Obstruction differential diagnosis

Bile salt deficiency must also be directly studied. It may occur in the absence of obstruction or obvious liver disease (R7). The majority of patients with one form or another of the sprue syndrome will be found to have pancreatic enzymes and bile salts within the normal range. Pancreatic enzymes are absent or markedly deficient in patients with pancreatogenous malabsorption syndrome (B17, F13). It is surprising how frequently this necessary step in differential diagnosis is omitted. 

The presence of LP-X in the plasma of patients with liver disease has been considered as a sensitive indicator of biliary obstruction and, thus, useful in the differential diagnosis of diseases of the liver (S29, Wl). However, the recent demonstration (see Section 8.2) that particles resembling LP-X occur also in the plasma of patients with LCAT deficiency poses serious reservations regarding the specificity of the proposed test. 

A severe cholestatic syndrome (H. Ballard et al., 1961) can be observed in patients suffering from alcoholic fatty liver, (s. fig. 28.16) The clinical picture may correspond to that of obstructive jaundice and cause great problems in differential diagnosis, particularly because such patients may not have been known before to be suffering from alcohol-induced liver disease. Extremely severe forms to the point of acute liver failure have been observed. 

The development of a bedside assay for plasma BNP has focused considerable attention on the use of BNP as an aid in the diagnosis of suspected heart failure. Plasma BNP concentration is positively correlated with the degree of left ventricular dysfunction and heart failure, and this assay is now used frequently in acute care settings to assist in the differential diagnosis of dyspnea [heart failure versus asthma, chronic obstructive pulmonary disease (COPD), or infection]. Recent studies found that an elevated BNP concentration is an independent predictor of heart failure as the cause of dyspnea and that in patients with decompensated heart failure, an elevated pre-hospital discharge BNP concentration is associated with an increased risk of death or readmission. Additional research is ongoing to better characterize the role of BNP measurement in the diagnosis and treatment of heart failure. 

In normal, healthy subjects, the fasting level of serum bile acids is low imd is less than 5 p,mol/liter. This level is greatly increased in various hepatobiliary diseases (A9, B6, F2, F3, P9, S34, Til). For example, some liver diseases and their reported range of fasting serum bile acid concentrations (in brackets) are liver cirrhosis (5-100 pmol/liter), viral hepatitis (78—405 p,mol/liter), and extrahepatic biliary obstruction (5-230 p,mol/liter) (P9). An elevated serum bile acid concentration is highly specific for liver disease, but there is no specificity as to the type of liver disease. Determination of the profile of individual bile acids and calculations such as the cholic to che-nodeoxycholic acid ratio have been proposed as useful in the differential diagnosis of liver disease (P9). In practice, however, there is too much overlap between diseases, so that the pattern of serum bile acids does not normally provide useful diagnostic information. 

Enzymatic estimations are only moderately helpful in distinguishing the various hepatic disorders from each other. The belief that high serum alkaline phosphatase activities are indicative of biliary obstruction while normal or only moderately elevated activities occur in association with hepatocellular damage is now known to be an oversimplification. There is considerable overlap between values in obstructive and nonobstructive hepatic disease (Fig. 10), so that serum alkaline phosphatase elevation or nonelevation in the differential diagnosis of hepatobiliary disease is useful only in a statistical sense (H14). 

Attempts have been made to allow for the effect of biliary obstruction by the use of a correction factor based on the 1-minute serum bilirubin concentration as a measure of the degree of obstruction (Z3). However BSP retention values corrected in this way were foimd to be less valuable in the differential diagnosis of jaundice than the results of the cephalin flocculation test or the thymol turbidity test (M21). 

Assessment of pulmonary ventilation in patients with chronic obstructive lung disease, and for the differential diagnosis of acute pulmonary embolism in combination with lung perfusion scintigraphy... 

AGE inhibitors such as captopril may facilitate the differential diagnosis of renovascular hypertension diuretics such as fiirosemide (Lasix) cause rapid washout of the radiotracer or demonstrate urinary tract obstruction (Kletter 1988). 

For practical purposes, the differential diagnosis of low intestinal obstruction in the neonate consists of five conditions. Two conditions involve the distal ileum and include ileal atresia and meconium ileus, and three involve the colon, which are colonic atresia, Hirschsprung s disease, and functional immaturity of the colon that includes meconium plug... 

Meiser G, Meissner K (1985) Sonographic differential diagnosis of intestinal obstruction results of a prospective study of 48 patients. Ultraschall Med 6 39-45... 

The patient with acute intermittent porphyria suffers a severe acute abdominal pain not definitely localized and without rigidity or tenderness of the abdominal wall. Moderate fever and leukocytosis develop. If the physician is not aware of the porphyria, he is likely to be confused and suspect appendicitis, renal or biliary colics, pancreatitis, perforated ulcer, acute bowel obstruction or another common cause of abdominal pain. The differential diagnosis of porphyria and bowel obstruction is further complicated because the attacks of porphyria hepatica are often associated with severe constipation. Abdominal X-rays of porphyric patients show colonic distension. The pathogenesis of the abdominal symptoms is not known. They could result either from a direct effect of porphobilinogen or porphyrin on the intestinal mucosa or be the consequence of an increased excitability of the autonomic system. 

Chung MH, Edinburgh KJ, Webb EM, et al. Mixed infiltrative and obstructive disease on high-resolution CT differential diagnosis and functional correlates in a consecutive series. J Thorac Imaging 2001 16(2) 69-75. 

Differential diagnosis of UPJ obstruction should include multicystic dysplastic kidney (MDK), infundibular stenosis, and UVJ obstruction. This differential diagnosis is easy in most cases. In IVIDK, no... 

The clinical presentation is completely different in older children. The main complaint is usually dys-uria or infection (Fig. 6.6). Megacystis and thickening of the bladder wall are less frequent. Kidneys are usually normal, as is renal function. The differential diagnosis should include the other causes of bladder outlet obstruction (see below) and functional disorders such as dysfunctional voiding with severe bladder-sphincter dyscoordination. Both VCU and urodynamic studies can be diagnostic (Fig. 6.7). In case of valves, there is reduced urinary flow with no reinforcement of the perineal electric activity. 

The association of ultrasound, VCU and cystoscopy helps establish a proper differential diagnosis among the causes of congenital or acquired bladder outlet obstruction. 

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