Mystery Kidney Disease in Nicaragua

Kidney failure in men is a lot more common in Nicaragua than in North America. The usual causes in Canada and the US are high blood pressure and diabetes, but these are not the explanation in Nicaragua.

Dialysis and transplantation are not practical options in Nicaragua, so when a young man develops end stage kidney failure, this means the individual will die. 

Nicaragua is struggling to offer basic primary care and does not have the resources to investigate this serious health problem. International interest has resulted in some research and a variety of risk factors have been identified. I did a Google Scholar literature search with the words kidney and Nicaragua, and 15 articles were identified in the world medical literature.

A 2010 article reported on a community based survey of individuals in five villages in Northwest Nicaragua. Eighteen (18) percent of the men in the community had an abnormal serum creatinine, which is the main laboratory marker of kidney failure. This is six times higher than the prevalence in Canada!

Occupation appears to have a major influence on the prevalence. The table below shows the differences in prevalence of an abnormal serum creatinine by occupation.

Other reports have also noted the higher prevalence in the farming and sugarcane sectors.

Age is clearly a factor. The prevalence increases with age.

Dehydration is a commonly reported consideration, which makes perfect sense, because as dehydration worsens, blood flow to the kidney decreases, and the risk of kidney damage increases. One article reported that sugarcane workers are paid based on how many tons of sugarcane they harvest. The incentive is therefore to work longer hours and to take fewer breaks, which results in more severe dehydration. The same report noted that some men lose up to 5 pounds over a work day! Fear of contaminated water might be another reason why the workers drink so little. Makes no sense, since better hydration would improve their mental alertness and physical energy. Sounds crazy that men would continue to work while so thirsty, but I can imagine that this does happen. History is replete with workers suffering under terrible conditions to earn a living for their family.

Likely there are additional factors. Pesticides are mentioned as a possible kidney toxin. The plantations in Nicaragua use chemicals that are banned in Canada. Modern safety precautions to protect workers are not usually practiced.

Treatment with diuretic, non-steroidal anti-inflammatory, and antibiotic medications might play a role. These are common treatments for "urine infection" in Nicaragua.

The general population knows about the Mystery Kidney Disease, and the populace is worried. I experienced this concern in my previous visits. Many mothers wanted me to check their child for urine infection. This heightened concern for urine problems perplexed me at first, but once I learned about the Mystery Kidney Disease problem, I understood.

The at-risk men who work as sugarcane workers often complain of chistata. A common symptom of chistata is discomfort with voiding. Discomfort with voiding is a typical symptom of infection in the bladder or urethra, but this is also a symptom associated with severe dehydration because the urine is very concentrated (dark) and in this situation, tiny crystals of calcium, phosphate, oxalate, or uric acid can precipitate out in the urine, and these crystals can be painful to pass. However, the discomfort with voiding in men with chistata is mostly presumed to be due to urine infection and since some of these men develop kidney failure, there is a common perception that the kidney failure is due to urine infection. The general population believe this and so do the many of the physicians.

The physicians I met on prior visits commonly over treat children and adults for possible urinary tract infection. Any urine symptom at all, or any positive urine dipstick test is usually treated with an antibiotic. This didn't make any sense to me and my first thought was that the medical education system in Nicaragua was to blame for the over-diagnosis and over-treatment. Now, I realize that the physicians might not be any more objective than the mothers! A recent article confirms my observations. Based on interviews, the study reported that pharmacists and physicians commonly prescribed antibiotics for individuals with "chistata." Other commonly prescribed medications included diuretics and non-steroidal anti-inflammatory agents. All of these medications are potentially toxic to the kidneys, especially in a dehydrated individual. It is possible, therefore, that local treatment practices are a factor! A very plausible scenario for the Mystery Kidney Disease might be repeated episodes of dehydration, treatment with medications toxic to the kidney while dehydrated, and time. 

Since Gigante, the community where I will help out as a paediatrician, is a fishing village, and since fishermen are at risk, during a visit I will talk to the mothers about the vital importance of hydration. As with families everywhere, if the mother understands, there is a good chance that all the family members will benefit.

References

Torres C et al. Decreased Kidney Function of Unknown Cause in Nicaragua: A Community-Based Survey. AJKD 2010;55:485-96.

Ramirez-Rubio O et al. Chronic Kidney Disease in Nicaragua: a Qualitative Analysis of Semi-structured Interviews with Physicians and Pharmacists. BMC Public Health 2013;13:350

Originally published on Helping Children in Nicaragua and Haiti