Estudo e diagnósticos diferenciais em paciente com diarréia crônica

Paciente, sexo F, +/- 30 anos.
1) Paciente com queixa de diarreia associada a cólica intestinal, náusea, vômitos e dor à deglutição há 20 dias. Um episódio de febre não termo metrada com prostração intensa. Episódios de cefaleia foram também relatados. Mudou a água que consumia há 1 mês e associa o quadro com esta mudança.
Exame físico – achados positivos: Paciente com fácies de dor durante a consulta. Dor abdominal difusa à palpação profunda. Ruídos hidroaéreos aumentados. Hiperemia de orofaringe. Linfonodomegalia em cadeia cervical anterior (linfonodos fibroelásticos, menores que 1 cm, móveis e indolores à palpação).
Foi iniciado antibióticoterapia com ciprofloxacino 500 mg devido à suspeita de shigelose (uma vez que o quadro se estendia por mais de 7 dias, descartando uma possível causa viral. Além disso havia história de prostração, diarreia importante (não lembro se havia sangue, muco ou pus nas fezes), cólica intestinal, vômitos, febre e cefaleia, caracterizando um quadro sistêmico debilitante). Além disso, foi prescrito metoclopramida (10mg) para aliviar os sintomas de náusea e vômitos. A paciente foi orientada a manter-se hidratada (diarreia e vômitos levam a desidratação).


Diarrhoea may be defined in terms of stool frequency, consistency, volume, or weight. Patients’ conceptions of diarrhea often focus around stool consistency. Indeed, faecal consistency is determined by the water holding capacity of the stool (that is, the amount of non-bound “free” water) and this perhaps best defines the concept of diarrhoea. However, quantification of this in clinical practice may prove difficult and so other criteria, such as the passage of more than three stools per day or stool weight, provide alternative means of definition. A stool weight of 200 g/day is often regarded as the upper limit of normal but this can be misleading as stool weights vary greatly and “normal” stool volumes can exceed this value, particularly when non-Western diets are encountered.
Conversely, distal colonic pathology may not increase stool weight above 200 g/day. A pragmatic definition incorporates these elements: diarrhea is the abnormal passage of loose or liquid stools more than three times daily and/or a volume of stool greater than 200 g/day.
Further potential for confusion arises from the discrepancy between the medical and “lay” concepts of diarrhea and these need to be clarified at the initial appraisal. Faecal incontinence in particular is commonly misinterpreted as diarrhea while symptoms relating to functional bowel disease can be difficult to distinguish from organic pathology on the basis of history alone. There is no consensus on the duration of symptoms that define chronic as opposed to acute diarrhoea. However, most groups would accept that symptoms persisting for longer than four weeks suggest a non-infectious aetiology and merit further investigation.

Como deve ser feita a investigação de diarreia crônica?
A detailed history is essential in the assessment of patients with chronic diarrhoea. This should attempt (a) to establish the likelihood that the symptoms are organic (as opposed to functional), (b) to distinguish malabsorptive from colonic/inflammatory forms of diarrhoea, and (c) to assess for specific causes of diarrhoea.
Symptoms suggestive of an organic disease include a history of diarrhoea of less than three months’ duration, predominantly nocturnal or continuous (as opposed to intermittent) diarrhoea, and significant weight loss. The absence of these, in conjunction with positive symptoms such as those defined in the Manning or Rome criteria and a normal physical examination, are suggestive of a functional bowel disturbance, but only with a specificity of approximately 52–74%.Unfortunately, these criteria do not reliably exclude inflammatory bowel disease.
Malabsorption is often accompanied by steatorrhoea and the passage of bulky malodorous pale stools. However, milder forms of malabsorption may not result in any reported stool abnormality. Colonic, inflammatory, or secretory forms of diarrhoea typically present with liquid loose stools with blood or mucous discharge. Inspection of the stool may be helpful in distinguishing these two. Specific risk factors, which increase the likelihood of organic diarrhoea or point to potential lines of investigation, should be sought. These include:

(1) Family history. Particularly of neoplastic, inflammatory bowel, or coeliac disease.

(2) Previous surgery. Extensive resections of the ileum and right colon lead to diarrhoea due to lack of absorptive surface and hence fat and carbohydrate malabsorption, decreased transit
time, or malabsorption of bile acids and a smaller bile acid diarrhoea that typically occurs after meals and usually responds to fasting and cholestyramine. Chronic diarrhoea may also occur in up to 10% patients after cholecystectomy through mechanisms that include increased gut transit, bile acid malabsorption, and increased enterohepatic cycling of bile acids.
(3) Previous pancreatic disease
(4) Systemic disease. Thyrotoxicosis and parathyroid disease, diabetes mellitus, adrenal disease, or systemic sclerosis may predispose to diarrhoea through various mechanisms, including endocrine effects, autonomic dysfunction, small bowel bacterial overgrowth, or the use of concomitant drug therapy.

(5) Alcohol. Diarrhoea is common in alcohol abuse. Mechanisms include rapid gut transit, decreased activity of intestinal disaccharidases, and decreased pancreatic function

(6) Drugs. Up to 4% of cases of chronic diarrhoea may be due to medications (particularly magnesium containing products, antihypertensive and non-steroidal anti-inflammatory drugs,
theophyllines, antibiotics, antiarrhythmics, and antineoplastic agents) and food additives such as sorbitol and fructose, and these should be carefully sought.

(7) Recent overseas travel or other potential sources of infectious gastrointestinal pathogens.

( Recent antibiotic therapy and Clostridium difficile infection. Many different tests are now available for the detection of C difficile but most clinical laboratories use a commercial enzyme
immunoassay for C difficile toxin.

9. Lactase deficiency
Screening blood tests should include full blood count, erythrocyte sedimentation rate, C reactive protein, urea and electrolytes, liver function tests, calcium, vitamin B12, folate, iron studies, and thyroid function. These have a high specificity but low sensitivity for the presence of organic disease.
• Although infectious diarrhoea is uncommon in immunocompetent patients from the developed world with chronic symptoms, stool cultures and stool microscopy should be performed.
• Coeliac disease is the most common small bowel enteropathy in Western populations. Patients with diarrhoea should be screened for this using serological tests (currently antiendomysium antibodies), which have a high sensitivity and specificity for the disease.
• Factitious diarrhoea becomes increasingly common in specialist referral practice, and screening for laxative abuse should be performed early in the course of investigation.

Referência Bibliográfica: Guidelines for the investigation of chronic diarrhoea, 2nd edition. P D Thomas, A Forbes, J Green, P Howdle, R Long, R Playford, M Sheridan, R Stevens,R Valori, J Walters, G M Addison, P Hill, G Brydon. Gut 2003;52(Suppl V):v1–v15