Nausea and Vomitting

Nausea ,vomitting are common go to side effects of a drug, when external examiner asks during viva of a medical student. But, these symptoms can reveal many underlying conditions and diseases apart from the side effects of many drugs.

Nausea is imminent desire to vomit and often precedes or accompanies vomitting. vomiting is the forceful expulsion of the gastric contents through mouth.

    PATHOPHYSIOLOGY:                  

    1. Activation of the CTZ ,sends the impulses to the vomiting centre in brainstem,

    2. Gastric fundus and gastroesophageal sphincter relaxes inturn cause raise in intra-abdominal pressure increase,due to increase in abdominal and diaphragm muscle contraction causes the gastric contents to enter the oesophagus ,

   3. Increased intra-thoracic pressure results in further movement of food material to mouth

4.Reflex elevation of the soft palate  and closure of glottis protect the nasopharynx and     trachea and completes the vomiting

Causes of vomiting: 
  1. DRUGS:
              -Cancer chemotherapy
              -Antibiotics
              -Cardiac antiarrhythmics
              -Digoxin
              -Oral hypoglycemics
              -Oral contraceptives
2.Metabolic and endocrine causes:
               -Pregnancy
               -Uremia
               -Ketoacidosis
               -Thyroid and parathyroid disease.
               -Adrenal insufficiency
3.Toxins:
              -Liver failure
              -Ethanol
4.Labyrinthine disease
             - Motion sickness 
             - Labyrinthitis
             - Malignancy
5. Bowel obstructing disorder
6. Cardiopulmonary disorders and cardiomyopathies
7.Enteric infections
      -viral
      -Bacterial
8.Inflammatory dieases.
      - cholecystitis.
      -Pancreatitis
      -Appendicitis
      -Hepatitis.
9.Intracerebral disorders
      -Intracerebral disorders  
      -Malignancy 
      -Abscess 
      -Hydrocephalus
10. Post operative vomiting
11.Impaired motor functions.
Careful clinical examination, will reveal the underlying 
 cause for nausea and vomiting, like ,vomiting that occurs
 predominantly in the morning is often seen in pregnancy,
 uremia, and alcoholic gastritis;projectile vomiting suggests
 increased intracranial pressure,vomiting during or shortly
 after a meal may be due to psychogenic causes or peptic 
 ulcer disease.

complications, can be Rupture of the esophagus,hematemesis
from a mucosal tear,dehydration, malnutrition, dental caries 
and erosions, metabolic alkalosis, hypokalemia, 
and aspiration pneumonitis.
Treatment is mainly based on the treatment of the underlying cause,
  -Antihistamines such as meclizine and dimenhydrinate are effective
for nausea due to inner ear dysfunction
  -Anticholinergics such as scopolamine are effective for nausea 
   associated with motion sickness
  -Haloperidol and phenothiazine derivatives such as
    prochlorperazine are often effective in controlling mild nausea 
    and vomiting, but sedation, hypotension, and parkinsonian 
    symptoms are common side effects.
  -Metoclopramide may be superior to the phenothiazines in treating 
   severe nausea and vomiting.IV metoclopramide may be effective 
   as prophylaxis against nausea when given before chemotherapy.
  -Ondansetron and granisetron, serotonin receptor blockers, 
   and glucocorticoids are used for treating nausea and vomiting 
    associated with cancer chemotherapy.
  -Aprepitant, a neurokinin receptor blocker, is effective at
    controlling nausea from highly emetic drugs like cisplatin