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Column originally published Aug 9, 2000

Strept Throat Can Cause Glomerulonephritis, It Usually Resolves Without Complication

Question: Our ten-year-old daughter developed a kidney condition called glomerulonephritis last month. She had a lot of tests done and we were told that it was the result of a Streptococcal infection, even though she had no sign of such infection. A few weeks before she got sick, our eldest son did have Strept throat and was treated with antibiotics. Because of our daughter’s kidney problem, our two youngest children were also tested at the time, but they were fine. They were treated with Penicillin for ten days. We are really worried. Can our daughter’s kidney problem progress to kidney failure? Would our other children come down with the same problem? What symptoms should we be looking for?


Your daughter developed an inflammatory condition of the kidneys, called glomerulonephritis, as a complication of streptococcal infection. This is almost always a self-limiting condition, and should not progress to kidney failure. You can relax and read on.

Streptococcus, also commonly called Strept, is a group of bacteria that can infect humans as well as other animals. There are many types of Streptococcus. Group A Streptococcus is most commonly associated with human infections, although Group B can cause serious pneumonia in newborn infants.

The most common infection caused by Group A Streptococcus is sore throat, frequently known as “Strept throat.” Skin infections called impetigo are also common, especially in warmer climates. The most famous infection, however, is the “flesh-eating disease” that Lucien Bouchard had several years ago. However, I will not discuss about this condition here.

The most common symptoms of Strept throat include fever, sore throat, headache, and occasionally abdominal pain. Some can also develop a red rash on the body that feels like fine sandpaper, and if this happens, the condition is called scarlet fever.

The throat is usually very red and swollen, often with white spots on the tonsils and palate. Sometimes there are red spots on the palate as a result of bleeding. However, it is very difficult to distinguish sore throat caused by Streptococcus from viral infections. A throat culture is necessary before antibiotic is given.

The Streptococcus that causes throat infection is spread mainly by droplets from infected people to those close by. Spread of infection happens most often among family members and in indoor environment. However, not everyone in the family will get infected. Furthermore, not everyone who gets infected will develop symptoms. Some can have the infection, and mount an antibody response, without any sign of being sick. This is called asymptomatic infection.

Sore throat from streptococcal infection usually lasts several days. All the symptoms can resolve even without antibiotics. The difference in the duration of illness, with or without antibiotics, has been estimated to be a few days only. The reason for using antibiotics is to prevent the complications that I am going to describe here.

The Streptococcus can spread directly from the throat into surrounding tissues, producing abscesses and infection of lymph glands in the neck. These are uncommon complications, but they require treatment with antibiotics and sometimes surgical drainage of abscesses.

There are two uncommon complications of streptococcal infection: these are rheumatic fever and glomerulonephritis.

Rheumatic fever used to be a common and dreaded medical condition in the early part of twentieth century in North America. With improvement of general health and living condition, as well as regular use of Penicillin for Strept throat, it has become one of the rare conditions that many doctors have never seen.

Rheumatic fever usually happens several weeks following streptococcal infection of the throat. The symptoms include fever and painful swelling of one or several large joints. Many of these afflicted individuals will go on with damaged heart valves that require valve replacement many years later.

Fortunately, with the advent of Penicillin, this dreadful illness is becoming quite rare. Sporadic outbreaks still occur in North America. Other parts of the developing world are not as fortunate; rheumatic fever still occurs frequently.

Glomerulonephritis is an inflammatory condition of the kidneys. Streptococcal infection is just one of the many causes of glomerulonephritis. Fortunately, the kind of kidney problem caused by Streptococcus is relatively mild and usually improves after a few weeks to several months, with no long-term complication.

The symptoms of glomerulonephritis include lethargy, swelling of the eyelids and ankles, and passing dark tea-coloured urine. The amount of urine output is often reduced.

Although the problem is often self-limiting, the blood pressure can become quite high, causing headaches and sometimes convulsions. Luckily, the blood pressure can be monitored and treated with safe medications. Very rarely will glomerulonephritis from streptococcal infection go onto kidney failure.

Streptococcus that leads to glomerulonephritis can invade the body through the throat as well as the skin. As a result, impetigo in warmer climates is a common cause for glomerulonephritis. Occasionally, as in your daughter’s situation, there was no recognized site of infection. Most likely, the bacteria invaded her body through the throat, although she did not develop enough symptoms to warrant attention.

Your doctor had done the right thing by checking both of your younger children for Streptococcus. Sometimes throat culture can be negative even though the bacteria were there. Since both of them had received a course of antibiotic (and I assume it was an effective one), the chance is very minimal that they will develop complications.

If you are still worried, you can watch for any dark-coloured urine. Glomerulonephritis, if it is going to occur, usually happens within two to four weeks after streptococcal infection.

I should mention here that the most effective antibiotic to treat streptococcal infection is still Penicillin. There is NO antibiotic that is more powerful than Penicillin itself. Newer antibiotics tend to have a broader spectrum and kill many beneficial bacteria and induce resistance, they should not be used to treat streptococcal infections. For those individuals who have serious penicillin allergy, erythromycin and clindamycin are good alternatives.

I hope the explanation that I have given will relieve some of your worries. Relax and enjoy the summer.