Laboratory support of the clinical nutrition service

British Intestinal Failure Alliance (BIFA) guidance - haematological and biochemical monitoring of adult patients receiving home parenteral nutrition

Home parenteral nutrition (HPN) is necessary for patients with prolonged intestinal failure which can be secondary to a variety of pathophysiological mechanisms or surgical resection. HPN is needed to supply micronutrients, macronutrients and water to reduce morbidity and mortality and to maximise the patient's quality of life. HPN requires close monitoring by a dedicated multidisciplinary team and is vital to minimise complications; both catheter related and metabolic. A regular comprehensive review is required including history, examination including anthropometry and blood testing. The focus of this review is on the monitoring of haematological and biochemical parameters. There is a paucity of evidence-based literature on the biochemical monitoring of HPN and existing guidance is sourced mostly on expert opinion and lower grade studies. Sources offering guidance on the frequency of biochemical monitoring for the stable adult HPN patient are the British Association for Parenteral and Enteral Nutrition, the European Society for Parenteral and Enteral Nutrition, the National Institute for Health and Care Excellence and the Australasian Society of Parenteral and Enteral Nutrition (AuSPEN). The aim of this work is to review and collate this existing guidance into one clear and concise review. It is recommended that biochemical parameters are checked at baseline, thereafter more frequently if concerns arise and less frequently when the patient's condition is stable, as assessed by the multidisciplinary team with expertise in HPN.

Mundane, yet challenging: the assessment of malnutrition in inflammatory bowel disease

Protein-energy malnutrition (PEM) is defined as a "state of nutrition in which a deficiency or excess (or imbalance) of energy, protein, and other nutrients causes measurable adverse effects on tissue/body form (body shape, size and composition) and function, and clinical outcome". Although this definition resulted from a long discussion among experts, it lacks concise assessment criteria. Essential to an effective practice of nutrition support, however, is the ability to identify who actually needs medical nutrition therapy. Patients with active inflammatory bowel disease (IBD) are a high risk group for protein-energy malnutrition, with a prevalence ranging up to 75%.

Clinical indications for plasma protein assays: transthyretin (prealbumin) in inflammation and malnutrition

A large number of circumstances are associated with reduced serum concentrations of transthyretin (TTR), or prealbumin. The most common of these is the acute phase response, which may be due to inflammation, malignancy, trauma, or many other disorders. Some studies have shown a decrease in hospital stay with nutritional therapy based on TTR concentrations, but many recent studies have shown that concentrations of albumin, transferrin, and transthyretin correlate with severity of the underlying disease rather than with anthropometric indicators of hypo- or malnutrition. There are few if any conditions in which the concentration of this protein by itself is more helpful in diagnosis, prognosis, or follow up than are other clinical findings. In the majority of cases, the serum concentration of C-reactive protein is adequate for detection and monitoring of acute phase responses and for prognosis. Although over diagnosis and treatment of presumed protein energy malnutrition is probably not detrimental to most patients, the failure to detect other causes of decreased concentrations (such as serious bacterial infections or malignancy) of the so-called visceral or hepatic proteins could possibly result in increased morbidity or even mortality. In addition to these caveats, assays for TTR have a relatively high level of uncertainty ("imprecision"). Clinical evaluation--history and physical examination--should remain the mainstay of nutritional assessment.

Considerations in the Difficult-to-Manage Urea Cycle Disorder Patient

Today, patients with urea cycle disorder (UCD) may survive well beyond infancy. The goal of keeping them in consistent nitrogen balance can be undermined by changing metabolic needs throughout various stages of life, resulting in hyperammonemia in the short term, and poor growth and development in the long term. The specific UCD genotype can affect the risk of metabolic destabilization and management difficulties, as can variable protein tolerance secondary to changing growth demands, biochemical complications, and environmental influences. Preventing catabolic stress is as important as controlling dietary protein intake for avoiding metabolic decompensation. Optimal treatment, specifically pharmacologic therapy, possible branched chain amino acid (BCAA) supplementation, accurate laboratory monitoring, and psychosocial support, requires thorough understanding and careful application of each component.

Oxidative stress status in patients with diabetes mellitus: relationship to diet

OBJECTIVE

To investigate the relationship between dietary intakes and in vivo oxidative stress (OS) status in diabetic patients.

DESIGN

Case-control study.

SETTING

Outpatient-Clinic and Laboratory Endocrinology, University Antwerp.

SUBJECTS AND METHODS

A total of 30 patients (24 type 1 diabetes mellitus (T1DM)/6 type 2 diabetes mellitus (T2DM) were asked to complete a 2 weekdays+1 weekend day food consumption questionnaire during the week preceding their yearly diabetes control consultation, when samples were collected for the assay of oxidative stress (OS) (blood levels of antioxidants, peroxides, malondialdehyde (MDA) and minerals). Blood samples were also collected from 25 age- and sex-matched healthy controls.

RESULTS

Diabetic patients had lower glutathione (5.80+/-1.15 vs 6.75+/-1.03 micromol/g Hb in the controls, P=0.002) and higher MDA (0.687+/-0.212 vs 0.545+/-0.101 micromol/l, P=0.002). Although the group average intakes were within the Belgian RDA, intakes of fat >35% energy, fibre <15 g/1000 kcal, fruit <2 portions and vitamin E <10 mg/day were seen in more than 20 patients. Blood antioxidants did not correlate with intakes of energy, fat, protein or fibres or of their respective antioxidant. Vitamins A and E correlated with serum lipids (r=0.58, P <0.0005 between serum alpha-tocopherol and cholesterol). Blood peroxide levels were only related to intakes of saturated fat and cholesterol (P<0.05). In diabetic subjects but not in controls (P<0.05) MDA was related to glutathione and uric acid.

CONCLUSIONS

In diabetic patients, blood levels of antioxidants are not related to their dietary intakes but to serum lipids. Levels of oxidative damage products are only related to intakes of saturated fats and cholesterol and to levels of endogenous antioxidants.