The patient who does not urinate, oliguria

Oliguria is a very important sign in internal medicine which is technically defined as the reduction of diuresis, ie the contraction of urine below 400 ml in a day (in newborns less than 1 ml / kg / h, in children 0.5 ml / kg / h , and 17 ml / hour in adults, while creatinine and azotemia are raised. This sign usually occurs suddenly and may have different meanings, from the most innocent of dehydration of the patient and we refer in particular to the elderly patient, the old patient who drinks only when stimulated, or who has experienced a sudden loss of fluids due to vomiting, profuse diarrhea, sweating, or to the most serious sign of heart failure, in the last stages of life, or for circulatory decompensation or hypovolaemic shock, for example, in infectious events, in prolonged fever leading to a reduction of renal flow.). Sometimes, more simply, the reduction of diuresis is attributable to an obstructive fact, that is to an impediment for example in the condition of prostatic hypertrophy, where the prostate, being enlarged, compresses the excretory urinary path. In the meantime, have you investigated? Have you checked the plasma concentration of sodium and blood pressure? If it falls below 100 or 90 mmHg, you want to urinate the patient! First we need to restore the volemia, as long as we are not faced with a shock condition in the circle, where only the amines can hold back the pressure, for example. dopamine, with renal dosing, which allows to maintain the flow of the kidney and allows for diuresis. Sometimes only the nephrologist, with appropriate specialized care (for example, the use of conjugated bicarbonate solutions, at the appropriate dosage and of furosemide, if this is possible by plasma concentration of sodium) manages to restart the oliguric kidney. In the meantime, when you're there and read the article, waiting for the First Aid service, have you observed if the patient is dehydrated? Look at the tongue, see if it's dry, consider if the patient breathes, if he's careful, if it's vital ...

scrotal tongue, in a dry patient

Classification of oliguria

Classically we can distinguish an oliguria due to acute renal failure (pre-renal, renal or post-renal) of reduced renal function or other causes.

Pre-Renal causes

- renal artery occlusion, renal vein occlusion,
- cirrhosis, heart failure, shock and sudden hypovolemia,
- sepsis

Renal causes

- glomerulopathies, acute tubular necrosis, chronic renal failure, pregnancy toxemia

Extrarenal causes

- prostatic hyperplasia, bladder neoplasm, retrograde peritoneal fibrosis, urethral stricture.

The patient's story

We begin by asking for information on urination, including frequency and quantity, if the patient feels an urinary burning (think of urinary tract infections), evaluating if there was pain in the lower abdomen. Does the patient suffer from kidney disease? Glomerular diseases? Is there blood in the urine, macroscopic or microscopic? Above all, did the patient have a trauma? Did you have any blood loss and was transfused? Was he in cardiogenic shock? In the latter case, in addition to immediately hospitalize the patient, which will certainly be hypothesized, with a filiform and imperceptible wrist, it is advisable to undertake an adequate resuscitation therapy, with vasoactive drugs such as dopamine at the appropriate dosage

Approach to the patient

Some routine investigations should be requested: blood count to rule out infectious diseases (leukocytosis), urine tests to detect proteinuria, blood sugar, creatinine, azotemia, serum electrolytes, protidemia and electrophoresis, GOT, GPT, chest X-ray, ECG, echocardiography.

On physical examination, evaluate myocardial function, exclude ischemic heart disease, exclude liver disease, cirrhosis, ascites, pneumopathy, if there are lymph node or neoplastic stations (see index of tumors).

Causes of oliguria

Acute tubular necrosis

These are all the conditions that cause damage to the renal tubule, even following a cardiogenic shock.

Prostatic hyperplasia

It is a pathology that occurs above 50 years, with oliguria and urinary obstruction, reduction of urinary jet force. The writer has had the experience of patients who had delusions of monstrous prostate, even of 9 cm in diameter, which have necessitated cystostomy to urinate with catheters positioned in the supra pubic.

Bladder neoplasia

This is also a condition that can determine oliguria, but it does not come to striking pictures, while the emission of blood in the urine is more frequent.

Stones

Oliguria and reflex anuria can occur in urinary calculosis, sometimes with the dramatic picture of ureterohydronephrosis, ie a calculation that impacts the urinary pathway and blocks the outflow of urine into the bladder. In these cases the patient presents dramatic clinical pictures, with abdominal pain in the right or left side and in the lumbar loggia and vomit.

Cirrhosis

In the established forms, cirrhosis can give the picture of the epatorenal syndrome, ie in the terminal hepatic insufficiency also the kidney goes to insufficiency with oliguria, ascites, edema, asthenia.

Acute glomerulonephritis

This pathology is characterized by fever, asthenia, macroscopic haematuria, generalized edema, hypertension, headache, nausea, vomiting and pain in the side and in the renal site, with signs of pulmonary stasis and dyspnoea.

Pyelonephritis and urinary tract infections

It is characterized by high fever with shaking shiver, asthenia, pain in the side, weakness, nocturia, dysuria, haematuria.

Heart failure (decompensation)

of pump). This is one of the most frequent causes of oliguria, after prostatic hypertrophy, especially in the elderly patient, due to the low cardiac output. In fact, as we know, renal perforation and the ultrafiltration process are a function of the force of myocardial contraction and, therefore, of cardiac output. In the patient with heart failure we will have dyspnea, pulmonary stasis, declining edema, jugular dilatation, tachycardia, tachypnea, rales and dry cough.

Renal artery occlusion

Very frequent cause in the vascular patient, for example in the patient with AOCP- The patient can become feverish, the intestinal peristalsis being torpid and there is always severe and severe abdominal pain.

Use of drugs

Amino glycosides and chemotherapeutic drugs, intoxication from ethylene glycol (the radiator liquid), sulfonamides, acyclovir, diuretics.