Nausea & Vomiting

Dr. Nawaf O. Al-AmriEmergency Medicine Resident

Saudi Board Of Emergency Medicine

Definitions Nausea : Vague , unpleasant sensation that precedes vomiting , it may happen alone , with retching or vomiting , and shares the same pathway of vomiting but due less stimulation of that .

Retching : Rythmatic synchronized contractions of the diaphragm , abdominal and intercostal muscles against a closed glottis causing the intra abdominal and decrease the intra thoracic pressure causing the gastric contents to go up through the esophagus .

Definitions Rumination : Regurgitation of the ingested food that subsequently is re-swallowed or ejected , mainly found in infants , children and mentally challenged adults .

Regurgitation : Gentle expulsion of gastric contents without having nausea or vomiting & without the involvement of abdominal or diaphragmatic muscles , but instead is due to the relaxation of the lower esophageal sphincter instead .

Definitions

Vomiting : Forceful expulsion of gastric contents thru the mouth.

Pathophysiology1- The vomiting center is located in the lateral reticular formation in the Medulla Oblongata , and receives impulses from the following areas :

A- Higher brain centers : responding to pain , sights , smells , tastes and even feelings and emotions

B- GI system ( Mainly Stomach ) : through direct and indirect irritation of any part of the GI tract , mainly the stomach going via Vagus and Sympathetic routes and over to the vomiting center .

PathophysiologyC- Heart : Through Vagus and Sympathetic Route .

D- Genitalia : Through Vagus and Sympathetic Route

E- Vestibular System : Mainly due to a primary infection or disposition locally or due to motion sickness , firing to the lateral vestibular nucleus .

F- Chemoreceptor Trigger Zone : Located in Area Posterma , which is in the floor of the 4th ventricle , its between the blood brain barrier ( In & Out ) >> Responds exogenous and endogenous substances .

Pathophysiology2- All of the previous areas have receptors that “ when triggered “ will send and afferent impulse to the vomit center :

A- GI Tract : has serotonin receptors .

B- CTZ : receives from within the Area Posterma which has Dopamine and Serotonin receptors , as well as outside the body substances which are mostly : drugs , uremia , radiation , chemotherapy , toxins ( B , V , F , P ) , hormones , and peptides , opiates , and digitalis or aspirin Via Canaboid , Substance P & Hydroxytryptamine receptors .

PathophysiologyC- Vestibular Nucleus : Muscarinic & Histaminic Receptors .

3- Now that we know the receptors and their physological zones and how they respond & where impulses go , we’ll discuss the actual mechanics of vomiting :

A- Afferent impulses due to any stress on any of the areas will shoot and impulse going to the vomiting center >> which generates Efferent impulses either Mild causing Nausea or Mild causing retching or Severe causing vomiting .

PathophysiologyB- Due to Mild impulses , the duodenal & jejunal muscles will contract while the gastric tone decreases >> causing reflux of intestinal contents to the stomach along with tachycardia , hyper-salivation & repetitive swallowing , Which now completes a ( Nausea Phase ) depending on the strength of the stimulus .

C- If impulses are moderate and had much time to act , the vomiting center starts to send impulses through the Phrenic nerve going to the ( Diaphragm ) , The Vagus nerve going to the ( Esophagus , Stomach & Duodenum ) , The Spinal nerves going to the ( Abdominal & Intercostal Muscles ) .

PathophysiologyD- Due to all of the pervious impulses , a rythmatic synchronized movement of contractions of the Diaphragm , Abdominal & Intercostal muscles , And closure of the Glottis >> Which causes the intra-abdominal pressure to rise and the intra-thoracic pressure to decrease , pushing contents up the esophagus against the glottis ( The Retching Phase ) .

E- When Severe & continuous prolonged impulses are at hand >> Abdominal muscles contract & the Hiatal part of the diaphragm relaxes >> the pyloric part of the stomach contracts While the Cardia & Fundus Parts Relax .

Pathophysiology

F- This will cause relaxation of the upper and lower esophageal sphincters , which will then allow the gastric contents that are under sever pressure to gush through the esophagus and out through the mouth , Thus reaching the long waited ( Vomiting Phase ) .

Classifications- Primary Vs. Secondary :

A- Primary : Usually due to a GI illness ( Obstruction Or Gastroenteritis )

B- Secondary : Due to either :

1- Sever visceral pain .2- Sever Systemic illnesses ( MI , Sepsis , Shock ) .3- Specific conditions like : pregnancy “ Hormonal “ , Raised ICP “ CNS Mechanism “ , Toxins “ Homeostatic Reflex “ . Motion Sickness “ Neuroendocrine “ Or Chemo “ CTZ “ .

Classifications- Acute Vomiting : Occurs ( < or = 1 Week ) , Usually associated with : obstruction , ischemic , toxic , metabolic , infectious , neurological and post-operative reasons .

- Chronic : Occurring for more than 1 Month , Usually due to partial obstruction , motility disorder , neurological chronic condition , pregnancy or functional reasons .

- Cyclic : Which has an onset of repetitive but interrupted cycles of high frequency vomiting , followed by an asymptomatic phase usually due to Viral Causes .

- Recurrent .

Most Common Cause Of Nausea And Vomiting

1- Acute Gastroenteritis

2- Systemic Febrile Illnesses .

3- Medications

Sequelae Of Vomiting-Aspiration :

Vomiting in a patient with altered mental status , low or depressed level of consciousness , or one that suffers from extremely repetitive cycles will most likely have bad epiglottic control or non for that matter , which in term will lead to aspiration of gastric contents whatever they are to the respiratory tract and lung causing aspiration pneumonia .

The results of that will almost always be troubling especially if the contents were of chemical or highly irritating to the respiratory tract causing compromise to the Airway .

Sequelae Of Vomiting - Mallory Weiss Syndrome :

Due to sever and repetitive retching and vomiting a partial tear of the mucosa and sub-mucosa in the stomach and gastroesophageal junction will form , which may lead to bleeding which most likely will be minimal and self limiting , but can proceed to a more catastrophic form .

Sequelae Of Vomiting- Boerhaave's Syndrome :

Which Happens commonly due to repetitive , extreme prolonged bouts of retching and vomiting , causing a full tear of all the layers of the esophagus , mainly and most commonly the posteriolatral lower part of the esophagus which is by itself a Lethal medical emergency .

Sequelae Of Vomiting-Hypovolemia :

due to a lot of vomiting , high water volume content and sodium and chloride will be lost from the body , which will cause contraction of the extracellular fluid space leading to activation of the Renin – Angiotensin – Aldosterone system .

Sequelae Of Vomiting- Electrolyte Imbalance :

Mainly Hypokalemia due to a very complex reflex due to volume depletion which will cause Hyperaldosteronism , Leading to increased re-absorption of Sodium & Increased Excretion of large amounts of Potassium in the urine .

Sequelae Of Vomiting- Hypochloremic Metabolic Alkalosis :

Although the acid base system in the body is well protective , it can decompensate due to a group of stressors that will shift it from equilibrium to either Acid or Alkali Side .

This is very evident in the setting of Continuous large amount vomiting for more than 3 Days Owing : ( Loss of H+ from HCL + Low Volume Concentration + Hypokalemia + Chloride Depletion + High Aldosteron + Shifting Of H+ from extra to intra cellular ) , All Gathering up to cause sever metabolic alkalosis due to extreme high frequency vomiting .

History 1- Duration : to define the type of vomiting and to give you a close picture of what kind of sequelae might have this patient developed .

2- Time + Onset / Offset : to define the type or the etiology causing it :

A- Acute Onset : Gastroenteritis , Pancreatitis , Cholycystitis , Appendicitis , Anaphylaxis , Medication Effect Or Toxicity .

B- Morning : Raised ICP , Primary Tension or Migraine Headaches , Pregnancy , Uremia , Alcoholism .

C – 1 Hour After Eating : Gastric Outlet Obstruction Or Gastroparisis .

D- 12 Hours After Eating : Gastric Or Intestinal Obstruction .

History 3- Content Of The Vomit :

- If Bilious >>> then Gastric outlet obstruction is out of the question , cause the area between the stomach and duodenum is intact .

- If Undigested Food >>> Achalasia Or Stricture

- If Digested Food >>>> Might be due to toxins or anaphylaxis .

- If Hematemisis >>> Suspect Upper GI Bleed with its causes .

- If Fecal Mater Or Smells So >>>> Distal Bowel Obstruction , Fistula , Bacteria Overgrowth due to long standing outlet obstruction .

History 4- Associated Symptoms : Hyper-salivation, defecation, tachycardia, bradycardia, atrial fibrillation, and termination of ventricular tachyarrhythmias are associated phenomena with nausea and vomiting. Chronic headaches with nausea and vomiting should raise the index of suspicion for an intracranial lesion. Also, vomiting without preceding nausea is typical of central nervous system pathology

5- Past Medical & Surgical Hx : The past medical history will reveal the presence of any GI disease or previous surgeries

6- Social & Traveling Hx : The social history should include inquiries about alcohol or other substance abuse.

7- Medications & Dietary Habits : Nutritional history is valuable in the consideration of failure to thrive in infancy thorough medication list, including over-the-counter drugs, should be included.

Physical Examination

Special Considerations In Pediatric Group * Bulging Fontanel >>>> Meningitis .

* Projectile Vomiting >>>> Pyloric Stenosis .

* Unusual Odors >>>> Metabolic Or Toxicological Causes .

* Visible Bowel Loops >>>> Obstruction .

* Enlarged Parotid Gland + Loss Of Dental Enamel >>>> Bulimia

* Mild Reflux & Rumination & Regurgitation might be normal in first few months of life .

* First Week Vomiting >>> Obstructive , Inborn Error Of Metabolism , Serious Infection .

* After 1 Week >>> Pyloric Stenosis , Feeding Problems .

* First Month >>>> Infections , Metabolic Causes , Caw Milk , Failure To Thrive , Subdural Hematoma in Abused Children .

* Adolescents + Teenagers >>> Cyclic Vomiting , Food Poisoning , HSP , Pneumonia , DKA , Anorexia Nervosa , Bulimia , Drug Abuse .

Tests- CBC : If Hb and HCT are High >>> Dehydration due to loss of dilutional effect .

- Electrolytes : Hypochloremia , Hypokalemia .

- BUN / Creatinine Ratio : If 20:1 >> Sever Dehydration .

- Lipase : Pancreatitis >>> Dehydration

- Urineanalysis : For UTI , Pregnancy Test , DKA , Hematouria , Stones , Sterile Pyoria in Appendicitis .

- Culture , Sensitivity & Titers : To Rule In Or Out Infection ( B , V , F , P ) .

- LFTs + Ammonia : Cholysystitis , Ascending Cholingitis , Liver Failure .

- Chest & Abdominal X-Rays : Focus , Perforation , Obstruction .

- CT & Angio : Ischemia & Infarction .

- ECG : MI - TFT : Thyroid Disease - Drug Levels

DDx In General Population

DDx In Pediatric Population

Assessment & Management

- Make sure you cover your : A-B-C-D-E

- Try to limit and stop lethal & Critical causes like Boerhaave's , GI Bleed , Mesenteric Ischemia , Intracranial Bleed , Meningitis , DKA , MI & Sepsis .

- Direct your therapy to the cause of nausea and vomiting while treating the effects of that process .

Assessment & Management

1- Rehydration & Electrolyte Imbalance: If the patient can take orally and tolerate it , Give ORS or Any rehydration fluids like Getorade , If cant take P.O >>>> I.V Aiming To Replenish Fluid Volume And Electrolytes Loss .

2- Nasogastric Tube : If the patient is persistently vomiting due to a GI bleed , Gastroparisis , Pancreatitis , Or Bowel Obstruction .

Assessment & Management3- Pharmacological Treatment (( Very Important )) :

A- Phenothiazine : (( Prochlorperazine , Droperidol, Promethazine ))

- Have Dopamine Antagonistic Effect In CTZ .

- Side Effects may include : Restlessness and Dystonia , Which can be treated with Diphenhydramine + Benztropine.

B- Serotonin Antagonists : (( Ondansetron“ Zofran “ ))

- Works Well In Area Posterma & The GI Tracts .

- Best For Chemotherapy & Theophylline Or Acetaminophen Toxicity Adjunct Therapy .

- Side Effects may include : Headaches & Constipation .

Assessment & ManagementC- Prokinetic Agents : (( Metoclopramide, Cisapride))

- Works as An Antagonist to Dopamine + Cholinergic + Serotonin Receptors .

- Cisapride Works On The GI Receptors Only Unlike Metoclopramide .

- They Both Increase Gastric Motility & Emptying .

- Side Effects may include : Restlessness , Lightheadedness & Dystonia .

D – Antihistamines : (( Dimenhydrinate , Meclizine ))

- Best used to prevent Motion Sickness & N&V Due To Vestibular Problems .

- Side Effects may Include : Drowsiness , Dry Mouth , & Hypertension .

Assessment & ManagementE – Anticholinergics: (( Scopolamine & Hyoscine“ Bascopan “ ))

- Which may be given as a supportive treatment to colicky pain in Uncomplicated acute gastroenteritis & and is also effective in prophylaxis of Motion Sickness

F- Benzodiazepines :

- Which are effective in Nausea and vomiting due to anxiety disorder .

G- Substance P Neurokinin 1 Antagonists : (( Aprepitant ))

- Used an adjunct therapy to prophylaxis against post Chemotherapy N&V as well as Post-Operative .

Etiology Directed Treatment- Pregnancy Related N&V :

* For Mild To Moderate >>> Rehydration P.O or I.V + Pyridoxine + Antihistamines + Prokinetic Agents + Ondansetron + Prochlorperazine.

* For Severe >>> Admission , Fluids + Electrolytes , Corticosteroids .

- Post Operative Related N&V : Due To Nitroxide & Propofol

* Ondansetron , Metoclopramide, Droperidol.

- Post Chemotherapy Related N&V : Acute ( 24 Hours ) Chronic ( > 1 Day )

* Ondansetron + Aprepitant + Dexamethasone.

Dosage

Nausea & Vomiting Dietary Steps- We cant expect all patients who had nausea and vomiting to resume their normal diet once vomiting stops , it should be in the following sequence to grantee a relaxed gradual coming back to normal diet :

Step 1 : Start With Water , Clear Fluids & Electrolyte Replenishing Drinks , Keep In Mind That Citrus & Sweet Flavored Can Irritate GI .

Step 2 : After Pt Has Tolerated Clear Fluids , Next Step Is Semi Liquids Like Soups , Bare In Mind Though That They Should Be Low Fat High Carbs .

Step 3 : Tolerating The Above , Start On A Moderate Diet Of High Protein And Low Fat

Step 4 : Patient Can Resume Normal Diet , If Above Are Tolerated .

DO NOT DISCHARGE IF1- There Is A Significant Underlying Disease .

2- If The Diagnosis Or Cause Of Nausea & Vomiting Isn’t Clear .

3- Poor , Relapse Or No Response To Treatment .

4- Nausea & Vomiting Continues Or Becomes Even More Frequent .

5- If The Patient Is Of The Extremes Of Age .

6- If The Patient Is Un-Able To Follow Up In The Clinic .

7- If The Patient Is Dependant Or Unable To Follow Instructions .

8- If The Patient Still Cant Take Per Oral .

DISCHARGE IF1- There Is No Significant Underlying Disease .

2- If The Cause Is Clear & Appears To Be No Serious .

3- Good Or Full Response To Treatment .

4- Nausea & Vomiting Becomes Less Or Stops .

5- If The Patient Can Actually Take Clear Fluids Per Oral .

6- If The Patient Has A Close Follow-Up In 24-48 Hours .

7- If The Patient Understands The Instructions & Is Able To Abide To Them And Is Self Dependant .

Take Home Message1- Understanding Pathophysiology Of N&V Is Important In Defining & Treating Lethal And Critical Causes .

2- Not Every Etiology Responds To Just Antiemetic Therapy , Your Goal Is To Know How And Why And From Where Its Happening In Order To Hit The Right Receptor With Your Medication .

3- Although Nausea & Vomiting Might Sound Easy And Less Serious Than A lot Of Signs & Symptoms , Its Sequelae Can Sometimes Be Catastrophic .

4- Abide To The ( A , B , C , D , E ) Protocol In Management .

5- Treat The Causes As You Are Treating The Sequelae Of N & V

Thank You