Acute Kidney Injury in Gastroenteritis
Acute gastroenteritis is a common disease, which is usually caused by bacteria and viruses present when we accidentally ingest spoiled food and from unsanitary water supply. It is usually mild and is commonly managed at home. This article reports a possible life-threatening complication of an apparently trivial disease.
The Unexpected Case of Mrs. A
Let us meet Mrs. A, a 58 year old lady who went for consult because of several episodes of relentless diarrhea and vomiting for four days. She reported that she ate Chinese food the day before she developed the symptoms. She thought that the condition will spontaneously resolve itself so she did not immediately sought for medical advise. Her appetite started to diminish and recently she is already unable to go to work. At this point, she is already generally feeling weak. Physical examination was done and the pertinent medical tests were requested.
For most readers, the case of Mrs. A may not be considered as an uncommon occurrence. Many have experienced unknowingly eating spoiled food and suffering from stomach upset then after. Nonetheless, this situation provides an insight how the seemingly common infection has caused an unusual complication, and such should not be simply set aside.
In order to specify how we ended up with an impression of a simple gastroenteritis, we should first consider even other types of diseases from other body systems. From there, we can analyze and safely rule them out as less likely causes.
Body System Involvement
General Disease Classification
Infectious/ Toxin, Obstructive Disorders, Organic Disorder
Uremia, Diabetic Gastropathy
Focus: On Diarrhea and Vomiting
The main symptom manifested by the patient emphasizes on the initial chief complaint of four days of (1) diarrhea, and (2) vomiting. With these symptoms, possible causes from different body systems were also considered. Essentially, the primary consideration focuses on the gastrointestinal system due to the epidemiology and the coincidence of both diarrhea and vomiting as common symptoms under this banner. Second consideration included are those metabolic derangements which may present with alteration in chemical balance leading to the said symptoms.
For the gastrointestinal system, the primary diagnosis considered are the following, ranked according to the likelihood of development:
- Infectious/Toxin Causing Disorders are the primary consideration since they are the most common cause of diarrhea and vomiting and also basing from the history that the patient manifested the disease process after ingestion of allegedly spoiled food.
- Obstructive Disorders are the second consideration since obstruction in any point of the gastrointestinal tract (GI tract) may initially present with diarrhea as the body tries to compensate with the alteration in peristalsis, and consequently it may cause vomiting as the intestinal contents are brought back to the upper GI.
- Organic disorders such as hepatitis may present rarely with diarrhea and vomiting due to the effects of metabolites in the body, however they are very unlikely origins and should only be deliberated when the main working impressions have been ruled out since there is the absence of the cardinal manifestations such as organomegaly, abdominal pain, and jaundice.
For the metabolic disorders three were considered: uremia and diabetic gastropathy - with respective prioritization.
- Uremia may cause both vomiting and gastrointestinal disturbance when it reaches sufficient levels. Basically this is defined is accumulation of nitrogenous waste in the blood and may correlate well with how the patient presents the symptoms.
- Diabetic gastropathy presents as a complication of long-standing diabetes mellitus. It may present insidiously if that the patient is a known hypertensive, in which there is a possible presence of other lifestyle diseases.
Hypovolemic Shock is a life-threatening condition if not addressed promptly and adequately. Knowing its causes and the manifestations is the key for early detection and treatment to avoid further complications.
Shock: The End-stage Effect of Massive Fluid Loss
Aside from the diarrhea and vomiting which are the presenting manifestations of the patient. Another pertinent cluster of symptoms seen in the patient involves the presence of signs of impending shock. This is can be derived from changes in the normal heart rate and blood pressure. Shock is a medical term used to define the state wherein the body is unable to supply the cells with the appropriate amount of nutrition or oxygen due to a variety of problems. This may be due to decreased blood supply, decreased pumping capacity of the heart, or inability of the blood vessels to properly conduct the blood.
Since it is known that the patient had episodes of fluid loss, the priority etiology may be hypovolemic causes- specifically dehydration which can be correlated with the presence of 5 days of fluid loss from diarrhea and vomiting with little to no fluid intake due to anorexia. Acute blood loss is a secondary type of hypovolemia but is not apparent in this case. Possible fluid secondary to septic shock related to gastroenteritis is a possible but less likely cause. This may be considered if there is still presence of signs of shock even after initial resuscitation.
Gastroenteritis At the Limelight
With all the data provided, we can now surmise that the initial impression for Mrs. A is gastroenteritis. This is commonly known as stomach flu for some people. The patient presented with acute onset diarrhea that is likely to be infectious in nature due to their exposure with spoiled food. Basing from the onset of symptoms, the pathogen may have be delineated based on the signs and presented the type of stool may be sued to be correlated on the type of organism that may cause the vomiting and diarrhea several characteristics that may be considered watery type, presence of fishy odor, absence abdominal pain, fever, and blood. The toxin producing agents are more likely cause of the patient’s diarrhea since it presents with vomiting and long-standing diarrhea as long as the microorganism involved is still able to produce toxins. Enteroinvasive organisms may not be the likely cause since they usually present with bloody stool while enteroadherent organisms should present with characteristic fish-odor stool with no vomiting and lesser time of diarrhea. Listed in the table are the most likely etiologies of gastroenteritis.
According to the World Health Organization (WHO) and UNICEF, there are about two billion cases of diarrheal disease worldwide every year, and 1.9 million children younger than 5 years of age perish from diarrhea each year, mostly in developing countries.— World Gastroenterology Organisation, 2012
Electrolytes Down the Drain!
Fluid and Electrolyte losses during the multiple episodes of diarrhea have predisposed this patient to the possibility of hypovolemia and electrolyte imbalance. Changes in electrolyte levels may lead to inability of the muscles to properly initiate and propagate action potentials leading to changes in membrane depolarization. The most common loss of electrolyte during diarrhea is losses of potassium. Since potassium is generally stored intracellularly, sudden changes in extracellular levels of potassium causes dramatic changes such as generalized muscle weakness.
Mrs. A has also decreased her appetite and reported that she had minimal to no oral solid food intake. This aggravates the inability of the body to replenish the losses of both fluids and electrolytes. The disease process itself may also be considered contributory. Increased stress in the body doe to any form of insult (such as an acute disease) will predispose a beta- adrenergic response. This causes an increase in influx of potassium from the ECF to the ICF. Hence, on top of the decrease in GI losses, decreased intake and intracellular shift causes further depletion. For further reading on the other possible effects of massive electrolyte loss—Please refer to the case of Mr. Q.
Acute Kidney Injury Explained
So we now go to the question—what makes the case of Mrs. A unique from your usual case of severe bad food ingestion?
Acute Kidney Injury (AKI) is defined by an abrupt decrease in kidney function that includes, but is not limited to, acute renal failure. AKI is a broad clinical syndrome encompassing various etiologies, including pre-renal azotemia, acute tubular necrosis, acute interstitial nephritis, acute glomerular and vasculitic renal diseases, and acute postrenal obstructive nephropathy. The technicalities about the staging of the disease and its usual causes are outlined below.
In the case presented, there was an acute decrease in circulating fluid volume (essentially there was decrease in blood circulating the patient’s system) related to (1) massive losses due to diarrhea and vomiting (2) decreased intake due to anorexia (3) possible fluid shift due to intestinal edema secondary to infection. Since the kidney consumes 25% of the total circulating blood volume, any alteration in body fluids may cause significant reduction in renal blood flow and may cause injury to the kidney. In this scenario, there could be accumulation of wastes in the blood and the diagnosis of uremia as presented with the signs and symptoms associated with renal failure. Further laboratory evaluation can be done which will likely reveal elevated BUN and creatinine which signify impairment in kidney function.
Fluid and Electrolyte replacement is a must!
At this point, how can we ascertain the cause of the patient’s gastrointestinal upset? What are the commonly used diagnostic tools when one visits the clinic? How is it managed?
The main goal for treatment of severe acute gastroenteritis is to manage the etiology. Since the patient presents with a possible entero-toxin producing pathogen, addressing the specific bacteria will halt production of toxin and such will help decrease the time of resolution of the bacterial diarrhea. Common laboratory tests requested may include blood chemistry for serum electrolytes, stool microbiologic studies, and fasting blood sugar levels.
Home-made Oral Replacement Therapy or Clinical Intervention with Fluids are being done. Continuous assessment of and monitoring of fluid level should be done to imbalance given that there is already signs of renal impairment. For those readers interested, the total fluid replacement can be computed using a formula. If the patient’s body weight is also given, and since there is serum sodium provided we can compute for the possible fluid deficit that needs to be replenished. Again, kindly refer for the case of Mr. Q for further discussion of the diagnostics and treatment protocol for electrolyte imbalance.
Hallmark Complication: Acute Kidney Injury Assessment and Management
For the main complication trademark of this case, it is also imperative to discuss the management of the main kidney complications.
- Urinalysis- Useful in basic assessment and screening of the components seen in the urine. This is a fast procedure which can be done to have an initial assessment of the components found in the patient’s urine. Possible etiologies may be derived based on the presence of solutes and casts seen with this basic procedure.
- Urinary Electrolyte level- used to assess the degree of tubular capacity to concentrate urine and secrete urinary metabolites
- Abdominal Ultrasound- may be useful to detect abnormalities in urine structure, and will out acute anatomic causes of the renal failure that is not attributable to dehydration/ hypovolemia entirely
The goal of management of AKI is to address the underlying cause with supportive measures to prevent further compromise of renal functions. The important thing to note is to define if the patient is volume responsive or volume unresponsive. Since the patient is starting to show signs of hypovolemia, resuscitation with plain saline (typically used sodium containing intravenous solution) is warranted. The same intervention mentioned for acute gastroenteritis.
Vasopressors may be used once the patient has progressed to full-blown shock. This is seen in patients which present with AKI which is unresponsive to initial resuscitation. Noradrenaline may be used since it has marked improvement in arterial pressure and glomerular filtration.
Continuous assessment of the BUN-creatinine levels is necessary to monitor response to treatment and progression of the condition. Diuretics are not useful in this case given that the patient is already dehydrated, however its use may be warranted during overload. If ever there are other electrolyte imbalance, it can also be addressed. For instance, a marked changes in serum potassium may cause cardiac compromise. Calcium gluconate or insulin may be given to antagonize the effect of potassium, or may cause electrolyte shift, respectively.
Not just your “daily bowel habit”
In summary, the case provides an insight that typical gastrointestinal upsets should be watched out for. Albeit that the renal complications may be not very common, it is still a dreaded condition that surely everyone should be wary of.
Besides the fact that the kidneys lie inside the abdomen, its neighboring organs indeed could lead to this unexpected complication!
Quiz Time! How much can you remember?
Further Readings and Journals Cited
- Getto, L., Zeserson, E., & Breyer, M. (2011). Vomiting, diarrhea, constipation, and gastroenteritis. Emergency Medicine Clinics of North America, 29(2), 211–37, vii–viii. doi:10.1016/j.emc.2011.01.005
- International Society of Nephrology. (2012). KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney International Supplements, 2(1).
- Jacob, R. (2003). Acute Renal Failure. Indian Journal Anaesth, 1.
- Kellum, J. a, & Lameire, N. (2013). Diagnosis, evaluation, and management of acute kidney injury: a KDIGO summary (Part 1). Critical Care (London, England), 17(1), 204. doi:10.1186/cc11454
- Shaw, J. (2007). Evaluation of Nausea and Vomiting. American Family Physician.
- Thomas, D. R., Cote, T. R., Lawhorne, L., Levenson, S. a, Rubenstein, L. Z., Smith, D. a, … Morley, J. E. (2008). Understanding clinical dehydration and its treatment. Journal of the American Medical Directors Association, 9(5), 292–301. doi:10.1016/j.jamda.2008.03.006
- Vivanti, A., Harvey, K., Ash, S., & Battistutta, D. (2008). Clinical assessment of dehydration in older people admitted to hospital: what are the strongest indicators? Archives of Gerontology and Geriatrics, 47(3), 340–55. doi:10.1016/j.archger.2007.08.016
© 2015 LM Gutierrez