Seizure Disorder: This is the most likely diagnosis given the symptoms of altered mental status and total body shaking, which are classic presentations of a generalized tonic-clonic seizure. The shaking could be the seizure activity itself, and the altered mental status could be pre-ictal, ictal, or post-ictal.

Hypoglycemia: Low blood sugar can cause confusion, altered mental status, and if severe, can lead to seizures or seizure-like activity, including total body shaking.
Drug or Alcohol Withdrawal: Withdrawal from certain substances, such as alcohol or benzodiazepines, can cause severe tremors, altered mental status, and even seizures.
Infection (e.g., Meningitis, Encephalitis): Infections affecting the central nervous system can present with altered mental status and may cause seizures or severe tremors due to inflammation of the brain or meninges.
Psychiatric Conditions (e.g., Psychotic Episodes): Though less likely to cause total body shaking, severe psychiatric conditions can lead to altered mental status and may be associated with agitation that could be mistaken for shaking.

Status Epilepticus: A life-threatening condition where the body is in a state of persistent seizure that lasts more than 5 minutes or when a person has recurrent seizures without regaining full consciousness between seizures. Immediate recognition and treatment are crucial.
Neuroleptic Malignant Syndrome (NMS): A rare but life-threatening side effect of neuroleptic medications, characterized by altered mental status, rigidity, and autonomic dysfunction, which could be mistaken for total body shaking.
Serotonin Syndrome: Another potentially life-threatening condition caused by an excess of serotonin, often due to medication interactions, which can present with altered mental status, agitation, and neuromuscular abnormalities including rigidity and tremors.
Stroke or Transient Ischemic Attack (TIA): Though less common in young males, a stroke or TIA can present with sudden onset of altered mental status and may cause focal or generalized seizures.

Tetanus: A bacterial infection characterized by muscle stiffness and spasms, which could be mistaken for total body shaking. It's rare in populations with good vaccination coverage but should be considered in those with inadequate vaccination or recent travel to endemic areas.
Rabies: In its late stages, rabies can cause agitation, confusion, and spasms, including hydrophobia, which might resemble total body shaking.
Hashimoto's Encephalopathy: A rare condition associated with Hashimoto's thyroiditis, presenting with altered mental status and seizures, among other neurological symptoms.
Wilson's Disease: A genetic disorder leading to copper accumulation in the brain, which can cause neurological symptoms including tremors, altered mental status, and seizures, though it's more commonly associated with liver disease and psychiatric symptoms.