22. Acute liver diseases in cats, feline hepatic lipidosis. Flashcards
Acute hepatic failure (AHF) of cats + clinical signs?
Acute Hepatic Failure (AHF) of Cats
As AHF of dogs
Technically a clinical syndrome, not a specific diagnosis; 70% of the liver parenchyma is affected
Acute hepatic failure shows histopathological necrosis, and this
should be remembered! Because of the necrotic nature of the disease,
the following outcomes of the condition are:
§ Recovery
§ Chronic liver disease
§ Death
CLINICAL SIGNS
Mild CSx → Slow progression (tissue regeneration/adaptation)
Severe CSx → Acute AHF (Ø tissue regeneration/adaptation)
§ Depression § Polydipsia
§ Dehydration § Icterus
§ Abdominal pain § Fever
§ Coagulopathy § Vomiting
§ CNS signs (HE) § Anorexia
Diagnosis of acute hepatic failure?
AHF caused by hepatotoxins?
AHF Caused By Hepatotoxins
The liver is sensitive to toxins and drugs, and plays a central role in their metabolism.
Toxic effects on the liver are divided into the following:
Intrinsic toxic effect
Reproducible
Dose-dependent
Toxic dose limit
Direct toxic effect
E.g. Paracetamol; Xylitol
Extrinsic toxic effect (rare)
Non-reproducible
Unique (non-calculable)
Not dose-dependent
E.g. Phenobarbital; Lomustine; Itraconazole
Paracetamol?
PARACETAMOL (ACETAMINOPHEN)
Ø Cats!
Rapidly depletes the body’s stores of glutathione (GSH); Produced
toxic metabolites which have an oxidative effect
Erythrocyte methemoglobinemia & hepatocyte necrosis
Clinical signs:
§ Cyanosis § Tachycardia
§ Dyspnoea § Tachypnoea
§ Facial oedema § Brown blood
Lab. D
§ Haemolytic anaemia; Methemoglobinemia
§ Abnormal RBCs: Nucleated; Schistocyte; Acanthocyte;
Heinz body
§ ALT ↑; Br ↑; Haemoglobinuria
Treatment
§ Flush the stomach & give activated charcoal
§ Stabilise patient: IVFT; Oxygen; Mannitol
§ Apply high amounts of antioxidants
§ Key treatment: N-Acetylcysteine
Diazepam & Clonazepam?
DIAZEPAM & CLONAZEPAM
Causes acute hepatic failure with high mortality
Idiosyncratic drug reaction; Particularly in PO drug form
Very poor prognosis
Lab. D: Liver enzymes ↑↑↑, especially ALT
Normal cases: Does not alter liver enzyme parameters
Treatment: Immediate withdrawal of the drug; Intensive support
Pathology: Centrilobular necrosis
Phenobarbital, Phenytoin , Primidone and potentiated sulphonamides ?
PHENOBARBITAL
Rarely causes hepatotoxicity; Idiosyncratic reaction
Dx: ↓ Albumin; ↑Br; Enlarged liver (or smaller if chronic)
Tx: ↓ The dose; Supportive therapy
PHENYTOIN
Very hepatotoxic
Causing: Acute/chronic hepatitis; Fatal intrahepatic cholestasis
Short half-life in dogs
PRIMIDONE
Metabolite of phenobarbitone; Must not be used in cats!
Hepatotoxic
Pathology: Liver necrosis; Lipidosis; Cholestasis
POTENTIATED SULPHONAMIDE
Idiosyncratic effect; Common
Forms of toxicosis:
§ Sulphonamide hypersensitivity: Thrombocytopenia;
fever; polyarthropathy
§ Acute hepatopathy: Liver necrosis & cholestasis
§ Destructive cholangitis: Idiosyncratic hypersensitivity →
Severe intrahepatic cholestasis → Acholic faeces
Xylitol toxicosis?
XYLITOL TOXICOSIS
Tolerated well in cats
May lead to hypoglycaemia; liver necrosis & acute liver failure
Lab. D
§ Hypoglycaemia
§ Hypokalaemia
§ ↑↑↑ Liver enzymes
§ ↑↑↑ Br
§ Hypophosphataemia → Hyperphosphataemia
Clinical signs
§ Vomiting § Lethargy
§ Weakness § Ataxia
§ Tremor § Seizure
§ AHF: Icterus; HE; Coagulopathy
Treatment
§ Emesis (unless ingestion was >30 mins ago)
§ Ø Activated charcoal → Ineffective
§ Monitor & maintain blood glucose
§ Coagulopathy: Fresh frozen plasma; Blood transfusion
§ Palliative therapy
Acute hepatic failure caused by pathogens (Feline Infectious peritonitis)?
AHF Caused By Pathogens
FELINE HERPESVIRUS
FELINE INFECTIOUS PERITONITIS (FIP)
Coronavirus infection
Multisystemic so lesions may be seen in: Peritoneum; Pleura;
Brain; Eyes; Parenchymal organs
Clinical signs
§ Ø CSx
§ Mild upper respiratory symptoms
§ Mild diarrhoea
Diagnosis: Ø Definitive test
Pathology: Pyogranulomatous hepatitis; Multifocal hepatic necrosis;
Immune-complex vasculitis; Liver is covered by a thick layer of
fibrin
Leptospirosis ( Zoonotic)?
LEPTOSPIROSIS [ZOONOTIC]
Cats are relatively resistant
Acute disease; Primarily acute renal failure + cholestatic hepatic
disease; Found in stagnant water and other hosts; Shedding via urine
§ L. icterohaemorrhagie → Icterus; Hepatic damage
§ L grippotyphosa → Chronic hepatitis; Fibrosis
§ L. canicola → Renal failure
Toxin causes:
§ Lysis of tight junctions
§ Intrahepatic cholestasis
§ Vascular damage → Bleeding tendancies
Lab. D
§ ALP ↑↑
§ ALT ↑
§ BA ↑
§ Br ↑
Clinical signs
§ Fever § DIC
§ Myalgia § Oedema
§ Jaundice § Haematemesis
§ Haematochezia § Vomiting
§ Vascular injury § Melena
§ Renal dysfunction § Epistaxis
§ Oliguria/anuria § Uveitis
Diagnosis
§ US: Double layer of the gallbladder: Thickened
§ Serology: Microscopic agglutination test (MAT)
§ PCR
§ Isolation from fresh urine (dark field microscopy)
Clostridium Piliformis (Tyzzers disease)?
CLOSTRIDIUM PILIFORMIS (TYZZER’S DISEASE)
Gram negative; Fusiform bacteria; Immunosuppression
Seen in dogs too
Clinical signs
Acute onset; Rapidly fatal (within 24-48 hours)
§ Anorexia
§ Lethargy
§ Abdominal discomfort
Diagnosis → Biopsy
§ Multifocal periportal hepatic necrosis
§ Hepatocyte & intestinal epithelium necrosis
Treatment: Ø Treatment; Palliative
Pathology: Multifocal hepatic necrosis; Necrotising ileitis
Hepatic abscess?
HEPATIC ABSCESS (EXTRAHEPATIC LIVER INFECTION)
Focal abscess → Hepatobiliary infection; Ischaemia
Multi-focal abscess → Systemic infection
Bacteria of concern (Cat): Streptococcus spp.; E. coli; Salmonella
spp.; Clostridium spp.
Immunosuppression
Haematogenous spread via: Bile duct; Umbilicus
Hypoxic conditions allow the proliferation of anaerobic bacteria
from normal flora
Clinical signs
§ Anorexia § Ascites
§ Depression § Weight loss
§ Vomitus § Hepatomegaly
§ Fever
Lab. D: Neutrophilia (left shift); Liver enzymes ↑; Br ↑↑
Treatment: Surgery →Drainage →Antibiotics (penicillin +
fluroquinolone)
Mycotic infection, protozoal and parasitic infection ?
MYCOTIC INFECTION
Systemic mycosis → Mononuclear phagocytosis → Hepatic signs
Clinical signs
§ Hepatomegaly
§ Ascites
§ Icterus
§ CSx: from inhalation: Cough; Dyspnoea
Lab. D: Liver enzymes ↑/-; SBA ↑; Br ↑; Albumin↓; DIC
Pathology: Granulomatous/pyogranulomatous inflammation
Histoplasmosis: Affecting: Bone marrow; Lymph nodes; GIT
Coccidiomycosis: Affecting: Bones; Joints; Lymph nodes;
Abdominal organs
PROTOZOAL INFECTION
Toxoplasmosis (Toxoplasma gondii) + Immunosuppression
Affecting: Lungs; Eye; Lymphoid tissue; Spleen; CNS; Heart
Clinical signs
§ Icterus
§ Abdominal pain
§ Fever
§ Uveitis
Pathology: Widespread multifocal necrosis; AHF
Treatment: Clindamycin
PARASITIC INFECTION
Dirofilaria immitis
Post caval syndrome/vena cava syndrome (heartworm disease)
Affecting: RA of heart, v. hepatica or vena cava
Clinical signs
Acute onset:
§ Anorexia § Haemoglobinuria
§ Weakness § Anaemia
§ Dyspnoea § Icterus
Lab. D: Intravascular haemolysis
Pathology: Acute, passive congestion of the liver; Necrosis
Feline hepatic lipidosis and clinical signs?
Feline hepatic lipidosis
↑ Hepatocellular accumulation of lipids & cholestasis, leading to hepatic failure.
The most common primary hepatopathy in Europe
Indoor, domestic shorthairs; Middle-aged; Obese cats that then undergo prolonged anorexia.
CLINICAL SIGNS
§ Anorexia § Hepatomegaly
§ Depression § Depression (HE)
§ Dehydration § Salivation (HE)
§ Icterus § GI signs (D & V)
§ Coagulopathy § Ventroflexion of head & neck
Two types of FHL exist:
§ Idiopathic hepatic lipidosis (IHL)
§ Secondary hepatic lipidosis
Idiopathic hepatic lipidosis?
IDIOPATHIC HEPATIC LIPIDOSIS
Multifactorial/unknown cause
Pathogenesis
Cats are obligate carnivores → High resting protein catabolism,
because of this, they can’t stop their postprandial enzyme activity and essential amino acid catabolism (Arginine, Methionine, Taurine and Carnitine) → These are therefore constantly lost Fasting during anorexia, illness, or stress → ↑ Fat mobilisation from
fat stores & ↓ lipoprotein synthesis → Lipid accumulation
Simultaneously:
↓ Arginine → ↓NH3 metabolism → HE; ↑Ammonia
Summary: Lipid accumulation & ↑Ammonia
Secondary hepatic lipidosis?
SECONDARY HEPATIC LIPIDOSIS
Most common type
Caused by metabolic/infective disease:
§ Cholangiohepatitis § DM
§ Cardiomyopathy § IBD
§ Pancreatitis § FORL
§ CKF § FIP
§ Neural diseases § Neoplasia
§ Toxins § Drugs (tetracycline)
