Metabolic and Nutritional Issues after Lower Digestive Tract Surgery: The Important Role of the Dietitian in a Multidisciplinary Setting

Many patients undergo small bowel and colon surgery for reasons related to malignancy, inflammatory bowel disease (IBD), mesenteric ischemia, and other benign conditions, including post-operative adhesions, hernias, trauma, volvulus, or diverticula. Some patients arrive in the operating theatre severely malnourished due to an underlying disease, while others develop complications (e.g., anastomotic leaks, abscesses, or strictures) that induce a systemic inflammatory response that can increase their energy and protein requirements. Finally, anatomical and functional changes resulting from surgery can affect either nutritional status due to malabsorption or nutritional support (NS) pathways. The dietitian providing NS to these patients needs to understand the pathophysiology underlying these sequelae and collaborate with other professionals, including surgeons, internists, nurses, and pharmacists. The aim of this review is to provide an overview of the nutritional and metabolic consequences of different types of lower gastrointestinal surgery and the role of the dietitian in providing comprehensive patient care. This article reviews the effects of small bowel resection on macronutrient and micronutrient absorption, the effects of colectomies (e.g., ileocolectomy, low anterior resection, abdominoperineal resection, and proctocolectomy) that require special dietary considerations, nutritional considerations specific to ostomized patients, and clinical practice guidelines for caregivers of patients who have undergone a surgery for local and systemic complications of IBD. Finally, we highlight the valuable contribution of the dietitian in the challenging management of short bowel syndrome and intestinal failure.

Recurrent Encephalopathy and Severe Anion Gap Metabolic Acidosis in a Patient with Short Bowel: It Is D-Lactic Acidosis

D-lactic acidosis is a rare and potentially underrecognized condition in patients with short bowel syndrome. We present the case of a 61-year-old female with a history of an ileojejunal bypass at age 18 who presented to hospital with acute-onset encephalopathy, ataxia, and severe anion gap metabolic acidosis (AGMA). On initial investigations there were no identifiable etiologies for the AGMA. Further history revealed that she had been experiencing these symptoms on a recurrent basis for the past 40 years. An oral carbohydrate load was given to the patient in hospital which reproduced her symptoms and the AGMA. A serum D-lactate level returned elevated several weeks later. A 2-month follow-up revealed that all her symptoms had ceased with limitation of carbohydrates to 150 g per day. Patients with short bowel syndrome are susceptible to developing D-lactic acidosis due to the large carbohydrate loads that are delivered to the colon, where they are then metabolized. Due to its rarity, it is likely that there is a delay in recognition of this condition. This case report describes a common clinical presentation of this rare condition and describes the pathophysiology, diagnosis, and management of D-lactic acidosis in small bowel syndrome.

D-lactic acidosis - a rare complication of short bowel syndrome

D-lactic acidosis represents a rare form of metabolic acidosis that occurs most commonly in patients with short bowel syndrome. This is a serious, sometimes life-threatening complication. The cause is the accumulation of D-lactate in the body, which is formed in excessive amounts by fermentation of unabsorbed carbohydrates by the intestinal microbiota. The nervous system is predominantly affected, which also results in clinical manifestations. The clinical picture is dominated by a wide range of non-specific neurological symptoms. The disease can sometimes manifest as somnolence to coma. From the aspect of laboratory diagnostics, the disease is characterized by severe metabolic acidosis with an increased anion gap. In this case report, we present a unique case of a 54-year-old woman with Crohns disease and short bowel syndrome who in a short time was repeatedly hospitalized for recurrence of severe metabolic acidosis with severe impaired consciousness. Based on the evaluation of anamnestic data, clinical picture and laboratory tests, the patient was diagnosed with D-lactic acidosis. In the discussion we discuss the individual steps that led to this diagnosis and compare our experience with data in the world literature.

High anion gap metabolic acidosis caused by D-lactate: mind the time of blood collection

Introduction

D-lactic acidosis is an uncommon cause of high anion gap acidosis.

Materials and methods

A 35-year old woman was admitted to the emergency room with somnolence, drowsiness, dizziness, incoherent speech and drunk appearance. Her past medical history included a Roux-en-Y bypass. Point-of-care venous blood analysis revealed a high anion gap acidosis. Based on the clinical presentation, routine laboratory results and negative toxicology screening, D-lactate and 5-oxoprolinuria were considered as the most likely causes of the high anion gap acidosis. Urine organic acid analysis revealed increased lactate, but no 5-oxoproline. Plasma D-lactate was < 1.0 mmol/L and could not confirm D-lactic acidosis.

What happened

Further investigation revealed that the blood sample for D-lactate was drawn 12 hours after admission, which might explain the false-negative result. Data regarding the half-life of D-lactate are, however, scarce. During a second admission, one month later, D-lactic acidosis could be confirmed with an anion gap of 40.7 mmol/L and a D-lactate of 21.0 mmol/L measured in a sample collected at the time of admission.

Main lesson

The time of blood collection is of utmost importance to establish the diagnosis of D-lactic acidosis due to the fast clearance of D-lactate in the human body.

D-lactic acidosis in humans: review of update

D-Lactic acidosis has been well documented in ruminants. In humans, D-lactic acidosis is very rare, but D-lactic acidosis may be more common than generally believed and should be looked for in a case of metabolic acidosis in which the cause of acidosis is not apparent. The clinical presentation of D-lactic acidosis is characterized by episodes of encephalopathy and metabolic acidosis. The entity should be considered as a diagnosis in a patient who presents with metabolic acidosis accompanied by high anion gap, normal lactate level, negative Acetest, history of short bowel syndrome or malabsorption, and characteristic neurologic manifestations. Low carbohydrate diet, bicarbonate treatment, rehydration, and oral antibiotics would be helpful in controlling symptoms.