL. Gastroscopy and ultrasound of the abdomen were both normal. An abdominal CT scan was normal apart from slight terminal ileal thickening. However, a subsequent colonoscopy showed a normal terminal ileum; histology revealed only mild non-specific inflammation and both ZN staining and TB culture of the biopsies were negative. Chest X-ray, Mantoux test and Yersinia serology were also negative. During this admission he exhibited behavioural disturbance, was transiently disoriented and threatened suicide. Although these features settled, a psychiatric assessment was undertaken. It transpired the patient had recently consulted his GP about marital difficulties due to erectile dysfunction, for which the GP had declined the patient's request for Viagra. Again all of his symptoms settled spontaneously, his ALT normalized and he was discharged.
Shortly after discharge however, he was re-admitted with further abdominal pain and
again displaying erratic behaviour. On this occasion an abdominal radiograph showed some
high density specks in the colon (Figure 1). ALT
was raised at 390 but again returned to normal soon after admission. A comprehensive
panel of blood tests screening for causes of liver disease was entirely negative and
magnetic resonance cholangiopancreatography (MRCP) revealed a normal liver and biliary
system. In view of the pain, constipation and psychological symptoms, urine and blood
were sent for porphyria testing. Although the urine porphyrin:creatinine ratio was
markedly raised at 230 (normal range 0–35), the Abdominal radiograph showing high density specks in the colon Secondary causes of porphyrinuria
8
Chelation therapy was considered, but as his symptoms had resolved, he was simply followed up with advice to avoid further ingestion of Kamagra tablets. At 6 weeks post discharge the lead level had fallen to 4.47umol/L and at 6 months to 1.85 umol/L, a roughly exponential decline reflecting lead's long half-life and thus supporting the story of discontinued exposure. No further rises in liver enzymes were seen and to date the patient has remained asymptomatic.
Discussion
End organ damage caused by lead poisoning
Sources of lead poisoning
Such cases present a diagnostic challenge due to the relative paucity of positive clinical findings and as such often lead to delayed diagnosis. In some cases appendicectomies and even laparotomies have been carried out before eventually arriving at the diagnosis of lead poisoning. 4, 5
The pattern of abdominal pain suffered by our patient is characteristic, with paroxysms of severe, colicky abdominal pain. The rise in ALT that we observed with symptomatic episodes has also been reported elsewhere as the only routine biochemical abnormality in lead poisoning. 6 As shown in Figure 1, lead particles themselves may be visualized on an abdominal radiograph shortly after ingestion.
Treatment of lead intoxication is by chelation with edentate disodium calcium or DMSA. This is effective at reducing blood levels acutely andimproving symptoms, though its role in the treatment of asymptomatic individuals with elevated blood lead levels is less certain, as the majority of the whole body lead content is stored in soft tissue and bone, where its half-life is in the order of decades. 1, 3
Cases of lead poisoning have declined overall in the Western world due to the regulation of industrial practices. 3 However, increasing numbers of cases are being reported as a result of the contamination of herbal and counterfeit medications. 1, 6 Ayurvedic medicines are commonly implicated, with more than 80 reported cases of lead poisoning from their use; analytic studies have found metals in 30–65% of Ayurvedic products sold outside the United States, and 20% of those sold in Boston, USA. 1 Lead may be present as a result of contamination from soil or manufacturing processes, or be included intentionally, either as an active ingredient or to add weight to preparations. 1
Cases relating to counterfeit or non-licensed medications are less well-documented, but as use of the Internet for the purchase of such items grows, reports are increasing. Kamagra, the medication taken by our patient, is a preparation of sildenafil produced in India. It is unlicensed in the UK but illegal distribution of genuine and counterfeit preparations is acknowledged as a major problem by the Medicines and Healthcare products Regulatory Agency. The dangers associated with Kamagra are illustrated by reports on the Internet of adverse events and even death following its use. Although the cause of such adverse events is often unknown, contamination of counterfeit medications with lead containing paint has been reported on several occasions by the United Nations Interregional Crime and Justice Research Institute Programme on Counterfeiting. 7
Although rare, clinicians should be aware of lead toxicity as a potential cause of abdominal pain, particularly when the symptoms are disproportionate to the clinical findings. Suspicion should be especially high where there is a history of non-prescription medication use, which patients are often reluctant to disclose.
Footnotes
DECLARATIONS
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Acknowledgements
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