Abstract
Erythropoietic protoporphyria (EPP) is an inherited defect in haem synthesis causing dangerous phototoxic reactions following exposure to wavelengths of light around 400nm. It can cause catastrophic post-operative complications following open surgery, in which environment various safety measures are now routinely employed. The dangers at laparoscopy have never been discussed in the literature, and nor have any specific precautions been recommended.
We describe a 35 year old woman with gallstones undergoing prophylactic laparoscopic cholecystectomy to prevent future cholestasis precipitating porphyric liver failure. A pre-operative trial of the cutaneous effects of the laparoscopic light source was performed to assess the potential risk of use within the peritoneal cavity. The procedure was uneventful and the patient suffered no adverse reaction.
We suggest that a trial of the effects of the laparoscopic light source on the skin of EPP patients provides valid reassurance regarding the safety of the laparoscopy for short surgical procedures.
INTRODUCTION
Erythropoietic protoporphyria (EPP) is an autosomal dominant defect in haem synthesis caused by defective ferrochelatase; the terminal enzyme. Excessive plasma protoporphyrin is deposited in the skin causing photosensitivity triggered by light wavelengths around 400nm (1). This corresponds to the absorption spectra of porphyrins, which are stimulated to produce free radicals and oxygen atoms (2).
EPP is usually detected before the age of 2, often following a history of screaming and pain when taken outside. Phototoxic burning may occur, although extreme blistering and oedema is more a feature of Gűnther’s disease – the rarer autosomal recessive form (3). Hepatic protoporphyrin accumulation may lead to liver failure (4).
Although the dangers associated with exposure to theatre lights at laparotomy have been reported (5,6), the possibility of phototoxicity during laparoscopy has never been explored.
CASE REPORT
A 35 year old woman presented for consideration of elective laparoscopic cholecystectomy. EPP was diagnosed after post-natal testing prompted by paternal carriage. Although her brother was severely affected, having undergone liver transplantation following hepatic failure, her own symptoms were purely cutaneous, marked photosensitivity causing pain and blistering.
Examination revealed mild scarring of the face and dorsal aspects of both hands, characteristic of EPP(3), but no other abnormal signs.
Abdominal ultrasonography (a routine prognostic tool in EPP) demonstrated a distended gallbladder containing multiple stones. The liver measured 14cm and exhibited normal echotexture. The CBD and biliary tree were of normal dimensions. Blood tests showed an isolated rise in ALT to 59u/L (0-50), and free protoporphyrin levels of 1.53μmol/L (<0.01). All other blood tests were normal.
Expectant management risked future complications, including cholestasis. In combination with potential porphyric hepatotoxicity, this could have prompted catastrophic hepatic failure were the gallbladder left in situ. We therefore elected to proceed with prophylactic cholecystectomy.
We improvised a trial of the cutaneous effects of the laparoscopic light source to assess the possible intra-peritoneal consequences. The laparoscope was fixed 15cm from the exposed forearm for 20 minutes with the light source at full intensity. There was no immediate reaction. Following a few hours uneventful observation the patient was allowed home. Telephone follow up the next day confirmed no delayed phototoxicity. Surgery was thus scheduled.
General anaesthesia was achieved with agents previously used safely in EPP (7,8). Laparoscopy revealed a thickened gallbladder with stones impacted in Hartmann’s pouch. The liver parenchyma was macroscopically normal. Dissection was complicated by an atypical waisted gallbladder, but exposure to the light source remained just 32 minutes.
The excised gallbladder contained 5 large pigment stones (fig 1).
Excised and opened gallbladder
Following an uneventful few hours on the ward, the patient was discharged and suffered no adverse events subsequently. In clinic 11 days later she was in good health and her scars were healing well.
DISCUSSION
High intensity operating lights are hazardous in EPP. One report describes severe 2nd degree burns to the abdominal wall after liver transplantation, later followed by wound dehiscence. The same case was further complicated by biliary fistulation leading to peritonitis, and duodenal ulceration requiring endoscopic adrenaline injection (5). A second report details a liver transplant complicated by phototoxic skin necrosis and multiple intestinal perforations (6).
Recent reports(1,7) describe complication-free aortic valve replacements and ventricular septal defect closures using yellow acrylate filters over theatre lights to eliminate wavelengths below 530nm. However, we are unaware of any reports on the effects of laparoscopic light sources on abdominal viscera.
Although the potential for internal phototoxicity from laparoscopy has not been formally evaluated, we felt that a trial of its cutaneous effects provided valid reassurance when considering a short procedure. As the main theatre lights were only utilised for a short time during peritoneal cannulation and port site closure, we did not use filters, although this is mandatory for longer exposure periods. Elimination of wavelengths below 530nm (the blue part of the spectrum) has raised safety concerns, as labels and monitors could feasibly be misread. However, no such incidents have been reported.
We used vecuronium, propofol, fentanyl and midazolam for anaesthesia, which have been reported as safe in porphyria (7,8). Other drugs are associated with porphyric crises, probably due to decreasing haem levels causing increased synthetic activity. These include common drugs such as diazepam, ketamine, pancuronium, thiopentone, enflurane and etomodate.
Although irrelevant in this case, if there is the potential for significant blood loss, circulating haemoglobin levels should be rigidly maintained with transfusions, avoiding the risk of intra-operative stimulation of haem synthesis precipitating a porphyric crisis (1).
Employing a simple strategy to evaluate the cutaneous reaction of an EPP patient to the laparoscopic light source gave maximal reassurance that laparoscopic cholecystectomy would not provoke intra-peritoneal complications. Our approach was appropriate when considering a short procedure, given the potential for disaster with expectant management. However, further research is necessary to validate the use of laparoscopy in EPP patients for longer or more complex procedures.
