The present report concerns a case of unusually late presentation of lactobezoar, or inspissated milk curd obstruction, leading to necrotising enterocolitis (NEC) in an extremely low birthweight (ELBW) boy infant, born at 26 weeks gestation with a birth weight of 750 g. He deteriorated acutely on day 84 of postnatal age (corrected age 38 weeks) needing intermittent positive pressure ventilation (IPPV). Over the next 3 days he developed signs of NEC, though a radiograph showed no diagnostic features. In view of increasing abdominal distension, silent abdomen and increasing ventilatory requirements, an emergency exploratory laparotomy was performed. The laparotomy revealed inspissated milk curd obstruction in the terminal ileum. There was also a small area of NEC at the ileocaecal valve. A limited hemicolectomy was performed with creation of an ileostomy and mucous fistula. Following this procedure his clinical status improved. Feeds were reintroduced after 7 days and he was on full enteral feeds by 14 days.
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Lactobezoar, or milk curd obstruction, is a well recognised although relatively rare gastrointestinal complication in extremely low birthweight (ELBW) infants. This case is important for two reasons, outlined below.
Firstly, lactobezoar normally occurs in the first few weeks of life. Reports in the literature suggest that the peak incidence of lactobezoar in infants occurs between 4 to 10 days of age, with the latest presentation being reported at 7 weeks of life.1,2 Our infant presented at 12 weeks of life, which demonstrates that in sick ELBW infants lactobezoar formation could present later than usual and hence there is a need for continued surveillance.
Secondly, although the association between lactobezoar and gastric perforation is well recognised, the coexistence of inspissated milk curd obstruction and necrotising enterocolitis (NEC) is extremely rare. To our knowledge there is only one case report in the literature of a gastric lactobezoar in association with extensive NEC,3 and either pathology could have occurred first. However, in our case as there was a long segment of terminal ileum obstructed with milk curd and a small patch of NEC at the ileocaecal valve, its seems more likely that formation of the lactobezoar must have occurred first, causing ischaemia of the bowel segment and probably leading to NEC.
A boy infant was born at 26+2 weeks gestation by caesarean section because of pregnancy-induced hypertension, oligohydramnios and absent and reversed end diastolic flow in umbilical arteries. He was born in a reasonable condition with Apgar scores of 5 at 1 min and 8 at 5 min. His stay in the neonatal unit was complicated with pulmonary haemorrhage and severe chronic lung disease, grade 3 intraventricular haemorrhage with arrested hydrocephalus, patent ductus arteriosus and a thrombus on the triscupid valve leading to subacute bacterial endocarditis (blood cultures positive for Klebsiella), conjugated hyperbilirubenaemia (secondary to prolonged parenteral nutrition) and persistent thrombocytopoenia (secondary to the thrombus). He was successfully extubated on the 67th day of life with a short course of dexamethasone. For the next 2 weeks he remained stable on nasal continuous positive airway pressure (CPAP) and continued on intravenous cefotaxime as treatment for his infective endocarditis.
On the 84th day of life he deteriorated with worsening abdominal distension, and needed reventilation. An abdominal x ray (AXR) showed dilated bowel loops but no diagnostic features of either NEC or obstruction. For the next 4 days his serial C-reactive protein levels (CRP) remained normal, blood culture remained sterile, and bowels were opening with active bowel sounds. On day 89, his CRP rose, his platelet count dropped, his serum sodium dropped and his lactate rose to 4 mmol/litre. His abdomen became rigid with absent bowel sounds and he passed a small amount of blood per rectum. Repeat AXR now showed featureless, dilated, fixed loops of small bowel in the right iliac fossa with peritoneal fluid. His ventilation deteriorated. A clinical diagnosis of NEC was made, his feeds were stopped, he was given triple antibiotics and a surgical referral was made. Following surgical review, an exploratory laparatomy was performed that showed inspissated milk curd obstruction of the terminal ileum with a small patch of NEC at the region of the ileocaecal valve.
After birth he was initially on parenteral nutrition. Enteral feeds (human milk) were started on the fourth day of life and were slowly increased. He was tolerating full enteral feeds by day 12. In view of poor weight gain he was given medium-chain triglyceride (MCT) supplementation from the 14th day of life onwards and mostly remained on it until a few days prior to surgery. Throughout this period he was either on fortified human milk (osmolality =371 mOsm/kg H2O) or preterm formula (a whey protein-dominant preterm formula (whey:casein ratio =1:1.5, osmolality =370 mOsm/kg H2O)) with MCT (giving 80 kcal/100 ml). Due to his latest episode of abdominal distension, 3 weeks prior to surgery his feeds were changed to full peptijunior (hydrolysed whey protein, osmolality =210 mOsm/kgH2O) but with no improvement.
In summary this was a high risk ELBW infant who received high calorie milk, human milk fortifier and MCT from early in his life, developing lactobezoar and NEC at 12 weeks of age.
Histopathology report of the resected necrotic bowel confirmed NEC and showed normal ganglion cells.
Molecular genetics studies for cystic fibrosis mutations were negative. The mutations tested account for 85% to 90% of cystic fibrosis mutations in British Caucasians.
An exploratory laparatomy was performed that showed inspissated milk curd obstruction of the terminal ileum with a small patch of NEC at the ileocaecal valve (fig 1). The bowel was eviscerated, evacuated and a limited hemicolectomy was performed with formation of ileostomy and mucous fistula.
OUTCOME AND FOLLOW-UP
Following this procedure, the baby was kept on intravenous antibiotics and nil orally for 7 days. He was also given parenteral nutrition. On his eighth postoperative day he was started on trophic feeds that were gradually increased over the next few days. He was on full enteral feeds by day 14 postoperatively. Although he had no further postoperative concerns, he died on day 142 of life due to respiratory failure from severe chronic lung disease.
Occurrence of lactobezoar is a rare but a well recognised cause of gastrointestinal obstruction in premature infants. This syndrome was first described by Wolf and Bruce in 1959.1 According to the report of Lohn et al, there were 43 cases of lactobezoars reported up to 1980 but only 2 cases in the next 2 decades.2 Since 2000 we have been aware of a few more case reports of this syndrome. The occurrence of milk curd obstruction in infants has never been described beyond 7 weeks of age.1,2 However, as with our case, lactobezoar formation can present as late as 12 weeks and hence there is a need for continued surveillance.
Although lactobezoars have been reported as a cause of spontaneous perforations, to the best of our knowledge it has never been reported as a cause of NEC. There has been only one case report showing coexistence of a gastric lactobezoar and extensive NEC, where the authors concluded that either pathology could have occurred first.3 On analysing our case and the intraoperative findings it seems more likely to assume that formation of the lactobezoar in the terminal ileum was a chronic process giving a non-specific chronic abdominal distension eventually leading to ischaemia and NEC at the ileocaecal valve, hence explaining the sudden acute deterioration.
The pathogenesis of milk curd obstruction seems to be multifactorial, with various predisposing factors reported in literature. The main factors implicated seem to be prematurity, low birthweight, early use of concentrated formula feeds high in calories and protein, addition of medium-chain or long-chain triglycerides, premature gastrointestinal physiology such as gastric emptying time and gastric acidity.4,5 There was inconclusive evidence that addition of medium-chain triglyceride supplementation affects gastric emptying time in premature infants.6 In the earlier reports, the majority of cases were reported in infants receiving formula feeds with a high casein/whey ratio and casein was implicated as the major contributing factor in development of the lactobezoar.4 More recently, cases have been reported in infants on human milk as well as on whey-dominant formulas. A literature review published in 2001 concluded that lactobezoar are not isolated to preterm infants on calorie dense formula, and suggested that bezoar formation may be more common than previously thought and a high index of suspicion could help avoid costly evaluations for obstructive symptoms.5 The possible risk factors in our patient were prematurity, low birthweight, early use of medium-chain triglyceride and the various high-calorie interventions. Interestingly, unlike most reports our baby was fed with human milk or whey-predominant formula.
Symptoms of this syndrome include abdominal distention, emesis, increased gastric residuals, abdominal mass, bloody stools and mimicry of NEC.1,2 Radiography is often diagnostic, showing an opalescent mass with air fluid levels, but can be normal as well.7 Barium studies and ultrasound have both been used to detect lactobezoars.1,8 In our patient, serial abdominal radiographs remained essentially normal until development of NEC, when dilated featureless fixed bowel loops could be seen. Ultrasound may have been helpful to diagnose lactobezoar earlier and perhaps prevent the occurrence of NEC in our case.
Occurrence of lactobezoar in extremely low birthweight (ELBW) infants can occur as late as 12 weeks of age.
Chronic unusual abdominal distension can be a sign of a lactobezoar, and abdominal radiograph alone may not be helpful to rule out the diagnosis.
Although high calorific milk and additives such as medium-chain triglycerides is often used to combat growth failure, its use might be associated with formation of lactobezoar. Hence the need for a high index of suspicion and continued surveillance in such infants.
If not diagnosed early, lactobezoar can lead to more serious pathology such as NEC or perforation.
Competing interests: None.
Patient consent: Patient/guardian consent was obtained for publication.
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