A Serious Case of Poisoning Caused by Oral Ingestion of Water-Soluble Fertilizer

Abstract

Current research is mostly focused on the impact of fertilizers on human health when they are ingested through food; the main form of this is chronic damage. Intoxication through oral ingestion of fertilizer is an extremely rare situation. We report a case of a 38-year-old man that attempted to commit suicide by ingesting only 20 mL of a water-soluble fertilizer. Acute kidney injury occurred early, which showed that the toxicity could not be ignored. It was necessary to seek medical attention as soon as possible. In addition, the patient experienced gastrointestinal dysfunction and a severe inflammatory response; inflammatory markers increased rapidly. Physicians implemented antimicrobial stewardship to reduce antimicrobial drug resistance and the risk of hospital infection, and the patient’s inflammatory response was well controlled. Although the damage was severe, the patient quickly recovered to normal after appropriate treatment. The prognosis is very good. This successful case provides guidance for clinical treatment.

1. Introduction

Pesticide poisoning is common in daily life. Soil and water are polluted by fertilizers, which indirectly affect people’s health through food [1]. However, poisoning caused by orally ingesting fertilizer is rare. Our department admitted a patient who ingested a water-soluble fertilizer with a large number of elements. The main components of the fertilizer are nitrogen, calcium phosphate, potassium, zinc, and boron. It is a water-soluble fertilizer with high phosphorus and potassium content. After ingesting the fertilizer, the patient developed system damage. The clinical manifestations, treatment, and prognosis of this case are described in detail.

2. Case

A 38-year-old man presented to the hospital about 4 h after orally ingesting a water-soluble fertilizer with a large number of elements. The brand name of the fertilizer is Crystal fluid phosphorus potassium, and the production address is the south side of Jinhui South Road, Ningguo Economic and Technological Development Zone. The water-soluble fertilizer contains various elements: nitrogen (N) ≥ 40 g/L, phosphorus (P₂O₅) ≥ 360 g/L, potassium (K₂O) ≥ 450 g/L, zinc (Zn) ≥ 1 g/L, and boron (B) ≥ 1 g/L. The patient intentionally consumed about 20 mL of the water-soluble fertilizer, resulting in subsequent vomiting of bright red blood and oliguria. No other symptoms were reported by the patient, who had previously been in good health. Furthermore, there was no history of hypertension, diabetes, tuberculosis, hepatitis, or any other medical conditions, and there were no drug allergies. Vital signs on admission were as follows: axillary temperature 36.5 °C, pulse 75 per minute, respiration 15 per minute, and blood pressure 136/77 mmHg (1 mmHg = 0.133 kPa). The patient remained lucid throughout the examination. Ancillary tests on admission were as follows: cholinesterase 41.5 U (reference: 30–80 U/L). As shown in Figure 1, renal-related indicators were abnormal, and renal damage occurred after oral fertilizer poisoning. Renal damage occurred early and had a progressive stage, but the patient’s renal function recovered quickly after treatment. As shown in

Table 1. Changes in renal function index after admission.

Renal Function Index	3rd Day	6th Day	Normal Range
NGAL, ng/ml	230.86	212.24	≤200
Urinary microalbumin, mg/L	110.11	30.36	0–15
Urinary β2-microglobulin, mg/L	6.15	2.52	0.1–0.3
Urinary transferrin, mg/L	4.48	2.89	0–2
Urinary a-2 macroglobulin, mg/L	5.9	3.2	0–4
uRBP, mg/L	1.42	0.91	0–0.7

NGAL—neutrophil gelatinase-associated lipocalin; uRBP—urinary retinol binding protein. Renal function recovered quickly after rehydration therapy and hemoperfusion.

and

Table 2. Changes in urine test items after admission.

Urine Test Items	3rd Day	7th Day
Urinary occult blood	1+	Negative (−)
Urinary protein	Weak positive (+−)	Negative (−)
Urinary leukocytes	Negative (−)	Negative (−)
Types of hematuria	Homogeneous type	Negative (−)
Degree of hematuria	2+	Negative (−)

Urine red blood cell testing returned to normal after treatment.

, the renal function index recovered quickly and urine red-cell phase testing returned to normal after treatment. As shown in

Table 3. Changes in inflammatory markers after admission.

Inflammatory Markers	1st Day	2nd Day	3rd Day	6th Day	Normal Range
WBCs × 109/L	21.07	11.97	11.74	8.02	3.5–9.5
NEUs, %	95.8	80.2	79.4	67.6	40–75
CRP, mg/L	0.29	27.38	13.63	4.52	0–8
PCT, ng/mL	9.07	17.29	/	/	<0.5
SAA, mg/L	92.9	11.74	/	/	0–10

WBCs—white blood cells; NEUs—neutrophils; CRP—C-reactive protein; PCT—procalcitonin; SAA—serum amyloid A protein. WBCs, NEUs, SAA, and CRP returned to normal quickly after treatment. PCT was high after treatment, but the patient had no obvious inflammation reaction.

, inflammatory markers were significantly increased, and white blood cells, neutrophils, and C-reactive protein returned to normal quickly after treatment. Procalcitonin was high after treatment, but the patient had no fever.

Other laboratory results indicated no significant abnormalities. Electrocardiogram (ECG) was normal on admission. The patient presented with hematemesis, and abdominal computed tomography (CT) was performed to screen for other causes of hematemesis. Findings on abdominal CT were as follows: local narrowing of sigmoid colon; accumulation of gas and fluid above the narrowed area; multiple gas–fluid levels; expansion of the bowel, suggesting possible obstruction; and no other significant abnormalities. On the sixth day after admission, abdomen CT revealed the primary intestinal obstruction had been basically resolved.

Combining the patient’s medical history and relevant examinations, the diagnosis was as follows: fertilizer poisoning, acute renal dysfunction, acute upper gastrointestinal hemorrhage, and incomplete intestinal obstruction.

As for treatment, because of acute upper gastrointestinal hemorrhage, the patient was not given gastric lavage. He received acid suppressants with PPIs. Hemoperfusion was performed daily for the first three days. Enemas were used to enhance poison elimination. The systemic inflammatory response was severe, and white blood cells, neutrophil percentage, CRP (C-reactive protein), and SAA (serum amyloid A protein) were significantly increased. PCT (procalcitonin) showed an increasing trend during the first two days. Serum levels of PCT were high. Due to incomplete intestinal obstruction, renal insufficiency, and fever (body temperature 37.5 °C), the patient was treated with cefperazone sulbactam sodium. Physicians implemented antimicrobial stewardship to reduce antimicrobial drug resistance and the risk of hospital infection.

3. Discussion

The overuse of fertilizers has had a negative impact on the environment and public health [1,2]. Farmers use excessive fertilizers to increase crop yields, leading to serious food poisoning [3]. Chronic poisoning due to fertilizer-contaminated foods entering the market and being absorbed by the body is common. Nitrogen fertilizers and phosphorus fertilizers are harmful to the human body, and nitrogen fertilizers can combine with the moisture on the mucous membranes to form weak alkaline ammonia, causing protein denaturation, fat saponification, and destruction of cell membrane structure, resulting in mucosal inflammation or burns. Calcium superphosphate is a water-soluble and fast-acting phosphorus fertilizer that causes skin symptoms such as rashes, burning sensations, and itching upon contact [4]. In this case, the patient ingested a water-soluble and high-phosphorus and -potassium fertilizer. The patient’s early symptoms included acute gastrointestinal bleeding and incomplete intestinal obstruction. After receiving acid suppressant with PPIs, the symptoms of gastrointestinal bleeding disappeared, and the intestinal obstruction disappeared after treatment with glycerol enema. Another study showed that regularly consuming vegetables, water, and food with high levels of lead and barium [5] may increase the risk of developing chronic kidney disease (CKDu). After investigation, the CKDu epidemic area was found to have high doses of toxic heavy metals, such as As, Pb, Cu, Ni, Cr, Zn, and Cd, in paddy soil, which were ingested through contaminated rice soil and affected human health [6]. When a 42-year-old man ingested a fertilizer containing sodium silicate, his serum creatinine increased, and a kidney biopsy showed acute tubular necrosis without infiltration of inflammatory cells [7]. The patient in this case study developed acute renal dysfunction after orally taking a water-soluble elemental fertilizer. His cardinal clinical symptoms included oliguria, elevated creatinine, hematuria, and proteinuria. After appropriate treatment with hemoperfusion, fluid replacement, etc., the patient’s urine output returned to normal, the patient’s renal function recovered completely, and hematuria and proteinuria disappeared. The patient was followed up for 3 months and he has completely returned to normal. But patients recover slowly when the damage is caused by chronic poisoning.

Fertilizers not only affect the kidneys and gastrointestinal tract, but also increase the risk of congenital defects in newborns and the risk of hypertension. One investigation found that Pingding County in southeastern China was a high-risk area for birth defects at the village level, and the use of fertilizers was associated with the occurrence of birth defects after adjusting for confounding factors at the individual level. After adjusting for confounding factors, the risk of birth defects for mothers with fertilizer use of at least 65 tons per year increased by 2.06 times (95% confidence interval 1.23–3.46) [8]. Between 2012 and 2015, the China Hypertension Large Sample Study included 31 provinces, 221 counties (cities and districts), and 379,467 survey subjects aged 18 years or older. The study found that compared with those with college or higher education, the risk of hypertension was increased in those with high school, junior high school, and elementary school or lower education, with values of 1.16 (1.12–1.21), 1.25 (1.20–1.30), and 1.49 (1.43–1.55), respectively [9]. Apart from that, humans inhaling poisonous gases released by P-fertilizer industry plants can develop hepatic failure, autoimmune diseases, and pulmonary disorders [10]. A case of acute methemoglobinemia caused by suicidal ingestion of a nitrate-containing liquid fertilizer was described [11]. Poisoning symptoms are different due to different ways of ingestion and types of fertilizer. It can be seen that the impact of fertilizers on human health is ubiquitous.

4. Conclusions

Current research is mostly focused on the impact of fertilizers on human health when they are ingested through food. The main form of this is chronic damage. Oral fertilizer ingestion will directly affect human health. In this case, we found that although the dose of oral fertilizer was small, organ function damage appeared early, which showed that the toxicity of fertilizers cannot be ignored. It was necessary to seek medical attention as soon as possible. In addition, the patient developed a severe inflammatory response, with increased inflammatory markers, especially PCT. Therefore, we had to pay attention to the selection of antibiotics. We could not choose restricted-grade antibiotics because of elevated inflammatory markers; this would also have increased the risk of drug resistance and hospital infection. However, the patient was able to recover after receiving appropriate treatment in a short period of time, and his prognosis is very good. This successful case provides guidance for clinical treatment.