Abdominal Pain in the Tropics Lecture Abdominal Pain in the

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					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
                       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
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
                    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
                              (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
                       b) GI bleeding
                       c) CNS disease (delirium, encephalitis, myelitis, meningitis, abscess,
                       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%
                                                            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%

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