Precision in nutritional diagnoses.
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Biomedical subjects
Publications and source records attributed to R M Craig.
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The significance of the human immunodeficiency virus (HIV) in the small intestinal lamina propria in patients with the acquired immune deficiency syndrome or conditions related to that syndrome who have chronic diarrhea and malabsorption is unclear. To investigate this issue, upper endoscopy (after a 12- to 16-hour fast) with duodenal biopsy and aspirate was performed in 20 HIV-infected seropositive homosexual men referred for diarrhea of more than 8 weeks duration (Group 2) and in 9 HIV-infected homosexual men referred for dysphagia or dyspepsia with no symptoms of malabsorption (Group 1). All biopsy specimens were examined by light microscopy and immunochemical staining with monoclonal antibody against HIV glycoprotein gp41. Electron microscopy was performed in 18 patients in Group 2 and in all patients in Group 1. Immunogold electron microscopy was used as a confirmatory test for identified HIV particles. In addition, D-xylose absorption was measured in all patients after a 25-g dose of D-xylose with measurement of serum D-xylose concentration 1 hour after the dose and measurement of 5-hour urinary D-xylose excretion. Mean serum D-xylose was 35.4 +/- 4.5 mg/dL in Group 1 and 15.8 +/- 2.3 mg/dL in Group 2 (P less than 0.001), whereas mean urine D-xylose was 5.5 +/- 0.6 g in Group 1 and 2.0 +/- 0.4 g in Group 2 (P less than 0.001). Immunoperoxidase for gp41 was positive in 5 (56%) patients in Group 1 and in 12 (60%) patients in Group 2. Lamina propria HIV viral particles were identified by electron microscopy in both patient groups. Viral particles were seen within and adjacent to the cytoplasm of mononuclear cells and were not present in enterocytes or neuroendocrine cells. There were no significant differences in serum or urine D-xylose tests between patients with and without lamina propria HIV. In addition, lipid accumulation in intercellular spaces near the basolateral membrane of adjacent enterocytes was seen in 33% of patients with chronic diarrhea. These findings suggest that lamina propria HIV is not a direct cause of enteropathy in HIV-infected patients and that lymphatic obstruction may be one pathophysiologic mechanism producing this malabsorptive state.
The AIDS wasting syndrome (AWS) is characterized by > 10% loss of baseline body weight during 6 months and may occur in patients with or without associated chronic diarrhea. To determine whether the presence of small-intestinal malabsorption is associated with the development of AWS in human immunodeficiency virus (HIV)-infected patients with chronic diarrhea, we retrospectively reviewed the results of D-xylose testing performed in the clinical evaluation of 21 consecutive HIV-infected patients with chronic diarrhea. A thorough search for small-intestinal pathogens was performed including upper endoscopy, duodenal biopsy, and aspirate for culture and ova and parasite examination. These studies were negative in all patients except two who were excluded from the study. In the 19 patients with no identifiable pathogens, the 1-h serum D-xylose concentration was significantly lower in patients with AWS than in those without, 8.3 +/- 0.8 versus 23.7 +/- 3.4 mg/dl, respectively, p < 0.001. Urine D-xylose excretion during 5 h was also significantly lower in the group with AWS, although creatinine clearance was similar in the two groups. Patients with AWS were more often refractory to standard antidiarrheal therapy with loperamide or diphenoxylate and carried a poor prognosis (90% mortality at 1 year versus 22% mortality in the group without AWS). These data indicate that small intestinal malabsorption is a major component in the severe wasting seen in some HIV-infected patients with chronic diarrhea. Patients with markedly abnormal D-xylose tests may require more potent antidiarrheal therapy and are expected to have a high mortality as a possible consequence of intestinal dysfunction.
It is well known that Crohn's disease can involve the duodenum, but isolated secondary complications such as pancreatitis or common bile duct obstruction have only rarely been reported, and never in the same patient. Herein, we describe a patient with duodenal Crohn's disease and both pancreatitis and calculous common bile obstruction. This unusual constellation of findings was managed with percutaneous techniques in which transhepatic catheterization of the bile duct permitted balloon dilatation of the ampulla of Vater, as well as a duodenal stricture. These maneuvers resulted in passage of the biliary stone and relief of the patient's symptoms. The management of this patient may serve as a guide possibly to delay or even prevent surgical intervention in similar cases of benign enteric strictures.
D-Xylose absorption was studied in 12 patients with acquired immunodeficiency syndrome (AIDS) or advanced AIDS-related complex who had had diarrhea for more than 8 weeks, averaged an 11% (range, 3% to 21%) body weight loss during the previous 6 months, and had had negative stool examinations for enteric pathogens. Patients were evaluated by duodenal aspiration and biopsy and received both 25 gm oral and 10 gm intravenous doses of D-xylose. Kinetic analysis of D-xylose absorption was characterized by an absorption rate constant (ka) and a rate constant (ko) reflecting nonabsorptive loss. Extent of D-xylose absorption averaged 18.4% +/- 9.3% (+/- SD) in the 12 patients (normal greater than 60%). Percentage of weight loss during the previous 6 months was negatively correlated with ka (r = -0.69; p = 0.018) in the 11 patients in whom this parameter was reduced but was not correlated with either ko or extent of D-xylose absorption. In these patients with human immunodeficiency virus enteropathy, ka was reduced out of proportion to the minor histologic changes present in the duodenal biopsy specimens.
Evaluation of nutritional needs in patients with swallowing disorders should include a global assessment. This includes a nutritional assessment, a determination of the metabolic state, and a separation of the causes of nutrient deficits due to the patient's underlying disease(s) from diminished nutrient intake related to the dysphagia. Techniques for intense nutritional support are surveyed, and the complications of each are discussed.
Although theoretically the spectrum of antimicrobial quinolone antibiotics are at low risk of producing Clostridium difficile overgrowth and diarrhea, a patient developed this clinical problem while receiving norfloxacin. We review the antimicrobial activity of the quinolone antibiotics, with respect to their predisposition for producing C. difficile-induced diarrhea.
Carcinoma of the gingiva is a significant risk to patients because the asymptomatic characteristics of erythroplastic lesions are not always readily identified. This case report shows the similarity in clinical appearance of squamous cell carcinoma of the gingiva to the common inflammatory changes associated with periodontal disease. A similar clinical presentation might be seen in any lesion with increased vascularity, including Kaposi's sarcoma associated with human immunodeficiency virus infection. Any erythroplastic change involving the oral mucosa should be viewed with suspicion and, if not resolved after removal of local sources of irritation, must be biopsied to establish a definitive diagnosis.
We describe two patients with Crohn's disease, secretory diarrhea, and concurrent giardiasis. As we review the pathophysiology of secretory diarrhea in Crohn's disease, we suggest that secretory diarrhea in Crohn's disease may be more common than has been believed.
A patient with a lymphangioma involving the labial commissure is reported. Key features of this disorder include its occurrence in young patients, asymptomatic nature, compressibility, and slow growth. Clinicians should understand that the lymphangioma may appear as a soft, grayish-blue, dome-shaped nodule, an irregular and papillary vesicular mass, or as a diffuse swelling. Appropriate clinical and radiographic tests are recommended before surgical excision. Histologically, the features of the lymphangioma may closely resemble those of a hemangioma.
The use of peroral small bowel biopsies has been shown to be a safe and effective procedure, useful in the diagnostic evaluation of malabsorption and other intestinal pathology. This report describes a young man who aspirated a small bowel biopsy capsule as part of an investigation of malabsorption. Forty-eight hours after this episode, he developed pneumonia. In this context, the literature of complications from small bowel biopsies is reviewed.
The efficacy of D-xylose testing in clinical situations has been reviewed in the light of recent kinetic studies. The standard 25-g D-xylose test in adults, based on analysis of 5-h urine collection and a 1-h serum sample, discriminates between normal subjects and patients with proximal small intestinal malabsorption with greater than 95% specificity and sensitivity. The 1-h serum level measured after administering this dose is also useful in evaluating malabsorption in patients with intermediate degrees of renal insufficiency and in the elderly. The 1-h serum test after administration of 5 g of D-xylose should be used in pediatrics and is greater than 91% sensitive and close to 100% specific. The [14C]D-xylose breath test with 1 g of D-xylose has been useful in identifying malabsorption caused by bacterial overgrowth in the small intestine.
A patient with white sponge nevus involving the buccal mucosa, labial mucosa, and soft palate is reported. The salient clinical and histological features of the disease were discussed. This diagnosis should be considered when bilateral white lesions of buccal mucosa are encountered. Early onset, a familial history, and the asymptomatic nature are key features to the disease. If historical data and clinical features are suspect, an incisional biopsy is adequate for diagnosis.
D-Xylose kinetics were studied after administering 25 gm oral and 10 gm intravenous doses to six normal subjects and to 12 patients who were being evaluated for the presence of intestinal malabsorption. D-Xylose absorption was characterized by an absorption rate constant (ka) and a rate constant reflecting nonabsorptive removal of D-xylose from the small bowel (ko). In normal subjects, mean ka was 0.915 +/- 0.228/hr (+/- SD), and the extent of oral D-xylose absorption averaged 81.0% +/- 11.6%. In seven of the 12 patients, D-xylose absorption was less than 60% complete. In four of them, ka was below the normal limit of 0.367/hr and was consistent with a primary defect in intestinal D-xylose absorption. Two patients with low ka values and the remaining three patients with less than 60% D-xylose absorption had ko values exceeding 0.650/hr, suggesting that excessive nonabsorptive loss contributed to low D-xylose bioavailability. We found that standard tests may identify some patients as having primary defects in D-xylose absorption rate or nonabsorptive loss and propose that breath H2 concentration measurements may also help distinguish between bacterial overgrowth and rapid intestinal transit as causes of excessive nonabsorptive loss.
D-Xylose kinetics were studied after oral and intravenous administration to 10 patients with impaired renal function, three of whom were being evaluated for intestinal malabsorption. The 0.32 +/- 0.06 L/kg (mean +/- SD) distribution volume of D-xylose in patients with uncomplicated renal impairment was larger than the value of 0.23 +/- 0.04 L/kg that we reported previously for normal subjects (P less than 0.01). Renal clearance was also reduced, averaging 87% of glomerular filtration rate estimated from creatinine clearance, so that the elimination-phase half-life was prolonged to 138 +/- 39 minutes from 75 +/- 11 minutes in normal individuals (P less than 0.01). The 25 gm oral D-xylose dose was 77.4% +/- 14.8% absorbed in the patients with uncomplicated renal impairment, similar to the 69.4% +/- 13.6% absorption reported in normal individuals. However, the absorption half-life was prolonged from 31 +/- 12 minutes in normal subjects to a value of 62 +/- 23 minutes (P less than 0.02). Of the usual clinical indexes of D-xylose absorption, the serum concentration measured 1 hour after the oral dose was best correlated with the extent of D-xylose absorption (r = 0.76; P less than 0.01), and the standard lower normal limit of 0.2 mg/ml was satisfactory.
A cellular blue nevus located on the palate of a 72-year-old female is reported. This intraoral finding is uncommon and should be distinguished from clinical entities it closely resembles. Practitioners should be aware that a pigmented palatal lesion in fact may be a malignant melanoma. Surgical excision with microscopic examination is the only means by which an accurate diagnosis can be made.
The lingual cortical mandibular defect is easily diagnosed radiographically. The key features include: a well-defined radiolucent area, location below the mandibular canal, and placement anterior to the angle of the mandible. Routine surgical exploration is not indicated, but sialography or radiographic follow-up may be useful.