The Massachusetts General Hospital Handbook of Neurology

Authors: Flaherty, Alice W.; Rost, Natalia S.

Title: Massachusetts General Hospital Handbook of Neurology, The, 2nd Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Medicine > GUT

GUT

A. Abdominal pain

• Common causes: Infection, obstruction, ulcer, GI bleed, cholecystitis, pancreatitis, mesenteric ischemia, kidney stone, drug, toxin, urinary tract infection, ectopic pregnancy, ovarian torsion, inferior MI, herpes zoster.

• H&P: N/V, stool appearance, bowel sounds, rebound.

• Tests: Consider CBC, electrolytes, -HCG, LFTs, amylase, UA, guaiac, abdominal x-ray, renal, right upper quadrant, or pelvic US, endoscopy, CT.

B. Constipation

• R/o obstruction in acute-onset constipation.

• Common neural causes: Pt. inactivity, medications (e.g., TCAs, opiates), depression, IBS, parkinsonism, spine trauma.

• Rx: Never give anything from above if pt. may be obstructed, i.e., lower afterload before raising preload or inotropy.

  • Change offending meds: E.g., use Comtan rather than Requip, Cymbalta rather than amitriptyline.

  • Afterload reducers: Dulcolax suppositories, Fleets enemas, mineral oil enemas.

  • Preload: MOM 30 cc PO qid prn.

  • Inotropy: Senokot 1-2 tabs bid prn, or Mg citrate 1 bottle, or lactulose 30 cc q2h until pt. stools.

  • Stool softeners: Colace 100 mg tid (not prn).

C. Diarrhea

Consider C. difficile infection. Symptomatic rx: Lomotil 2 tabs PO qid prn, loperamide 2 mg PO prn (max. 16 qd).

D. GI bleed (GIB)

• Upper GIB: From ulcer, varix, Mallory-Weiss tear.

• Lower GIB: From ischemia, thrombosis, intussusception, dysentery, colitis, diverticulosis, cancer, polyp, hemorrhoids, anal fissure/ulcer, AVM, angiodysplasia.

• Nasogastric tube with cold lavage helps both dx and rx.

  • Contraindications: Variceal bleeding.

  • False negatives: Can have upper GIB with negative nasogastric lavage if bleed is duodenal. Look for high BUN.

• Labs: CBC, blood bank sample, PT, PTT, DIC screen, consider emergent endoscopy.

• Rx of GIB:

  • Orders: NPO, orthostatic BPs, two large IVs, guaiac all stools, cardiac monitor. GI consult.

  • IV fluid or blood.

  P.202

  • Upper GIB: IV ranitidine; consider H. pylori Abx. Ranitidine will increase phenytoin and warfarin levels.

  • Varices: Consider pitressin + nitroglycerine, or octreotide (fewer side effects than vasopressin), or DDAVP (selective splanchnic bed constriction, emergent endoscopy for banding, or sclerotherapy). Pt. should eventually be on long-term beta-blockade.

  • Catastrophic bleed: Blakemore tube.

  • Bleed on anticoagulants: Reverse anticoagulation. see p. 161.

E. Hiccups

From diaphragmatic or phrenic irritation; consider brainstem lesion. Treat cause, or:

• Hypercarbia: Try repeated breath holding or rebreathing into a paper bag.

• Vagal stimulation: Try drinking ice water rapidly, tongue traction, eyeball pressure.

• Meds: Sometimes helped by baclofen 5 mg tid, chlorpromazine 25 mg bid, scopolamine, amphetamine, opiates .

F. Liver dz

• Hepatic encephalopathy:

  • H&P: Confusion, asterixis in pt. with liver failure, usually with precipitating illness.

  • DDx: Other deliriums, Wernicke's syndrome, aphasia, psychosis.

  • Tests: Ammonia high, but it may take several days for pt. to recover even after ammonia has returned to baseline. MRI may show T1 signal in basal ganglia, but is not that helpful. EEG will show slowing or triphasic waves.

  • Rx: Lactulose, low-protein diet, oral neomycin.

• Bilirubin: Direct = conjugated. High indirect suggests hemolysis, ineffective erythropoiesis, Gilbert's syndrome.

• Alkaline phosphatase up but 5 -nucleotidase normal suggests extrahepatic source of alk phos, e.g., bone.

• Transferases: ALT = SGPT; AST = SGOT.

G. Vomiting

• H&P: Nausea, color of vomit, diarrhea, fever, precipitating factors, diet, drugs, previous bowel surgery, vertigo, double vision, dysarthria, hearing loss. Neuro and abdominal exam. Always see the pt. walk to rule out ataxia.

P.203

• DDx: GI infection, vertigo, drugs, toxins, alcohol, obstruction, gastroparesis, perforated bowel, pregnancy, metabolic disturbance (e.g., uremia and hyperglycemia), brainstem lesion, severe fear or pain.

• Complications: Dehydration and orthostasis, acidosis, low K, gastric or esophageal (Mallory-Weiss) bleed, perforated esophagus.

• Tests: Electrolytes; consider tox screen, MRI for brainstem lesion.

  • Abdominal x-ray is low-yield unless abdomen is severely tender or there is a high suspicion of obstruction.

• Rx of vomiting:

  • Orders: NS + 20 KCl, NG tube, NPO.

  • Antidopaminergic drugs (q.v. p. 169):

    • Indications: GI causes, surgery, radiation, or chemotherapy.

    • Contraindications: Movement disorders, vertigo. In young people, watch for acute dystonia.

    • Butyrophenones: E.g., droperidol 0.0625-2.5 mg q3-6h IV/IM. Sedating. Good for nausea from morphine. Beware prolonged QT, torsades; should be used only for refractory nausea/vomiting.

    • Phenothiazines: Avoid in epilepsy, head trauma. Promethazine (Phenergan) 25-50 mg q4-6h PO/IM/PR risks dystonia and seizures less than prochlorperazine (Compazine).

    • Metoclopramide (Reglan): 10 mg IV/IM q2-3h or 10-30 mg PO qid before meals and qhs. A motility agent. Avoid in GI obstruction. Good for gastroparesis.

  • Antihistamines: E.g., meclizine (Antivert) 25 mg PO qid. Suppresses the vestibular apparatus in vertigo.

  • Anticholinergics (q. v., p. 168): E.g., scopolamine.

    • Indications: Motion sickness.

    • Contraindications: Outlet obstruction, DM gastroparesis, glaucoma.

  • Central: E.g., ondansetron (Zofran) 4 mg IV or 8 mg PO, or granisetron (Kytril) 750 g IV or 1 mg PO.