Animal Bite — Adults

Antivenom-trigger values. Tap any lab for what to watch for and the next clinical action.

• ▸Platelets <150k (critical <50k) — venom-induced thrombocytopenia; bleeding risk

  Watch for

  Petechiae, gingival bleeding, ecchymoses extending beyond bite, oozing from IV sites, hematuria, melena. Trend q4–6h ×24h then q24h.

  Next action

  Give or re-dose antivenom (CroFab 4–6 vials, repeat until control). Transfuse platelets only for clinically significant bleeding or platelets <20k — antivenom first; transfused platelets are consumed without it. Hold anticoagulants/NSAIDs.
• ▸Fibrinogen <150–200 mg/dL (critical <100) — consumptive coagulopathy; bleeding / DIC

  Watch for

  Bleeding at IV sites, mucosal bleeding, expanding hematoma, falling Hgb. Especially with concurrent ↓ platelets and ↑ INR (DIC pattern).

  Next action

  Re-dose antivenom (CroFab 4–6 vials). Cryoprecipitate 10 units only for active bleeding (transient without antivenom). Type & cross 2 units PRBC. Alert blood bank for possible MTP.
• ▸INR >1.2 (critical >3) — venom-induced coagulopathy

  Watch for

  Spontaneous bruising, bleeding from puncture sites, hematuria, intracranial bleed (any AMS or new headache → STAT non-contrast head CT).

  Next action

  Re-dose antivenom (CroFab 4–6 vials, repeat q1h until INR <1.5 and stable). FFP only for life-threatening bleeding (transient without antivenom). Recheck PT/INR q4–6h.
• ▸aPTT prolonged (>1.5× ULN) — intrinsic pathway disruption

  Watch for

  Bleeding pattern with normal INR (factor-specific consumption). Trend with INR and fibrinogen for full coagulopathy picture.

  Next action

  Re-dose antivenom. Avoid heparin and other anticoagulants. Recheck q4–6h until trending down.
• ▸D-dimer elevated (often markedly) — venom-driven fibrinolysis; supports envenomation

  Watch for

  Combined with ↓ fibrinogen, ↓ platelets, ↑ INR → DIC. Persistent elevation 3–7 d post-CroFab signals recurrent coagulopathy.

  Next action

  Treat as part of coagulopathy workup — re-dose antivenom if other parameters worsening. Schedule outpatient labs day 2–3 and 5–7 for recurrence.
• ▸Hgb drop ≥2 g/dL — hemolysis or local/systemic bleeding

  Watch for

  Expanding limb circumference, compartment syndrome (pain out of proportion, tense compartment, paresthesia), GI bleeding, hematuria, hypotension, tachycardia.

  Next action

  Type & cross, transfuse PRBC if symptomatic or Hgb <7 (Hgb <8 if cardiac disease). Re-dose antivenom. Surgical/ortho consult for suspected compartment syndrome — measure pressures (do NOT fasciotomize without confirmed elevated pressure; antivenom usually resolves swelling).
• ▸CK >1,000 U/L — rhabdomyolysis (local tissue injury or Mojave myotoxin)

  Watch for

  Tea-colored urine, muscle pain/weakness, oliguria, ↑ K⁺, ↑ Cr. Mojave envenomation can cause systemic myotoxicity with delayed respiratory weakness.

  Next action

  IV crystalloid at 1.5–2× maintenance, target urine output 1–2 mL/kg/h. Monitor K⁺ and Cr q4–6h. Re-dose antivenom. For Mojave-pattern weakness, monitor airway and consider ICU.
• ▸Cr ↑ >1.5× baseline — AKI from rhabdo, hemolysis, or hypoperfusion

  Watch for

  Oliguria (<0.5 mL/kg/h), rising K⁺, metabolic acidosis, fluid overload. Trend BMP q4–6h.

  Next action

  IV crystalloid resuscitation, hold nephrotoxins (NSAIDs, contrast). Treat underlying cause (antivenom for ongoing envenomation, transfuse for bleeding). Nephrology consult if Cr doubles or oliguria persists; dialysis for refractory hyperkalemia, acidosis, or volume overload.
• ▸K⁺ >5.5 mEq/L — hyperkalemia from hemolysis / rhabdo

  Watch for

  Peaked T waves, widened QRS, loss of P waves, sine wave on ECG. Get STAT 12-lead ECG for any K⁺ >6.0 or rising rapidly.

  Next action

  If ECG changes: calcium gluconate 1–2 g IV (membrane stabilization), then insulin 10 U + D50 1 amp, albuterol 10–20 mg neb, sodium bicarb if acidotic. Definitive: dialysis if refractory or AKI. Treat rhabdo source (fluids, antivenom).

Any new/worsening abnormality → give or re-dose antivenom. Recurrent coagulopathy is common 2–7 days post-CroFab — recheck CBC + coags at outpatient follow-up day 2–3 and 5–7.

Order if suspected systemic loxoscelism, severe widow envenomation, or hemolysis/AKI signs. Tap any lab for what to watch for and the next clinical action.

• ▸Hgb drop ≥2 g/dL with ↑ retics — Loxosceles intravascular hemolysis

  Watch for

  Pallor, tachycardia, dark urine, jaundice, fatigue. More common in children and within 24–72 h of bite.

  Next action

  Type & cross, transfuse if symptomatic or Hgb <7 (<8 if cardiac disease). Admit for monitoring; trend CBC q6–12h. Hematology consult if severe. Steroids/dapsone are NOT proven — supportive care.
• ▸Platelets <100k — DIC from severe loxoscelism

  Watch for

  Petechiae, mucosal bleeding, oozing IV sites, falling Hgb. Combined with ↑ INR / ↓ fibrinogen confirms DIC.

  Next action

  Admit ICU. Treat underlying envenomation/sepsis. Transfuse platelets only for active bleeding or <20k. Hematology consult.
• ▸INR / aPTT prolonged, fibrinogen <150, D-dimer ↑ (DIC pattern) — consumptive coagulopathy

  Watch for

  Bleeding from multiple sites, microvascular thrombosis (purpura, organ dysfunction). Trend coags q6h.

  Next action

  ICU admission. Treat underlying cause. FFP and cryoprecipitate ONLY for active bleeding (transient). Platelets <20k or active bleeding.
• ▸CK >1,000 U/L — rhabdomyolysis (severe envenomation)

  Watch for

  Muscle pain (especially with widow autonomic crisis), tea-colored urine, ↑ K⁺, ↑ Cr.

  Next action

  IV crystalloid 1.5–2× maintenance, target UOP 1–2 mL/kg/h. Monitor BMP q4–6h. Pain control with opioids + benzos for widow cramping (reduces muscle injury).
• ▸Cr ↑ >1.5× baseline — AKI from hemolysis / rhabdo

  Watch for

  Oliguria, rising K⁺, acidosis. Trend BMP q4–6h.

  Next action

  IV fluids, hold nephrotoxins. Nephrology consult if doubling or oliguria. Dialysis for refractory hyperkalemia or volume overload.
• ▸K⁺ >5.5 mEq/L — hyperkalemia from hemolysis / rhabdo

  Watch for

  STAT 12-lead ECG: peaked T waves, widened QRS, sine wave.

  Next action

  If ECG changes: calcium gluconate 1–2 g IV, insulin 10 U + D50, albuterol 10–20 mg neb, bicarb if acidotic. Dialysis if refractory.
• ▸UA cola-colored, +blood without RBCs — hemoglobinuria / myoglobinuria

  Watch for

  Concurrent ↑ CK (myoglobin) vs ↓ haptoglobin / ↑ LDH (hemoglobin). Distinguish source — both injure tubules.

  Next action

  Aggressive IV crystalloid to maintain UOP. Avoid bicarbonate alkalinization unless documented severe rhabdo with persistent acidosis. Recheck UA + CK q6h.
• ▸LDH ↑, haptoglobin ↓, indirect bili ↑ (hemolysis triad) — intravascular hemolysis

  Watch for

  Falling Hgb, jaundice, dark urine, splenomegaly. Peripheral smear: schistocytes (microangiopathic) vs spherocytes.

  Next action

  Type & cross, hematology consult. Transfuse for symptomatic anemia. Supportive care; no specific antivenom for Loxosceles in US.
• ▸Lactate >2 mmol/L — hypoperfusion in widow autonomic crisis

  Watch for

  Severe HTN with sympathetic surge, then potential collapse, tachycardia, end-organ ischemia.

  Next action

  IV opioids + benzos for cramping/HTN. Latrodectus antivenom for severe (HTN crisis, pregnancy, peds, refractory) — pre-medicate for anaphylaxis. ICU monitoring.

Order in severe bites or signs of sepsis. Tap any lab for what to watch for and the next clinical action.

• ▸Hgb drop ≥2 g/dL — hemorrhage; trigger transfusion

  Watch for

  Hypotension, tachycardia, pale/cool skin, ongoing wound bleeding, expanding hematoma. Recheck after each transfusion.

  Next action

  Type & cross 4 units PRBC. Activate MTP if class III/IV shock. Direct pressure / tourniquet for limb hemorrhage. Surgical/vascular consult for operative control.
• ▸Platelets <100k — trauma-induced coagulopathy / DIC

  Watch for

  Mucosal bleeding, oozing IV sites, persistent wound bleeding despite local control.

  Next action

  Transfuse platelets if <50k with active bleeding or <20k. Concurrent FFP and cryo per MTP ratios (1:1:1). Treat underlying shock and infection.
• ▸INR >1.5, fibrinogen <150, D-dimer ↑ (coagulopathy) — trauma coagulopathy / DIC

  Watch for

  Bleeding from multiple sites, microvascular thrombosis. Combined with ↓ platelets confirms DIC.

  Next action

  FFP 10–15 mL/kg, cryoprecipitate 10 units (target fibrinogen >150–200). TXA 1 g IV within 3 h of injury. Treat shock and source.
• ▸Lactate >4 mmol/L — shock / hypoperfusion; sepsis

  Watch for

  Tachycardia, hypotension, AMS, oliguria. Recheck q1–2h to assess resuscitation response.

  Next action

  Aggressive crystalloid (30 mL/kg), blood products as needed, vasopressors (norepi) for MAP >65. Broad-spectrum antibiotics within 1 h. Source control (debridement). ICU.
• ▸CK >1,000 U/L — rhabdomyolysis from crush

  Watch for

  Tea-colored urine, muscle pain, ↑ K⁺, ↑ Cr, compartment syndrome (pain out of proportion, tense compartment).

  Next action

  IV crystalloid 1.5–2× maintenance, target UOP 1–2 mL/kg/h. Monitor BMP q4–6h. Surgical consult for compartment syndrome (measure pressures, fasciotomy if >30 mmHg).
• ▸Cr ↑ >1.5× baseline — AKI from shock / rhabdo

  Watch for

  Oliguria, rising K⁺, acidosis, fluid overload.

  Next action

  IV fluids, hold nephrotoxins, optimize perfusion. Nephrology consult if doubling. Dialysis for refractory hyperkalemia, acidosis, or volume overload.
• ▸K⁺ >5.5 mEq/L — rhabdo / massive transfusion

  Watch for

  STAT 12-lead ECG: peaked T waves, widened QRS, sine wave. Risk highest after multiple PRBC units.

  Next action

  If ECG changes: calcium gluconate 1–2 g IV, insulin 10 U + D50, albuterol neb, bicarb. Use washed/fresh PRBC for ongoing transfusion. Dialysis if refractory.
• ▸WBC >15k or <4k with bands — Vibrio / Aeromonas sepsis

  Watch for

  Rapidly progressive hemorrhagic bullae (Vibrio vulnificus — esp. cirrhotic, immunocompromised), high fever, hypotension. Mortality >50% if delayed.

  Next action

  Doxycycline + ceftriaxone (or cipro) IV STAT — do NOT wait for cultures. Add Pip-tazo for severe/septic. Surgical debridement urgently. ICU.
• ▸Wound culture (Gram + aerobic + anaerobic + Vibrio media) — guides targeted antibiotics

  Watch for

  Specifically request Vibrio media (TCBS) for saltwater exposure — routine cultures miss it.

  Next action

  Obtain BEFORE first antibiotic dose if possible (do not delay empiric coverage). Narrow antibiotics on sensitivities at 48–72 h.
• ▸Blood cultures × 2 if febrile, immunocompromised, or septic — rule out bacteremia

  Watch for

  Persistent fever, rigors, hypotension, end-organ dysfunction.

  Next action

  Draw before antibiotics if possible. Continue IV antibiotics ≥14 d if bacteremia. Repeat cultures if persistent fever.

Order if febrile, systemically ill, or delayed presentation with rash/arthralgia. Tap any lab for what to watch for and the next clinical action.

• ▸WBC >15k with left shift — secondary wound infection / rat-bite fever

  Watch for

  Fever, migratory polyarthralgia, maculopapular/petechial rash on extremities (palms/soles), wound erythema/purulence.

  Next action

  Empiric Penicillin G IV (DOC for S. moniliformis) or doxycycline if PCN allergy. If wound infection, Augmentin or IV Unasyn. Admit if febrile/septic.
• ▸CRP / ESR ↑ (CRP >50, ESR >40) — supports rat-bite fever or deep infection

  Watch for

  Persistent fever despite first-line treatment, joint swelling (septic arthritis), endocarditis stigmata.

  Next action

  Trend to assess treatment response. Echo if persistent bacteremia or new murmur (S. moniliformis endocarditis is uncommon but described).
• ▸Blood cultures × 2 if febrile — Streptobacillus moniliformis (fastidious; alert lab)

  Watch for

  Slow growth — alert micro lab to hold cultures ≥7 d and use enriched media. Notify of suspected diagnosis.

  Next action

  Empiric IV PCN G 200,000 U/kg/d (or ceftriaxone). Switch to oral amoxicillin or doxycycline ×14 d once afebrile. Repeat cultures if persistent fever.
• ▸Wound culture if purulent — guides targeted antibiotics

  Watch for

  Polymicrobial: Pasteurella, Staph, Strep, anaerobes.

  Next action

  Augmentin 875 mg PO BID 5–7 d. IV Unasyn if cellulitis or systemic. Narrow on sensitivities.
• ▸LFTs AST/ALT ↑ >2× ULN — disseminated S. moniliformis (hepatitis, endocarditis)

  Watch for

  RUQ pain, jaundice, persistent fever, new murmur. Suggests metastatic infection.

  Next action

  Extend IV antibiotics to 4 weeks. Echo, abdominal US/CT. ID consult.
• ▸Lactate >2 mmol/L — sepsis / hypoperfusion

  Watch for

  Tachycardia, hypotension, AMS, oliguria. Recheck q2h.

  Next action

  Sepsis bundle: 30 mL/kg crystalloid, broad-spectrum antibiotics within 1 h, vasopressors for MAP >65, ICU.
• ▸Cr ↑ >1.5× baseline — AKI from sepsis or rare hantavirus exposure

  Watch for

  Oliguria, fever + thrombocytopenia + AKI triad → consider hantavirus (HFRS) in deer-mouse exposure regions.

  Next action

  IV fluids, hold nephrotoxins. Hantavirus serology if exposure history fits. Nephrology consult.

Order in severe crush, signs of infection / sepsis, or large wounds. Tap any lab for what to watch for and the next clinical action.

• ▸WBC >15k with left shift — wound infection / sepsis

  Watch for

  Spreading erythema, purulent drainage, fever, fluctuance, lymphangitic streaking.

  Next action

  IV Unasyn (or pip-tazo if severe). Surgical consult for I&D / debridement. Admit if systemic toxicity or hand involvement.
• ▸CK >1,000 U/L — rhabdomyolysis from crush

  Watch for

  Tea-colored urine, muscle pain, ↑ K⁺, ↑ Cr, compartment syndrome.

  Next action

  IV crystalloid 1.5–2× maintenance, target UOP 1–2 mL/kg/h. BMP q4–6h. Surgical consult for compartment pressures if concern.
• ▸Cr ↑ >1.5× baseline — AKI from rhabdo or sepsis

  Watch for

  Oliguria, rising K⁺, acidosis, fluid overload.

  Next action

  IV fluids, hold nephrotoxins. Nephrology consult if doubling. Dialysis for refractory hyperkalemia or volume overload.
• ▸K⁺ >5.5 mEq/L — rhabdo / hyperkalemia

  Watch for

  STAT ECG: peaked T waves, widened QRS, sine wave.

  Next action

  If ECG changes: calcium gluconate, insulin + D50, albuterol, bicarb. Dialysis if refractory.
• ▸Lactate >4 mmol/L — sepsis / hypoperfusion

  Watch for

  Hypotension, tachycardia, AMS, oliguria.

  Next action

  Sepsis bundle: 30 mL/kg crystalloid, broad-spectrum antibiotics within 1 h (Pip-tazo), source control, ICU.
• ▸INR >1.5, fibrinogen <150 (coagulopathy) — trauma-induced coagulopathy / DIC

  Watch for

  Bleeding from multiple sites, persistent wound oozing.

  Next action

  FFP 10–15 mL/kg, cryoprecipitate. TXA 1 g IV if within 3 h of injury. Treat shock and source.
• ▸Wound culture (aerobic + anaerobic) — Pasteurella, Actinobacillus, anaerobes

  Watch for

  Pig bites — request Actinobacillus suis specifically. Crush wounds — anaerobic coverage essential.

  Next action

  Obtain before first antibiotic dose if possible. Empiric Augmentin or Unasyn covers most. Narrow on sensitivities.
• ▸Blood cultures × 2 if systemic toxicity — polymicrobial sepsis

  Watch for

  Persistent fever, rigors, hypotension. Capnocytophaga in immunocompromised → fulminant sepsis.

  Next action

  Draw before antibiotics. IV Pip-tazo or carbapenem for severe. ID consult if persistent bacteremia. Continue IV ≥14 d if bacteremic.