Emergency Cases

Insufficient consumption of water after physical exercise may result in kidney failure


Sze-sze, a first-year student at university, took part in an orientation camp of her university. In one of its games, she and other freshers, upon instructions of senior students, had to run here and there in town under a scorching sun. Although the heat was quite unbearable, she persisted in running only because she was afraid of being labelled an unsociable person.

Muscle pain and orange urine are signs of rhabdomyolysis

After finishing their dinner in a hurry, the first-year students were required to visit every senior student in dormitory overnight. Despite reluctance, Sze-sze had no choice but went with the flow, walking up and down the building to knock at the doors of the seniors. It was when the activity came to an end at dawn she spotted out that there was something wrong with herself: other than muscle pain and weakness, she had been out of urine production for eight to nine consecutive hours. On the same day, when the group was about to continue with its schedule after lunch, Sze-sze finally felt the need for micturition and thus went to the toilet, but she was shocked by finding that her urine turned orange.

She went to the emergency room at once. After listening to her description, a doctor on duty arranged tests on kidney function and muscle enzyme with her, and rhabdomyolysis was diagnosed in the end. The doctor pointed out that kidney failure might develop if treatment was delayed.

"Why me? How could such a serious disease happen to me all of a sudden?" In denial, Sze-sze burst into tears out of fear. The doctor explained that people who rarely do physical exercise may be unaware of over-exercising themselves when they undergo strenuous physical activities. As a result, their muscles could be torn, and thus a large amount of myoglobin is released into the bloodstream.

Crystals of myoglobin block renal tubules

If replenishment of water is insufficient, the loss of body water will continue and the level of blood acidity will rise. Under these conditions, myoglobin casts will easily be formed and cause blockage in renal tubules, damaging the kidneys. This disease is rhabdomyolysis, which may lead to acute kidney failure if timely treatment is unavailable. In addition, some medicines, such as statins (a group of drugs used for elevated cholesterol), could be a factor of the disease.

The common causes of rhabdomyolysis are hard collision and prolonged crush on the muscle, as well as excessive physical exercise. Clinically, there are relatively more young males suffering from the disease. It is believed that their higher proportion of muscle is of relevance. Besides, the season of the university orientation camp is also the peak time for rhabdomyolysis.

Similar to the condition of Sze-sze, patients of rhabdomyolysis show symptoms including faintness, muscle discomfort and discolouration of urine, which may be dark or tea-coloured, at the beginning. As the kidneys are being damaged, the production of urine is likely to reduce and even cease. There have been patients who needed undergoing dialysis immediately because acute renal failure had developed only within one day since the bout of rhabdomyolysis.

There was a case in which a Hong Kong citizen who worked on the Chinese Mainland was trapped in a car after being robbed. Upon escape, the victim hurried to return to Hong Kong for clinical treatment. Owing to muscular injuries and the muscle being crushed, the victim suffered from rhabdomyolysis as a result and was required to undergo dialysis at once due to an extremely high level of muscle enzyme. Permanent dialysis might have been necessary for the patient if treatment had been delayed for two or three extra hours.

When the urine turns orange, the same situation as Sze-sze, it alerts the people to the existence of renal problem. They should therefore seek immediate medical consultation. Additionally, myoglobin itself is also broken down into substances which are harmful to the kidneys and cause direct damages to the renal tubular epithelial cells. Generally speaking, the average case fatality rate (CFR) of rhabdomyolysis is approximately 5%, while specific CFRs and possibilities for complications vary depending on different causes of the disease.

With respect to diagnosis, since myoglobin is similar with hemoglobin in terms of structure, it is possible for occult blood to happen in the paper-based urine test, but no red blood cells can be identified under the microscopy. The blood test shows creatine phosphokinase and potassium at elevated levels. When abnormal kidney function begins, the levels of creatinine and urea in blood will also rise in consequence.

Timely replenishment of water helps protect the kidneys

The most important objective of treatment is to avoid damage to the kidneys. Patients have to replenish themselves with a large amount of water, along with the use of diuretics, so as to diminish the damage to the kidneys caused by myoglobin. Doctors may, if necessary, prescribe patients medicines to make the pH value of urine alkaline with the view of hindering the crystallisation of myoglobin in the renal tubules. Once acute kidney failure occurs, immediate dialysis is necessary.

The doctor reminded Sze-sze and her schoolfellows that they should not do strenuous physical exercise merely on a whim with inadequate preparation. After such activities continue for a long while or finish, they should drink sufficient water to help excrete myoglobin from the body, reducing the chance of damage to renal function.

Sze-sze really learned a lesson from this experience and has not forced herself to take part in too vigorous activities ever since.