IMPACT OF VENOMOUS ANIMAL BITES ON RENAL FUNCTION: AN ANALYSIS OF THREE CLINICAL CASES

The bites of venomous animals are a significant concern for global health, often leading to a wide range of clinical manifestations and complications (1)(2). These poisonings can result from bites or stings from various creatures, including snakes, spiders, and insects. Although the immediate effects of these poisonings are well-documented, the long-term impact on organic systems, particularly renal function, remains an area of ongoing research.

The kidneys play a fundamental role in maintaining the body's internal balance by regulating fluid and electrolyte balance and removing waste products from the bloodstream. In this context, they are particularly vulnerable to the systemic effects of venom toxins introduced during a poisoning event. While numerous case reports and clinical studies have detailed the consequences of venomous animal bites on renal health, comprehensive analyses focused on the collective experiences of multiple cases are relatively limited.

This study presents a detailed examination of three distinct clinical cases, each involving a different type of encounter with venomous animals, with a specific focus on the impact on renal function. By analyzing these cases collectively, we aim to provide a broader understanding of the varied clinical presentations and long-term renal consequences associated with poisonings. Additionally, we intend to shed light on possible diagnostic and management strategies to optimize patient outcomes in such scenarios.

The study references work by Moura Silva et al in Brazil, indicating that the most frequent ophidian accident is caused by the Bothrops genus. Similarly, a study by Cedeño and Toro in Peru concludes that this snake genus records the highest cases of renal insufficiency (16.43%) (3)(4). In Paraguay, especially in border departments with Brazil, Bothrops envenomation is also the most frequent (5).

Botropic envenomation is characterized by being proteolytic, coagulant, and hemorrhagic, with potential effects on both local and systemic levels, including renal involvement that may progress to acute kidney injury with anuria, and coagulation disorders, and hemodynamic instability (6)(7).

The violin spider, known as 'ñandupé' in Paraguay, belongs to the Loxosceles genus and is medically relevant due to its bite causing necrosis, hemolytic anemia, and severe renal failure, sometimes with fatal consequences. The toxicity of the violin spider's venom in humans is attributed to phospholipases D, metalloproteases, and cystine knot inhibitors (8)(9).

Within insect bites, it's crucial to differentiate between bee and wasp stings, noting that a bee's stinger remains embedded in the skin after the sting, leading to its death, while a wasp's stinger does not, allowing it to sting multiple times. Wasp venom contains inflammation mediators, hyaluronidase, and antigenic proteins responsible for anaphylactic reactions (10).

The clinical nature of hymenopteran envenomations contrasts with other animal venoms, including other arthropods, primarily because allergic reaction, not direct intoxication, is the primary concern. Clinically significant toxic envenomations by bees require a massive number of stings, often in the range of hundreds to thousands, although a smaller number of stings causing severe conditions have been reported, and some individuals have survived several thousand stings or, in the case of a baby, several hundred stings (11).

During the period from January 2022 to November 2023, one spider bite, one snakebite, and one bee sting accident were reported, all requiring hemodialytic treatment.

In our hospital center, consultations for insect bites are infrequent, making this case report particularly significant.

Retrospective observational study of a quantitative descriptive nature with a non-experimental design.

Case one:

A 44-year-old male patient with a pre-hospital scenario of a violin spider (ñandupe) insect bite approximately 15 days ago, presenting cellulitis in the lower limb. He reports delayed consultation and subsequent admission to the Chaco hospital. Twenty-four hours later, he requests voluntary discharge and comes to our hospital, where he is admitted to the Intensive Care Unit for hemodynamic monitoring. The patient is in a fair overall condition, lucid, afebrile, eupneic, with stable hemodynamics requiring vasopressors, a urinary output of 1800 ml/12 hrs, and no presence of edema. Antibiotic therapy with piperacillin + tazobactam and vancomycin is administered, adjusted according to estimated glomerular filtration rate (eGFR). The patient undergoes surgery for debridement of necrotic tissue and fasciotomy in the area affected by the post-spider bite infectious process.

Vital signs:

Blood pressure: 116/60 mmHg Heart rate: 94 bpm Temperature: 36.5°C Oxygen saturation: 99%

Admission diagnoses:

1. Acute Renal Failure

2. Loxosceles spider bite (ñandupe)

3. Septic shock involving skin and soft tissues

4. Necrotizing fasciitis of the right lower limb

5. Immediate postoperative state after debridement and fasciotomy of the right lower limb

6. Cellulitis of the posterior aspect of the right lower limb

7. Type 2 Diabetes Mellitus

Hemodialysis is initiated, and serology for Hepatitis B, Hepatitis C, HIV is requested. Approximately 48 hours after admission to our hospital, daily hemodialysis treatment begins, completing a total of ten sessions.

See tabla 1.

Final Diagnoses:

1. Pre-renal Acute Kidney Injury (AKI)

2. Septic shock originating from the skin and soft tissues due to Hemolytic Group A Streptococcus B or pyogenes.

3. Necrotizing fasciitis of the right lower limb.

4. Compartment syndrome of the right lower limb.

5. Postoperative state after debridement and fasciotomy of the right lower limb.

6. Cellulitis of the right lower limb following a spider bite (ñandupe).

7. Type 2 Diabetes Mellitus.

8. Severe anemia.

The patient maintains urinary output through a bladder catheter with physiological values, but with a worsening general condition, leading to a decision to transfer to a more complex hospital where the patient eventually passes away.

Case two:

A 33-year-old male patient with a history of bee stings. Information provided by the patient and accompanying family is credible. They report that approximately 18 days ago, the patient was stung by a wasp. They cannot specify the quantity but describe being completely surrounded, receiving stings on the face, anterior chest, and limbs. Four days ago, he sought medical attention due to general malaise, nausea, vomiting, and respiratory distress, initiating oral treatment. With worsening symptoms, he decided to go to the emergency department at the Regional Hospital of Concepción, where Kussmaul breathing, dry mucous membranes, and a distressed facial expression were observed.

Upon admission, the patient is conscious and cooperative. Stable hemodynamics with a tendency towards tachycardia and hypertension, tachypneic with poor respiratory mechanics. The patient is anuric.

Vital signs:

Blood pressure: 183/110 mmHg Heart rate: 132 bpm.

Oxygen saturation: 95% with supplemental oxygen at 10 liters through a facial mask.

Axillary temperature: 36°C.

Admission to the Adult Intensive Care Unit (AICU):

Admitted on a stretcher, accompanied by nursing staff, with psychomotor agitation, Glasgow Coma Scale 12/15 due to the absence of verbal response, poor respiratory mechanics with oxygen through a facial mask, stable hemodynamics, indwelling urinary catheter with no output.

Sedation and orotracheal intubation are performed for mechanical respiratory assistance (MRA), obtaining central venous access for hydration/medication, and femoral venous access with a double-lumen catheter for hemodialysis.

VITAL SIGNS: HR: 89 BP: 125/67 RR: 16 SPO2: 100% TEMP: 35.5°C

AICU Admission Diagnosis:

1. Acute renal failure.

2. Severe acute respiratory failure requiring MRA.

3. Severe metabolic acidosis.

4. Severe hyperkalemia.

5. Severe dehydration.

See tabla 2.

An emergency conventional hemodialysis session is initiated with zero net ultrafiltration for two hours, with good tolerance to the treatment.

Final Diagnoses:

1. Spider bite.

2. Pre-renal acute kidney injury.

3. Mixed shock (hypovolemic and septic).

4. Necrotizing fasciitis of the right lower limb.

5. Compartment syndrome.

6. Postoperative state after debridement and fasciotomy of the right lower limb.

7. Cellulitis of the posterior right lower limb.

8. Type 2 Diabetes Mellitus.

9. Severe anemia.

The patient, with a progressively deteriorating general condition, undergoes nine hemodialysis sessions without improvement and eventually passes away on day XX.

Case three:

81-year-old patient with a history of snakebite three days ago, currently experiencing acidotic breathing with O2 support through a facial mask with a reservoir, obstructive-appearing anuria due to a distended bladder. The patient reports having normal urination characteristics before this event, with a history of prostate surgery.

Vital signs:

BP: 184/100 mmHg HR: 97 bpm RR: 31 bpm SPO2: 100%

See tabla 3.

Diagnoses:

1. Acute renal failure.

2. Brotropic snakebite.

3. Acute urinary retention of undetermined etiology.

4. Arterial hypertension.

There is a clear need for a more comprehensive understanding of the diverse clinical presentations and long-term renal health consequences associated with injuries caused by venomous animals. The analysis of cases revealed the diversity of renal effects produced by different types of bites. The importance of considering bites from snakes of the Bothrops genus, bites from the violin spider (ñandupé), and bee stings was emphasized, underscoring the medical relevance of these events. The bite of the violin spider was associated with necrosis, hemolytic anemia, and severe renal failure due to the toxicity of its venom. On the other hand, the need to consider allergic reactions to bee stings was highlighted, which can have significant clinical consequences, especially in cases of multiple stings.

Emphasis is placed on the complexity and severity of renal effects caused by these bites, underscoring the importance of prompt and appropriate clinical management since the time elapsed between the bite and the initiation of treatment can make the difference between life and death.