Basically, diarrhea can be defined as production of loose watery stool that occurs at a higher frequency than normal with increased overall stool bulk. Essentially, it reflects the reversal of the normal absorptive condition of electrolytes and water to secretion of the same. The increased water content in the feces, which normally is approximately 10mL/kg/day in infants and children and 200g/day in adults and teenagers, is a result of the imbalance in the physiologic function of the small and large bowel, which are the principal segments involved in uptake of ions, organic substances, and water.
The increased intraluminal fluid leads to enhanced peristaltic movements resulting in more frequent loose stool. It should be noted early that this condition can be protective in certain instances. Care should be taken in its treatment as inhibiting protective diarrhea such as the one clearing bacteria can result in effects that are more serious. The bacteria become more invasive, which can lead to systemic spread.
Types of diarrhea
Episodes of this condition can be classified into acute or/ and chronic also known as persistent based on the duration before remission. Acute variant can be describe as an episode with a rapid onset and lasts up to or less than 14 days. Acute gastroenteritis can be used interchangeable with acute diarrhea although the former is a misnomer. This is because this condition can occur even in the absence of inflammation.
However, it should be noted gastroenteritis can cause this condition. Chronic lasts longer than acute i.e. more than 14 days. This classification is important in management of the different variants. Both the acute and chronic variants have different causes, management strategies and prognosis.
Causes of diarrhea right after meal
As mentioned earlier, both acute and persistent variants have different causes. Acute type can transform to chronic in some individuals. Bacterial infection is one of the major causes implicated in the pathogenesis of the acute variant.
Bacteria such as salmonella, Escherichia coli, among other enterobacteriacea inhibit the normal absorption of fluids and electrolytes from the bowel lumen through alteration of the proteins involved or direct ulceration of the absorptive mucosa. This results in fluid accumulation leading to altered bowel habit. Enteric viruses are also implicated.
Major known culprits are the norovirus and rotavirus family particularly in children. Parasitic infections especially in immunocompromised individuals can cause life-threatening diarrhea. Giardia lamblia causes steatorrhea or presence of excess fat in faeces giving foul smelling loose stools. Pharmacological therapy if not well monitored can also result in this condition. Examples of medications implicated are antacids, antibiotics and chemotherapeutic drugs in malignancy treatment.
The chronic variant is caused by long-standing pathological conditions involving the gastrointestinal tract. Eating any type of a meal may serve as a trigger to the established condition. Celiac disease is an autoimmune condition, which leads to small intestine mucosa damaging. The damage results from a reaction with gluten, which is a component in foods such as barley, rye and wheat. The absorbing surface is greatly reduced leading to persistent diarrhea.
In crohn’s disease, this condition results from the inflammatory reaction in the GI tract. Any segment of the tract can be affect although the intestines are more commonly affected. Ulcerative colitis is a variant of crohn’s that affects the colon alone. These two conditions are major contributors to the persistent type.
Other major causes include the dumping syndrome in which the GI tract just acts as a conduit and little or no absorption takes place, irritable bowel syndrome, lactose intolerance characterized by inability to absorb lactose, microscopic colitis, and post-operative condition such as cystectomy and sugar intolerance.
Symptoms
Symptoms mainly depend on the type. They are gastrointestinal tract or system centered and mainly abdominal. Symptoms seem to be self-limiting in many cases though life-threatening manifestations can occur.
A loose, watery and frequent stool is invariably present. Due to muscle fatigue, there is abdominal cramps and pain. Fever is common especially in infective acute variant. Dysentery due to imperforation of the GI wall and bloating are also common. Dehydration and metabolic alkalosis can occur due to excessive loss of fluid and acid from the body respectively.
Diarrhea right after meal is also called postprandial diarrhea. It makes it hard for one to enjoy a meal due anxiety and fear of the consequences. Major causes are due to either reduced absorptive surface as in surgery or hypermotility of the GI tract. This state may occur immediately after meal or two to three hours after meal.
Causes can be neurogenic as in decreased gastric emptying time due to increased muscular activity or defective pylorus opening. Gastrointestinal hormones such as insulin are also implicated. Surgery particularly on the pylorus or gastrectomy reduces the emptying time causing accumulation in the lower tract. Risk factors include gastrectomy, vagotomy, gastric bypass surgery, and fundoplication.
Prevention and treatment
Prevention involves maintaining personal hygiene such as washing your hands before meal, serving food right away or refrigerating it. One needs to maintain hygiene in the kitchen, drink uncontaminated fluids, and travelling to non-endemic places. This condition is mostly self-limiting but medication such as anti-inflammatory and antibiotics can be used.
