Neobook — clinical reference

Introduction
Differential Diagnosis
Evaluation Priorities

Context: Emergency Unit

Introduction

Nausea and vomiting are very common symptoms, and frequently trigger a visit to the emergency unit. The differential diagnosis is huge; surgical conditions represent a minority of these but can be lethal if missed or mismanaged.

A practical approach is to evaluate if a patient has a ”surgical” cause of vomiting or not, then to decide which of the surgical causes you are dealing with. This is primarily a clinical decision, based on a good quality history, full clinical examination, and some investigations, typically urine analysis, blood U&E’s, FBC, lipase, and some plain abdominal and chest X-rays.

You have to ask explicitly what is the nature of vomitus- is it deep green, feculent, yellow or old food? What is the volume and frequency? Is pain an associated feature? What is the gut function like? Is the patient passing stool, and is it normal? Is the patient passing flatus?

Non-surgical Causes	Surgical Causes
Drugs & intoxication	Vomiting associated with intra-abdominal sepsis or inflammation Appendicitis Cholecystitis Perforated viscus Pancreatitis Mesenteric ischaemia
Infectious causes Gastro-enteritis Systemic sepsis (ie.pyelonephritis orotitis)
CNS Raised intracranial pressure Migraines & seizures Labyrinthine disorders	Vomiting due to a mechanical obstruction Gastric outlet obstruction Small bowel obstruction Large bowel obstruction
Psychiatric	Vomiting due to gut dysmotility Achalasia Gastroparesis Intestinal pseudo-obstruction
Metabolic & Endocrine Pregnancy DKA Acute liver or renal failure

On examination pay specific attention to signs of dehydration, weight loss, anaemia and pyrexia. The abdominal examination must include all hernia sites (it is easy to miss inguinal and femoral hernias), rectal examination, and an evaluation of previous scars or penetrating injuries to the abdomen and chest.
Differential Diagnosis
Differentiating the surgical causes is difficult, and it is not unusual to get it wrong. The table below will be of some assistance: we have highlighted the dominant symptoms and signs.

Click to open the table

Evaluation Priorities
How bad is this?

Resuscitate and/ or rehydrate the patient
Consider nasogastric tube drainage
Admit to the ward

Is this a mechanical obstruction or is this an “ileus” due to intra-abdominal sepsis?

The presence of pyrexia and peritonism strongly suggests intra-abdominal sepsis

Does the patient need an urgent operation tonight or can we re-evaluate the case tomorrow morning with a colleague?

Septic shock & diffuse peritonism mandate urgent surgery
Most cases will benefit from 12-24 hours of IV rehydration and NGT decompression before surgical decisions are made

What other investigations must I consider?

This depends on the working diagnosis-
- GOO will require upper GI endoscopy
- LBO may need a colonoscopy or CT scan
- SBO may be treated conservatively if caused by adhesions

Real problem scenarios! I am not sure what’s going on! Is this large or small bowel obstruction?

Get a consultant to review the case.
Consider a CT scan.
Be wary of operating because you don’t know what else to do
bowel obstruction = challenging laparotomy.