Case 14 - Complete Analysis: Rodenticide Poisoning

Patient Summary

Vitals Over 5 Days

• The fever spike on D4 and drop in SpO2 to 93% suggest a secondary infection or aspiration event, which explains why piperacillin-tazobactam was given.

Laboratory Investigations - What Was Elevated and Why

1. Serum Amylase: 722 U/L (HIGH - normal: 30-110 U/L)

2. PT/INR (Coagulation Screen) - MARKEDLY ELEVATED

• Inhibit Vitamin K epoxide reductase (VKOR) enzyme
• Block regeneration of active Vitamin K (Vitamin K hydroquinone)
• This depletes Vitamin K-dependent clotting factors: II (prothrombin), VII, IX, and X
• The result is a dramatically prolonged prothrombin time/INR

3. Liver Function Tests (LFTs) - PROGRESSIVELY WORSENING

1. Direct hepatotoxicity of the rodenticide: Many rodenticide compounds are hepatotoxic. The dramatic rise in SGOT/SGPT to >1000 IU/L indicates acute hepatocellular necrosis.
2. Alcoholic liver background: The ultrasound showed hepatomegaly with fatty liver, confirming pre-existing alcoholic liver disease. This makes the liver far more vulnerable to toxic insults.
3. Rising bilirubin (predominantly direct/conjugated): The shift toward direct bilirubin (5.2 out of 8.7 mg/dL) suggests intrahepatic cholestasis from hepatocyte dysfunction - damaged hepatocytes cannot excrete conjugated bilirubin into bile.
4. Falling albumin (4.2 → 3.9) and falling total protein: Reflects declining synthetic function of the liver - a marker of severity.
5. The transaminases (SGOT/SGPT) rise to >1000 IU/L by Day 4-5, representing acute-on-chronic liver injury (toxic hepatitis on a background of alcoholic fatty liver).

4. Electrolytes

5. CBC Findings

• WBC: 3.47 × 10³/µL (leukopenia) - may reflect bone marrow suppression
• Monocytes: 13.5% (elevated) - reactive monocytosis from toxic/inflammatory state
• Eosinophils: 0.1% (low)
• MCHC: 30.7 g/dL (low) - suggests hypochromic anemia, consistent with chronic alcoholism or blood loss from GI erosions

6. ECG: T-wave Abnormality in II, III, aVF, V1-V6

• The widespread T-wave changes (inferior and precordial leads) likely reflect electrolyte imbalance (hypokalemia and hyponatremia) and/or autonomic/metabolic effects of toxin-induced multi-organ dysfunction.
• Hypokalemia classically flattens or inverts T-waves.

7. Ultrasound Abdomen: Hepatomegaly with Fatty Liver

8. Endoscopy Findings: Gastroduodenitis + Edematous Mucosa (D1) + Erosions at Cardia and Body of Stomach

9. HCV: Negative

10. Serum Creatinine: 1.8 → 1.7 → 1.6 mg/dL (Elevated - normal < 1.2)

• Reduced renal perfusion (hypotension on D3-D4)
• Direct nephrotoxicity from the rodenticide metabolites
• Hepatorenal physiology (liver failure reducing effective renal perfusion) The improving trend (1.8 → 1.6) suggests response to IV fluid resuscitation.

Treatment Plan - Drug-by-Drug Explanation

1. Inj. Pipnios (Piperacillin + Tazobactam) - 4.5g IV BD

• Broad-spectrum antibiotic for the fever (101°F on D4), leukopenia, and endoscopy-confirmed mucosal erosions that pose an infection risk.
• Piperacillin is an extended-spectrum penicillin; tazobactam is a beta-lactamase inhibitor that protects it from resistant Gram-negative bacteria.
• Used to prevent/treat secondary bacterial infection (e.g., aspiration pneumonia, wound infection, translocation from the damaged gut mucosa), and to cover gastroduodenitis with mucosal breaks.
• Given on D1-D4, consistent with covering the fever episode.

2. Inj. NAC (N-Acetylcysteine) - 10mg IV BD

• Hepatoprotective agent - the most important drug for liver rescue in toxic hepatitis.
• Mechanism: NAC replenishes glutathione stores in hepatocytes. Glutathione is the liver's main antioxidant that neutralizes toxic free radicals generated by rodenticide metabolites.
• Goldman-Cecil Medicine confirms: "N-acetylcysteine is commonly recommended in acute liver failure caused by idiosyncratic drug-induced liver injury and hepatitis," and is established as the treatment for toxic hepatocellular injury.
• Given the SGOT/SGPT rising to >1000 IU/L and bilirubin to 8.7, early NAC is appropriate to limit further hepatocyte necrosis.

3. Inj. Vit-K (Phytomenadione) - 10mg IV BD

• Direct antidote for coumarin/anticoagulant rodenticide poisoning.
• Mechanism: Rodenticides inhibit Vitamin K epoxide reductase; supplementing with Vitamin K1 (phytomenadione) bypasses the block by providing exogenous active Vitamin K.
• This restores production of clotting factors II, VII, IX, and X.
• The Tietz Textbook confirms: "Acute vitamin K deficiency tends to manifest as a bleeding tendency because of inadequate vitamin K-dependent coagulation factors; this can be treated with phytomenadione."
• The PT/INR (up to 2.3) is the direct biochemical justification for this drug.

4. Inj. Pontin (Pantoprazole) - 40mg IV BD

• Proton pump inhibitor to suppress gastric acid secretion.
• Protects the erosive gastroduodenitis seen on endoscopy from further acid damage.
• Promotes healing of gastric and duodenal erosions/ulcers by raising gastric pH > 4, reducing peptic injury.
• Essential when endoscopy shows active mucosal erosions.

5. Inj. Vonikind (Ondansetron) - 4mg IV TID

• 5-HT3 receptor antagonist antiemetic - controls nausea and vomiting.
• The patient presented with vomiting at admission. Ongoing vomiting causes fluid/electrolyte loss and prevents oral medication absorption.
• Also prevents aspiration risk in a toxic-metabolic state.

6. Inj. Tramasure (Tramadol) - 2mg in 100mL NS IV SOS

• Opioid agonist/weak analgesic for pain relief (SOS = as needed).
• Addresses abdominal pain from pancreatitis/gastroduodenitis/hepatic inflammation.
• Used at low dose (2mg) in 100mL NS infusion to minimize hepatic metabolism burden.

7. Syr. Duphalac (Lactulose Solution) - 15mL PO TID

• Non-absorbable synthetic disaccharide used to prevent/treat hepatic encephalopathy.
• Mechanism: In the colon, gut bacteria degrade lactulose into lactic acid and acetic acid. This acidifies the colon, trapping ammonia (NH3 → NH4+) which is then excreted in stool. This reduces blood ammonia levels.
• Rosen's Emergency Medicine states: "Management of hepatic encephalopathy includes lactulose (30-60g/day)."
• Also acts as an osmotic laxative, evacuating nitrogenous waste from the gut.
• Indicated here because the patient has acute liver failure (SGOT/SGPT >1000, bilirubin 8.7) putting him at risk of encephalopathy.

8. IV Fluids (10 NS + 20 RL) at 100mL/hr

• Fluid resuscitation and electrolyte correction.
• Normal Saline corrects hyponatremia (Na 133) and hypovolemia from vomiting/reduced intake.
• Ringer's Lactate (RL) provides balanced electrolyte replacement and mild alkalinizing effect.
• Supports renal perfusion (to address the elevated creatinine 1.8 mg/dL).

9. Inj. Buscopan (Hyoscine Butylbromide) - 10mg IV BD (started D3)

• Anticholinergic/antispasmodic agent.
• Relieves abdominal cramps, spasms, and colic caused by gastroduodenitis and intestinal irritation from the toxic ingestion.
• Given from D3 onwards once GI motility complaints were prominent.

10. Syr. Kralfate-O (Sucralfate + Oxetacaine) - 10mL PO TID (1hr before food)

• Sucralfate forms a protective barrier over ulcerated/eroded gastric mucosa by binding to damaged tissue and acting as a physical coating against acid and pepsin.
• Oxetacaine is a local anesthetic that reduces pain from the esophageal and gastric erosions (seen on endoscopy at cardia and body of stomach).
• Together they protect and soothe the damaged mucosal lining, especially relevant given the endoscopic finding of erosions.

11. Inj. Meniplus (Mannitol 20%) - 10mL/100mL IV BD (started D4)

• Osmotic diuretic to reduce cerebral edema in the context of acute liver failure.
• Acute liver failure can cause cytotoxic cerebral edema as part of hepatic encephalopathy progression (grades III-IV).
• Mannitol (20%) draws water out of brain cells by creating an osmotic gradient, reducing intracranial pressure.
• Its introduction on D4 (when bilirubin spiked to 6.6, SGOT 986, creatinine peaked at 1.8) aligns with worsening liver failure and encephalopathy risk.

12. T. Rifagut-50 (Rifaximin) - 550mg PO BD (started D4)

• Minimally absorbed antibiotic specifically used for hepatic encephalopathy prevention and treatment.
• Mechanism: Rifaximin kills ammonia-producing gram-negative bacteria in the gut (mainly coliform organisms), reducing the amount of ammonia absorbed into portal blood.
• Sabiston Textbook of Surgery states: "Rifaximin is an antibiotic that eradicates gram-negative bacilli responsible for ammonia generation in the bowel. Guidelines recommend using rifaximin as an adjunct to lactulose."
• Started on D4 as a combination with lactulose for maximal ammonia control, indicating the team was managing overt or impending hepatic encephalopathy.

Clinical Synthesis - Why This Pattern of Multi-Organ Involvement?

1. Ingestion → Immediate GI mucosal damage (gastroduodenitis, erosions on endoscopy) + vomiting
2. Absorption of toxin → Vitamin K epoxide reductase inhibition → elevated PT/INR
3. Hepatotoxic metabolites + pre-existing alcoholic liver disease → acute-on-chronic hepatocellular injury (SGOT/SGPT >1000, bilirubin rising to 8.7)
4. Liver failure → reduced albumin/protein synthesis, coagulopathy, risk of encephalopathy (Lactulose + Rifaximin + Mannitol added)
5. Reduced renal perfusion + direct nephrotoxicity → AKI (creatinine 1.8, improving with fluids)
6. Fever D4 + erosive mucosa → secondary infection risk (Pip-Taz antibiotic given)
7. Electrolyte imbalance (hyponatremia, hypokalemia, hypochloremia) from vomiting + liver failure → ECG T-wave changes