Infections of the urinary tract are probably the most common infections in women. This type of infection is divided into two subtypes: upper urinary tract infections and lower urinary tract infections. The latter is more common and includes infection to the urethra and urinary bladder, and the former is a bit less common and it is an infection of the kidneys. In the natural history of a kidney infection, it is commonly preceded by a lower urinary tract infection that colonized the bladder and worked its way upwards to the upper urinary tract. However, it is possible to have a bloodborne infection coming from any other infected area of the body.
Since upper and lower urinary tract infections usually coexist in the same patient, most of them display symptoms for both. However, if we have an isolated infection of the kidneys without any associated infection of the urinary bladder, the symptoms are different from a usual urinary infection.
In this article, we will give you a complete list of symptoms to help you detect an infection of the kidneys with and without an associated infection of your urinary bladder.
1) Flank pain
The first symptom to stand out in a kidney infection is flank pain. The kidneys are located near the lower back, at each side of the spine. People with a kidney infection often experience dull pain in this location. It can range from mild discomfort to severe lower back pain. When performing a physical examination, your doctor will probably need to test for flank pain with a soft pat in this area. It is important to report any discomfort or pain triggered by this movement.
Flank pain results from the stimulation of the nerve terminals by inflammatory mediators released by the infected kidney. In some cases, it might result from other associated problems, such as kidney stones and swelling of the organ, which is a medical condition called pyelonephritis. Kidney stones are the most common cause of flank pain, and when they move into the urinary tract flank pain starts radiating downwards to the genitals and thigh. It is usually located on one side because most kidney infections are located in one kidney, but when both kidneys are taken it will be bilateral.
2) Fever
Similar to any other infection in the organism, fever is one of the most important symptoms to detect kidney infections. However, it is often a late symptom instead of an early warning sign. Fever appears in a late stage of the disease, only when the infection is sustained and progresses without restraint. It is one of the immune responses to protect the organism against pathogens or microbial invaders. Increasing body temperature is another way the body has to destroy bacteria, and this effect is triggered by the inflammatory mediators released to the bloodstream.
In this regard, we should note the difference between a kidney infection in infants and adults. Different from adults, infants would have fever as one of the most predominant symptoms, and it is often the only one. In many cases, fever with unknown origin in an infant is caused by a kidney infection, and your pediatrician would need to perform a physical exam and diagnostic tests to figure out the difference.
Fever usually stops as the antibiotic therapy is initiated, and it is usually a mild fever but sometimes would reach 40°C and more. Since fever is a common symptom in many infectious diseases, it is important to figure out the real cause before starting medications. Thus, do not neglect your condition, do not self-medicate, and go to your doctor to get a proper assessment of your health condition.
3) Chills
It is a symptom that comes along with fever, and it is actually closely related to the development of fever. Patients usually experience chills when they have very high temperatures, and especially as the temperature reaches its peak. Chills is a common way the body has to create body heat. All infectious diseases release inflammatory mediators that reach the brain centers associated with body temperature. These brain centers increase the temperature threshold making the rest of the body believe it’s very cold and we need to create body heat. One of the ways to do this is by promoting jerking movements in the muscle tissue and transforming chemical energy into heat.
Similar to fever, a patient with shivers and chills will not likely be in an early phase of the disease. If you have fever and chills as a predominant symptom in kidney infections, it is very likely you have an ongoing and very aggressive colonization that requires immediate treatment. In most cases, both fever and chills are gone after a few days of antibiotic treatment.
4) Nausea and vomiting
It is another effect of inflammatory cytokines in the body. However, nausea and vomiting may have a distinctive value when it comes to diagnosing kidney infection. In the majority of cases, patients with an infection in the lower urinary tract do not develop nausea and vomiting. It is more common in kidney infections. Thus, if you have this problem, it is unlikely you will have an associated bladder infection. Still, there are exceptions, and it is prudent to perform diagnostic tests to make sure your condition has not spread from the lower urinary tract.
As a symptom, nausea is a gastrointestinal problem, and it is not directly related to the urinary tract. Therefore, it is important to rule out gastrointestinal disease if you have nausea and vomiting as a predominant symptom. Talk to your doctor so you can clearly differentiate the real causes of your symptoms and obtain the best results of your treatment.
5) Blood or pus in the urine
This is a very important sigh of urinary tract infections, and it is sometimes visible to the naked eye. In other cases, you will need to take a urine sample to the lab in order to detect hidden blood or pus in the urine. Pus in the urine is named pyuria and blood in the urine is named hematuria. The former gives urine a cloudy and blurry appearance, and the latter would rather change the color of the urine to a darker tone, and it might be red in some cases, especially when associated with kidney stones.
When your urine has pus it is because white blood cells have already crowded your kidneys or any other part of the urinary tract. In their struggle against the pathogens, they released inflammatory mediators and toxins to destroy the invaders and died. Thus, the magnitude of white blood cells in the lab samples would relate to the severity of the infection and the immune response against it. This is not a predominant symptom in patients with immune deficiency because it is associated with a normal immune function.
6) Feeding problems in infants
Infants are often difficult to diagnose, and they display fever as a symptom with nothing much to track where it comes from. Since they are unable to communicate their symptoms, there’s no easy way to figure out what is wrong. However, there are certain cues the doctor will notice when examining your children, and one of them is whether or not he’s feeding as he normally does.
Feeding is not only a rational thing an infant does when they are hungry. It is an instinct and a reflex they trigger automatically. Thus, feeding and sucking as a reflex can say much about the central nervous system in an infant. As the infection escalates, your infant may start having more and more problems to feed. In the end, they may even reject all attempts to feed them, and parents often come to the consulting room worried about an infant that is not eating properly and may have some mild fever as well.
This is a sign of possible involvement in the urinary tract, but it is a common warning sign of an infection. Thus, your doctor will not only perform urine tests but other diagnostic laboratory exams to make sure he’s properly addressing the problem. Remember this is not only a sign of urinary involvement and talk to your doctor before starting any medication with your infant.
7) Failure to thrive in infants
Another distressing symptom in infants with an infection, a kidney infection included, is a difficulty to thrive, also known as faltering weight. It might result from eating difficulties, but in general, it is seen in patients with an ongoing infection lasting for quite a long time. These are often irritable children with feeding difficulties, and they usually develop fever, but sometimes this is not the case. Thus, if your child is getting stuck in the same weight or started dropping size unexpectedly, talk to your doctor to figure out the reason. You don’t need to have extra symptoms to consider this a distressing problem that requires medical assistance.
8) Foul-smelling urine
We have already discussed pus in the urine as one of the symptoms in kidney infections. This is one of the factors that contribute to developing foul-smelling urine. Plus, the urine becomes concentrated and with a strong smell. As the infection becomes worse, it is common to experience an especially distinctive smell. This is one of the earliest symptoms of a kidney infection, it is also common in a bladder infection, and it is easily mistaken with other health conditions. For instance, a strong smell in the urine might be the result of not drinking enough water throughout the day, and your doctor will need a urine test to see whether or not you have a urinary tract infection.
9) Frequent urination and burning pain
Patients with a kidney infection often have an associated bladder infection as well. In these cases, they might have extra urinary symptoms, such as frequent urination and burning pain while urinating. Keep in mind that an isolated kidney infection will not have any of these symptoms. Even if the antibiotic treatment is similar for both conditions, sometimes kidney infections are more dangerous than bladder infections, and we need to make a clear distinction between them both.
Frequent urination results from an irritation in the linings of the urinary bladder. It becomes unable to carry around too much urine and triggers the sensation of going to the bathroom more frequently. Similarly, burning pain while urinating is caused by irritation in the urethra. The urine has some acidity to it, and it would stimulate the pain nerve terminals upon passing through the urethra to be eliminated.
10) Confusion and other neurologic symptoms
This is a common symptom in very advanced stages of the disease when the infection has spread to the nervous system, and especially in the elderly population. These patients are more susceptible to kidney infections, and they are usually affected by various conditions that compromise the normal function of their immune system.
Kidney infections quickly become a problem in the elderly, and patients may start displaying mild changes as mood swifts and drowsiness from the very beginning of the infection. As the problem becomes worse, patients may start having more concerning symptoms such as lethargy, confusion, and other alterations of the consciousness.
Similar to infants, seniors require urgent medical attention to address their medical problems. Otherwise, a simple urinary tract infection might turn into sepsis, fall into organic decompensation and lead to a life-threatening condition. Thus, if you find any abnormal behaviour or distressing symptoms in this population, keep in mind they are more susceptible than the rest and will not display the usual array of signs and symptoms we expect in young adults.
Read Also:
Kidney Stone Symptoms; 7 Signs and Symptoms of Kidney Stones
7 most important signs and symptoms associated with kidney stones
References
Johnson, J. R., & Russo, T. A. (2018). Acute pyelonephritis in adults. New England Journal of Medicine, 378(1), 48-59.
Ramakrishnan, K., & Scheid, D. C. (2005). Diagnosis and management of acute pyelonephritis in adults. Am Fam Physician, 71(5), 933-42.
Gürgöze, M. K., Akarsu, S., Yilmaz, E., Gödekmerdan, A., Akça, Z., Çiftçi, I., & Aygün, A. D. (2005). Proinflammatory cytokines and procalcitonin in children with acute pyelonephritis. Pediatric Nephrology, 20(10), 1445-1448.
Roberts, J. A. (1991). Etiology and pathophysiology of pyelonephritis. American Journal of Kidney Diseases, 17(1), 1-9.