50 “Abdominal Pain in the Tropics” Lecture “Abdominal Pain in the Tropics” Speaker Mark Topazian, MD Objectives 1) To describe common causes of dyspepsia and management strategies 2) To discuss the differential diagnosis of hepatomegaly, splenomegaly, abdominal obstruction, and acute abdomen in the tropics 3) To understand abdominal presentations of enteric fever Lecture Outline I. Background A. Abdominal pain is common in many tropical countries B. Diagnostic tools are limited, but astute clinical evaluation combined with basic laboratory and imaging studies often lead to successful diagnosis and treatment II. Approach to abdominal pain A. Typical patterns and presentations 1. Dyspepsia 2. Biliary colic 3. Pancreatitis 4. Small bowel ischemia 5. Small bowel obstruction 6. Peritonitis, colitis 7. Irritable bowel syndrome, 8. Renal colic 9. Pelvic abscess 10. Ectopic pregnancy, etc B. Organ-by-organ approach (after Cope): 1. The attic (heart, lungs, esophagus) 2. The 2nd floor (stomach, liver, biliary tree, pancreas, spleen) 3. The ground floor (small bowel, appendix, colon) 4. The basement (ovaries, fallopian tubes, uterus, urinary bladder, rectum) 5. The back yard (aorta) C. Location of pain 1. UIper abdominal 2. Para-umbilical 3. Infra-umbilical 4. Left/center/right D. Mechanisms of pain 1. Ulcerative 2. Obstructive 3. Ischemic 4. Infiltrative 5. Neuropathic, etc III. Specific Syndromes and Diseases: A. Splenomegaly 1. Hyper-reactive malarial splenomegaly (“tropical splenomegaly”) a) Abnormal immune response to malaria. b) Increased susceptibility to bacterial infections. c) Treatment (1) Chronic malaria prophylaxis (2) Vaccinations (pneumococcus, meningococcus) 2010 Missionary Medicine Seminar 51 2. Portal hypertension a) Schistosomiasis, portal fibrosis (1) Both cause pre-hepatic portal hypertension with normal liver function) b) Cirrhosis (alcohol, hepatitis B/C, metabolic diseases, etc) 3. Infiltrative disease a) Tumor b) TB c) Amyloid 4. Hematologic a) Thalessemia b) Sickle cell disease c) Spherocytosis d) ITP 5. Infectious a) Mononucleosis b) Endocarditis c) TB B. Hepatomegaly 1. Mass lesion a) Abscess (ameobic, bacterial) b) Echinococcal cysts c) Malignancy 2. Hepatitis a) Alcohol (left lobe hypertrophy) b) Viral c) Metabolic, etc 3. Infiltrative disease a) Granulomatous (TB) b) Melioidosis (1) Pseudomonas pseudomallei infection mimicking TB (2) Occurs in southeast Asia c) Bacillary angiomatosis (opportunistic infection seen in AIDS) d) Malignancy C. Dyspepsia 1. Chronic upper abdominal pain is common worldwide. 2. Clinical history helps with differential diagnosis in 50% of cases. 3. The commonest causes vary by region but typically include the following. a) Gastroesophageal reflux disease (GERD): brash, substernal burning after meals and when recumbent b) Peptic ulcer disease: chronic relapsing epigastric pain relieved by eating c) Non-ulcer dyspepsia: chronic post-prandial bloating, no alarm symptoms, poorly responsive to acid blocking medications d) Upper GI malignancy: alarm symptoms of dysphagia, weight loss, vomiting, anemia, GI bleeding 4. Treatment of dyspepsia varies by cause: a) GERD: diet modification (no caffeine, citrus products, onions; no food or drink for 3 hours before bedtime); stop smoking; elevate head of bed by 3 to 6 inches; antacid medication; motility agents (metaclopramide, cisapride, domperidone); surgery b) Peptic ulcer disease: antacid medication; Helicobacter pylori Rx; surgery for complications 52 “Abdominal Pain in the Tropics” c) Non-ulcer dyspepsia: motility agents (metaclopramide, cisapride, domperidone); drugs to increase gastric accommodation (buspirone, clonidine); low-dose tricyclic antidepressants d) Upper GI malignancy: surgery; chemotherapy/radiation; expandable stents 5. There are 2 main clinical approaches to dyspepsia a) Order a test (1) H. pylori test (likely to be positive in the developing world); endoscopy (useful for diagnosis of peptic ulcer or malignancy, may be normal in GERD, should be normal in non-ulcer dyspepsia). b) Empiric treatment (1) Antacids or acid blockade or H. pylori Rx, with endoscopy for alarm symptoms or failure of empiric therapy. (a) Helicobacter pylori treatment (i) Eradication of infection requires Rx with 3 or 4 drugs together, for 2 weeks, at full recommended doses (a) Bismuth + metronidazole 500 QID + either TCN or Amoxicillin 500 QID + PPI BID (b) Clarithromycin 500 BID + Amoxicillin 1 gram BID + PPI BID (ii) Eradication rates are < 30% if antibiotic resistance is present. Key issue is metronidazole and/or clarithromycin resistance. (a) Resistance varies by region, but metronidazole resistance is now common in many parts of Africa and Asia, and dual metronidazole/clarithromycin resistance is common in Hong Kong D. Bowel Obstruction 1. Cope: “Perhaps the most surprising difference between the acute abdominal surgery of temperate and tropical climes is to be found in the large group of obstructions of the intestine. Strangulated hernia is common in both climes, but in almost every other respect the surgeon will find unexpected differences.” – Early Diagnosis of the Acute Abdomen p.174 2. Leading causes in the developing world a) Hernias b) Volvulus c) Ascariasis d) Abscess e) Intussusceptions f) Tumors g) Less common causes (compared to the U.S.): adhesions. 3. Abdominal cocoon a) Filamentous constricting cocoon that encloses the mesentery b) Association with TB 4. Ascariasis a) Typically causes small bowel obstruction in children, but may present with colonic or biliary obstruction. b) There is typically a heavy infestation with a history of worms from the anus or mouth. c) Recent mebendazole Rx may predispose to obstruction. d) Ultrasound may demonstrate ascarids in the small bowel. 2010 Missionary Medicine Seminar 53 e) Medical treatment is appropriate if there are no signs of peritonitis or perforation (1) NG suction (2) Piperazine salt 75 mg/kg daily for 3 days via the NG tube (3) Hypertonic saline enemas (see references). f) Surgery may include milking worms into the colon, an enterotomy for removal of worms, resection of gangrenous bowel, or ileostomy. 5. Sigmoid volvulus a) Common in parts of Africa b) May be temporarily treated by sigmoidoscopy c) One-stage surgery with resection and reanastamosis (without bowel prep) appears to be safe IV. Acute Abdomen A. Anisakiasis 1. A genus of parasitic nematodes. 2. Infection occurs from consumption of raw or undercooked fish. 3. Severe abdominal pain develops within hours of ingestion, and may be due to an allergic reaction to the larva or to perforation of the small bowel by the larva, which can be found free in the peritoneum. 4. An eosinophilic granulomatous response mimicking Crohn’s disease can occur. 5. In the absence of perforation or peritonitis, worms can be treated with albendazole or removed from the upper GI tract by endoscopy. B. Sickle Crisis 1. A vaso-occlusive episode in a patient with sickle cell disease, presenting with pain in the chest, abdomen, back, or extremities. 2. The pain can mimic cholecystitis or appendicitis. 3. Abdominal complications include acute ischemic hepatitis or colitis, and acute splenic or hepatic sequestration. 4. Diagnosis is made by a “sickle prep” available in many African mission hospital labs. 5. Treatment a) IV hydration b) Supplemental oxygen c) Pain management d) Evaluation for other causes of abdominal pain. e) Exchange transfusions are warranted for treatment of complications. C. Enteric Fever 1. A systemic illness caused by salmonella typhi or paratyphi. 2. It has a variable clinical presentation, and accurate diagnosis requires blood cultures that are often unavailable. 3. In addition, prior antibiotic treatment is common in patients presenting for care. 4. Differential diagnosis for enteric fever includes a) Malaria b) Sepsis c) Meningitis d) Colitis e) Ricketsial illnesses (1) Q fever (elevated LFTs, low platelets) (2) Leptospirosis (jaundice, renal failure) 54 “Abdominal Pain in the Tropics” 5. Complications a) Ileal perforation in 1% to 5% (1) Perforations are often multiple. (2) Serial abdominal exams and upright abdominal films are warranted in some patients; if free air develops laparotomy should be performed b) GI bleeding c) CNS disease (delirium, encephalitis, myelitis, meningitis, abscess, hemorrhage) d) Myocarditis 6. Treatment a) Antibiotic resistance is common and resistance patterns vary by region. b) Response to empiric therapy can be difficult to judge as mean time to defervescence on appropriate therapy is 4 to 6 days in culture-proven cases. c) Antibiotic choices include ampicllin (resistance common), TMP/SMX (resistance common), nalidixic acid, chloramphenicol, quinolones, ceftriaxone, and azithromycin. (1) In meta-analysis quinolones appeared better than chloramphenicol for prevention of relapse. Exam in culture-proven cases Bradycardia 0% to 50% Rose spots 0% to 50% Labs in culture-proven cases Hepatomegaly or 20% to 40% Normal WBC count 75% to 85% splenomegaly Leukopenia 0% to 20% Leukocytosis 0% to 20% Symptoms in culture-proven cases Thrombocytopenia 25% Fever 65% to 100% Hyperbilirubinemia 25% Headache 50% to 90% Elevated serum ALT 40% Vomiting 20% to 50% Widal test positive 50% to 70% Abdominal pain 30% to 50% Loose stools 30% to 50% References • Soomro MA, Akhtar J. Non-operative management of intestinal obstruction due to ascaris lumbricoides. J Coll Physicians Surg Pak. 2003 Feb;13(2):86-9. • Gangopadhyay AN, Upadhyaya VD, Gupta DK, Sharma SP, Kumar V. Conservative treatment for round worm intestinal obstruction. Indian J Pediatr. 2007 Dec;74(12):1085-7. • Mohanty D, Jain BK, Agrawal J, Gupta A, Agrawal V. Abdominal cocoon: clinical presentation, diagnosis, and management. J Gastrointest Surg. 2009 Jun;13(6):1160-2. Epub 2008 Jul 23 • Thaver D, Zaidi AK, Critchley J, Azmatullah A, Madni SA, Bhutta ZA. A comparison of fluoroquinolones versus other antibiotics for treating enteric fever: meta-analysis. BMJ. 2009 Jun 3;338:b1865. doi: 10.1136/bmj.b1865. • Hosolgu S, Boşnak V, Akalin S, Geyik MF, Ayaz C. Evaluation of false negativity of the Widal test among culture proven typhoid fever cases. J Infect Dev Ctries. 2008 Dec 1;2(6):475-8. • Walia M, Gaind R, Paul P, Mehta R, Aggarwal P, Kalaivani M. Age-related clinical and microbiological characteristics of enteric fever in India. Trans R Soc Trop Med Hyg. 2006 Oct;100(10):942-8. • Ford AC, Moayyedi P, Jarbol DE, Logan RF, Delaney BC. Meta-analysis: Helicobacter pylori'test and treat' compared with empirical acid suppression for managing dyspepsia. Aliment Pharmacol Ther. 2008 Sep 1;28(5):534-44. Epub 2008 Jun 27. • De U, Ghosh S. Single stage primary anastomosis without colonic lavage for left-sided colonic obstruction due to acute sigmoid volvulus: a prospective study of one hundred and ninety-seven cases. ANZ J Surg. 2003 Jun;73(6):390-2.